> The fact of being able to put some numbers on a poor orbit does not
> change the fact that as far as I know, the last major asteroid impact
> was hundred of thousands of years ago, and we don't have that many
> proofs of asteroid impacts happening every week end, or every year or
> century for that matter.

Are you saying that you'd rather not know about the next Tunguska
event?  Someone in Siberia might consider it a "major asteroid impact".
After all, if you get killed by it, does it matter whether the rock
was 50 meters or 500 meters in diameter?

Of course I would, but I know that with the current set of telescopes it
is very unlikely we will detect it before impact.
See the table at bottom of this page :
http://astrosurf.com/maury/asteroides/spaceguard/index.html

In the scale of asteroid impacts, it is as you know rather on the small
end. If I were to receive an meteorite on the head, it would of course
be for me a major impact :)
Alain

> Did JPL actually make a press release, as opposed to simply putting a
> statement on a web page?  There is a difference between making information
> available on a web page, which is passive in the sense that interested
> parties have to go and get it, and issuing a press release, which is
> active in the sense that various media are contacted and provided with
> information that they may or may not choose to use in their regular
> disseminations to the public.

Good point; I couldn't find anywhere where it was pushed out.

>> Perhaps the Torino scale for the public should be collapsed into Green,
>> Yellow, Orange, Red colors?
> It has been color coded.  See http://neo.jpl.nasa.gov/torino_scale1.html

I know. By "collapsed" I meant the actual scale numbers removed; thus the
scale would be color coded only: white, green (with hazards that would have
been TS1-4 as part of green), yellow, orange, red (with yellow, orange and
red mapped across TS 5-10 as appropriate).

Is the "precision" of 0-10 needed for the public? One could argue it is
already too confusing for "Joe Sixpack" with all of the caveats and
footnotes.

Having the footnote that yellow as "meriting attention by astronomers" seems
contradictory to the purpose of the scale (to inform the public about the
level of threat/risk).

If the public need not be concerned about a TS1-4, why is that band
"yellow"?

Glenn

> Now this is the kind of stuff I would like to see in magazines
> dedicated to astronomy.

Working on it.  I've been given some motivation to proceed with
my proposal, and prior to heading off for a New Years party, I
put a few more words into the word processer.

> Yes; think of the Earth inside of an error ellipse.  If the Earth
> is centered in that ellipse, then as the size of the ellipse
> shrinks (as the orbit is improved), the Earth remains inside and
> the ratio of the Earth cross-sectional area to the area of the
> ellipse increases.  If the Earth is near the edge of the ellipse,
> then as the size of the ellipse shrinks, the Earth can suddenly
> find itself outside the ellipse.  The former corresponds to the
> impact probability increasing, and the latter corresponds to the
> impact probability decreasing.
>
> Now, the example is crude and for illustrative purposes only.  In
> reality, the ellipse should be replaced by a probabilty density
> whose contours would be elliptical in shape, with highest density
> in the center of those contours and gradually decreasing outward.

Thanks to Alan and Dave, who attempted, despite the non-graphic nature of the
list, to explain the situation. Thanks also to Genny, who pointed me to a very
clear, graphic illustration here, with textual explanation, here:
http://spaceguard.esa.int/NScience/neo/neo-when/previsions.htm

Now this is the kind of stuff I would like to see in magazines dedicated to
astronomy.

- Greg

>> Are you saying that you'd rather not know about the next Tunguska
>> event?  Someone in Siberia might consider it a "major asteroid impact".
>> After all, if you get killed by it, does it matter whether the rock
>> was 50 meters or 500 meters in diameter?

> This is the main problem, you guys believe really that we are bound for
> an impact,

In the long term, yes; don't you?

My high school physics teacher used to say "In probability, there is
certainty; in randomness, there is order."  Given a long enough time
span, the probability of the Earth being hit by something of a given
size becomes large enough that you can say with fairly high confidence
that it will occur.  For example, given a time span of a few minutes,
we can be quite confident that a meteor occurred somewhere in the
Earth's atmosphere.  I don't need to tell you how the impact frequency
drops with increasing size.

> and moreover that with a setup of lousy D~1m telescopes, we
> will detect it in time.

No, I have no illusions of being able to detect the next Tunguska.
Current resources do allow us to detect objects smaller than
Tunguska, but invariably the arcs are short, therefore our ability
to predict a future collision with such a small object is virtually
nonexistent.  Objects as large as Tunguska can be followed for a
longer time, as I have done with SG344, and could potentially be
used for an impact prediction, though the chances of stumbling onto
the next Tunguska are still vanishingly small with current survey
instruments.

> You are dreaming. Again, get your feet back on
> the ground. You and I will very likely die from a cancer of the
> infarctus, or a version of it, like everybody else :).

Are you thinking of changing fields and becoming a cancer
researcher?

----- Original Message -----
From: "Glenn Wallace" <glenn@...>
To: <mpml@yahoogroups.com>
Sent: Friday, December 31, 2004 9:16 AM
Subject: Re: {MPML} Earth's Axis Shift: a scientific explanation from UAI
physicist


>
> > http://www.uai.it/index.php?tipo=A&id=670
> >
> > I think this one of the clearest contributions to the
> > public understanding of the event.
>
> A diagram would have been more useful than a picture of the south pole.
>
>
Almost anything.  I can follow it but my wife hasn't a clue.  Do experts
really need to be told these things?  Couldn't they have just said it didn't
change the rotation but did change ever so slightly the axis upon which that
rotation occurs?  Day has changed on the ground by a miniscule amount.
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> MPML is supported in part via the 2002 Shoemaker NEO Grant Program of The
Planetary Society (http://www.planetary.org)
>
> NOTICE: Material quoted or re-posted from the Minor Planet Mailing List
should be proceeded
> by the following attribution:
>
> FROM THE MINOR PLANET MAILING LIST [date]. For the full text or to
subscribe, please visit:
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> MPML FAQ: http://www.bitnik.com/mp/MPML-FAQ.html
> Yahoo! Groups Links
>
>
>
>
>
>
>

> Just a footnote here.

> The real danger is that the media and the public become blase about
> these reports.

There are two sides about this phrase. If indeed we continue ringing the
alarm bell something like once a year, just to maintain a good shape,
people will know we are fools, and will not care about it anymore, apart
of course from all the end of the world lunatics which we will feed. On
the other hand, if we don't talk about them, it will be business as
usual, nobody will know about asteroid impacts, as they should. The fact
that we are able to detect them will not make the impact any more
frequent, therefore don't hold your breath, it is not going to happen
anytime soon.
If asteroid impacts were anywhere near as frequent as earthquakes, they
would require a similar treatment. We are talking about things happening
every centuries, or thousands of years. The number of close approaches
are incredibly higher than the real impact. Objects going somewhere on
the torino scare are the close approaches of the future, not the future
impacts. In all probabilities, of course.

> Are you saying that you'd rather not know about the next Tunguska
> event?  Someone in Siberia might consider it a "major asteroid
impact".
> After all, if you get killed by it, does it matter whether the rock
> was 50 meters or 500 meters in diameter?

This is the main problem, you guys believe really that we are bound for
an impact, and moreover that with a setup of lousy D~1m telescopes, we
will detect it in time. You are dreaming. Again, get your feet back on
the ground. You and I will very likely die from a cancer of the
infarctus, or a version of it, like everybody else :).

On another question (binary scale adapted to Indian ocean earthquake),
imagine that every magnitude 4 earthquake in the region would have
created a tsunami alert on the tsurino scale (if there had been an alert
system), very likely people would have either not cared, or gone to the
beach to see the tsunami. Again different risk, one which really kills
real people, and another one, which is very very very rare, and which we
can predict in a binary fashion, if we don't rush into announcing the
results of our beautiful calculations. While earthquakes can not be
predicted (we know where they have happened and are bound to happen
again but that's it), asteroid impacts can. In the case of the Indian
ocean tsunami, a binary system was possible. There were several hours
between the earthquake and the arrival of the tsunami in Sri Lanka for
example. Some sirens ringing would have been enough to save several
thousands of people, if not everybody (maybe in the Aceh province the
time delay was too short).
The only problem with the asteroids is that you want (or I least I want)
to avoid false alarms (created by correct calculations of course) every
year. I think it would be rather cynical to consider this type of crying
wolf behaviour as a good way to maintain public attention, and therefore
funding. I don't agree with the statement that 1 in 37 impact
probability meant 36 in 37 it would go away. The probability that we
detect an impacting object is right now in the 10-5, and therefore in
reality, everytime, the objects will go high on the torino scale and go
down. I think Brian Marsden's suggestion of waiting a certain amount of
time, for example 0.02 or 0.05 the time between the discovery of the
possible impactor and the date of the possible impact is a wise one. It
would have meant 1.25 years for this object. It will very likely allow
to bring the probability of impact to 0. If we are not so eager to
communicate immediately (of course, feeding the lunatics is important
too), we can very easily go into a binary scheme, which will have for
results that we will only announce secure things, as far as possible.

I was also thinking about the next false alarm. The one where it will
momentarily reach 6 on the Torino scale, then 8, then 8.5... this
"numbers can't lie attitude" is really a very stupid way to handle the
situation.
Be calm, wait till you have a good orbit (inform the observers of
course), and then, if in the very unlikely event there would be really
an impact in the next 50 years, talk to the UN or other organism.
Happy new year to all of you.
Alain

> Fascinating debate about 2004 MN4.
>
> I wrote:
>
> The weather people say that their satellite images show it might rain
> in Hampshire later today. Later those same weather maps show the
> chance of that happening has declined or gone away. It was a false
> alarm and no data was faulty or fraudulent.
>
> Dave Tholen replied:
>
> "I disagree; the word "might" leaves open the possibility of "might not".
> If it does not rain, then there was nothing false about the alarm.  To
> revisit my hurricane example, if landfall does indeed occur between
> Melbourne and Daytona Beach, does that make the previous day's estimate of
> Miami to Jacksonville a false alarm for the people of Miami?  Not at all.
> The forecast said landfall would be between points A and B, and indeed
> landfall was somewhere between points A and B.  The alarm was not false, but
> the residents of Miami are relieved."
>
> I wrote:
>
> Sure there is the strong possibility
> that further observations will reduce the chances of an impact (that's
> a reasonable assumption but only an assumption). That's what happened.
> The subsequent observations did neither invalidate the position that
> led to the
> 1 - 37 assessment nor the concern/alarm it merited. The alarm was
> false but not unjustified.
>
> Dave Tholen replied:
>
> "First of all, I once again disagree that there was any "alarm", as least as
> far as the public is concerned.  I also disagree with the use of "false", as
> the probability calculations were cross-checked and found to be correct."
>
> **
>
> I disagree. You are adding your own provisos and qualifications to the
> simple grammatical definition of a false alarm - an alarm that was raised
> that was later recinded.

Which "provisos and qualifications" have I allegedly added to the
definition?  What "alarm" was "recinded [sic]"?  The statement noted
that the impact probability was expected to eventually drop to
effectively zero.  That's what happened.  Why would someone rescind
a correct statement?  Would a rescission of that statement mean that
the impact probability did not drop to zero?

> Sky and Telescope were quite correct in their use of the term.

Then you should have no trouble identifying what the "alarm" is and
what was "false" about it.  Nobody has done so yet, including you.
How many times does a statement have to say "no cause for public
concern" before one will admit that there is no alarm intended
(for the public)?

> Putting "might" in an alarm does not invalidate it because an
> alarm is a warning of an expectation that might, or might not, come to pass.

But you're assuming that there was an "alarm" in this case.  Where
is the alarm?  No cause for public concern.

> You say that Sky and Telescope are wrong because no alarm was raised:

Correct.

> Alarm
> 1 a warning of danger etc. (gave the alarm).

Gee, if there was some danger, you would expect the official statement
to say so, but instead, it specifically stated that there is no cause
for public concern.  In other words, there was no warning of danger,
hence this definition does not apply to this instance.

> 2 a a warning sound or device (the burglar alarm was set off accidentally).

There was no warning sounded.  Quite the opposite; the statement noted
that there was no cause for public concern.  Again, this definition
does not apply.

> b = alarm clock.

I hope that we can dismiss this definition as also not applicable to
the present case.

> 3 frightened expectation of danger or difficulty (were filled with alarm).
> v.tr.
> 1 frighten or disturb.
> 2 arouse to a sense of danger.

I'm at a loss here; why should the public be frightened by a statement
that specifically states that there is no cause for public concern?
If you wish to argue that the public was indeed frightened, despite
being told that there is no cause for public concern, then where does
the blame belong, on the statement or the reader ignoring the contents
of that statement?

> Considering this, I think an alarm was raised among many observers,

We're not talking about the observers here.  Observers were alerted to
obtain more observations.  That has been acknowledged.  It's a necessary
step in the orbit improvement process.

> journalists and possibly the public but without a survey what do any of us
> know what the public think or are alarmed about?

Well, then perhaps S&T should do a survey and find out before claiming
that there was an alarm.

> I said:
>
> On one day there was a 1 - 37 chance of an impact in 2029. This is
> certainly cause for concern and arguably  alarm.
>
> Dave Tholen replied:
>
> "Perhaps to you.  Perhaps to the NEO astronomers who need to work the issue.
> But not to the general public.  According to the wording of Torino Scale 4,
> attention by the public is merited only if the encounter is less than a
> decade away.  That wasn't the case here.  The initial NASA announcement
> specifically noted that it wasn't a cause for concern.  If you wish to be
> concerned, that's your choice, but no blame to the NEO community is
> justified, contrary to what other contributors have written."
>
> Public attention not merited!! The Torino Scale says that the public need
> only be alarmed if the impact is less than a decade away! That's a relief.
> But this assumes that the public or the media will be reassured or even
> impressed by the TS.

Not at all; it's more than just the Torino Scale that said there is no
alarm.  The statement came right out and said that there was no cause
for public concern, quite independently of any reference to the Torino
Scale.

> Actually they have the right to take it or leave it.
> 2029 is well within my lifetime and my children (and their children if they
> ever have them) so I'll be alarmed no matter what the TS or Nasa says I
> should be alarmed about.

Why?

> 1 - 37 is far, far higher than any other rock we
> have dealt with.

So what?  The Earth was bound to be better centered in an uncertainty
region sooner or later.

> I would be very alarmed if odds of 1 - 37 (even if
> transitory) applied to certain other areas of my life especially if my
> children were involved.

Why?  Can you provide an analogous example?

> In my humble opinion, the problem some scientist seem to have with
> Sky & Telescope's use of the term 'false alarm' is caused by their
> apparent assumption that language is of an exact nature, which of
> course it isn't. 'False alarm' is a well-known phrase in common
> language, without a well-defined definition (at least, various
> dictionaries differ in their description), but generally meaning some
> thing like a warning about an event that subsequently doesn't occur.
> When people use the phrase, they do not necessarily think of something
> being false in the strict sense (or something being alarming); they
> just use a well-known phrase, just like people still use the phrase of
> 'dialing a number', although telephones have no dials anymore. I believe
> publications like S&T should certainly keep communicating with the
> audience at large in common language, and to blame them for using the
> term 'false alarm' is unjust. (It reminds me of the student saying
> that her locker is empty, and the science teacher correcting her with
> the remark that it is completely full -- with air.) --Govert

If you wish to argue that the terminology is ambiguous, then we have
to rely on context to properly interpret the terminology.  In this
particular case, we also have "hype" and a history of "Chicken Little-
style" news stories.  That is the context in which "false alarm" must
be interpreted.

> 2004 MN4 seemed to increase its chances of impact and then was
> suddenly relegated to the safe bin. In my perception, increasing
> numbers of observations across a larger arc have usually led to a
> steadily decreasing chance of impact. So what orbital oddities
> caused this? Can it be explained diagrammatically?

Yes; think of the Earth inside of an error ellipse.  If the Earth
is centered in that ellipse, then as the size of the ellipse
shrinks (as the orbit is improved), the Earth remains inside and
the ratio of the Earth cross-sectional area to the area of the
ellipse increases.  If the Earth is near the edge of the ellipse,
then as the size of the ellipse shrinks, the Earth can suddenly
find itself outside the ellipse.  The former corresponds to the
impact probability increasing, and the latter corresponds to the
impact probability decreasing.

Now, the example is crude and for illustrative purposes only.  In
reality, the ellipse should be replaced by a probabilty density
whose contours would be elliptical in shape, with highest density
in the center of those contours and gradually decreasing outward.
There is no hard boundary as in the example, but I think it serves
to explain the situation.  The Earth was more centered in the
2004 MN4 uncertainty ellipse for 2029 April 13, but not perfectly
centered, so the impact probability kept going up as the ellipse
shrank in size for a longer time than you're accustomed to seeing,
but eventually the ellipse shrank to the point that the Earth was
finally "outside", and the impact probability dropped dramatically.

> Even though I agree with Dave Tholen that the fine print of the Torino scale
> makes it clear what the risk actually is (magnitude of impact, range of
> probability of impact, the likelihood of going back to TS 0 etc.), the
> public doesn't have time to digest the criteria (nor is it readily
> transmitted by the press).

Press:  take note.

> The fact that JPL/NASA even made a press release
> is some kind of a signal in and of itself, whether that was the intent or
> not.

Did JPL actually make a press release, as opposed to simply putting a
statement on a web page?  There is a difference between making information
available on a web page, which is passive in the sense that interested
parties have to go and get it, and issuing a press release, which is
active in the sense that various media are contacted and provided with
information that they may or may not choose to use in their regular
disseminations to the public.

> Perhaps the Torino scale for the public should be collapsed into Green,
> Yellow, Orange, Red colors?

It has been color coded.  See http://neo.jpl.nasa.gov/torino_scale1.html

At 06:22 AM 12/31/2004, Greg Crawford wrote:

>I think, of far more interest to many amateur astronomers than concerns about
>whether something will be perceived as a "false alarm" is the nature of how
>increasing observations extending an orbital arc can first increase, then
>decrease, the chances of impact. 2004 MN4 seemed to increase its chances of
>impact and then was suddenly relegated to the safe bin. In my perception,
>increasing numbers of observations across a larger arc have usually led to a
>steadily decreasing chance of impact. So what orbital oddities caused
>this? Can
>it be explained diagrammatically?
>
>- Greg

Since attached images are not allowed on MPML, I'll try a crude graphic to
explain.  An "error ellipse" projected far into the future is more of an
"error line" of varying thickness (probability), like this:
                                                **
                                             *      *
x     x    x   x  x xxxxxxxXXXXXXXXXXXXXXXXXXXXXXXXXXXXxxxxxxx
x  x   x    x     x
                                             *      *
                                                **

I indicate the Earth's cross section within the "ellipse with the *
circle.  Sometime later, the "error ellipse" shrinks with an improved orbit
solution:

                                                **
                                             *      *
               x    x   x  x xxxxXXXXXXXXXXXXXXXXXXXXxxxx x  x   x     x
                                             *      *
                                                **

Since the total probability sums to unity, when the "ellipse" becomes
shorter, the "probability density" goes up, and if the Earth remains in the
inner portion of the "ellipse", then the probability of impact (the
fraction of the "ellipse" that lies within the cross section of the Earth)
goes up.  The continually improved orbit solution has a continually
shrinking error ellipse, and unlike the case shown above, there is no
guarantee the center of the ellipse stays in the same location.  As it
shrinks further, it may look like this:

                                                **
                                             *      *
               x   x  x xxXXXXXxx x x  x   x
                                             *      *
                                                **

In which the impact probability has now fallen off to near zero (the patern
of up first and then down), or it could look like this:

                                                **
                                             *      *
                                   x   x  x xxXXXXXxx x x  x   x
                                             *      *
                                                **

in which case the probability is still higher.  Eventually, the probability
either turns around and goes down, or there is an impact.  So the pattern
of an increasing probability followed by a drop is perfectly normal if the
initial solution places the Earth deep within the probability "ellipsoid",
as was the case for 2004 MN4.  If the initial prediction has the Earth out
on the edge of the probability "ellipsoid", then it is likely that the
probability will go down with each succeeding orbit solution, as has been
the case in past instances.

Cheers,

Alan

*******************************************************************
Alan W. Harris
Senior Research Scientist
Space Science Institute
4603 Orange Knoll Ave.          Phone:  818-790-8291
La Canada, CA 91011-3364        email:  awharris@...
*******************************************************************

> http://www.uai.it/index.php?tipo=A&id=670
>
> I think this one of the clearest contributions to the
> public understanding of the event.

A diagram would have been more useful than a picture of the south pole.

Dear colleagues,

New peculiar asteroid 2004 YY23 with a cometary orbit was discovered
on Dec. 22 and became bright as 16 mag in late December when passing
near by the earth.

Just before the discovery, it must have been very close by Comet
C/2004 U1, which was just in outburst and bright as 13 mag.

2004 Dec. 18  12h UT  0.509 deg ( 30.5 arcmin)
   C/2004 U1 ( LINEAR )  07h13m.3  +49o21'  13.7 mag
   2004 YY23 	 07h16m.2  +49o31'  17.0 mag

Best regards,

--
Seiichi Yoshida
comet@...
http://www.aerith.net/

A rather informal gauge of public panic can be measured by the number of emails
received at Camarillo Observatory.  Several years ago during the evolution of
the
2002 NT7 scare, (and it was indeed a public "scare"), we received several dozen
emails regarding the situation.  One email in particular was distressing, which
was
published along with our response: 
http://www.CamarilloObservatory.com/pr01.htm.

Something that occurred to me at that time was the fact that a checklist is
published for just about any emergency imaginable.   However, there is no such
beast
for an asteroid impact.  For my own amusement, I compiled one which would have
worked for each media disaster up to that point.   I dug it up from the deep
recesses of the harddrive, dusted it off and confirmed that it would have worked
well in this situation too.

I would like to introduce the "CamO" checklist for asteroid impacts:
http://www.CamarilloObservatory.com/CamOChecklist.jpg

Finally, the public has something to protect itself from future news media
panics.


Enjoy

> I think, of far more interest to many amateur astronomers than concerns
> about
> whether something will be perceived as a "false alarm" is the nature of
> how
> increasing observations extending an orbital arc can first increase, then
> decrease, the chances of impact. 2004 MN4 seemed to increase its chances
> of
> impact and then was suddenly relegated to the safe bin. In my perception,

The NASA description of 2,3,4 on the Torino scale contemplates the
progression (back to TS 0).

Even though I agree with Dave Tholen that the fine print of the Torino scale
makes it clear what the risk actually is (magnitude of impact, range of
probability of impact, the likelihood of going back to TS 0 etc.), the
public doesn't have time to digest the criteria (nor is it readily
transmitted by the press). The fact that JPL/NASA even made a press release
is some kind of a signal in and of itself, whether that was the intent or
not.

While some sectors of the public have been educated enough to understand
something non-linear like the Richter scale, even at the low end of that
scale, an event still "occurred" - the scale only contemplates the severity,
not the probability of an event occuring.

Hearing that an object has reached 4 on the Torino scale, where no other
object has ever been placed before, certainly gained a lot of public
attention. Whether you call it a false alarm or not, and even if the fine
print made clear the actual risk, the end result was a lot of people got
quite interested in a short period of time.

Perhaps the Torino scale for the public should be collapsed into Green,
Yellow, Orange, Red colors? (no jokes about the US terror alert system
please) Green could be changed to encompass TS 1-4 with astronomers being
smart enough to discern when extra attention is warranted within that range.
The public is capable of discerning Green is not grounds for panic and Red
is probably very bad. (one can argue that with TS 8 it is still pretty bad
for those at the impact point)

Another option would be to change the probability threshold for the yellow
band to e.g. 3% (which persumably would have kept 2004 MN 4 at TS 1 until
further observations were done).

Or to put it another way, should the public care about the difference
between TS 2,3,4 and TS 1? If the answer is that TS 4 is an interesting
event for astronomers, but that the public should not yet be concerned, then
I would argue that the Torino scale has failed.

Glenn

At 10:55 PM 12/30/2004, Roger W. Sinnott wrote:

>At 03:11 PM 12/30/04 -1000, Dave Tholen wrote:
> >Well, S&T did call it a false alarm, but I'm still waiting for
> >somebody -- anybody -- to point out anything in the NASA announcement
> >that was false or alarming.
>
>Dave, Alan, and others (some of whom commented privately):
>
>Thanks for clarifying what's bothered you the most.  No contest here -- I
>agree that the words "false alarm" in the caption of our Web article, out
>of context, could easily be misconstrued.

And thanks for your understanding and acceptance of the point.  A major
misunderstanding that persists in the popular press (mostly newspapers
etc.) is exactly the distinction between "screwing up" and simply improving
the solution.  You have only to review the long dreary archive of media
stories on "killer asteroids" to see that for the most part, the
distinction is rarely made to the general public.  Publications that bridge
the gap between professional journals and the general public, like S&T, can
paly an important role making that distinction.  But unfortunately it must
be made over and over and over again in order to imprint it in the
public.  And a single mis-statement undoes the good of a dozen carefully
made correct statements.

Cheers,

Alan

*******************************************************************
Alan W. Harris
Senior Research Scientist
Space Science Institute
4603 Orange Knoll Ave.          Phone:  818-790-8291
La Canada, CA 91011-3364        email:  awharris@...
*******************************************************************

Fascinating debate about 2004 MN4.

I wrote:

> The weather people say that their satellite images show it might rain
> in Hampshire later today. Later those same weather maps show the
> chance of that happening has declined or gone away. It was a false
> alarm and no data was faulty or fraudulent.

Dave Tholen replied:

"I disagree; the word "might" leaves open the possibility of "might not".
If it does not rain, then there was nothing false about the alarm.  To
revisit my hurricane example, if landfall does indeed occur between
Melbourne and Daytona Beach, does that make the previous day's estimate of
Miami to Jacksonville a false alarm for the people of Miami?  Not at all.
The forecast said landfall would be between points A and B, and indeed
landfall was somewhere between points A and B.  The alarm was not false, but
the residents of Miami are relieved."

I wrote:

> Sure there is the strong possibility
> that further observations will reduce the chances of an impact (that's
> a reasonable assumption but only an assumption). That's what happened.
> The subsequent observations did neither invalidate the position that
> led to the
> 1 - 37 assessment nor the concern/alarm it merited. The alarm was
> false but not unjustified.

Dave Tholen replied:

"First of all, I once again disagree that there was any "alarm", as least as
far as the public is concerned.  I also disagree with the use of "false", as
the probability calculations were cross-checked and found to be correct."

**

I disagree. You are adding your own provisos and qualifications to the
simple grammatical definition of a false alarm - an alarm that was raised
that was later recinded. Sky and Telescope were quite correct in their use
of the term. Putting "might" in an alarm does not invalidate it because an
alarm is a warning of an expectation that might, or might not, come to pass.

You say that Sky and Telescope are wrong because no alarm was raised:

Alarm
1 a warning of danger etc. (gave the alarm).
2 a a warning sound or device (the burglar alarm was set off accidentally).
b = alarm clock.
3 frightened expectation of danger or difficulty (were filled with alarm).
v.tr.
1 frighten or disturb.
2 arouse to a sense of danger.

Considering this, I think an alarm was raised among many observers,
journalists and possibly the public but without a survey what do any of us
know what the public think or are alarmed about?


I said:

> On one day there was a 1 - 37 chance of an impact in 2029. This is
> certainly cause for concern and arguably  alarm.

Dave Tholen replied:

"Perhaps to you.  Perhaps to the NEO astronomers who need to work the issue.
But not to the general public.  According to the wording of Torino Scale 4,
attention by the public is merited only if the encounter is less than a
decade away.  That wasn't the case here.  The initial NASA announcement
specifically noted that it wasn't a cause for concern.  If you wish to be
concerned, that's your choice, but no blame to the NEO community is
justified, contrary to what other contributors have written."



Public attention not merited!! The Torino Scale says that the public need
only be alarmed if the impact is less than a decade away! That's a relief.
But this assumes that the public or the media will be reassured or even
impressed by the TS. Actually they have the right to take it or leave it.
2029 is well within my lifetime and my children (and their children if they
ever have them) so I'll be alarmed no matter what the TS or Nasa says I
should be alarmed about. 1 - 37 is far, far higher than any other rock we
have dealt with. I would be very alarmed if odds of 1 - 37 (even if
transitory) applied to certain other areas of my life especially if my
children were involved.


But enough of this. It's New Years Eve. Greetings and Best Wishes to you
all.


Regards,

David.

I think, of far more interest to many amateur astronomers than concerns about
whether something will be perceived as a "false alarm" is the nature of how
increasing observations extending an orbital arc can first increase, then
decrease, the chances of impact. 2004 MN4 seemed to increase its chances of
impact and then was suddenly relegated to the safe bin. In my perception,
increasing numbers of observations across a larger arc have usually led to a
steadily decreasing chance of impact. So what orbital oddities caused this? Can
it be explained diagrammatically?

- Greg

Italian Amateur astronomers Union (UAI) published
today an article featuring a precise and easy-to-read
explanation of what exactly happened to the Earth's
axis after the Sumatra's earthquake:

http://www.uai.it/index.php?tipo=A&id=670

I think this one of the clearest contributions to the
public understanding of the event.

The author is Alfonso Mantero, italian physicist at
the University of Genoa and at the CERN of Geneva.

Best regards,

Daniele Cossu
UAI-ASTROnews
Italian Amateur astronomers Union
http://www.uai.it
astronews@...

Dave Tholen wrote:
> Well, S&T did call it a false alarm, but I'm still waiting for
> somebody -- anybody -- to point out anything in the NASA announcement
> that was false or alarming.

In my humble opinion, the problem some scientist seem to have with Sky &
Telescope's use of the term 'false alarm' is caused by their apparent assumption
that language is of an exact nature, which of course it isn't. 'False alarm' is
a well-known phrase in common language, without a well-defined definition (at
least, various dictionaries differ in their description), but generally meaning
something like a warning about an event that subsequently doesn't occur. When
people use the phrase, they do not necessarily think of something being false in
the strict sense (or something being alarming); they just use a well-known
phrase, just like people still use the phrase of 'dialing a number', although
telephones have no dials anymore. I believe publications like S&T should
certainly keep communicating with the audience at large in common language, and
to blame them for using the term 'false alarm' is unjust. (It reminds me of the
student saying that her locker is empty, and the science teacher correcting her
with the remark that it is completely full -- with air.) --Govert

Deal all,

The computer "newton" hosting NEODyS at Pisa has failed again and there
is no hope for any action to be taken before Jan 3.

For those of you who are users of NEODyS, please point your browser at
NEODyS in Spain at:

http://unicorn.eis.uva.es/cgi-bin/neodys/neoibo

Even if the failure of newton can be fixed next week (which is not
sure), please keep in mind that, once the computer is brought online
again, I will need some time to update the system at Pisa after these
days of forced stop.

In any case, you can get all the services from NEODyS at Valladolid,
which will continue to be timely updated.

Best regards,

Genny.

--
+----------------------------------+---------------------------------+
|  Maria Eugenia Sansaturio        |  Phone #: +34 - 983 - 42 33 88  |
|  E.T.S. Ingenieros Industriales  |  Mobile#: +34 - 696 - 82 28 87  |
|  Paseo del Cauce s/n             |  Fax   #: +34 - 983 - 42 34 06  |
|  47011 Valladolid, SPAIN         |           +34 - 983 - 42 33 10  |
|----------------------------------+---------------------------------|
|                   http://wmatem.eis.uva.es/~marsan/                |
+----------------------------------+---------------------------------+

I truly don't think this is "reader abuse" by Roger, and I certainly think that
all the
opinions and threads that I have read thus far on this forum, including yours,
is worthy
of consideration and input.  Incidences such as this one and the previous one
make for
excellent discussion, and if one cannot speak his or her mind in the heat of
things
without others "canceling subscriptions" or taking the football and going home
then this
forum serves no purpose in my opinion.

Agree or not with any or all of these postings, you have to admit that there are
loopholes
in the entire process on the way the NEO prediction, projection and protection
plan works.
In short, "...it ain't no Homeland Security" and even if it were, there are
going to be
circumstances that none of us can predict.

In some ways, it almost seems as though we place blame on _individuals_ for an
asteroid
who failed to keep its dinner appointment on April 13, 2029.  By contrast, if
the object
was still on course, we would likely be assigning failure messages to other
individuals
because 2044 MN4 was coming to dinner.

A lot of good folks on this forum are getting blasted or examined for both
information
they did NOT issue as well as information they DID issue....others are receiving
flack
from the "wording" of the way information was disseminated.

A rose by any other name.....
I still think that all circles handled this - and the reporting and discussion
of it -
very well.

Clay
--------------------
Dr. P. Clay Sherrod
Arkansas Sky Observatories
Harvard MPC H41 (Petit Jean Mountain)
Harvard MPC H43 (Conway)
Harvard MPC H44 (Cascade Mountain)
http://www.arksky.org/

NOTE that all ASO outgoing mail is protected by McAfee, Zone Alarm and
tcworks.net
security
     and is certified Virus and Spam-free

----- Original Message -----
From: "Greg Crawford" <gc@...>
To: <mpml@yahoogroups.com>
Sent: Thursday, December 30, 2004 7:50 PM
Subject: RE: {MPML} 2004 MN4 Recommendations


>
> > It is sad to see some of the wild accusations against the media, and S&T in
> > particular, that have been posted to the MPML in the last few days.  At
least
> > Alain Maury and Jim Baer have been sympathetic (and eloquent) concerning our
> > situation.  To the rest, I just have to say: Go fly a kite!
>
> If that is your attitude towards your readership, then you may well lose sales
> to the opposition - and there is plenty of that. Abusing readers who express
> disappointment at the poor quality of S & T articles is like cutting off the
> hand that feeds you. Perhaps the headline should read, "Senior Editor of Sky &
> Telescope says to critics, 'Go fly a kite!' "  I think their actual response
> will be to go and buy another astronomy magazine.
>
> Readers of a magazine dedicated to astronomy expect the magazine's journalists
> and editors to have an understanding of their subject and to be able to
> interpret it accurately for their readers. Instead, the relevant article
speaks
> of "hype", and associates the very appropriate course of alerts issued with
> "Chicken Little-style news stories". Such associations are a complete
distortion
> of the appropriate actions taken.
>
> Instead of abusing your readers, why don't you call the relevant staff
together
> and tell them to lift their game.
>
> - Greg
>
>
>
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> MPML is supported in part via the 2002 Shoemaker NEO Grant Program of The
Planetary
Society (http://www.planetary.org)
>
> NOTICE: Material quoted or re-posted from the Minor Planet Mailing List should
be
proceeded
> by the following attribution:
>
> FROM THE MINOR PLANET MAILING LIST [date]. For the full text or to subscribe,
please
visit:
> MPML Home page: http://www.bitnik.com/mp
> MPML FAQ: http://www.bitnik.com/mp/MPML-FAQ.html
> Yahoo! Groups Links
>
>
>
>
>
>

Fascinating debate about 2004 MN4.

I wrote:

> The weather people say that their satellite images show it might rain
> in Hampshire later today. Later those same weather maps show the
> chance of that happening has declined or gone away. It was a false
> alarm and no data was faulty or fraudulent.

Dave Tholen replied:

"I disagree; the word "might" leaves open the possibility of "might not".
If it does not rain, then there was nothing false about the alarm.  To
revisit my hurricane example, if landfall does indeed occur between
Melbourne and Daytona Beach, does that make the previous day's estimate of
Miami to Jacksonville a false alarm for the people of Miami?  Not at all.
The forecast said landfall would be between points A and B, and indeed
landfall was somewhere between points A and B.  The alarm was not false, but
the residents of Miami are relieved."

I wrote:

> Sure there is the strong possibility
> that further observations will reduce the chances of an impact (that's
> a reasonable assumption but only an assumption). That's what happened.
> The subsequent observations did neither invalidate the position that
> led to the
> 1 - 37 assessment nor the concern/alarm it merited. The alarm was
> false but not unjustified.

Dave Tholen replied:

"First of all, I once again disagree that there was any "alarm", as least as
far as the public is concerned.  I also disagree with the use of "false", as
the probability calculations were cross-checked and found to be correct."

**

I disagree. You are adding your own provisos and qualifications to the
simple grammatical definition of a false alarm - an alarm that was raised
that was later recinded. Sky and Telescope were quite correct in their use
of the term. Putting "might" in an alarm does not invalidate it because an
alarm is a warning of an expectation that might, or might not, come to pass.

You say that Sky and Telescope are wrong because no alarm was raised:

Alarm
1 a warning of danger etc. (gave the alarm).
2 a a warning sound or device (the burglar alarm was set off accidentally).
b = alarm clock.
3 frightened expectation of danger or difficulty (were filled with alarm).
v.tr.
1 frighten or disturb.
2 arouse to a sense of danger.

Considering this, I think an alarm was raised among many observers,
journalists and possibly the public but without a survey what do any of us
know what the public think or are alarmed about?


I said:

> On one day there was a 1 - 37 chance of an impact in 2029. This is
> certainly cause for concern and arguably  alarm.

Dave Tholen replied:

"Perhaps to you.  Perhaps to the NEO astronomers who need to work the issue.
But not to the general public.  According to the wording of Torino Scale 4,
attention by the public is merited only if the encounter is less than a
decade away.  That wasn't the case here.  The initial NASA announcement
specifically noted that it wasn't a cause for concern.  If you wish to be
concerned, that's your choice, but no blame to the NEO community is
justified, contrary to what other contributors have written."



Public attention not merited!! The Torino Scale says that the public need
only be alarmed if the impact is less than a decade away! That's a relief.
But this assumes that the public or the media will be reassured or even
impressed by the TS. Actually they have the right to take it or leave it.
2029 is well within my lifetime and my children (and their children if they
ever have them) so I'll be alarmed no matter what the TS or Nasa says I
should be alarmed about. 1 - 37 is far, far higher than any other rock we
have dealt with. I would be very alarmed if odds of 1 - 37 (even if
transitory) applied to certain other areas of my life especially if my
children were involved.


But enough of this. It's New Years Eve. Greetings and Best Wishes to you
all.


Regards,

David.

--- "Roger W. Sinnott" <rsinnott@...> wrote:
>
> At 03:11 PM 12/30/04 -1000, Dave Tholen wrote:
> >Well, S&T did call it a false alarm, but I'm still waiting for
> >somebody -- anybody -- to point out anything in the NASA
> announcement
> >that was false or alarming.
>
> Dave, Alan, and others (some of whom commented privately):
>
> Thanks for clarifying what's bothered you the most.  No contest here
> -- I agree that the words "false alarm" in the caption of our Web
> article, out of context, could easily be misconstrued.  According to
> my dictionary (Webster's II), a false alarm is "an alarm sounded when
> no danger exists" -- nothing more, nothing less.  I know for sure
> that Dave Tytell never intended to imply that NASA/JPL was deceiving
> the public, and it is unfortunate that people are reading this into
> it.

That's not what bothers me about the phrase.
I think that most people, with the possible exception of those who play
the lottery, understand basic probability, but when it comes to
science, the large majority of the general public goes into serious
brain lock.  Discussions I've heard among the general public after
other "asteroid scares" is that when the alert is rescinded, most
people don't know why.  They're not aware of the idea that further
observations allowed the orbit to be refined, and a surprising number
think that the initial alert must have been due to miscalculations.  In
other words, that the scientists were incompetent.

My impression of the phrase "false alarm" is that it probably didn't
come into common use until fire alarms and other electronic monitoring
intruments were developed, and that it originally meant an alarm
sounded due to faulty detection equipment (or, sometimes, deliberate
fraud).  But in recent decades we have so many types of emergency
alerting devices and systems that the number of false alarms has become
a minor nuisance, and the phrase is now used more loosely for anything
that doesn't turn out to be bad enough to worry about, such as the
tsunami alerts when the wave turns out to only be 2 feet high.  That
definition does fit this case, but many of the general public think
that the "false" asteroid scares more closely fit the original, more
literal definition of false alarm- in this case caused by incompetence.
  So calling this "yet another false alarm" can propogate that idea.

Of course, the fact that there was no "alarm", and that there was
remarkably little "hype", make me wonder what David's motivation was
for his wording.  Twice in the last few years I've had well-intentioned
but uninformed people give me subscriptions to Astronomy magazine as
gifts.  I haven't read it in years, and gave up after a few issues this
time due to the preponderance of technical errors in the writing.  I
routinely recommend S&T to other amateur astronomers as a very solid
source of reliable info.  But that caption read like something out of
the National Enquirer.

-John



__________________________________
Do you Yahoo!?
Read only the mail you want - Yahoo! Mail SpamGuard.
http://promotions.yahoo.com/new_mail

> -----Original Message-----
> From: Dave Tholen [mailto:tholen@...]
> Sent: Friday, 31 December 2004 8:55 PM
> To: mpml@yahoogroups.com; rsinnott@...
> Subject: Re: {MPML} 2004 MN4 Recommendations
>
>
> > According to my dictionary (Webster's II), a false alarm is "an alarm
> > sounded when no danger exists" -- nothing more, nothing less.
>
> But no alarm was sounded.  There was merely an announcement that an
> object had been found whose orbit was not yet known well enough to
> rule out a collision with Earth, specifically noting that the situation
> was not of public concern.  How can that possibly be interpreted as an
> alarm for the general public?

In most Western countries the threat of terrorism has led to a basic stance of
being "alert, but not alarmed". Surely this is now a widespread notion
understood by the general public which can be applied to PHAs, and appropriately
communicated by journalists?

- Greg

> According to my dictionary (Webster's II), a false alarm is "an alarm
> sounded when no danger exists" -- nothing more, nothing less.

But no alarm was sounded.  There was merely an announcement that an
object had been found whose orbit was not yet known well enough to
rule out a collision with Earth, specifically noting that the situation
was not of public concern.  How can that possibly be interpreted as an
alarm for the general public?

> Just watched a history channel documentary about tsunamis deaths in
> Hawaii AFTER an early warning system was installed. The warning system
> was 100 percent accurate in predicting the occurance of a tsunami but
> couldn't predict it's size. After many "false alarms" where the tsunami
> turned out be only two feet high, people became blase. Sometimes
> citizens would gather on the beach to watch the tsunami come in. In one
> instance there were hundreds of deaths because the tsunami watchers were
> treated to a 30-foot high tsunami instead of the diminutive wave they
> had come to expect.

I've lived in Hawaii over 20 years now, and if memory serves, the
tsunami warning sirens have been sounded (other than for testing
purposes) three times in those years.  In none of those cases was
there any significant wave here.  Were there reporters pointing
fingers at the tsunami forecasters blaming them for a "false alarm"?
Not to my knowledge.  Were people inconvenienced?  Absolutely.  Better
safe than sorry, however.

> I do not agree with the statement made on this list that a false alarm is
> based on faulty or fraudulent data. In my view it is an alarm that went away
> as more data was collected.

Were collected.  Or have you joined the crowd claiming that the use of
"data" in the singular is acceptable?  I've had more than one person
say so.

> The weather people say that their satellite
> images show it might rain in Hampshire later today. Later those same weather
> maps show the chance of that happening has declined or gone away. It was a
> false alarm and no data was faulty or fraudulent.

I disagree; the word "might" leaves open the possibility of "might not".
If it does not rain, then there was nothing false about the alarm.  To
revisit my hurricane example, if landfall does indeed occur between
Melbourne and Daytona Beach, does that make the previous day's estimate
of Miami to Jacksonville a false alarm for the people of Miami?  Not at
all.  The forecast said landfall would be between points A and B, and
indeed landfall was somewhere between points A and B.  The alarm was
not false, but the residents of Miami are relieved.

> On one day there was a 1 - 37 chance of an impact in 2029. This is certainly
> cause for concern and arguably  alarm.

Perhaps to you.  Perhaps to the NEO astronomers who need to work the issue.
But not to the general public.  According to the wording of Torino Scale 4,
attention by the public is merited only if the encounter is less than a
decade away.  That wasn't the case here.  The initial NASA announcement
specifically noted that it wasn't a cause for concern.  If you wish to be
concerned, that's your choice, but no blame to the NEO community is
justified, contrary to what other contributors have written.

> Sure there is the strong possibility
> that further observations will reduce the chances of an impact (that's a
> reasonable assumption but only an assumption). That's what happened. The
> subsequent observations did neither invalidate the position that led to the
> 1 - 37 assessment nor the concern/alarm it merited. The alarm was false but
> not unjustified.

First of all, I once again disagree that there was any "alarm", as least
as far as the public is concerned.  I also disagree with the use of "false",
as the probability calculations were cross-checked and found to be correct.

I have been following the MN4 debate here closely and all I can say
is that everything was done just right. Opinions on the proper
coverage of these 'events' can vary - in no circumstance, of course,
information should be withheld from the public and reserved for the
selected few. It is true, as some have said here, that we should not
pay much attention to 'professional conspiracy theorists' but, alas,
the general public seems to pay more attention to them than to real
science. Some 30% of Americans (if I am not mistaken) believe in
UFO's - generated by a combination of conspiracy theorists ('the
government is hiding information from us') and people fond of
misinterpretation of natural or man-made phenomena. Any attempt to
made information on orbital elements of asteroids or comets may
create more of the UFO-like nonsense widespread.

In the case of MN4, however, the right balance between potential and
actual danger was struck and, frankly, there is not much to be added
here or elsewhere.

Perhaps, we can soon close this thread.

Ladislav Nemec
MPC 452 Big Cypress