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Cambridge Conference Debate - April 2, 1998

CAMBRIDGE-CONFERENCE DEBATE, 2 April 1998
----------------------------------------

(1) DON'T COUNT YOUR CHICKENS BEFORE THEY HATCH, PARTICULARLY NOT ON 
    APRIL 1st
    Benny J Peiser 

(2) JUST WHEN YOU THOUGHT 1997 XF11 HAD GONE AWAY
    Brian G. Marsden 

(3) ON ADOPTING A NEO HAZARD INDEX
    Gerrit Verschuur 

(4) AXIOM ON PUBLIC ANNOUNCEMENTS SHOULD BE APPLIED INTERNATIONALLY
    Richard Binzel  

(5) A COMMENT ON DUNCAN STEEL'S "PANDORA'S BOX"
    Clark Chapman  

=====================
(1) DON'T COUNT YOUR CHICKENS BEFORE THEY HATCH, PARTICULARLY NOT ON 
    APRIL 1st

From: Benny J Peiser 

Can you imagine how much I shrieked with laughter when an American 
colleague was so kind to tell me that one of our honourable members 
almost swallowed yesterday's message by Coffee Anan?  

> Tom, Bob, Jim, and Dan:
> 
> I received a message via the CC Digest saying the UN is going to spend
> $500,000,000 to build a "global system of NEO detection and R&D in NEO
> deflection for the next 10 years."  This is, however, released on 1 April
> 1998, so its authenticity is suspect.  Do you have any independent
> verification that such a committment has been made? 

While this reaction certainly made my day, I was even more pleased when 
I was informed by a reliable source that yesterday's UN "committment" 
was - guess what - actually forwarded to the Secretary General, Kofi 
Anan, by one of his acquaintances. And that's no joke!

The rest of today's debate on the CCNet is, I'm afraid to say, of a 
more serious nature. It is the start of a critical re-assessment of the 
events surrounding asteroid 1997 XF11 and the main lessons the 
astronomical community in general and NEO researchers in particular 
have to learn for similar events in the future. With more than 
1,000,000 amateur astronomers world-wide and numbers growing 
continuously, the discovery of new asteroids and comets on an orbit 
with close approch to Earth is inevitable and just a question of time. 
Thus this discussion is of great concern to all who are either directly 
involved or simply interested in NEO research and, more importantly, 
the fundamental implications of the NEO threat on human, social and 
scientific conduct in the free world. 

Benny J Peiser

==================
(2) JUST WHEN YOU THOUGHT 1997 XF11 HAD GONE AWAY
 
From: Brian G. Marsden 
 
My article in the March 29 Boston Sunday Globe, as well as the extended 
version that appeared in the March 30 CC DIGEST, was obviously a 
popularized account of my view of the 1997 XF11 affair. It had been my 
intention, at some stage, to address the more complex issues in more 
detail, and Clark Chapman's "case study", which appeared in the 
otherwise delightful April 1 issue of the CC DIGEST, provides an 
appropriate impetus. Since, in his capacity as new chairman of the IAU 
Working Group on Near-Earth Objects, Dave Morrison was gratuitous 
enough to send Chapman's item and my extended Globe article to much of 
the IAU leadership, I shall trust that my response here receives the 
same treatment. Note that I shall basically refer to the particular 
version of Chapman's remarks that actually appears in the CC DIGEST, 
although DIGEST readers will be aware of the reference there to 
Chapman's 2500-line Web manifesto, parts of which are being construed 
by many as libelous, and on which I might touch.  If, as Chapman notes 
in his introductory paragraph to the DIGEST (but not the distributed) 
version, "the detailed technical analysis ... is still not fully 
understood" by him, one rather wonders how he can so confidently 
describe what happened.
 
Is it more important to make probability estimates of impacts on the 
basis of limited observational data or to try and secure additional 
data? This is an interesting question, and your answer may well depend 
on whether you are a theoretician or an observer.  Chapman takes the 
view that only the former is important, the additional 1990 data being 
just "icing on the cake". (But why stop there?  If the 1990 data were 
mere icing, why not also the Shelus data from 1998 March 3 and 4 that 
he so chided me for withholding?). The fact is that 1997 XF11 is one of 
the largest objects that CAN come very close to the earth, and that it 
WOULD come particularly close in 2028 was already evident from the data 
in the February MPCs, and even from those in the January MPCs. The 
worrisome thing is that nobody became interested in the object earlier: 
Shelus' observations were the first ones in a whole month, and those 
interested in such things seem not to have made any effort to obtain 
physical data that could establish an albedo and size. It should not in 
fact have been necessary for there to be an urgent scramble on March 12
to search for old images. As soon as objects are added to the list of 
PHAs (as 1997 XF11 was in December), they should (if reasonably bright) 
surely become prime candidates for physical studies; and as soon as 
there is a halfway decent orbit determination (January, certainly 
February, for XF11), mechanisms should be established for searching for 
old images. Such activities must be considered part of the NEO 
enterprise, and they (and follow-up astrometry generally) are every bit 
as deserving of funding as are searches for new objects.  After all, 
examination of old plates, and CCD recovery attempts for faint objects, 
were the principal modi operandi of the late and very much lamented NEO 
program at Siding Spring.
 
So, considering that we were dealing with a computation, from available 
data, that even amateur astronomers could do (as Duncan Steel also 
aptly pointed out in the April 1 CC DIGEST), there was every reason to 
issue IAUC 6837, with a call for further observations, even physical 
observations. The possibility of finding past observations was handled 
in the accompanying "press information sheet" (or whatever it should be 
called) in the WWW, this sheet also being designed to answer questions 
readers (including, but not restricted to, the press) of the admittedly 
terse IAU Circulars may have.
 
But, accepting that some people might just be interested in whether 
there might be an earth impact prior to the availability of further 
data, I used, on IAUC 6837, the perhaps unfortunate but deliberately 
not wholly quantitative phrase "Error estimates suggest that passage 
within 0.002 AU is virtually certain". Note in particular the word 
"suggest". Is that a word one uses when he is absolutely convinced of 
something? Sure, this was perhaps a "1 sigma" when it might have been 
better to consider a "3 sigma", but is that the end of the world (pun 
intended, I suppose)--given that Karri Muinonen estimated the 
probability of passage within 0.002 AU to be as high as 90 percent?  
No, Clark, my calculations were not "faulty". I did not even 
misinterpret them.  Whether I used "ill-chosen" words is a subjective 
judgment--especially if you want to consider that I am writing this 
whole document on April 1.
 
"The chance of an actual collision is small, but one is not entirely 
out of the question."  Given that the press information sheet was put 
together more hastily than the IAU Circular, this statement is perhaps 
also somewhat unfortunate. I have agreed that it is VERY DIFFICULT to 
bring the object within 0.00019-0.00021 AU of the earth in 2028--on the 
basis of the 88-day arc. But as recently as March 28, Muinonen and 
Chodas were STILL arguing about whether an actual collision was 
POSSIBLE.  Until this argument is resolved, it is impossible to say 
whether the probability of impact was precisely zero or not.
 
Don Yeomans' e-mailed request for observations of 1997 XF11 reached my 
computer at 17:45 EST on March 11.  That was after "normal office 
hours" (whatever they are!), but I did in fact send them as soon as was 
practical, together with a friendly note to both him and Paul Chodas, 
at 19:32 EST (hardly a terrible delay under the circumstances, surely), 
saying I "shall be interested to hear what you find, [but] the whole 
point is to get ... possible images from old plates".  Chodas had 
already indicated to me that he wished "to compute a formal probability 
of impact".  Sure, I could be "interested" in this result, but it 
obviously would not be the last word. In any case, when Yeomans, in a 
message that was widely distributed (I received it at 20:15 EST), gave 
the "close approach distance" as "0.00058 +/- 0.00897 (3-sigma) AU", it 
immediately occurred to me that this was a decidedly odd way of 
expressing an uncertainty that just had to be much more "+" than "-"!  
 
Now to the events of March 12.  I was up early because I had to be at a 
local television studio for a live program at 7:00 EST. I quickly 
checked the overnight e-mail an hour earlier, noted the requests to 
publish a "correction", to the effect that there could be "no 
collision", and I responded to them at 6:10 EST to the effect that that 
"unmodeled effects surely make [the probability] nonzero.  We need more 
data." Back from the studio and--like everyone else--in the thick of 
further press enquiries and interviews, I received from Muinonen (to 
whom I had also sent the March 3-4 observations, as he had requested) 
his assessment of the situation, which was that he obtained a nominal 
miss distance of 0.00033 AU (when I had 0.00031 AU) and was "in 
agreement with" me "that collision with the Earth cannot be ruled out 
at the moment".  This was in flat contradiction to Yeomans and Chodas!  
In any case, since I had not even mentioned on the IAU Circular that a 
collision with the earth was a possibility (however remote), what, 
indeed, was the point of publishing a new remark against or in favor of 
this proposition?
 
Then, around 12:15 EST, I received word that Eleanor Helin and Ken 
Lawrence had images from 1990!  It would take a few hours to get 
measurements, of course. On the interview for the CBS Evening News I 
taped at 12:30 I in fact MENTIONED this important new development, but 
I don't know if it were used in the broadcast. It was also around this 
time that I received a phone call from Chapman "ordering" me to discuss 
probability analysis with Chodas and Yeomans. I may or may not have 
mentioned the forthcoming 1990 observations to Chapman: they were 
obviously not of relevance to him anyway, although I knew they would be 
of relevance to Chodas and Yeomans, who would obviously agree with me 
that these solved the problem completely.  
 
We received the March 23 measurements from Helin at 14:00 EST, whilst I 
was again in the midst of an interview, and Gareth Williams had 
computed an orbit showing the 0.006-AU miss distance by the time I was 
driven off again to the television studio at 14:20.  Since Paul Chodas 
wrote that he had computed this at 14:49 EST, Williams was clearly the 
first to get this result. But single-night measurements can be 
problematic, and the MPC standards require the data from the second 
night that we knew would be forthcoming. The March 22 measurements 
arrived around 17:00, about the time I got back to my office, and 
Williams had completed the definitive computation, again with the 
0.006-AU miss distance, within minutes. Amidst further interruptions 
for phone calls and e-mail messages, I then prepared the IAUC 6839, 
finally managing to complete it around 19:30 EST. It was put into the 
CBAT/MPC Computer Service five minutes later, e-mailed to subscribers 
over the course of the next 15 minutes and was  available for FREE 
viewing on the WWW at 19:55.
 
At 20:00 I participated in two more television interviews, including 
one for the next morning's NBC "Today Show", here in the office. The 
crews left shortly after 21:00, and I received notification of the JPL 
orbit computations, obviously identical with ours, at 21:20.  On 
arrival home at 22:15 I did yet one more radio interview, for CBS news, 
while eating the dinner my wife had prepared for me hours earlier (how 
did we manage before microwaves?), this then signaling for me the end 
of what had been--and obviously not just for me--a rather strenuous 
day... This feeling is compounded if one realizes that the combined 
scientific expertise for the IAUCs and the MPCs is contained in just 
three people, one of whom was on sick leave for part of March 12.  Our 
part-time secretary stayed late to field calls. Our administrator was 
on vacation for the week. The head of the Smithsonian Astrophysical 
Observatory's public affairs office was also out of town, and this is 
one of the complications that led to the unfortunate circumstance that 
the Press Officer of the American Astronomical Society distributed our 
press information sheet as a full-blown press release on behalf of the 
IAU.
 
To suggest that the IAU Circulars should be "peer reviewed" and to 
imply that this requires that "all data from the international 
astronomical community should be disseminated as rapidly as is 
technically possible" is a red herring. A formal review process simply 
takes too long. Nevertheless, the editors do frequently consult with 
experts in particular areas, and as a result the number of outright 
errors on the IAU Circulars is actually surprisingly small.  Speed will 
often tend to spawn errors, but to produce in a slow and plodding 
manner is not a guarantee that they will be eliminated.
 
At the NASA policy discussion in Houston on March 17, a couple of 
participants insisted that they needed to have all the astrometric data 
immediately they were received by the MPC, without the need for 
checking.  As I pointed out, this is a complete impracticality, in that 
most contributors of data EXPECT that we shall do what we can to verify 
their data.  To send out masses of unchecked data, not related to 
specific objects, would cause both mass confusion as well as mass 
embarrassment.  For example, just during the past couple of weeks, we 
received an extensive batch of near-equatorial observations that 
omitted the sign of the declination, whether that was in the range 0 to 
+1 degree or in the range -1 to 0 deg.  While we were able to sort this 
out before any observations were actually published, this could have 
been a very damaging situation that would also have involved our 
receiving e-mails enquiring about specific problems for months to come. 
In any case, since the interest is in NEOs, to make available 4000 or 
more observations every day would quickly overwhelm the most ardent MPC 
subscriber. Nobody should be under the illusion that our checking of 
the data is a "pet research project of ours".  Believe me, we get far 
fewer interesting and publishable results out of it than one might 
think, considering the effort we put into it.  Some might instead be 
tempted to regard this activity, carried out by Williams over the 
course of many hours seven days per week, as a thankless task--although 
it is in fact clearly appreciated by essentially all of the observers.
 
My compromise was that we should be able to make available, generally 
on a daily basis, all new observations of unnumbered NEOs. Such a move 
would have allowed others to keep fully on top of the 1997 XF11 
situation, right from the start. Whether they would actually have DONE 
so is quite a different matter.
 
BGM, 1998 Apr. 1

=====================
(3) ON ADOPTING A NEO HAZARD INDEX

From: Gerrit Verschuur 

Late last year Sky & Telescope commissioned me to write an article 
related to NEOs for their June 1998 edition, timed to coincide with 
the release of a couple of Hollywood movies on the subject of impacts. 
I completed the article by the mid-February deadline, a week or so 
before the 1997 XF11 furor hit the headlines. Sky & Tel had defined a 
theme for the article: how should the public be informed in the case of 
an impending impact? They specifically asked me to discuss Richard 
Binzel's Hazard Index, something he has written and talked about for 
several years. A Hazard Index could be used to indicate the probability 
of an impact as well as the magnitude of the likely event. If you see 
the Sky & Tel article bear in mind that at the time of writing 
1997 XF11 was a complete unknown to me. I like odd coincidences, but 
this one was too close for comfort.  
 
The moral of the story is that the NEO community might do well to 
consider the implementation (on an international level) of some form of 
Hazard Index to be used in all future reporting of close passes and 
potential strikes. I fully appreciate that probabilities mean little to 
most lay people, and that is why the use of some numerical scale makes 
sense. Consider the Richter Scale for earthquakes. Most lay people 
appreciate that a magnitude 7 quake is very bad whereas a 5 is usually 
not so significant and that a 3 is not worth writing about. But they 
don't actually have a clue as to what the 3, 5 or the 7 mean in terms 
of absolute energies, say. If some form of Hazard Index for NEOs was to 
be adopted the public might begin to appreciate that near misses are 
common, that misses inside the moon's orbit are less common, that 
strikes by small objects occur from time to time, and that civilization 
destroying impacts are infrequent. The use of a cleverly constructed 
scale may prevent false alarms while also serving to realistically 
communicate a warning taking into account uncertainties in orbital 
predictions at any given time. As Binzel notes, an Index value will 
change over time as the predictions improve with new data. 
 
The International Spacegaurd Foundation or the IAU may wish to take the 
lead in deciding whether a Hazard Index is worth considering, how to 
define such an index, and how toimplement its use in the future.
 
Gerrit L. Verschuur

PS. Thanks to all those who responded to me survey last year. I used 
some of your input in the above-mentioned article.

====================
(4) AXIOM ON PUBLIC ANNOUNCEMENTS SHOULD BE APPLIED INTERNATIONALLY

From: Richard Binzel  

Dear Benny,
 
I am a bit surprised by Duncan Steel's response to my proposed axiom 
regarding public announcements pertaining to Earth approaching objects 
for which a collision cannot be ruled out, which I repeat below.
 
There is nothing in this axiom regarding nationality, control over NEO 
researchers, or censorship. It is an axiom describing a responsible 
code of scientific conduct which can be followed by either professional 
or amateur researchers regardless of nationality.
 
Sincerely,
Richard P. Binzel
Associate Professor of Planetary Science
M.I.T.
 
--------------------------------------------------------------------
"A public statement regarding an Earth approaching object for which
a collision cannot be ruled out should not be issued without:
 
     a) Giving a quantitative value for the probability;
     b) Having independent verification on this probability;
     c) Placing this probability into the context of the
        collision probability with the background population
        of similar-sized objects."

=====================
(5) A COMMENT ON DUNCAN STEEL'S "PANDORA'S BOX"

From: Clark Chapman  
 
Much of what Duncan Steel (April 1 CC Digest) has said about
the undesirability and impossibility of controlling information is valid. 
But he misses an essential point.  The world has long been exposed to
the uncensored "babble" of anyone who wants to say something and has
access to a printing press.  With the advent of the Internet, the babble has
increased to a roar.  Yet society, and the scientific community, have
developed ways to deal with it, to sort out the wheat from the chaff.
 
Among reputable scientists, that way is to "certify" reputable
scientific results by having them checked, peer-reviewed, and published
in technical journals.  Associated with that, the scientific community has
traditionally regulated itself, by not going to the public media until the
date of publication of the peer-reviewed technical article.  That approach
is *required* by Science and Nature, for example.
 
Such procedures don't prohibit lay people, amateurs, truthsayers,
fortune-tellers, pseudo-scientists, and professional scientists who don't
care about their reputations from publishing their hasty results immediate-
ly -- on the Internet, or anywhere -- and such stories are frequently
reproduced in the supermarket tabloids.  But serious people, opinion
leaders, policy makers, and the like rely on those media (like the New
York Times, in America, for example) that attempt to abide by society's
self-regulating procedures in order to report stories with a higher degree
of reliability.
 
No procedures developed in the U.S. or anywhere will prohibit
casual, unchecked results from going out. As many people may not
know, just a few days before the 1997 XF11 affair, there was Internet
chat of a preposterous claim by some "Russian scientists" (not the
reputable experts that I know) that the asteroid Icarus might hit the Earth
in the year 2006. This story, however, did not create banner headlines
around the world. Nor should it have done so.
 
It is appropriate and necessary that serious astronomers, and the
serious media, adapt to the modern realities of the Internet and establish
effective procedures -- essentially peer-review -- to reduce the chances
that mistakes like 1997 XF11 will happen again.  It is appropriate that
entities like the I.A.U., NASA, the Spaceguard Foundation, and all
manner of amateur and professional astronomical societies, funding
agencies, etc. (national and international) adopt procedures to ensure that
centuries of traditional peer-review procedures are maintained in the
current Information Age.
 
The Minor Planet Center represents itself to be, should be, and
was taken (by the media) to be a *reliable* source of information,
representing the astronomical community.  All of us, not just the MPC,
lost some credibility a few weeks ago when failures in the peer-review
process at the MPC led to the XF11 scare.  It is wholly appropriate to
mandate procedures of peer-review.  To be sure, as Steel says, the
conspiracy theorists -- like those who believe that NASA is suppressing
information about the "Face on Mars" -- will complain.  But that is a
small price to pay for ensuring that scientists continue to retain the
amazingly high level of credibility that they currently hold in the public's
eye.
 
Clark Chapman