A list for asteroid and comet researcher



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From: mpml@yahoogroups.com
To: mpml@yahoogroups.com
Sent: Wednesday, November 30, 2011 1:39 PM
Subject: {MPML} Digest Number 3992


A list for asteroid and comet researcher

Acclaimed Canadian Astronomer Dr. David Levy's Logbooks Now Online
Posted by: "Ron Baalke" baalke@...
Wed Nov 30, 2011 9:33 am (PST)

November 29, 2011

Royal Astronomical Society of Canada

Contacts:
Deborah Thompson / Randall A. Rosenfeld
thompson@... / levylogbooks@...
+1 416-924-7973 (DT)

ACCLAIMED CANADIAN ASTRONOMER DR. DAVID LEVY'S LOGBOOKS NOW ONLINE

The Royal Astronomical Society of Canada (RASC) in conjunction with
Jarnac Observatory is pleased to announce the launch of the David Levy
Logbooks archive. The project offers full and free access to digital
facsimiles of over sixteen thousand observing sessions by David H.
Levy chronicling more than half a century of astronomical exploration
and discovery: http://www.rasc.ca/logbooks/levy

Dr. David H. Levy, co-discoverer of comet Shoemaker-Levy 9, is one of
the most acclaimed amateur astronomers of our time. He is the
discoverer or co-discoverer of twenty two comets and more than 150
asteroids, and is the first person to have discovered comets visually,
photographically, and electronically. Dr. Levy is a well-known
popularizer of astronomy, who has spent a lifetime advancing the
active engagement of others in the rich cultural pursuit of astronomy
by personal example and through live appearances, and print and
electronic media. The conviction that astronomical observation, both
recreational and scientific, provides a way to discover more about our
place in the universe and to better know ourselves is shared by Dr.
Levy and the Royal Astronomical Society of Canada (RASC), an
organization of which he has been a member for nearly as long as he
has been an astronomer.

The David Levy Logbooks offer a glimpse into one man's personal
engagement with the night sky, an engagement as dynamic and pristine
now as when he commenced his records at age eleven with a partial
solar eclipse in 1959. In the logbook pages readers will encounter his
personal entries of notable discoveries -- comets and near earth
objects found with Eugene M. and Carolyn Shoemaker through the Palomar
Asteroid and Comet Survey (PACS), including the unfolding drama of
Shoemaker-Levy 9 impacting Jupiter -- interspersed with records of
variable star observations for the American Association of Variable
Star Observers (AAVSO) and searches for the RASC's COMET and NOVA
Section, along with recreational observing of deep-sky objects (DSO)
and solar-system phenomena. An attractive feature of the logbooks is
their witness to astronomical friendship -- accompanying Dr. Levy's
notes are the autograph comments of those who have observed with him,
ranging from Clyde Tombaugh the discoverer of Pluto, to observers as
young as Dr. Levy was when he started in astronomy. Observational
sketches, photographs, and quotes from literature reflecting astronomy
can be found throughout, attesting to the wider cultural matrix in
which astronomy is embedded.

Complementing the digital logbook facsimiles are several interpretive
essays, one introducing the logbooks by Dr. Roy Bishop, a long-time
personal friend and mentor of Dr. Levy's, and another setting the
logbooks in historical context by RASC Archivist R.A. Rosenfeld.

Few primary sources of significant amateur scientists are available in
their entirety on the web. The logbooks should be of interest to all
intrigued by the variety of 20th- and 21st-century practices of
astronomy, and should prove a resource for those researching the
history of amateur astronomy, pro-am collaboration, continuities and
adaptation in modes of discovery, astronomy education and public
outreach, and the scientific notebook as a literary genre, a locus for
memory, and an agent for creating filiations and structuring
scientific communities. The pages of the David Levy Logbooks can also
aid amateur observers in finding their own voice and style of
astronomical note taking through emulation, modification, and
antithesis.

# # #

The David Levy Logbooks are a joint project of the Jarnac Observatory
and the RASC through its History Committee. The project team consists
of Roy Bishop, David and Wendee Levy, Walter MacDonald, R.A.
Rosenfeld, and Nanette Vigil.

Founded in 1868, The Royal Astronomical Society of Canada is the
nation's leading astronomy organization bringing together over 4,200
enthusiastic amateurs, educators and professionals from Canada and
abroad. The Vision of the RASC is to inspire curiosity in all people
about the Universe, to share scientific knowledge, and to foster
collaboration in astronomical pursuits, and our Mission is to
encourage improved understanding of astronomy for all people, through
education, outreach, research, publication, enjoyment, partnership,
and community.

A list for asteroid and comet researcher


----- Original Message -----
From: mpml@yahoogroups.com
To: mpml@yahoogroups.com
Sent: Friday, December 02, 2011 11:48 AM
Subject: {MPML} Digest Number 3993


Messages In This Digest (4 Messages)
1. Asteroids, Mars and Drought Among NASA News Highlights at AGU Meetin
From: Ron Baalke
2. Dawn Soars Over Asteroid Vesta in 3-D From: Ron Baalke
3. NASA's Deep Impact Spacecraft Eyes the Future From: Ron Baalke
4. Dawn Journal - November 29, 2011 From: Ron Baalke

1. Asteroids, Mars and Drought Among NASA News Highlights at AGU Meetin
Posted by: "Ron Baalke" baalke@...
Thu Dec 1, 2011 12:00 pm (PST)

Dec. 1, 2011

Steve Cole
Headquarters, Washington
202-358-0918
stephen.e.cole@...

MEDIA ADVISORY: M11-242

ASTEROIDS, MARS AND DROUGHT AMONG NASA NEWS HIGHLIGHTS AT AMERICAN
GEOPHYSICAL UNION MEETING

WASHINGTON -- NASA researchers will present new findings on a wide
range of Earth and space science topics at the 2011 fall meeting of
the American Geophysical Union. The meeting takes place Dec. 5-9 at
the Moscone Convention Center, 747 Howard St., in San Francisco.
Media registration for the event is open.

Media briefings during the meeting will feature topics such as new
results about the asteroid Vesta, the future risk of major droughts,
new discoveries at the edge of our solar system, and the 2011
Japanese tsunami. In addition, NASA scientists and their colleagues
who use NASA research capabilities will present noteworthy findings
during scientific sessions that are open to registered journalists.

For a complete list of NASA-related news briefings at the meeting,
visit:

http://www.nasa.gov/agu

The website contains detailed information about how reporters can
participate in the briefings, both on-site and remotely. The site
will be updated throughout the week with additional information about
NASA presentations.

For more information about NASA and agency programs, visit:

http://www.nasa.gov

-end-



Messages in this topic (1)

2. Dawn Soars Over Asteroid Vesta in 3-D
Posted by: "Ron Baalke" baalke@...
Thu Dec 1, 2011 2:13 pm (PST)

http://www.jpl.nasa.gov/news/news.cfm?release=2011-366

Dawn Soars Over Asteroid Vesta in 3-D
Jet Propulsion Laboratory
November 30, 2011

PASADENA, Calif. - Glide over the giant asteroid Vesta with NASA's Dawn
spacecraft in a new 3-D video. Dawn has been orbiting Vesta since July
15, obtaining high-resolution images of its bumpy, cratered surface and
making other scientific measurements.

The new video is available online at:
http://www.jpl.nasa.gov/video/index.cfm?id=1041 . Best viewed with
red-blue glasses, the video incorporates images from Dawn's framing
camera from July to August 2011. It was created by Dawn team member Ralf
Jaumann of the German Aerospace Center (DLR).

The images were obtained when Dawn was making its approach to Vesta, and
while orbiting the giant asteroid in its first science orbit, known as
survey orbit, at an altitude of about 1,700 miles (2,700 kilometers).
The video begins with a global view of Vesta from the plane of its
equator, where a mysterious band of linear ridges and troughs can be
seen. The movie cuts to a flyover of young craters in the northern
hemisphere, whose peculiar alignment has led some scientists to refer to
them as the "snowman." Then this virtual tour of Vesta takes the viewer
around a massive mountain at the south pole of Vesta that is about 16
miles (25 kilometers) high, or more than twice the height of Mt. Everest.

"If you want to know what it's like to explore a new world like Vesta,
this new video gives everyone a chance to see it for themselves,"
Jaumann said. "Scientists are poring over these images to learn more
about how the craters, hills, grooves and troughs we see were created."

Vesta is the second most massive object in the asteroid belt between
Mars and Jupiter. Dawn is currently spiraling down to its low altitude
mapping orbit, which will bring the spacecraft to about 130 miles (210
kilometers) above Vesta's surface.

"Dawn's data thus far have revealed the rugged topography and complex
textures of the surface of Vesta, as can be seen in this video," said
Carol Raymond, deputy principal investigator at NASA's Jet Propulsion
Laboratory, Pasadena, Calif. "Soon, we'll add other pieces of the puzzle
such as the chemical composition, interior structure, and geologic age
to be able to write the history of this remnant protoplanet and its
place in the early solar system."

Dawn launched in September 2007 and arrived at Vesta on July 15, 2011.
Following a year at Vesta, the spacecraft will depart in July 2012 for
the dwarf planet Ceres, where it will arrive in 2015.

Dawn's mission to Vesta and Ceres is managed by JPL for NASA's Science
Mission Directorate in Washington. JPL is a division of the California
Institute of Technology in Pasadena. Dawn is a project of the
directorate's Discovery Program, managed by NASA's Marshall Space Flight
Center in Huntsville, Ala. UCLA is responsible for overall Dawn mission
science. Orbital Sciences Corp. in Dulles, Va., designed and built the
spacecraft. The German Aerospace Center, the Max Planck Institute for
Solar System Research, the Italian Space Agency and the Italian National
Astrophysical Institute are international partners on the mission team.

For more information about the Dawn mission, visit:
http://www.nasa.gov/dawn
and http://dawn.jpl.nasa.gov .

To follow the mission on Twitter, visit: http://www.twitter.com/NASA_Dawn .

Jia-Rui Cook/Priscilla Vega 818-354-0850/4-1357
Jet Propulsion Laboratory, Pasadena, Calif.
jccook@.../priscilla.vega@...

2011-366



Messages in this topic (1)
3. NASA's Deep Impact Spacecraft Eyes the Future
Posted by: "Ron Baalke" baalke@...
Thu Dec 1, 2011 2:16 pm (PST)

http://www.jpl.nasa.gov/news/news.cfm?release=2011-367

NASA's Deep Impact Spacecraft Eyes the Future
Jet Propulsion Laboratory
December 01, 2011

Deep Impact Mission Status

PASADENA, Calif. - NASA's Deep Impact spacecraft completed a 140-second
firing of its onboard rocket motors on Thursday, Nov. 24. The rocket
burn was performed to keep the venerable comet hunter's options open for
yet another exploration of a solar system small body.

"The burn was right on the money. Not bad for a spacecraft whose prime
mission successfully concluded in 2005," said Tim Larson, Deep Impact
project manager from NASA's Jet Propulsion Laboratory in Pasadena,
Calif. "We've logged a lot of miles and at least one comet flyby since
our '05 encounter with comet Tempel 1. With this burn, we keep the door
open for Deep Impact logging even more miles and exploring more small
worlds before all is said and done."

Last Thursday, Larson and his Deep Impact team watched from their
mission support area at JPL as their spacecraft began the maneuver at 4
p.m. PST (7 p.m. EST). The spacecraft's two-minute, 20-second burn
changed its velocity by 19.7 mph (8.8 meters per second). If NASA
approves a third mission extension for Deep Impact, a second rocket burn
will be executed next fall.

Launched in January 2005, Deep Impact traveled about 268 million miles
(431 million kilometers) to the vicinity of comet Tempel 1. On July 3,
2005, the spacecraft deployed an impactor that was essentially "run
over" by the nucleus of comet Tempel 1 on July 4. Sixteen days after
comet encounter, the Deep Impact team placed the spacecraft on a
trajectory to fly past Earth in late December 2007. This extended
mission of the Deep Impact spacecraft culminated in the successful flyby
of comet Hartley 2 on Nov. 4, 2010.

JPL, a division of the California Institute of Technology in Pasadena,
manages the Deep Impact mission for NASA's Science Mission Directorate,
Washington. The mission is part of the Discovery Program managed at
NASA's Marshall Space Flight Center in Huntsville, Ala. The spacecraft
was built for NASA by Ball Aerospace & Technologies Corp., Boulder, Colo.

For more information about Deep Impact, please visit:
http://solarsystem.nasa.gov/deepimpact .

DC Agle 818-393-9011
Jet Propulsion Laboratory, Pasadena, Calif.
agle@...

Dwayne Brown 202-358-1726
NASA Headquarters, Washington
Dwayne.c.brown@...

2011-367


Messages in this topic (1)
4. Dawn Journal - November 29, 2011
Posted by: "Ron Baalke" baalke@...
Thu Dec 1, 2011 3:35 pm (PST)

http://dawn.jpl.nasa.gov/mission/journal_11_29_11.asp

Dawn Journal
Dr. Marc Rayman
November 29, 2011

Dear Dawnward Spirals,

Continuing its ambitious campaign of exploration deep in the asteroid
belt, Dawn has spent most of the past month spiraling ever closer to Vesta.
Fresh from the phenomenal success of mapping the alien world in detail in
October, the spacecraft and its human team members are
engaged in one of the most complicated parts of the mission. The reward
will be the capability to scrutinize this fascinating protoplanet further.

Thanks to the extraordinary performance of its ion propulsion system,
Dawn can maneuver to different orbits that are best suited for
conducting each of its scientific observations. The probe is now headed
for its low altitude mapping orbit (LAMO),
where the focus of its investigations will be on making a census of the
atomic constituents with its gamma ray and neutron sensors
and on mapping the gravity field in
order to determine the interior structure of this protoplanet.

As secondary objectives, Dawn will acquire more images with its camera
and more spectra with its visible and infrared mapping spectrometer. As
we will see in a future log, these measurements will receive a smaller
share of the resources than the high priority studies. The spectacular
pictures obtained already will keep scientists happy for years, and you
can continue to share in the experience of marveling at the astonishing
discoveries by seeing some of the best views here,
http://dawn.jpl.nasa.gov/multimedia/imageoftheday/archives.asp?month=2011-Decemb\
er
including scenes captured during the spiral to LAMO.

Planning the low altitude mapping orbit around massive Vesta, with its
complicated gravity field, required a great deal of sophisticated
analysis. Before Dawn arrived, mission designers studied a range of
possible gravitational characteristics and honed the methods they would
use for plotting the actual orbit once the details of the protoplanet's
properties were ascertained. In the meantime, the team used a tentative
orbit at an altitude over the equator of 180 kilometers (110 miles).
As explained in a previous log, the altitude varies both because the orbit
is not perfectly circular and because Vesta displays such exceptional
topography. The highest elevations turn out to be at the equator, and
the average altitude of that orbit would be 200 kilometers (125 miles).

Now that navigators have measured Vesta's gravity, they have the
knowledge to refine the design for LAMO, and they decided to raise it by
10 kilometers (6 miles). The target then is an average altitude of 210
kilometers (130 miles). But there is more to the specification of the
orbit than simply its height. To meet all of the scientific objectives,
the orientation of this orbit needs to be different from the orientation
of the previous orbits, the high altitude mapping orbit (HAMO)
and survey orbit. To picture the different orbits, let's recall our
discussion of how the orbit shifted from survey to HAMO. Readers
unconcerned about the details of the geometry may safely (and wisely) skip
this explanation.

Think of Dawn's orbit as a ring encircling Vesta, going over both poles
and crossing the equator at a right angle. Globes of Earth often are
supported by a ring like that, and it may be helpful to have a
terrestrial globe in mind, or even in sight, as you ponder the celestial
arrangement. For the purpose of this illustration, you may rest assured
that no inhabitants (permanent or temporary) of Vesta will object if we
pretend that the world does not rotate, so a ring that is aligned with a
longitude line represents one of Dawn's orbits. To start, let's say
survey orbit hovers over the 15 degree west longitude line (and, to make
a complete circle, goes over the 165 degree east longitude line as
well). HAMO would be shifted to 30 degrees west (and 150 degrees east on
the other side of the globe). Dawn is now on its way to LAMO, which will
be at about 46 degrees west (and 134 degrees east). The complex scheme
for moving from HAMO to LAMO then involves not only lowering the
altitude but also rotating the plane of the orbit by 16 degrees. We will
delve into why this value was chosen after the spacecraft has arrived in
LAMO.

These differing orientations are a crucial element of the strategy for
gathering such a wealth of scientifically valuable data on Vesta.
The ion propulsion system allows the probe to fly from one orbit to
another without the tremendous penalty of carrying a massive supply of
propellant. In general, it requires a great deal of maneuvering to
change the plane of a spacecraft's orbit. Indeed, one of the reasons
traveling from Earth to Vesta (and later Ceres) requires ion propulsion
is the challenge of tilting the orbit around the sun. (A more extensive
discussion of this and a table showing Dawn's progress in altering the
angle of its solar orbit to match Vesta's were presented on the fourth
anniversary of launch.

As long as we have used the globe to illustrate the orientation of the
orbits, we can enhance the picture for those readers who want to sharpen
their mental images of the geometry. Suppose Vesta, which Dawn has
transformed from a smudge of light into a richly detailed world, is 30
centimeters (1 foot) in diameter. Even in this miniaturized universe,
the sun is 204 kilometers (129 miles) away. (Space is big!) To get the
alignments right, we will place the sun over (albeit very, very far
over) the prime meridian, the 0 degree longitude line on our stationary
Vesta. Setting the longitude of the sun is important here because Dawn's
orbits were chosen on the basis of their angles relative to the sun. Now
we recall that Vesta, like Earth, has seasons because its axis is tipped.
It is southern hemisphere summer there, so the sun is not over the equator;
rather, it is at about 25 degrees south latitude. (On Sept. 1,
when we first used the analogy of the globe, the sun was at 27 degrees
south latitude. Since then, it has moved a little bit north because of
the progression of seasons.) Although Earth's location doesn't matter
for this discussion, we can accurately position it 204 kilometers (129
miles) away, high above a point at 26 degrees south latitude and 26
degrees west longitude.

Survey orbit in this Vesta-centric universe is a hoop a little more than
1.5 meters (5 feet) above the 15 degree west longitude line (and, again,
the 165 degree east longitude line on the night side). It was from that
vantage point that the first thorough mapping was conducted in August.
The ring representing HAMO is only about 38 centimeters (15 inches) over
the 30 degree west (and 150 degree east) longitude line. The lower
altitude of HAMO afforded much better views of the great variety of
surface features than the reconnaissance from survey orbit. In addition,
because the orbit was shifted farther from the sun, the angle of light
on the landscape beneath the spacecraft was different, aiding in
formulating a more accurate portrait of the terrain. Dawn is now nearing
LAMO, less than 12 centimeters (only 4.7 inches) above the 46 degree
west (and 134 degree east) longitude line.

Although the ion propulsion system accomplishes the majority of the
orbit change, Dawn's navigators are employing another novel propulsion
system as well: they are enlisting Vesta itself. Some of the ion
thrusting was designed in part to put the spacecraft in certain
locations from which Vesta would twist its orbit toward the target LAMO
angle. As Dawn rotates and the world underneath it revolves (unlike the
static picture we used to visualize the orientation of the orbits), the
spacecraft feels a changing pull. There is always a tug downward, but
because of Vesta's heterogeneous interior structure, the product of its
complex geologic history, sometimes
there is also a slight force to one side or another. With their
knowledge of the gravity field, the team plotted a course that took
advantage of these variations to get a free ride. This is akin to
experienced sailors not only relying on their ships' engines but also
following routes that use known currents to let nature do some of the
work. Of course, sailors benefit from knowledge of currents measured by
those who plied the waters before them. Dawn is the first, venturing
boldly into mysterious seas never visited before. But the measurements
of the gravity field in HAMO, even though it was at a higher altitude,
gave navigators enough information about what lay ahead on the horizon
that our vessel could safely and productively ride the gravitational
currents. The flight plan from HAMO to LAMO then is a complex affair of
carefully timed thrusting and equally carefully timed coasting. Under
ion thrust, the spacecraft flies to a certain location in a certain
orbit at a certain time, waits a certain interval as Vesta propels it to
the next waypoint, and then it resumes thrusting.

This itinerary was worked out in exquisite detail when Dawn was still in
HAMO, but it is impossible to follow the mathematically perfect path.
Although navigators measured the gravity field, they were not able to
detect all of its convolutions, so the ship is subjected to slightly
different currents from those expected. Occasional firings of the
spacecraft's small jets and tiny discrepancies between the planned
strength of the ion thrust and the actual value contribute more to the
deviation of the trajectory. Mission planners studied these and other
effects thoroughly and have been well prepared to account for all of them.

Every few days during the spiral transit from HAMO to LAMO, the
spacecraft points its main antenna to Earth so navigators can get an
accurate fix on it. The time for radio signals (traveling, as all
readers can attest, at the universal limit of the speed of light) to
make the round trip allows them to measure the probe's distance. The
slight change in the frequency of the signal, known as the Doppler shift,
reveals how fast the craft is moving. Combining these with their best
mathematical description of the gravity field and other data, as well
as the plan that is onboard for upcoming
thrusting and coasting, they determine Dawn's orbit and calculate where
it will be at a certain time in the future. For most of the way between
HAMO and LAMO, that time is three days, which is just long enough for
the entire operations team to perform an intricate set of carefully
choreographed steps.

Following the computation of where the spacecraft will be, trajectory
designers develop an update to the ideal reference they formulated while
Dawn was still in HAMO, now accounting for the observed discrepancies.
They devise a new profile of thrusting and coasting. Next, others on the
operations team translate that into the sequence of timed commands that
the robotic probe will execute in order to accomplish the maneuvers.
(Some of the principal challenges faced in guiding the ship through
these ever tightening spiral loops were described in February.
As we saw then, the spacecraft even
simulated a portion of this complex flight; now it is really doing it,
and it is doing it extremely well.)

While all of that is taking place at JPL, Dawn is continuing to fly
around Vesta, carrying out the previous set of instructions it received
to thrust and coast. Right on schedule, the team completes the work,
including all the diligent checks to make sure every detail is right, in
time to transmit the new sequence to the adventurer when the one already
onboard calls for it to turn its main antenna to Earth once again.
Almost as soon as the process is finished, it starts again, with a
measurement of Dawn's latest orbit.

In some of the more dynamic parts of the transfer from HAMO to LAMO,
three days is too long to let the spacecraft fly on its own without an
update to the plan, so the team had to do all that work in two days.
Thanks to the meticulous planning, preparation, and rehearsing, this
complex work has been conducted with the smooth professionalism that has
characterized the entire mission. As a result, Dawn remains on course
and on schedule to begin its scientific observations in LAMO on December
12.

Very far from home, the spacecraft is making excellent progress in its
expedition at a fascinating world that, until a few months ago, had
never seen a probe from Earth. This unique mission to a place unlike any
that has been visited before has already produced a tremendous bounty of
fabulous pictures and other important scientific data. Soon it will be
ready to undertake a new phase of exploration, revealing ever more about
this behemoth of the asteroid belt. Both patient and ambitious, Dawn
plumbs the depths of alien waters, stirring the imagination and
nourishing the spirit and the mind of everyone on distant Earth who ever
gazes at the sky in wonder or who longs to know the cosmos.

Dawn is 240 kilometers (150 miles) from Vesta. It is also 2.41 AU (361
million kilometers or 224 million miles) from Earth, or 935 times as far
as the moon and 2.45 times as far as the sun today. Radio signals,
traveling at the universal limit of the speed of light, take 40 minutes
to make the round trip.

The first Earth-sized planet found to lie definitely in the habitable zone of
its star!

http://www.jpl.nasa.gov/news/news.cfm?release=2011-373

Jason

Here's an article I wrote for a kids' news outlet.  It's also a great place for
adults, too.

http://htekidsnews.com/exciting-space-discoveries/

It's all about the Earth-like planet, and the supermassive black holes recently
discovered.

Jason Kendall
NASA/JPL Solar System Ambassador

A list for asteroid and comet researcher



----- Original Message -----
From: mpml@yahoogroups.com
To: mpml@yahoogroups.com
Sent: Tuesday, December 13, 2011 12:45 PM
Subject: {MPML} Digest Number 4003


A list for asteroid and comet researcher

1a. Is Vesta the 'Smallest Terrestrial Planet?' From: Ron Baalke
1b. Re: Is Vesta the 'Smallest Terrestrial Planet?' From: Gerald McKeegan
1c. Re: Is Vesta the 'Smallest Terrestrial Planet?' From:
amaury@...

1a. Is Vesta the 'Smallest Terrestrial Planet?'
Posted by: "Ron Baalke" baalke@...
Mon Dec 12, 2011 10:44 am (PST)


http://science.nasa.gov/science-news/science-at-nasa/2011/09dec_vestaplanet/

Is Vesta the "Smallest Terrestrial Planet?"
NASA Science News
December 9, 2011

NASA's Dawn spacecraft spent the last four years voyaging to asteroid
Vesta - and may have found a planet.

Vesta was discovered over two hundred years ago but, until Dawn, has
been seen only as an indistinct blur and considered little more than a
large, rocky body. Now the spacecraft's instruments are revealing the
true complexity of this ancient world.

"We're seeing enormous mountains, valleys, hills, cliffs, troughs,
ridges, craters of all sizes, and plains," says Chris Russell, Dawn
principal investigator from UCLA. "Vesta is not a simple ball of rock.
This is a world with a rich geochemical history. It has quite a story to
tell!"

In fact, the asteroid is so complex that Russell and members of his team
are calling it the "smallest terrestrial planet."

Vesta has an iron core, notes Russell, and its surface features indicate
that the asteroid is "differentiated" like the terrestrial planets
Earth, Mercury, Mars, and Venus.

Differentiation is what happens when the interior of an active planet
gets hot enough to melt, separating its materials into layers. The light
material floats to the top while the heavy elements, such as iron and
nickel, sink to the center of the planet.

Researchers believe this process also happened to Vesta.

The story begins about 4.57 billion years ago, when the planets of the
Solar System started forming from the primordial solar nebula. As
Jupiter gathered itself together, its powerful gravity stirred up the
material in the asteroid belt so objects there could no longer coalesce.
Vesta was in the process of growing into a full-fledged planet when
Jupiter interrupted the process.

Although Vesta's growth was stunted, it is still differentiated like a
true planet.

"We believe that the Solar System received an extra slug of radioactive
aluminum and iron from a nearby supernova explosion at the time Vesta
was forming," explains Russell. "These materials decay and give off
heat. As the asteroid was gathering material up into a big ball of rock,
it was also trapping the heat inside itself."

As Vesta's core melted, lighter materials rose to the surface, forming
volcanoes and mountains and lava flows.

"We think Vesta had volcanoes and flowing lava at one time, although
we've not yet found any ancient volcanoes there," says Russell. "We're
still looking. Vesta's plains seem similar to Hawaii's surface, which is
basaltic lava solidified after flowing onto the surface.

Vesta has so much in common with the terrestrial planets, should it be
formally reclassified from "asteroid" to "dwarf planet"?

"That's up to the International Astronomical Union, but at least on the
inside, Vesta is doing all the things a planet does."

If anyone asks Russell, he knows how he would vote.

Author: Dauna Coulter
Editor: Dr. Tony Phillips
Credit: Science@NASA


1b. Re: Is Vesta the 'Smallest Terrestrial Planet?'
Posted by: "Gerald McKeegan" geraldspace@...   geraldspace
Mon Dec 12, 2011 2:32 pm (PST)


Hmmmm... It's gone from "asteroid" to "protoplanet" to "terrestrial planet."

Might be time for another IAU convention. ;-)

Gerald


1c. Re: Is Vesta the 'Smallest Terrestrial Planet?'
Posted by: "amaury@..." amaury@...   geocroiseur
Mon Dec 12, 2011 2:42 pm (PST)


Sometimes I am good at predicting the future. A couple of months ago,
I thought we would soon get such a ridiculous message from the dawn's
team... "the smallest terrestrial planet..."
That's only because Dawn is still quite high, pretty soon it will see
trees, and vestians, and their six legged dogs, and what not... I hope
Dawn as a vestian-english dictionary aboard...

The truth is it should not even be considered a dwarf planet at all.
Nobody should use dwarf planets. To paraphrase Sheldon Cooper, in
which universe is a dwarf something not a something ?

When you try to decide what is a dwarf planet, you get something as
ridiculous as http://www.gps.caltech.edu/~mbrown/dps.html
That means a very long list of objects where the object might be,
could be, might not be and clearly is not a dwarf planet. Except that
table is full of measuring errors (not because it was compiled by Mike
Brown ;), many others contributed to the measurements errors too). You
can not measure precisely the shape of objects that far from us. It's
quite unfortunate, but you CAN NOT.

I have observed a few TNO's occultations in the recent past, and guess
what, you are more successful when the object is large. To do it
correctly you would need a continental size network of 1 to 2m
telescopes and a lot of time. With the current telescopes it is random
and very poor luck. If you get a positive occultation you only get a
chord, a lower estimate of the diameter.
On the big objects you can get a few positive occultations per year,
on the 800km ones, I'd say one chord every few years?
So here we are with a basket full of stones of different sizes, you
can clearly see which ones are large, even though it may take a lot of
time (remember the 5000 km Pluto, and the 2500 to 4000km Eris, and
those are the very easy ones), you can clearly see the smallest ones,
and in between you just can't tell because there are not two groups of
clearly separated objects, they are all the same objects, called...
asteroids. We are talking thousands of objects for which we can't
tell. What a lousy classification.

Let's not make a differentiation when there is none, and when we can't
make it. If we would put the SDP (stupid dwarf planet) size limit to
500km, then we have very likely tens of thousands of unclassifiable
objects...
Vesta is a differentiated asteroid, and as Miles Davis would say, so
what ? Is it really that bad ? There must be psychologists able to
cure the "astronomer working on small bodies" inferiority complex...
Because that's where the problem is.
Alain
PS: and we haven't seen anything yet, if all goes well, Ceres is next.
That one I believe should be the smallest of the giant planets in the
universe...

A list for asteroid and comet researcher


----- Original Message -----
From: mpml@yahoogroups.com
To: mpml@yahoogroups.com
Sent: Friday, December 16, 2011 12:21 PM
Subject: {MPML} Digest Number 4006


A list for asteroid and comet researcher
Messages In This Digest (4 Messages)

2. Meteorite Shockwaves Trigger Dust Avalanches on Mars From: Ron Baalke
3. Lovejoy survived perihelion (!) From: Patrick Wiggins
4. Lovejoy reemerging movies From: Patrick Wiggins
View All Topics | Create New Topic Messages

2. Meteorite Shockwaves Trigger Dust Avalanches on Mars
Posted by: "Ron Baalke" baalke@...
Thu Dec 15, 2011 4:03 pm (PST)

FOR IMMEDIATE RELEASE
FROM THE UNIVERSITY OF ARIZONA

Dec. 15, 2011

This story and photos are online at: http://uanews.org/node/43798 .

Contact information follows this story.

Meteorite Shockwaves Trigger Dust Avalanches on Mars

Dust avalanches around impact craters on Mars appear to be the result of
the shock wave preceding the actual impact, according to a study led by an
undergraduate student at the UA.

When a meteorite careens toward the dusty surface of the Red Planet, it
kicks up dust and can cause avalanching even before the rock from outer
space hits the ground, a research team led by an undergraduate student at
the University of Arizona has discovered.

"We expected that some of the streaks of dust that we see on slopes are
caused by seismic shaking during impact," said Kaylan Burleigh, who led
the research project. "We were surprised to find that it rather looks like
shockwaves in the air trigger the avalanches even before the impact."

Because of Mars' thin atmosphere, which is 100 times less dense than
Earth's, even small rocks that would burn up or break up before they could
hit the ground here on Earth crash into the Martian surface relatively
unimpeded.

Each year, about 20 fresh craters between 1 and 50 meters (3 to 165 feet)
show up in images taken by the HiRISE camera on board NASA's Mars
Reconnaissance Orbiter. The High Resolution Imaging Science Experiment, or
HiRISE, is operated by the UA's Lunar and Planetary Laboratory and has
been photographing the Martian surface since 2006, revealing features down
to less than 1 meter in size.

For this study, the team zoomed in on a cluster of five large craters,
which all formed in one impact event close to Mars' equator, about 825
kilometers (512 miles) south of the boundary scarp of Olympus Mons, the
tallest mountain in the solar system. Previous observations by the Mars
Global Surveyor orbiter, which imaged Mars for nine years until 2006,
showed that this cluster was blasted into the dusty surface between May
2004 and February 2006.

The results of the research, which Burleigh first took on as a freshman
under former UA Regents Professor H. Jay Melosh, are published in the
planetary science journal Icarus. Previous studies had looked at dark or
light streaks on the Martian landscape interpreted as landslides, but none
had tied such a large number of them to impacts.

The authors interpret the thousands of downhill-trending dark streaks on
the flanks of ridges covering the area as dust avalanches caused by the
impact. The largest crater in the cluster measures 22 meters, or 72 feet
across and occupies roughly the area of a basketball court. Most likely,
the cluster of craters formed as the meteorite broke up in the atmosphere,
and the fragments hit the ground like a shotgun blast.

Narrow, relatively dark streaks varying from a few meters to about 50
meters in length scour the slopes around the impact site.

"The dark streaks represent the material exposed by the avalanches, as
induced by the the airblast from the impact," Burleigh said. "I counted
more than 100,000 avalanches and, after repeated counts and deleting
duplicates, arrived at 64,948."

When Burleigh looked at the distribution of avalanches around the impact
site, he realized their number decreased with distance in every direction,
consistent with the idea that they were related to the impact event.

But it wasn't until he noticed a pair of peculiar surface features
resembling a curved dagger, described as scimitars, extending from the
central impact crater, that the way in which the impact caused the
avalanches became evident.

"Those scimitars tipped us off that something other than seismic shaking
must be causing the dust avalanches," Burleigh said.

As a meteor screams through the atmosphere at several times the speed of
sound, it creates shockwaves in the air. Simulating the shockwaves
generated by impacts on Martian soil with computer models, the team
observed the exact pattern of scimitars they saw on their impact site.

"We think the interference among different pressure waves lifts up the
dust and sets avalanches in motion. These interference regions, and the
avalanches, occur in a reproducible pattern," Burleigh said. "We checked
other impact sites and realized that when we see avalanches, we usually
see two scimitars, not just one, and they both tend to be at a certain
angle to each other. This pattern would be difficult to explain by seismic
shaking."

In the absence of plate tectonic processes and water-caused erosion, the
authors conclude that small impacts might be more important in shaping the
Martian surface than previously thought.

"This is one part of a larger story about current surface activity on
Mars, which we are realizing is very different than previously believed,"
said Alfred McEwen, principal investigator of the HiRISE project and one
of the co-authors of the study. "We must understand how Mars works today
before we can correctly interpret what may have happened when the climate
was different, and before we can draw comparisons to Earth."

# # #

LINKS:

The accepted manuscript is available online at

http://www.sciencedirect.com/science/article/pii/S0019103511004192

doi:10.1016/j.icarus.2011.10.026

The final typeset version is scheduled for publication in January 2012.

CONTACTS:

Kaylan Burleigh

480-862-4256 (cell)
kaylanb@...
Alfred McEwen

520-621-4573
mcewen@...


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Messages in this topic (1)


3. Lovejoy survived perihelion (!)
Posted by: "Patrick Wiggins" paw@...   scubaskydivepilot
Thu Dec 15, 2011 10:15 pm (PST)


Here's a piece indicating northern hemisphere observers may be able to see
it a few minutes before sunrise Friday morning:

http://news.yahoo.com/comet-lovejoy-survives-fiery-plunge-sun-nasa-says-01570640\
3.html

patrick
718

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Messages in this topic (1)


4. Lovejoy reemerging movies
Posted by: "Patrick Wiggins" paw@...   scubaskydivepilot
Thu Dec 15, 2011 10:41 pm (PST)


Space Weather http://www.spaceweather.com/ has a couple of movies showing
Lovejoy reemerging from behind the Sun. So incredible they almost don't look
real.

patrick
718

A list for asteroid and comet researcher




---- Original Message -----
From: mpml@yahoogroups.com
To: mpml@yahoogroups.com
Sent: Saturday, December 17, 2011 10:43 AM
Subject: {MPML} Digest Number 4007


A list for asteroid and comet researcher

1. Comet Lovejoy Plunges into the Sun and Survives
Posted by: "Ron Baalke" baalke@...
Fri Dec 16, 2011 11:01 am (PST)

http://science.nasa.gov/science-news/science-at-nasa/2011/16dec_cometlovejoy/

Comet Lovejoy Plunges into the Sun and Survives
NASA Science News
December 16, 2011

This morning, an armada of spacecraft witnessed
something that many experts thought impossible. Comet Lovejoy flew
through the hot atmosphere of the sun and emerged intact.

"It's absolutely astounding," says Karl Battams of the Naval Research
Lab in Washington DC. "I did not think the comet's icy core was big
enough to survive plunging through the several million degree solar
corona for close to an hour, but Comet Lovejoy is still with us."

The comet's close encounter was recorded by at least five spacecraft:
NASA's Solar Dynamics Observatory and twin STEREO probes, Europe's
Proba2 microsatellite, and the ESA/NASA Solar and Heliospheric
Observatory. The most dramatic footage so far comes from SDO, which saw
the comet go in (movie
<http://science.nasa.gov/media/medialibrary/2011/12/16/comet_whoosh.m4v>)
and then come back out again (movie
<http://science.nasa.gov/media/medialibrary/2011/12/16/lovejoyemerges.m4v>).

In the SDO movies, the comet's tail wriggles wildly as the comet plunges
through the sun's hot atmosphere only 120,000 km above the stellar
surface. This could be a sign that the comet was buffeted by plasma
waves coursing through the corona. Or perhaps the tail was bouncing
back and forth off great magnetic loops known to permeate the sun's
atmosphere. No one knows.

"This is all new," says Battams. "SDO is giving us our first look^1 at
comets travelling through the sun's atmosphere. How the two interact is
cutting-edge research."

"The motions of the comet material in the sun's magnetic field are just
fascinating," adds SDO project scientist Dean Pesnell of the Goddard
Space Flight Center. "The abrupt changes in direction reminded me of
how the solar wind affected the tail of Comet Encke in 2007 (movie
<http://science.nasa.gov/science-news/science-at-nasa/2007/01oct_encke/>)."

Comet Lovejoy was discovered on Dec. 2, 2011, by amateur astronomer
Terry Lovejoy of Australia. Researchers quickly realized that the new
find was a member of the Kreutz family of sungrazing comets. Named
after the German astronomer Heinrich Kreutz, who first studied them,
Kreutz sungrazers are fragments of a single giant comet that broke apart
back in the 12th century (probably the Great Comet of 1106). Kreutz
sungrazers are typically small (~10 meters wide) and numerous. The Solar
and Heliospheric Observatory sees one falling into the sun every few days.

At the time of discovery, Comet Lovejoy appeared to be at least ten
times larger than the usual Kreutz sungrazer, somewhere in the in the
100 to 200 meter range. In light of today's events, researchers are
re-thinking those numbers.

"I'd guess the comet's core must have been at least 500 meters in
diameter; otherwise it couldn't have survived so much solar heating,"
says Matthew Knight. "A significant fraction of that mass would have
been lost during the encounter. The remains are probably much smaller."

SOHO and NASA's twin STEREO probes are monitoring the comet as it
recedes from the sun. It is still very bright and should remain in range
of the spacecrafts' cameras for several days to come.

What happens next is anyone's guess.

"There is still a possibility that Comet Lovejoy will start to
fragment," continues Battams. "It's been through a tremendously
traumatic event; structurally, it could be extremely weak. On the other
hand, it could hold itself together and disappear back into the recesses
of the solar system."

"It's hard to say," agrees Knight. "There has been so little work on
what happens to sungrazing comets after perihelion (closest approach).
This continues to be fascinating."

Author:Dr. Tony Phillips
Production editor: Dr. Tony Phillips
Credit: Science@NASA

A little note from your local Inwood Astronomer...

A pair of planets orbiting a star other than our Sun was just announced today!

http://www.facebook.com/pages/NASA-JPL-Solar-System-Ambassador-Jason-Kendall/220\
265948049172

Come on over to my website to learn more.

Or get it firsthand yourself here: 
http://kepler.nasa.gov/news/nasakeplernews/index.cfm?FuseAction=ShowNews&NewsID=\
172

Jason

Come join the Amateur Astronomers' Association of New York for a holiday star
party on the Ross Terrace at the American Museum of Natural History. It's right
after the planetarium show in the Hayden Planetarium. The star party is free and
open to the public. The planetarium show is a separate ticket to see the famous
Zeiss Projector in action.

If you are a member of the AAA, and you'd like to bring a telescope (and see the
show as a comp!), please email Leo Genn at outreach@...

Information and tickets for the planetarium show are here:

http://www.amnh.org/calendar/event/Winter-Skies-/

It's all on Tuesday, December 27.  The planetarium show starts at 6:30 PM and
the stargazing follows the show.  Location is 81st Street and Central Park West.
The Ross Terrace is the elevated area adjacent to the glass Rose Center on 81st
Street and Central Park West.

It's the best kind of holiday party you can ask for!

See you there!

Jason Kendall
AAA Board Member

A list for asteroid and comet researcher


----- Original Message -----
From: mpml@yahoogroups.com
To: mpml@yahoogroups.com
Sent: Thursday, December 22, 2011 12:18 PM
Subject: {MPML} Digest Number 4011


A list for asteroid and comet researcher

Dawn Obtains First Low Altitude Images of Vesta From: Ron Baalke
Posted by: "Ron Baalke" baalke@...
Wed Dec 21, 2011 9:20 am (PST)

http://www.jpl.nasa.gov/news/news.cfm?release=2011-391

Dawn Obtains First Low Altitude Images of Vesta
Jet Propulsion Laboratory
December 21, 2011

PASADENA, Calif. - NASA's Dawn spacecraft has sent back the first images
of the giant asteroid Vesta from its low-altitude mapping orbit. The
images, obtained by the framing camera, show the stippled and lumpy
surface in detail never seen before, piquing the curiosity of scientists
who are studying Vesta for clues about the solar system's early history.

At this detailed resolution, the surface shows abundant small craters,
and textures such as small grooves and lineaments that are reminiscent
of the structures seen in low-resolution data from the higher-altitude
orbits. Also, this fine scale highlights small outcrops of bright and
dark material.

A gallery of images can be found online at:
http://www.nasa.gov/mission_pages/dawn/multimedia/gallery-index.html .

The images were returned to Earth on Dec. 13. Dawn scientists plan to
acquire data in the low-altitude mapping orbit for at least 10 weeks.
The primary science objectives in this orbit are to learn about the
elemental composition of Vesta's surface with the gamma ray and neutron
detector and to probe the interior structure of the asteroid by
measuring the gravity field.

The Dawn mission to the asteroids Vesta and Ceres is managed by NASA's
Jet Propulsion Laboratory, a division of the California Institute of
Technology in Pasadena, for NASA's Science Mission Directorate,
Washington. Dawn is a project of the directorate's Discovery Program,
managed by NASA's Marshall Space Flight Center in Huntsville, Ala. UCLA
is responsible for overall Dawn mission science. The Dawn Framing
Cameras have been developed and built under the leadership of the Max
Planck Institute for Solar System Research, Katlenburg-Lindau, Germany,
with significant contributions by DLR German Aerospace Center, Institute
of Planetary Research, Berlin, and in coordination with the Institute of
Computer and Communication Network Engineering, Braunschweig. The
framing camera project is funded by the Max Planck Society, DLR, and
NASA/JPL.

More information about the Dawn mission is online at:
http://www.nasa.gov/dawn and http://dawn.jpl.nasa.gov .

Jia-Rui Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jccook@...

2011-391

----- Original Message -----
From: "Carolyn Porco" <cpcomments@...>
To: <undisclosed-recipients:>
Sent: Thursday, December 22, 2011 1:59 PM
Subject: Happy Holiday Treats ... from Saturn!


>
> December 22, 2011
>
>
> Dear Friends and Colleagues,
>
> The holiday season is finally upon us!  So, today, in celebration of
> this beloved time of year and to mark Planet Earth's northern winter
> solstice, the Cassini imaging team is releasing a small collection of
> specially processed images of Saturn's largest and most colorful moon,
> Titan ... the only moon in the solar system with a substantial
> atmosphere.  A couple of Saturn's stark, airless, icy moons also appears
> in these scenes, seeming to dangle beside Titan's orange orb.  The
> atmosphere of Titan is of great interest because of its similarities to
> the atmosphere believed to exist long ago on the early Earth.
>
> Now it's time.  Go to ...
>
>
>         http://www.ciclops.org/view_event/167/
>
>
> ... look under the tree, carefully pick only the packages with the red
> bows, and you'll find your extraterrestrial surprises waiting within.
>
> (Also find an image advisory that we released a short while ago attached
> to this email.)
>
> And now, from all of us to all of you, a brimming sleigh-full of warm
> wishes that your holidays are happy, peaceful, relaxing and safe.
>
>
> Enjoy!
>
> Carolyn Porco
> Cassini Imaging Team Leader
> Director, CICLOPS
> Space Science Institute
> Boulder, CO
>
> http://ciclops.org
> http://twitter.com/carolynporco
> http://www.facebook.com/carolynporco
>
> PS.  To unsubscribe from this list, go to the right hand column of the
> CICLOPS home page ( http://ciclops.org ) and find and click the
> [Unsubscribe] link

I created an Astronomy Humor website (AstronomyHumor.com). My topics include:
Astronomy, Astronomers, Books for Adults and Children, Space Ships, NASA, Solar
System, the Sun and Moon, Planets, Stars,  Aliens, and Astronauts both human and
animal.

I also created a 450 page e-book called 'Your Galaxy Needs You: Astronomy,
Astronaut and Alien Humor'.

Contributions of humor from New York Sidewalk Astronomers are welcome. such as
funny stories about astronomical experiences in New York.

My website and e-book are personal projects. However, I am also a volunteer with
the Marie Drake Planetarium in Juneau, AK  I am also the President of 'The
Friends of the Marie Drake Planetarium', a non-profit.

Cristina Della Rosa

Creator AstronomyHumor.com

A list for asteroid and comet researcher



Closing in on the source of eucrites, howardites, and diogenites.

----- Original Message -----
From: mpml@yahoogroups.com
To: mpml@yahoogroups.com
Sent: Saturday, December 31, 2011 12:26 PM
Subject: {MPML} Digest Number 4015


A list for asteroid and comet researcher

Mountain on Vesta Produces Terrestrial Meteorites
Posted by: "Ron Baalke" baalke@...
Fri Dec 30, 2011 7:34 pm (PST)

http://science.nasa.gov/science-news/science-at-nasa/2011/30dec_spacemountain/

Space Mountain Produces Terrestrial Meteorites
NASA Science News
December 30, 2011

When NASA's Dawn spacecraft entered orbit around giant
asteroid Vesta in July, scientists fully expected the probe to reveal
some surprising sights. But no one expected a 13-mile high mountain, two
and a half times higher than Mount Everest, to be one of them.

The existence of this towering peak could solve a longstanding mystery:
How did so many pieces of Vesta end up right here on our own planet?

For many years, researchers have been collecting Vesta meteorites from
"fall sites" around the world. The rocks' chemical fingerprints leave
little doubt that they came from the giant asteroid. Earth has been
peppered by so many fragments of Vesta, that people have actually
witnessed fireballs caused by the meteoroids tearing through our
atmosphere. Recent examples include falls near the African village of
Bilanga Yanga in October 1999 and outside Millbillillie, Australia, in
October 1960.

"Those meteorites just might be pieces of the basin excavated when
Vesta's giant mountain formed," says Dawn PI Chris Russell of UCLA.

Russell believes the mountain was created by a 'big bad impact' with a
smaller body; material displaced in the smashup rebounded and expanded
upward to form a towering peak. The same tremendous collision that
created the mountain might have hurled splinters of Vesta toward Earth.

"Some of the meteorites in our museums and labs," he says, "could be
fragments of Vesta formed in the impact -- pieces of the same stuff the
mountain itself is made of."

To confirm the theory, Dawn's science team will try to prove that
Vesta's meteorites came from the mountain's vicinity. It's a "match
game" involving both age and chemistry.

"Vesta formed at the dawn of the solar system," says Russell. "Billions
of years of collisions with other space rocks have given it a densely
cratered surface."

The surface around the mountain, however, is tellingly smooth. Russell
believes the impact wiped out the entire history of cratering in the
vicinity. By counting craters that have accumulated since then,
researchers can estimate the age of the landscape.

"In this way we can figure out the approximate age of the mountain's
surface. Using radioactive dating, we can also tell when the meteorites
were 'liberated' from Vesta. A match between those dates would be
compelling evidence of a meteorite-mountain connection."

For more proof, the scientists will compare the meteorites' chemical
makeup to that of the mountain area.

"Vesta is intrinsically but subtly colorful. Dawn's sensors can detect
slight color variations in Vesta's minerals, so we can map regions of
chemicals and minerals that have emerged on the surface. Then we'll
compare these colors to those of the meteorites."

Could an impact on Vesta really fill so many museum display cases on
Earth? Stay tuned for answers..

Author: Dauna Coulter
Editor: Dr. Tony Phillips
Credit: Science@NASA <http://science.nasa.gov/>

More Information

After revealing more Vesta surprises, Dawn will depart next summer for
Ceres, where it will arrive in 2015. Dawn's mission to Vesta and Ceres
is managed by the Jet Propulsion Laboratory, Pasadena, Calif., for
NASA's Science Mission Directorate in Washington. JPL is a division of
the California Institute of Technology in Pasadena. Dawn is a project of
the directorate's Discovery Program, managed by NASA's Marshall Space
Flight Center in Huntsville, Ala. UCLA is responsible for overall Dawn
mission science. Orbital Sciences Corp. in Dulles, Va., designed and
built the spacecraft. The German Aerospace Center, the Max Planck
Institute for Solar System Research, the Italian Space Agency and the
Italian National Astrophysical Institute are international partners on
the mission team. More information about the Dawn mission is at:
http://www.nasa.gov/dawn and http://dawn.jpl.nasa.gov
<http://dawn.jpl.nasa.gov/>. To follow the mission on Twitter, visit:
http://www.twitter.com/NASA_Dawn .

And here is a great place in NYC to come see them....

http://www.moonbeam.net/InwoodAstronomy/location-IHP-OVERLOOK.shtml

Jason

Quadrantid Meteor Shower report.

I woke myself up at 2:30 and went out for the event. It took my bike up to the
hilltop a half-mile away. No streetlights are in the park at all, so all i have
to deal with is skyglow and clouds. There weren't many clouds, but a few high
ones. In the 90 minutes I was up at the hilltop, I saw 3 meteors, and 2
"hairline" meteors. They all appeared to radiate south from the handle of Ursa
Major, just like you saw. The brightest was pretty short going only 5 degrees in
length and staying just north of Spica and Saturn. (That's a nice combo, too.)
Right around 3:30 is when I saw them, and I was out there with one guy, James
McNamara who drove up from Queens. The brightest meteor was easily as bright as
Sirius, and did have a bluish tinge, as expected by some guides. I, too, had to
be in for work at 8, so we packed it in around 4, right near the end. I am
continually surprised by the fact that I can pick out 4th magnitude stars in
NYC, as I saw them in Gemini's "body".

So, yup, we were able to see a good smattering!

Jason

Excellent! It sounds like only one other person made that considerable effort:
mounting the ridgetop at that late hour and in such cold weather. But it sounds
like it paid off! Good for you!

Bruce

--- In nyswa@yahoogroups.com, "Jason Shiling Kendall" <jkendall@...> wrote:
>
> Quadrantid Meteor Shower report.
>
> I woke myself up at 2:30 and went out for the event. It took my bike up to the
hilltop a half-mile away. No streetlights are in the park at all, so all i have
to deal with is skyglow and clouds. There weren't many clouds, but a few high
ones. In the 90 minutes I was up at the hilltop, I saw 3 meteors, and 2
"hairline" meteors. They all appeared to radiate south from the handle of Ursa
Major, just like you saw. The brightest was pretty short going only 5 degrees in
length and staying just north of Spica and Saturn. (That's a nice combo, too.)
Right around 3:30 is when I saw them, and I was out there with one guy, James
McNamara who drove up from Queens. The brightest meteor was easily as bright as
Sirius, and did have a bluish tinge, as expected by some guides. I, too, had to
be in for work at 8, so we packed it in around 4, right near the end. I am
continually surprised by the fact that I can pick out 4th magnitude stars in
NYC, as I saw them in Gemini's "body".
>
> So, yup, we were able to see a good smattering!
>
> Jason
>

A list for asteroid and comet researcher



----- Original Message -----
From: mpml@yahoogroups.com
To: mpml@yahoogroups.com
Sent: Thursday, January 05, 2012 1:48 PM
Subject: {MPML} Digest Number 4020


A list for asteroid and comet researcher
Messages In This Digest (9 Messages)
1. Dawn Journal - December 30, 2011 From: Ron Baalke
2a. Vesta From: Jean Meeus
2b. Re: Vesta From: lebofsky@...
2c. Re: Vesta From: dfischer@...
2d. Re: Vesta From: gpobs
2e. Re: Vesta From: P. Clay Sherrod
2f. Re: Vesta From: gpobs
2g. Re: Vesta From: dfischer@...
2h. Re: Vesta From: P. Clay Sherrod
View All Topics | Create New Topic Messages

1. Dawn Journal - December 30, 2011
Posted by: "Ron Baalke" baalke@...
Wed Jan 4, 2012 4:45 pm (PST)

http://dawn.jpl.nasa.gov/mission/journal_12_30_11.asp

Dawn Journal
Dr. Marc Rayman
December 30, 2011

Dear Indawnmitables,

Dawn concludes 2011 more than 40 thousand times nearer to Vesta than it
began the year. Now at its lowest altitude of the mission, the bold
adventurer is conducting its most detailed exploration of this alien
world and continuing to make thrilling new discoveries.

Circling the protoplanet 210 kilometers (130 miles) beneath it every 4
hours, 21 minutes on average, Dawn is closer to the surface than the
vast majority of Earth-orbiting satellites are to that planet. There are
two primary scientific objectives of this low altitude mapping orbit
(LAMO). With its gamma ray and neutron detector (GRaND), the probe is
measuring the faint emanations of these subatomic particles from Vesta.
Some are the by-products of the bombardment by cosmic rays, radiation
that pervades space, and others are emitted through the decay of
radioactive elements. Vesta does not glow brightly when observed in
nuclear particles, so GRaND needs to measure the radiation for weeks at
this low altitude. This is analogous to using a long exposure with a
camera to photograph a dimly lit subject. If GRaND only detected the
radiation, it would be as if it took a black and white picture, but this
sophisticated instrument does more. It measures the energy of each particle,
just as a camera can measure the color of light. The energies reveal the
identities of the elements that constitute the uppermost meter (yard) of
the surface. Dawn devotes most of its time now flying over Vesta to
collecting the glimmer of radiation. It requires a long time, but this
spacecraft has demonstrated tremendous patience in its use
of the gentle but efficient ion propulsion system that made the mission
possible, so it can be patient in making these measurements.

The second motivation for diving down so low is to be close enough that
Vesta's interior variations in density affect the spacecraft's orbit
discernibly. We have seen before that the distribution of mass inside
the protoplanet reveals itself through the changing strength of its
gravitational tug on Dawn. Exquisitely sensitive measurements of the
ship's course can be translated into a three-dimensional map of the mass.
In the plans discussed for LAMO one year ago, the delicate tracking of the
spacecraft required pointing the main antenna to Earth. That provides a
radio signal strong enough to achieve the required accuracy. Since then,
navigators have determined that the radio signal received from one of
the craft's auxiliary antennas, although far weaker, is sufficient. The
main antenna broadcasts a tight beam, whereas the others emit over a
much larger angle, exchanging signal strength for flexibility in pointing.

This allows an extremely valuable improvement. The spacecraft cannot aim
GRaND at the surface and the main antenna at Earth concurrently, because
both are mounted rigidly, just as you cannot simultaneously point the
front of your car north and the back east. Therefore, in the original
plan, gravity measurements and GRaND measurements were mutually
exclusive. Now, as Dawn turns throughout its orbit to keep Vesta in
GRaND's sights, it can transmit a weak radio signal that is just
perceptible at Earth. This enables an even greater science return for
the time in LAMO.

Unlike the science camera and the visible and infrared mapping
spectrometer (VIR), GRaND and gravity observations do not depend on
the sun's illumination of the surface. Even as it orbits over a dark,
cold, silent landscape, Dawn is fully capable of continuing to build its
maps of elements and the interior structure.

The signal from the auxiliary antenna is just sufficient for the
measurement of the spacecraft's motion, but it is not strong enough to
carry data as well. So the spacecraft is still programmed to point its
main antenna to Earth three times each week, allowing the precious GRaND
observations that have been stored in computer memory to be transmitted.
As always, the myriad measurements of temperatures, voltages, currents,
pressures, and other parameters that engineers use to ensure the health
of the ship are returned during these communications sessions as well.

Although the pictures of Vesta from survey orbit and the high altitude
mapping orbit (HAMO) have exceeded scientists' expectations, not only in
quality and quantity but also in the truly fascinating content, as
enthusiastic explorers, the Dawn team could not pass up the opportunity
for more. When GRaND is pointed at the surface, the camera is too, and
already well over one thousand images have been returned, revealing detail
three times finer than the spectacular images from HAMO. For readers who
cannot go to Vesta on their own, go here
</multimedia/imageoftheday/archives.asp>
for a selection of the best views, each showing surprising and captivating
alien landscapes.

In addition to the bonus photography, beginning in January VIR will take
observations. Although the instrument has already acquired nearly seven
million spectra in the higher orbits, this new vantage point will allow
sharper resolution, just as it does for the camera.

The ultra-long-distance communication between Dawn and Earth requires
extraordinary technology on both ends. Even with all the sophistication,
the amount of information that can be transmitted in a given time
remains very limited. The remote spacecraft sends data at speeds
significantly lower than a typical home Internet connection. Engineers
use that precious communications link very carefully, judiciously
selecting what information to instruct the probe to return. Because of
the high priority given to GRaND, which needs to be pointed at the
surface as long as possible, much of the limited time spent with the
main antenna aimed at Earth is devoted to transmitting that instrument's
findings (and the measurements of spacecraft subsystems). This restricts
how much data from the camera and VIR can be communicated.

In the next log, we will see another limitation on the number of camera
images and VIR spectra in LAMO. It is a consequence of another aspect of
the complex operations in this low orbit around a massive body, and that
is the small but real differences between the predicted orbit and the
actual orbit. We will cover the first part of the explanation here.

Navigators use their best knowledge of the many forces acting on Dawn to
chart an orbital course for it. The forces can be traced to three
principal sources: gravity, light, and Dawn itself. We have discussed
all of these before in detail (see, for example, this explication of the
last two), but let's review them here.
This is an involved story, so readers are advised to be in a comfortable
orbit while following it. You can safely skip the next four paragraphs
and no one ever need know.

Vesta has a complicated gravity field, and that leads to a complicated
orbit. The spacecraft does not follow a
perfectly circular, repetitive path because the gravitational pull on it
changes according to where it is as the colossus beneath it rotates and
it loops around. The map of the gravity field has been improving
throughout Dawn's residence there, but its completion awaits the LAMO
gravity measurements. In the meantime, unknown details of the variation
of mass lead to small divergences in the orbit. All the other bodies in
the solar system exert gravitational pulls on the spacecraft as well
(just as they do on you), but those are more easily accounted for. The
distances from Dawn are so great that the variations in their gravity
fields don't matter. So although the effects of the faraway objects need
to be accounted for, they do not contribute much to the discrepancies.

Dawn depends on sunlight for its power, using its large solar arrays to
make electricity to run all systems. The sun also propels the
spacecraft, because in the frictionless conditions of spaceflight, the
ship recoils slightly in response to the miniscule but persistent
pressure of the light. The force depends on
whether the light is absorbed (whereupon it is converted to electrical
power by the arrays or to heat by whatever component it illuminates) or
reflected. If it is reflected, the angle makes a difference, so smooth
shiny surfaces that act like mirrors cause different effects from the
materials that present a matte finish or are curved or angled. As the
spacecraft rotates to keep GRaND pointed at the ground below, different
parts of the ship are presented to the sun, so the force from the light
changes, and the orbit is constantly subjected to a variable disturbance.

Dawn itself adds to the complexity of its orbital path.
The spacecraft carries reaction
wheels, which are spun to help it control its orientation. These devices
gradually spin faster, so every few days they need to be slowed down.
That is accomplished by firing the small reaction control system
thrusters during windows specified by mission
controllers. In addition to the thrusters providing the needed torque on
the craft to reduce the wheels' speeds, they impart a force that changes
the orbit slightly.

The physical principles underlying all these phenomena that perturb
Dawn's orbit are understood with exceptional clarity. Although the
values of the myriad parameters involved are ascertained quite
accurately, they are not known perfectly. As a result, navigators'
prediction of the ship's course includes some degree of uncertainty.
Even their ability to determine the present orbit is subject to a
variety of small errors typical in sensitive physical measurements.

For all of these reasons, the craft's actual orbit departs slightly from
the plan, and the deviations tend to grow, albeit gradually. As
designers expected, in survey orbit and HAMO, the differences were small
enough that they did not affect the complex operations plans. Analysis
well before Dawn arrived at Vesta predicted that the discrepancies in
LAMO would be large enough that occasional adjustments of the orbit
would be necessary. Therefore, mission controllers scheduled a window
every week (on Saturdays, as it turned out) to use the ion propulsion
system to fine-tune the spacecraft's trajectory, bringing it back to the
intended orbit. These are known as "orbit maintenance maneuvers," and
succumbing to instincts developed during their long evolutionary
history, engineers refer to them by an acronym: OMM. (As the common
thread among team members is their technical training and passion for
the exploration of the cosmos, and not Buddhism, the term is spoken by
naming the letters, not pronouncing it as a means of achieving inner
peace. Instead, it may be thought of as a means of achieving orbital
tranquility and harmony.)

The LAMO phase began on December 12, and OMMs were performed on December
17 and 24. In contrast to the long periods of thrusting required with
ion propulsion for other parts of the mission, the corrections needed
were so small that each OMM needed less than 15 minutes. The whisper-like
thrust changed the spacecraft's speed by less than five centimeters per
second (one-tenth of a mph). But that was enough to nudge Dawn back to
the planned orbit.

The ship was so close to the designated course that the OMMs for
December 31 and even January 7 have already been canceled. Not executing
the OMMs allows the probe to spend more time collecting neutrons and
gamma rays from Vesta. The operations team productively uses the time
saved in designing, checking, and transmitting the OMM commands to do
other work to ensure LAMO proceeds smoothly and productively.

In the last log we discussed the complicated and
dynamic spiral descent from HAMO to LAMO, which was still in progress.
The flight required not only reducing the altitude from 680 kilometers
(420 miles) to 210 kilometers (130 miles) but also twisting the plane of
Dawn's orbit around Vesta. As with all orbiting bodies, whether around
Vesta, Earth, or the sun, the lower the orbital altitude, the shorter
the orbital period. Vesta's gravitational
grip strengthened as Dawn closed in, forcing the spacecraft to make
faster loops around it. This meant that as the probe performed the
intricate choreography to align its ion thruster with the changing
direction needed to alter its orbit, it had to pirouette faster.

When engineers command Dawn to rotate, they usually instruct it to use
the same stately speed as the minute hand on a clock.
The spacecraft may have to move a little
faster however, as it pivots to keep its solar arrays pointed at the sun
while accomplishing the required turn. Sometimes it knows that at the
end of a turn, it will have to initiate another turn. For example, it
may rotate to the orientation required to begin a session of ion
thrusting. But while it is thrusting and curving around its orbit, it
generally needs to steer the thruster to execute the maneuver. As a
result, the robot may choose to turn at a slightly different rate from
what its human team members command in order to make a smooth transition
from the first turn to the second.

On Dec. 3, when preparing for one of the final thrust segments required
to reach LAMO, the combination of all these factors caused the
spacecraft to rotate faster than usual. That led to a temporary
discrepancy between where it was pointed and where it expected to be
pointed during the turn. When protective software detected the
inconsistency, it interrupted the ongoing activities and put the
spacecraft into safe mode.

When the safe mode signal was received by the Deep Space Network, the
operations team responded with its usual calm and skill. They quickly
determined that Dawn was fully healthy, diagnosed the cause of the
safing, and began guiding the spacecraft back to its normal operational
configuration. In addition, they devised a new flight profile that would
compensate for the thrusting that was not completed. The team also
determined how to prevent the same problem from recurring for subsequent
maneuvers. While doing all this work, they were putting the finishing
touches on the first LAMO science observation sequences.
Controllers managed to complete
everything flawlessly and even kept the mission on schedule, allowing
LAMO to commence on Dec. 12.

The general plan for Dawn's three-month approach <journal_05_03_11.asp>
plus one year in orbit around Vesta was described in logs in 2010
</mission/journal.asp>. The time was apportioned among the different
science phases and the transfers between science orbits to ensure a
comprehensive and balanced exploration of this mysterious and
fascinating world. Fully appreciating that in such an exceedingly
ambitious undertaking, some unexpected problems are inevitable, mission
planners worked hard to devise an itinerary that left 40 days
uncommitted. Their strategy was that as they recovered from anomalies,
they would draw from that time and still not have to compromise any of
their carefully designed activities. They also planned that any unspent
margin would be used to extend LAMO.

To the great delight (and, to be honest, surprise) of all, not one day
of the 40-day reserve has been needed. Although there have indeed been
unanticipated difficulties, from the beginning of approach on May 3 to
this point, the team has been able to resolve all of them without having
to withdraw from that account. This is remarkable considering that Dawn
is the first visitor from Earth to Vesta, with its many unknown physical
properties. This expedition is the first ever in which humankind has
sent a spacecraft to orbit such a massive body without first conducting
a reconnaissance with a flyby spacecraft. Dawn has maintained a rapid
pace of scrutinizing its enigmatic destination. Performing all of this
so successfully without needing to use even a little of the spare time
they provided for themselves was considered quite unlikely. And yet the
entire 40 days remain available.

More ambitious operations lie ahead, with the rest of LAMO, the spiral
ascent to HAMO2 <journal_02_27_11.asp#completed>, HAMO2 itself, and the
escape in July to begin the long interplanetary cruise to reach Ceres on
schedule in February 2015. We will see in 2012 that each of these phases
includes new challenges, and it is certain new problems will arise.
Nevertheless, all 40 days are being used to extend LAMO. Therefore, the
indomitable explorer will remain at this low altitude through the end of
March, continuing to tease out secrets about the dawn of the solar
system and revealing more startling and thrilling discoveries on behalf
of everyone on distant Earth who yearns to reach out into the vastness
of space.

Dawn is 210 kilometers (130 miles) from Vesta. It is also 2.79 AU (418
million kilometers or 260 million miles) from Earth, or 1045 times as
far as the moon and 2.84 times as far as the sun today. Radio signals,
traveling at the universal limit of the speed of light, take 46 minutes
to make the round trip.


2a. Vesta
Posted by: "Jean Meeus" jmeeus@...
Wed Jan 4, 2012 9:58 pm (PST)


Why is Baalke always calling Vesta a "protoplanet"?
A protoplanet is a planet in formation, in the early times of
the solar system. Our solar system is now so old that there
can no longer be protoplanets nowadays.

Jean Meeus

[Non-text portions of this message have been removed]


2b. Re: Vesta
Posted by: "lebofsky@..." lebofsky@...   llebofsky
Thu Jan 5, 2012 2:49 am (PST)


Hello Jean:

Do not shoot the messenger. Ron is just reporting what is sent out as a
news release, in this case from the Dawn Team. The following is my
opinion, so I take responsibility for it. The Dawn scientists have been
good at recreating Vesta. They have called Vesta a protoplanet (wrong) and
they have called it the smallest terrestrial planet (wrong). There are
lots of other complaints that I have with the news releases that are
sometimes a little misleading (caution in what one says can lead to
misconceptions).

Larry


2c. Re: Vesta
Posted by: "dfischer@..." dfischer@...   skyweek
Thu Jan 5, 2012 7:43 am (PST)


> The Dawn scientists have been
> good at recreating Vesta. They have called Vesta a protoplanet (wrong) and
> they have called it the smallest terrestrial planet (wrong).

When the Dawn PR Dept. first began calling the first target a - left-over!
- protoplanet, I actually had some e-mail argument with a scientist that
was quoted using that term. And she pointed me to an earlier scientific
paper that indeed used 'protoplanet' as an expression for ex-planetesimals
that just didn't make it into real planets.

A bibliographic and web search then led me to the surprising conclusion
that 'protoplanet' can mean very different things (I found about half a
dozen definitions, often mutually exclusive) to astrophysicists and - some
- planetologists, and as long as there isn't an IAU Resolution about it,
one just cannot tell who's right and wrong ...

Dan


2d. Re: Vesta
Posted by: "gpobs" gpobs@...   roy_tucker2000
Thu Jan 5, 2012 8:02 am (PST)


Oh Boy! We've whipped the "Is Pluto a planet" thing to death, now we can
start working on "Is Vesta a protoplanet?" We can waste bandwidth for years!
Woohoo!


2e. Re: Vesta
Posted by: "P. Clay Sherrod" drclay@...   drclay2002
Thu Jan 5, 2012 8:43 am (PST)


I really think that this does not need to be an IAU Resolution.
Use of the term "protoplanet" is simply incorrect and a misinformed label to
apply to
larger asteroids; leaders in the field before the discussions became
splintered
never, ever referred to larger asteroidal bodies as "protoplanets", but more
frequently as "planetesimals" to differentiate them from the smaller bodies
of the
system of minor planets. These same scientists will continue using the
improper term
simply to keep from, as we say it in Arkansas "eating crow." Eventually the
language
of the science is diluted and the bastardized word becomes "acceptable" as
do so many
things in today's society.
Just because it is "accepted" does not make it correct.

At some point, even scientists need to come to grips with "not changing the
lingo"
that is in acceptable usage in all fields, from agronomy to zoology. Those
in the
habit of constantly using the wrong moniker to express themselves are not
correct
simply because they are "educated" in the field in which they are butchering
the
language.

Clay
_____
Dr. P. Clay Sherrod
Arkansas Sky Observatories
MPC H45 - Petit Jean Mountain South
MPC H41 - Petit Jean Mountain
MPC H43 - Conway West
http://www.arksky.org/



2f. Re: Vesta
Posted by: "gpobs" gpobs@...   roy_tucker2000
Thu Jan 5, 2012 9:20 am (PST)


Yes... Perhaps the answer is to use a language that is no longer changing do
to common usage. A dead language that is not subject to evolution by slang
and popular speaking. Of course! We can start speaking and publishing papers
in Latin! Would that be "protoplanetae" and "planetesimalae"? This will
remove the discussion from the media and popular debate. Only in the pages
of the Latin edition of Icarus may one then find the heated discussion of
this issue.

"Quidquid latine dictum sit, altum viditur"

Royus Tuckerus
(Tongue firmly in cheek)


2g. Re: Vesta
Posted by: "dfischer@..." dfischer@...   skyweek
Thu Jan 5, 2012 9:59 am (PST)


For what it's worth, here is my 'research' into the meaning of
'protoplanet' from last July again:
http://tech.groups.yahoo.com/group/mpml/message/25780 ...

And here's the reply of one of the authors of the 2009 Science paper
mentioned there: <<In our 2009 paper, we used the term "protoplanet" as
often used by asteroid and minor body scientists. For example, there was a
conference abstract by McCord and others at the 2006 AGU conference that
described the use of the term. The term "protoplanet" has no size
implications per se (authors use the term widely for a range of object
sizes) aside from larger than a small fragment (what most people picture
as an "asteroid"): what it implies is a body whose formation into a planet
has started but not been completed. For Vesta--round, and likely
hydrostatic prior to some cooling and the formation of the south polar
impact structure (i.e. it was at one time a dwarf planet), the gravity of
Jupiter prevented it from becoming large enough to "clear out its orbit"
like a larger planet, making it very much a protoplanet. A similar
orbital/impact history is likely true of Pallas. Vesta and Pallas are not
considered a dwarf planets because they are not currently hydrostatic
bodies. This is likely due to later-stage impacts once the bodies cooled.
The term "protoplanet" is thereby a nod to the fact that these large
bodies are much more like planets in many respects than they are like the
traditional asteroids. Fragments and rubble piles are not necessarily in a
state of arrested development, while Vesta and Pallas likely were at the
time of their cooling and remain today as mostly intact. Thus the term
'protoplanet' that describes a planet precursor not yet completely formed
is an appropriate term for these bodies by better capturing their size and
evolutionary history relative to other types of bodies.>>

So there ...

Daniel (still considering Vesta a minor planet, but a most interesting one)


2h. Re: Vesta
Posted by: "P. Clay Sherrod" drclay@...   drclay2002
Thu Jan 5, 2012 10:07 am (PST)


Indeed and good information....but to describe the resultant trash left
after the
actual and original "protoplanet" failed to complete its course with the
same term as
the parent body is entirely confusing and misleading.

It is like looking on the floor after a wind gust and seeing your huge
picture window
laying on the carpet....you do not say "Look at all that Picture Window!"
Rather, I
would suspect you would exclaim, "Look at all that broken glass!" and make
no
reference to what used to be a window.

I am from the old school and set in my ways perhaps. I have always been a
staunch
defender of the King's English or the Pharaoh's Egyptian, or whatever
language might
be in use in intelligent discussions.

Clay
_____
Dr. P. Clay Sherrod
Arkansas Sky Observatories
MPC H45 - Petit Jean Mountain South
MPC H41 - Petit Jean Mountain
MPC H43 - Conway West
http://www.arksky.org/

Giving your children an interest in astronomy will provide a lifetime of
pleasure and satisfaction, a sense of wonder at the universe, a potentially
lifelong hobby, as well as a possible professional career for them in later
years!
Before you give them binoculars or buy them a telescope or a hand held
planetarium, get your kids outside on a clear night to look at the stars in the
way humans have always done - with their eyes. Naked eye astronomy is the way to
begin learning about the heavens. That's because, apart from the moon, Venus,
Jupiter, Saturn and a few other night sky objects like the Pleiades, looking at
something through binoculars or a telescope can be difficult and disappointing.
The star which is a tiny point of light in the sky will remain a tiny point of
light when magnified. Even holding binoculars steady enough for viewing is
likely to be challenging for smaller children anyway.
It's much better to get children inspired about the night sky by having them
learning about and watching the phases of the moon, or the shapes of the
brighter constellations, without using instruments.
Of course, if you are hazy about things like the names of the constellations
yourself you will be setting out on a voyage of discovery with your kids as
well! There are many great software programs available which will display the
currently visible night sky on your computer, or you can check the
constellations in the charts in any good astronomy guidebook. Then you can pass
on your knowledge when stargazing.
Another recommendation before venturing out in the dark - dress your kids
warmly, make them wear hats, and don't try to do too much on the first night.
Whether you stargaze in your yard, in the local park, or have to drive outside
the city to get away from the artificial light and streetlights and get a clear
view of the stars, don't let your kids get too cold. I know from bitter
experience that this will make it harder to get them out the next time.
You can also be very clever about your first night sky adventure by choosing to
go out when there are likely to be meteor showers. Consult a guidebook or an
online web site to find out when and from which area of the sky the next meteor
shower will come, and get your kids out to see it. This is exciting for kids as
well as adults, and you can compete to see who can count the most.
If you live in higher latitudes, auroras (the northern or southern lights) are
another spectacular night sky event: I have even roused my children from their
beds to see a good one, and I'm sure they will thank me for it when they are
older!
Spotting planets is another fine game, and the kids will soon be adept at
pointing out Venus or Jupiter at dusk, given a clear sky.
As always with education, the secret is with reinforcement - if you mention the
blue color of Rigel or the red color of Betelgeuse one night, ask the kids if
they can remember the name of the red or blue stars in Orion the next time you
go out. If you have been working on why the moon has phases, get them to
experiment with a tennis ball and a flashlight. One method: place a flashlight
(representing the sun) on a chair pointing at the child who then turns while
they hold the tennis ball at arm's length to simulate the moon circling the
earth.
Ways to teach about the night sky are limited only by your imagination, and when
your kids have grasped the basics, you can then think about a telescope, and
mastering that. At that point, the universe will really open up for parent and
child.

A list for asteroid and comet researcher



----- Original Message -----
From: mpml@yahoogroups.com
To: mpml@yahoogroups.com
Sent: Thursday, January 26, 2012 4:02 AM
Subject: {MPML} Digest Number 4039


A list for asteroid and comet researcher
Messages In This Digest (3 Messages)
1. Space Debris Experts Confirm Estimate for Phobos-Grunt Reentry From: Ron
Baalke
2. Vesta Likely Cold and Dark Enough for Ice From: Ron Baalke
3. MRO HiRISE Images - January 25, 2012 From: Ron Baalke

1. Space Debris Experts Confirm Estimate for Phobos-Grunt Reentry
Posted by: "Ron Baalke" baalke@...
Wed Jan 25, 2012 11:13 am (PST)

http://www.esa.int/SPECIALS/Operations/SEMMXUH8RXG_0.html

Space debris experts confirm estimate for Phobos-Grunt reentry
European Space Agency
25 January 2012

Before the reentry of Russia's Phobos-Grunt Mars probe on 15 January, ESA
established a final prediction for reentry of 17:45 GMT, referring to an
altitude of 10 km. Within the expected uncertainties, the prediction has
been largely confirmed by observations.

Refining the reentry estimates

Following the 15 January Phobos-Grunt reentry, the US Strategic Command
confirmed a reentry time of 17:46 GMT, referring to an altitude of 80 km at
46 deg S and 87 deg W, near the South American coastline. This corresponds
to a pass at 10 km altitude about seven minutes later -- very close to ESA's
prediction.

"While this was an uncontrolled reentry, the location of the potential
impact area was largely over ocean, with a correspondingly low probability
of any detrimental effects," said Prof. Heiner Klinkrad, Head of ESA's Space
Debris Office in Darmstadt, Germany.

Orbital data furnished by European sources, including France and Germany,
were also used to refine the reentry estimates. ESA communicated regular
updates to European civil protection authorities in the days leading up to
the reentry.

The US Strategic Command (US Stratcom) operates a network of radar and other
sensors that also track such objects in orbit.

The effort was also part of a comprehensive reentry prediction campaign for
Phobos-Grunt conducted by the Inter-Agency Space Debris Coordination
Committee (IADC), a technical forum for the worldwide coordination of
activities related to human-made and natural debris in space.

IADC is an inter-agency forum for the worldwide coordination of activities
related to the issues of human-made and natural debris in space. Member
agencies include ESA, NASA, European national agencies and the Russian,
Chinese, Canadian, Japanese, Ukrainian and Indian space agencies.

ESA contributed data and analysis

In recent years, IADC members have developed a data communication network
specifically supporting hazardous reentry risk assessment, which allows the
exchange of tracking data and the refinement of reentry predictions.

ESA contributed data to the campaign and conducted analysis of pooled
contributions. The server for the network is located at ESOC, ESA's Space
Operations Centre, where it is managed by the Space Debris Office.

In addition to the Agency's decades-long and continuing involvement in space
debris research, including modelling, protection and mitigation of debris,
ESA in 2009 launched the Space Situational Awareness (SSA) Preparatory
Programme.

SSA -- detect, predict and asset risks

SSA aims to increase Europe's capabilities to detect, predict and assess the
risk to life and property for human-made space objects, reentries, on-orbit
collisions, potential impacts of Near-Earth Objects, and the effects of
space weather.

"The SSA programme aims to develop and enhance European capabilities to
provide accurate tracking of potentially hazardous space objects," says
Nicolas Bobrinsky, Head of the SSA Office.

"This will increase warning times and boost prediction accuracy, helping
civil authorities to react in the most appropriate manner, protecting people
and property on Earth."


2. Vesta Likely Cold and Dark Enough for Ice
Posted by: "Ron Baalke" baalke@...
Wed Jan 25, 2012 4:40 pm (PST)

http://www.jpl.nasa.gov/news/news.cfm?release=2012-024

Vesta Likely Cold and Dark Enough for Ice
Jet Propulsion Laboratory
January 25, 2012

Though generally thought to be quite dry, roughly half of the giant
asteroid Vesta is expected to be so cold and to receive so little
sunlight that water ice could have survived there for billions of years,
according to the first published models of Vesta's average global
temperatures and illumination by the sun.

"Near the north and south poles, the conditions appear to be favorable
for water ice to exist beneath the surface," says Timothy Stubbs of
NASA's Goddard Space Flight Center in Greenbelt, Md., and the University
of Maryland, Baltimore County. Stubbs and Yongli Wang of the Goddard
Planetary Heliophysics Institute at the University of Maryland published
the models in the January 2012 issue of the journal Icarus. The models
are based on information from telescopes including NASA's Hubble Space
Telescope.

Vesta, the second-most massive object in the asteroid belt between Mars
and Jupiter, probably does not have any significant permanently shadowed
craters where water ice could stay frozen on the surface all the time,
not even in the roughly 300-mile-diameter (480-kilometer-diameter)
crater near the south pole, the authors note. The asteroid isn't a good
candidate for permanent shadowing because it is tilted on its axis at
about 27 degrees, which is even greater than Earth's tilt of roughly 23
degrees. In contrast, the moon, which does have permanently shadowed
craters, is tilted at only about 1.5 degrees. As a result of its large
tilt, Vesta has seasons, and every part of the surface is expected to
see the sun at some point during Vesta's year.

The presence or absence of water ice on Vesta tells scientists something
about the tiny world's formation and evolution, its history of
bombardment by comets and other objects, and its interaction with the
space environment. Because similar processes are common to many other
planetary bodies, including the moon, Mercury and other asteroids,
learning more about these processes has fundamental implications for our
understanding of the solar system as a whole. This kind of water ice is
also potentially valuable as a resource for further exploration of the
solar system.

Though temperatures on Vesta fluctuate during the year, the model
predicts that the average annual temperature near Vesta's north and
south poles is less than roughly minus 200 degrees Fahrenheit (145
kelvins). That is the critical average temperature below which water ice
is thought to be able to survive in the top 10 feet or so (few meters)
of the soil, which is called regolith.

Near Vesta's equator, however, the average yearly temperature is roughly
minus 190 degrees Fahrenheit (150 kelvins), according to the new
results. Based on previous modeling, that is expected to be high enough
to prevent water from remaining within a few meters of the surface. This
band of relatively warm temperatures extends from the equator to about
27 degrees north and south in latitude.

"On average, it's colder at Vesta's poles than near its equator, so in
that sense, they are good places to sustain water ice," says Stubbs.
"But they also see sunlight for long periods of time during the summer
seasons, which isn't so good for sustaining ice. So if water ice exists
in those regions, it may be buried beneath a relatively deep layer of
dry regolith."

The modeling also indicates that relatively small surface features, such
as craters measuring around 6 miles (10 kilometers) in diameter, could
significantly affect the survival of water ice. "The bottoms of some
craters could be cold enough on average -- about 100 kelvins -- for
water to be able to survive on the surface for much of the Vestan year
[about 3.6 years on Earth]," Stubbs explains. "Although, at some point
during the summer, enough sunlight would shine in to make the water
leave the surface and either be lost or perhaps redeposit somewhere else."

So far, Earth-based observations suggest that the surface of Vesta is
quite dry. However, the Dawn spacecraft is getting a much closer view.
Dawn is investigating the role of water in the evolution of planets by
studying Vesta and Ceres, two bodies in the asteroid belt that are
considered remnant protoplanets - baby planets whose growth was
interrupted when Jupiter formed.

Dawn is looking for water using the gamma ray and neutron detector
(GRaND) spectrometer, which can identify hydrogen-rich deposits that
could be associated with water ice. The spacecraft recently entered a
low orbit that is well suited to collecting gamma ray and neutron data.

"Our perceptions of Vesta have been transformed in a few months as the
Dawn spacecraft has entered orbit and spiraled closer to its surface,"
says Lucy McFadden, a planetary scientist at NASA Goddard and a Dawn
mission co-investigator. "More importantly, our new views of Vesta tell
us about the early processes of solar system formation. If we can detect
evidence for water beneath the surface, the next question will be is it
very old or very young, and that would be exciting to ponder."

The modeling done by Stubbs and Wang, for example, relies on information
about Vesta's shape. Before Dawn, the best source of that information
was a set of images taken by NASA's Hubble Space Telescope in 1994 and
1996. But now, Dawn and its camera are getting a much closer view of Vesta.

"The Dawn mission gives researchers a rare opportunity to observe Vesta
for an extended period of time, the equivalent of about one season on
Vesta," says Stubbs. "Hopefully, we'll know in the next few months
whether the GRaND spectrometer sees evidence for water ice in Vesta's
regolith. This is an important and exciting time in planetary exploration."

Dawn's mission to Vesta and Ceres is managed by NASA's Jet Propulsion
Laboratory, Pasadena, Calif., for NASA's Science Mission Directorate in
Washington. JPL is a division of the California Institute of Technology
in Pasadena. Dawn is a project of the directorate's Discovery Program,
managed by NASA's Marshall Space Flight Center in Huntsville, Ala. UCLA
is responsible for overall Dawn mission science. Orbital Sciences Corp.
in Dulles, Va., designed and built the spacecraft. The German Aerospace
Center, the Max Planck Institute for Solar System Research, the Italian
Space Agency and the Italian National Astrophysical Institute are
international partners on the mission team. The asteroid modeling by
Stubbs and Wang is an extension of analysis originally applied to the
moon and partially funded by the NASA Lunar Science Institute.

Jia-Rui C. Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jccook@...

Elizabeth Zubritsky 301-614-5438
Goddard Space Flight Center, Greenbelt, Md.
elizabeth.a.zubritsky@...

2012-024


Messages in this topic (1)
3. MRO HiRISE Images - January 25, 2012
Posted by: "Ron Baalke" baalke@...
Wed Jan 25, 2012 4:42 pm (PST)

MARS RECONNAISSANCE ORBITER HIRISE IMAGES
January 25, 2012

o Double Layer Ejecta in an Arabia Region Crater
http://hirise.lpl.arizona.edu/ESP_024872_2175

After an impact, there sometimes multiple phases of material
that fall to the ground, creating the appearance of layered-ejecta.

o Fluvial Fan on a Crater Floor
http://hirise.lpl.arizona.edu/ESP_024887_2155

This observation shows a terrific fan-shaped deposit, beginning
where the channel enters a crater.

o Dune Composition
http://hirise.lpl.arizona.edu/ESP_025042_1375

Patterns of dune erosion and deposition provide insight into the
sedimentary history of the surrounding terrain.

o Very Fresh Impact Crater Superposing a Wrinkle Ridge in Hesperia Planum
http://hirise.lpl.arizona.edu/ESP_025237_1600

Wrinkle ridges are long, winding topographic highs and are often
characterized by a broad arch with superposed narrow asymmetric ridges.

All of the HiRISE images are archived here:

http://hirise.lpl.arizona.edu/

Information about the Mars Reconnaissance Orbiter is
online at http://www.nasa.gov/mro. The mission is
managed by NASA's Jet Propulsion Laboratory, a division
of the California Institute of Technology, for the NASA
Science Mission Directorate, Washington, D.C. Lockheed
Martin Space Systems, of Denver, is the prime contractor
and built the spacecraft. HiRISE is operated by the
University of Arizona. Ball Aerospace and Technologies
Corp., of Boulder, Colo., built the HiRISE instrument.

A list for asteroid and comet researcher


----- Original Message -----
From: mpml@yahoogroups.com
To: mpml@yahoogroups.com
Sent: Saturday, February 04, 2012 4:10 AM
Subject: {MPML} Digest Number 4046


A list for asteroid and comet researcher


Mission to Land on a Comet (Rosetta)
Posted by: "Ron Baalke" baalke@...
Fri Feb 3, 2012 2:58 pm (PST)

http://science.nasa.gov/science-news/science-at-nasa/2012/02feb_rosetta/

Mission to Land on a Comet
NASA Science News
February 2, 2012

Europe's Rosetta spacecraft is en route to intercept a comet - and to make
history. In 2014, Rosetta will enter orbit around comet
67P/Churyumov-Gerasimenkoand land a probe on it, two firsts.

Rosetta's goal is to learn the primordial story a comet tells as it
gloriously falls to pieces.

Comets are primitive leftovers from our solar system's 'construction'
about 4.5 billion years ago. Because they spend much of their time in
the deep freeze of the outer solar system, comets are well preserved - a
gold mine for astronomers who want to know what conditions were like
back "in the beginning."

As their elongated orbits swing them closer to the sun, comets transform
into the most breathtaking bodies in the night sky. A European Space
Agency mission launched in 2004 with U.S. instruments on board, Rosetta
will have a front-row seat for the metamorphosis.

What we know of comets so far comes from a handful of flyby missions.

"In some ways, a flyby is just a tantalizing glimpse of a comet at one
stage in its evolution," says Claudia Alexander, project scientist for
the U.S. Rosetta Project at JPL. "Rosetta is different. It will orbit
67P for 17 months. We'll see this comet evolve right before our eyes as we
accompany it toward the sun and back out again."

Fierce solar heat will have a profound effect on Rosetta's target.
"We'll watch the comet start as just a little nugget in space and then
become something poetic and beautiful, trailing a vast tail."

At the moment, Rosetta is "resting up" for the challenges ahead. It's
hibernating, engaged in its high-speed chase while fast asleep.

Reveille is on or around New Year's Day 2014, when the spacecraft begins
a months-long program of self-checkups.

If all goes well, in August of the same year, Rosetta will enter orbit
around 67P's nucleus and begin scanning its surface for a landing site.
Once a site is chosen, the spacecraft will descend as low as 1 km to
deploy the lander.

The lander's name is "Philae" after an island in the Nile, the site of
an obelisk that helped decipher - you guessed it - the Rosetta Stone.

Touchdown is scheduled for November 2014, when Philae will make the
first ever controlled landing on a comet's nucleus.

"When we land, the comet could already be active!" says Alexander.
Because a comet has little gravity, the lander will anchor itself with
harpoons. "The feet may drill into something crunchy like permafrost, or
maybe into something rock solid," she speculates.

Once it is fastened, the lander will commence an unprecedented
first-hand study of a comet's nucleus. Among other things, it will
gather samples for examination by automatic onboard microscopes and take
panoramic images of the comet's terrain from ground level.

Meanwhile, orbiting overhead, the Rosetta spacecraft will be busy, too.
Onboard sensors will map the comet's surface and magnetic field, monitor
the comet's erupting jets and geysers, measure outflow rates, and much
more. Together, the orbiter and lander will build up the first 3D
picture of the layers and pockets under the surface of a comet.

The results should tell quite a story indeed.

Author:Dauna Coulter
Editor: Dr. Tony Phillips
Credit: Science@NASA

The following true story won front page coverage in the San Diego Union
Tribune, The Daily Californian, The Beach & Bay Press and GOOD TIMES Magazine.
It was featured as well in The Los Angeles Times, SLAMM Magazine and The
National Examiner. It was also the subject of over 27 radio interviews across
the United States and Canada and was highlighted in a special on KFMB CBS
Channel 8.

      On July 1 1990, 10 airborne craft were accidentally photographed hovering
over the San Diego River Valley in a clear daylight 35mm photo. A detailed
analysis of the enlargements revealed a hidden code in the form of a repeating
pattern on one of the objects that successfully linked UFOs to each other as
well as to ancient artifacts from around the world and the Nazca Lines in Peru.
Known as the "Inaja UFO Photo" it recently completed a year long tour as proof
of Aliens and UFOs at the "Science of Aliens" exhibit at the San Diego Air &
Space Museum and has been the subject of numerous front page features most
recently a July 4th 2011 front page article in the San Diego Union Tribune by
Senior Writer John Wilkens 619-293-2236. Mr. Wilkens had seen the evidence on my
non-profit website and Youtube video that the Los Angeles Times and CBS News had
labeled "Unsettling."

       Numerous ancient artifacts from around the world including ancient sites
like Giza, Stonehenge, Petra and Nazca all have the same signature projecting
acorn or triangular shape that match five separate UFO photos. Even the Russians
were convinced of the legitimacy of this discovery as Marina Popovitch, a famous
Russian test pilot, held up the "Inaja UFO photo" during her TV interview on ABC
KGTV Channel 10. This event will hopefully have a profound effect on the search
for E.T. and expand the consciousness of our civilization concerning this
important topic. Furthermore an extreme enlargement of the formation reveals a
thin "beam" entering from above and piercing the middle of one of the objects
and continuing down to the ground. This is most likely a communication device.
This enlargement is available upon request. For more info Google "Mike Orrell"
or "Inaja UFO Photo."  Any comments would be most welcome.  Best regards  Mike
Orrell  orre@...

http://www.orreman7.com/BestUFOphotoever.html
http://www.youtube.com/watch?v=YbszqFRYaVY

What the fuck is this crap doing in this newsgroup???

Pardon my French

--- In nyswa@yahoogroups.com, <orre@...> wrote:
>
>
>      The following true story won front page coverage in the San Diego Union
Tribune, The Daily Californian, The Beach & Bay Press and GOOD TIMES Magazine.
It was featured as well in The Los Angeles Times, SLAMM Magazine and The
National Examiner. It was also the subject of over 27 radio interviews across
the United States and Canada and was highlighted in a special on KFMB CBS
Channel 8.
>
>      On July 1 1990, 10 airborne craft were accidentally photographed hovering
over the San Diego River Valley in a clear daylight 35mm photo. A detailed
analysis of the enlargements revealed a hidden code in the form of a repeating
pattern on one of the objects that successfully linked UFOs to each other as
well as to ancient artifacts from around the world and the Nazca Lines in Peru.
Known as the "Inaja UFO Photo" it recently completed a year long tour as proof
of Aliens and UFOs at the "Science of Aliens" exhibit at the San Diego Air &
Space Museum and has been the subject of numerous front page features most
recently a July 4th 2011 front page article in the San Diego Union Tribune by
Senior Writer John Wilkens 619-293-2236. Mr. Wilkens had seen the evidence on my
non-profit website and Youtube video that the Los Angeles Times and CBS News had
labeled "Unsettling."
>
>       Numerous ancient artifacts from around the world including ancient sites
like Giza, Stonehenge, Petra and Nazca all have the same signature projecting
acorn or triangular shape that match five separate UFO photos. Even the Russians
were convinced of the legitimacy of this discovery as Marina Popovitch, a famous
Russian test pilot, held up the "Inaja UFO photo" during her TV interview on ABC
KGTV Channel 10. This event will hopefully have a profound effect on the search
for E.T. and expand the consciousness of our civilization concerning this
important topic. Furthermore an extreme enlargement of the formation reveals a
thin "beam" entering from above and piercing the middle of one of the objects
and continuing down to the ground. This is most likely a communication device.
This enlargement is available upon request. For more info Google "Mike Orrell"
or "Inaja UFO Photo."  Any comments would be most welcome.  Best regards  Mike
Orrell  orre@...
>
> http://www.orreman7.com/BestUFOphotoever.html
> http://www.youtube.com/watch?v=YbszqFRYaVY
>

I heartily agree that it's crap. Still, I didn't feel the need to censor it. If
enough people object to it, I'll reject future posts of this nature as spam.

Bruce

--- In nyswa@yahoogroups.com, antoine_ny <no_reply@...> wrote:
>
> What the fuck is this crap doing in this newsgroup???
>
> Pardon my French
>
> --- In nyswa@yahoogroups.com, <orre@> wrote:
> >
> >
> >      The following true story won front page coverage in the San Diego Union
Tribune, The Daily Californian, The Beach & Bay Press and GOOD TIMES Magazine.
It was featured as well in The Los Angeles Times, SLAMM Magazine and The
National Examiner. It was also the subject of over 27 radio interviews across
the United States and Canada and was highlighted in a special on KFMB CBS
Channel 8.
> >
> >      On July 1 1990, 10 airborne craft were accidentally photographed
hovering over the San Diego River Valley in a clear daylight 35mm photo. A
detailed analysis of the enlargements revealed a hidden code in the form of a
repeating pattern on one of the objects that successfully linked UFOs to each
other as well as to ancient artifacts from around the world and the Nazca Lines
in Peru. Known as the "Inaja UFO Photo" it recently completed a year long tour
as proof of Aliens and UFOs at the "Science of Aliens" exhibit at the San Diego
Air & Space Museum and has been the subject of numerous front page features most
recently a July 4th 2011 front page article in the San Diego Union Tribune by
Senior Writer John Wilkens 619-293-2236. Mr. Wilkens had seen the evidence on my
non-profit website and Youtube video that the Los Angeles Times and CBS News had
labeled "Unsettling."
> >
> >       Numerous ancient artifacts from around the world including ancient
sites like Giza, Stonehenge, Petra and Nazca all have the same signature
projecting acorn or triangular shape that match five separate UFO photos. Even
the Russians were convinced of the legitimacy of this discovery as Marina
Popovitch, a famous Russian test pilot, held up the "Inaja UFO photo" during her
TV interview on ABC KGTV Channel 10. This event will hopefully have a profound
effect on the search for E.T. and expand the consciousness of our civilization
concerning this important topic. Furthermore an extreme enlargement of the
formation reveals a thin "beam" entering from above and piercing the middle of
one of the objects and continuing down to the ground. This is most likely a
communication device. This enlargement is available upon request. For more info
Google "Mike Orrell" or "Inaja UFO Photo."  Any comments would be most welcome. 
Best regards  Mike Orrell  orre@
> >
> > http://www.orreman7.com/BestUFOphotoever.html
> > http://www.youtube.com/watch?v=YbszqFRYaVY
> >
>

It is of course spam, but perhaps this is a good time to talk as a group about
the best ways to teach science and why suc things are not newsworthy.  Perhaps
it's time for an "Occupy" movement of our own.  pushing back on all this
nonsense.

Well, maybe this will inspire some more members of this group to begin posting.
Jason and I are very nearly the only ones who post here.

Bruce

--- In nyswa@yahoogroups.com, "Jason Shiling Kendall" <jkendall@...> wrote:
>
> It is of course spam, but perhaps this is a good time to talk as a group about
the best ways to teach science and why suc things are not newsworthy.  Perhaps
it's time for an "Occupy" movement of our own.  pushing back on all this
nonsense.
>

We're keeping up the good fight.

Anyway, along the lines of getting people to come out, I hope people will join
Astrobeer tonight at 6pm at the Carriage House at 59th and 3rd in Manhattan. 
We'll try to take over the front area.

Jason

A list for asteroid and comet researcher



----- Original Message -----
From: mpml@yahoogroups.com
To: mpml@yahoogroups.com
Sent: Thursday, February 09, 2012 4:11 AM
Subject: {MPML} Digest Number 4051


A list for asteroid and comet researcher
Messages In This Digest (1 Message)
1. NASA's Chandra Finds Milky Way's Black Hole Grazing on Asteroids From:
Ron Baalke
View All Topics | Create New Topic Message
1. NASA's Chandra Finds Milky Way's Black Hole Grazing on Asteroids
Posted by: "Ron Baalke" baalke@...
Wed Feb 8, 2012 1:13 pm (PST)

Feb. 8, 2012

Trent J. Perrotto
Headquarters, Washington
202-358-0321
trent.j.perrotto@...

Megan Watzke
Chandra X-ray Center, Cambridge, Mass.
617-496-7998
mwatzke@...

RELEASE: 12-049

NASA'S CHANDRA FINDS MILKY WAY'S BLACK HOLE GRAZING ON ASTEROIDS

WASHINGTON -- The giant black hole at the center of the Milky Way may
be vaporizing and devouring asteroids, which could explain the
frequent flares observed, according to astronomers using data from
NASA's Chandra X-ray Observatory.

For several years Chandra has detected X-ray flares about once a day
from the supermassive black hole known as Sagittarius A*, or "Sgr A*"
for short. The flares last a few hours with brightness ranging from a
few times to nearly one hundred times that of the black hole's
regular output. The flares also have been seen in infrared data from
ESO's Very Large Telescope in Chile.

"People have had doubts about whether asteroids could form at all in
the harsh environment near a supermassive black hole," said Kastytis
Zubovas of the University of Leicester in the United Kingdom, and
lead author of the report appearing in the Monthly Notices of the
Royal Astronomical Society. "It's exciting because our study suggests
that a huge number of them are needed to produce these flares."

Zubovas and his colleagues suggest there is a cloud around Sgr A*
containing trillions of asteroids and comets, stripped from their
parent stars. Asteroids passing within about 100 million miles of the
black hole, roughly the distance between the Earth and the sun, would
be torn into pieces by the tidal forces from the black hole.

These fragments then would be vaporized by friction as they pass
through the hot, thin gas flowing onto Sgr A*, similar to a meteor
heating up and glowing as it falls through Earth's atmosphere. A
flare is produced and the remains of the asteroid are swallowed
eventually by the black hole.

"An asteroid's orbit can change if it ventures too close to a star or
planet near Sgr A*," said co-author Sergei Nayakshin, also of the
University of Leicester. "If it's thrown toward the black hole, it's
doomed."

The authors estimate that it would take asteroids larger than about
six miles in radius to generate the flares observed by Chandra.
Meanwhile, Sgr A* also may be consuming smaller asteroids, but these
would be difficult to spot because the flares they generate would be
fainter.

These results reasonably agree with models estimating of how many
asteroids are likely to be in this region, assuming that the number
around stars near Earth is similar to the number surrounding stars
near the center of the Milky Way.

"As a reality check, we worked out that a few trillion asteroids
should have been removed by the black hole over the 10-billion-year
lifetime of the galaxy," said co-author Sera Markoff of the
University of Amsterdam in the Netherlands. "Only a small fraction of
the total would have been consumed, so the supply of asteroids would
hardly be depleted."

Planets thrown into orbits too close to Sgr A* also should be
disrupted by tidal forces, although this would happen much less
frequently than the disruption of asteroids, because planets are not
as common. Such a scenario may have been responsible for a previous
X-ray brightening of Sgr A* by about a factor of a million about a
century ago. While this event happened many decades before X-ray
telescopes existed, Chandra and other X-ray missions have seen
evidence of an X-ray "light echo" reflecting off nearby clouds,
providing a measure of the brightness and timing of the flare.

"This would be a sudden end to the planet's life, a much more dramatic
fate than the planets in our solar system ever will experience,"
Zubovas said.

Very long observations of Sgr A* will be made with Chandra later in
2012 that will give valuable new information about the frequency and
brightness of flares and should help to test the model proposed here
to explain them. This work could improve understanding about the
formation of asteroids and planets in the harsh environment of Sgr
A*.

NASA's Marshall Space Flight Center in Huntsville, Ala., manages the
Chandra program for NASA's Science Mission Directorate in Washington.
The Smithsonian Astrophysical Observatory controls Chandra's science
and flight operations from Cambridge, Mass.

For Chandra images, multimedia and related materials, visit:

http://www.nasa.gov/chandra

For an additional interactive image, podcast, and video on the
finding, visit:

http://chandra.si.edu

-end-

A list for asteroid and comet researcher


----- Original Message -----
From: mpml@yahoogroups.com
To: mpml@yahoogroups.com
Sent: Wednesday, February 15, 2012 4:13 AM
Subject: {MPML} Digest Number 4056


NASA Reaches Higher With Fiscal Year 2013 Budget Request From: Ron Baalke
Posted by: "Ron Baalke" baalke@...
Tue Feb 14, 2012 1:32 pm (PST)

Feb. 13, 2012

David Weaver
Headquarters, Washington
202-358-1600
david.s.weaver@...

RELEASE: 12-051

NASA REACHES HIGHER WITH FISCAL YEAR 2013 BUDGET REQUEST

WASHINGTON -- NASA announced Monday a $17.7 billion budget request for
fiscal year 2013 supporting an ambitious program of space exploration
that will build on new technologies and proven capabilities to expand
America's reach into the solar system.

Despite a constrained fiscal environment, the NASA FY13 budget
continues to implement the space science and exploration program
agreed to by President Obama and a bipartisan majority in Congress,
laying the foundation for ground-breaking discoveries here on Earth
and in deep space, including new destinations, such as an asteroid
and Mars by 2035.

"This budget in-sources jobs, creates capabilities here at home -- and
strengthens our workforce, all while opening the next great chapter
in American exploration," NASA Administrator Charles Bolden said.
"And as we reach for new heights in space, we're creating new jobs
right here on Earth, helping to support an economy that's built to
last."

The NASA budget includes $4 billion for space operations and $4
billion for exploration activities in the Human Exploration
Operations mission directorate, including close-out of the Space
Shuttle Program, and funding for the International Space Station,
$4.9 billion for science, $669 million for space technology and $552
million for aeronautics research.

"This budget puts us on course to explore farther into space than ever
before, revealing the unknown and fueling the nation's economy for
years to come," Deputy Administrator Lori Garver said. "We are
committed to ensuring that our astronauts are once again launched
from U.S. soil on American-made spacecraft, and this budget provides
the funds to make this a reality."

The budget supports NASA's continued work to develop the Space Launch
System, a new heavy-lift rocket to carry astronauts to destinations
such as an asteroid and Mars, and the Orion crew capsule in which
they will travel. Included are resources for final preparation and
manufacturing milestones for Orion's 2014 Exploration Flight Test 1
and preliminary design reviews of major Space Launch System elements.

NASA has prioritized funding for its partnership with the commercial
space industry to facilitate crew and cargo transport to the station.
The $830 million for this work in the FY13 budget advances progress
towards a vibrant space industry that will create well-paying,
high-tech jobs to the U.S. economy, and reduce America's reliance on
foreign systems.

The budget also enhances use of the International Space Station to
improve life on Earth and help make the next great leaps in
scientific discovery and exploration.

NASA's science budget supports a balanced portfolio of innovative
science missions that will reach farther into our solar system,
reveal unknown aspects of our universe, and provide critical data
about our home planet. The agency will continue to develop and
conduct critical tests on the James Webb Space Telescope leading to
its planned launch in 2018. As the successor to Hubble Space
Telescope, James Webb again will revolutionize our understanding of
the universe. NASA also is developing an integrated strategy to
ensure the next steps for the robotic Mars Exploration Program will
support science as well as long-term human exploration goals.

Space Technology work supported in the budget will drive advances in
new high-payoff space technologies such as laser communications and
zero-gravity propellant transfer, seeding innovation that will expand
our capabilities in the skies and in space, supporting economic
vitality, lowering the cost of other government and commercial space
activities, and helping to create new jobs and expand opportunities
for a skilled workforce.

NASA supports its commitment to enhancing aviation safety and airspace
efficiency, and reducing the environmental impact of aviation by
helping to accelerate the nation's transition to the Next Generation
Air Transportation System through investments in revolutionary
concepts for air vehicles and air traffic management.

"The 2013 budget moves us forward into tangible implementation of a
sustainable and affordable exploration program," NASA's Chief
Financial Officer Elizabeth Robinson said.

The NASA budget and supporting information are available at:

http://www.nasa.gov/budget

-end-