Date sent: Tue, 08 Apr 1997 10:17:49 -0400 (EDT)
Priority: NORMAL

Folks -
You may find my comments interesting.

M. J. Mumma

Date: Mon, 24 Mar 1997 09:49:22 -0400 (Michael J. Mumma)
Subject:Re: NEO News (3/21/97)

Dave -

The delivery of hazardous interstellar chemicals by
cometary dust is nil, if the dust is distributed in
individual particles of small size. All chemicals are
destroyed high in the atmosphere during entry, as you
know. If held in a larger body, say 50 m diameter or so,
airbursts rule, so some chemicals may survive but this is
poorly understood at present. For km and larger bodies,
surface impact occurs but again chemical survival is
uncertain. The suggestion that some cometary chemicals
survived during S-L 9 infall (e.g. HCN) is a speculation,
nothing more.

I can't get too exercised about the idea of "coherent
catastrophism" - impacts do occur, and there is no reason
to think that they are any more significant if regular
than if random. The whole issue of catastrophism is
an unfortunate misnomer, in my opinion. Clearly,
evolutionary changes driven by (slow) global plate
motions and (fast) impact induced punctuated
extinction/evolution both do occur and have occurred.
They differ principally by inducing different temporal
response functions in the biosphere. They both occur and
they are both important - albeit on different time
scales. The current impact-induced scenario is so
different from pre-Darwin "catastrophism" as to dictate
that the same name should not be used for both. If I
understand the historical debate correctly, the old
"catastrophism" was almost verbatim Biblical dogma
(creation myths, floods, etc.) and the events were even
'dated' from Biblical sources.It is highly misleading to
use the same term for impact-induced change.


Dr. Michael J. Mumma
Laboratory for Extraterrestrial Physics
Code 690
NASA Goddard Space Flight Center
Greenbelt, MD 20771
voice: 301-286-6994
fax: 301-286-0212


From: Bob Kobres <>
Organization: University of Georgia Libraries
Date sent: Tue, 8 Apr 1997 13:52:58 EST
Subject: Seeking input on an interesting question.
Copies to:
Priority: normal

Below is a link to an interesting question. Hopefully there is some stored
knowledge among the Cambridge Conferees that will shed light on what seems to be
a common [Comet related?] story or ritual symbolically represented by these
artifacts, which are far separated from one another in time.


Note: If your browser will not do inline jpegs, use:


to fetch the images.

Bob Kobres

email= <>

phone= 706-542-0583


Date sent: Tue, 08 Apr 1997 08:41:50 -0400 (EDT)
Priority: NORMAL

From: NEO News 4/2/97


By Sandra Bull, AAP Science Correspondent

CANBERRA, March 31 AAP -

Australian skywatching for "killer rocks" could be
resurrected following intervention by Prime Minister John
Howard. Federal funding for asteroid expert Dr Duncan
Steel's Spaceguard search and tracking project dried up
at the end of last year despite pleas from the renowned
Planetary Society, whose members include director Steven
Spielberg, to Mr Howard. But Science Minister Peter
McGauran told AAP that Mr Howard recently asked himself,
Education Minister Amanda Vanstone and Defence Minister
Ian McLachlan to examine whether Australia's asteroid
spotting effort could continue. "He asked us to meet on
this issue and see if there's a way that Dr Steel can be
funded because he seems to have slipped between
portfolios at present," Mr McGauran said. Departmental
officials had held a preliminary meeting and the
ministers hoped to conclude the matter shortly, Mr
McGauran said. "That doesn't mean that anyone will pick
up funding for the issue but we're treating it as a case
where individuals can fall between portfolios because
they don't neatly fit in one or the other," he said.
But Mr McGauran said he did not believe this type of
project, previously funded by Senator Vanstone's
department, fitted within his portfolio as it lacked the
necessary research and industrial relevance. At a major
science conference here last year, Adelaide-based Dr Steel
accused the government of focusing on obvious
preventative measures, such as enforcing air safety
regulations, while ignoring the greater risk of
Australians dying from an asteroid impact. "The amount
that needs to be spent is not large, of the order of a
few million dollars per year - about as much as Australia
spends on supporting its canoeing and volleyball teams,"
Dr Steel told delegates. He estimated the energy
released from a two kilometre wide asteroid hitting Earth
at 30 km/sec was equivalent to a million megatons of TNT.
Human survival could be threatened by consequences
ranging from a cooling effect caused by pulverised rock
thrown into the upper atmosphere to massive tidal
waves. Dr Steel has said he would be willing for the
Defence Department to take over the project. The
Planetary Society said the demise of the Australian
program meant half the Earth's sky, the Southern
Hemisphere, would go unwatched as other near Earth object
monitoring programs were restricted to scanning the
Northern Hemisphere.

Meanwhile, the Press Association reported today that a
major scientific conference at Cambridge will hear claims
that debris from a giant comet caused the wholesale
collapse of civilisations and was immortalised in the
Biblical tale of Sodom and Gomorrah. Dr Victor Clube, a
senior research fellow in astrophysics at the University
of Oxford, believes the next intergalatic upheaval will
strike in about 1,000 years due to the reappearance of a
lethal cocktail of particles in the Taurid meteorite


Date sent: Tue, 08 Apr 1997 08:35:02 -0400 (EDT)
Subject: NEO News 4/2/97
Priority: NORMAL

From: SMTP%""
3-APR-1997; 04:15:42.83
Subj: NEO News (4/2/97)

NEO News (4/2/97)


The March 24 issue of Aviation Week and Space Technology
contains a two-page article by William B. Scott called
"Asteroid Threat Spurs New Defense Analyses". It is a
report on a talk given by George Friedman of the
University of Southern California in a key address to the
1997 IEEE Aerospace Conference at Snowmass. The tone of
the article is that government concern about NEO impacts
is new information, and that Friedman has carried out a
new analysis based on risk management techniques. The
article lead says that "a feasible approach focuses on
investment in space sensors and long-range radars".

Most of the background information on the NEO impact risk
is reasonably accurate, but the specific presentation of
options, attributed to Friedman, is disturbingly
off-course. A sequence of possible responses is given in
order of cost. None of these options includes a
Spaceguard-type survey. The options go from continuing
present efforts to accelerating current detection rates
to development of space-based sensors and long-range
Earth-based and space-based radars. Yet the only hazard
that is being mitigated against is impact by NEOs one
kilometer or more in diameter, which of course are the
ones that can be easily dealt with by an Earth-based
telescopic survey such a Spaceguard. The idea of using
space-based sensors and radars to detect kilometer-scale
NEOs is ludicrous.

Thus this article once more displays a fundamental
confusion about the role of a Spaceguard Survey in a
program of NEO defense. For some reason, we cannot seem
to get through to people that 1-km NEOs can be discovered
from the ground long in advance of their hitting the
Earth, and that Spaceguard has nothing to do with
last-minute detections. It is silly to even think of
detecting NEOs on their final plunge into the Earth,
giving only a few days or hours of warning. This strategy
seems obvious to me, but clearly it is a point that
others have difficultly accepting.

David Morrison


From: Bob Kobres <>
Organization: University of Georgia Libraries
Date sent: Tue, 8 Apr 1997 11:15:32 EST
Copies to:
Priority: normal

Earlier, (Michael J. Mumma)

> .... The current impact-induced scenario is so
> different from pre-Darwin "catastrophism" as to dictate
> that the same name should not be used for both. If I
> understand the historical debate correctly, the old
> "catastrophism" was almost verbatim Biblical dogma
> (creation myths, floods, etc.) and the events were even
> 'dated' from Biblical sources.It is highly misleading to
> use the same term for impact-induced change.

I think you may have an oversimplified view of the earlier contest between
these radically different views of how conditions might change on Earth.



(for pertinent hyper-links go to the above address)

The potential problem with any research paradigm is the radical premise
upon which it builds. If this footing slips the foundation crumbles, and an
edifice of thought construct comes tumbling down. Sir Charles Lyell, like his
philosophical model James Hutton, simply could not conceive of a deity so
indifferent or incompetent as to allow global catastrophes to occur. Lyell had a
particular disdain for speculation on comet induced upheavals. References to
these hoary threats are not indexed in "Principles" and when mentions of
hypothetical comet caused catastrophes do appear in Lyell's work they are
treated in a flippant condescending fashion. A bit of the barrister shows
through clearly here, Lyell was making his case. There is irony in the timing of
Lyell's quest to establish an only gradually changing motif for our world with
its " . . . perfect harmony of design and unity of purpose." The very year
(1827) Lyell first carried his preliminary manuscript to the publisher there was
in progress a contest sponsored by the University of Edinburgh for the "best
Essay on Comets." The winner of the gold medal and fifty pounds was David Milne
who produced a superb overview of what was then known of comets. The work was
published in 1828 under the title of Essay On Comets. Milne reviews earlier
ideas about comets and sequentially dismisses all previous hypotheses on
extraterrestrially-induced catastrophe with the exception of one, a direct
impact or very, very close brush with our planet. He goes on to identify the
then recently (1818) discovered comet, Pons/Encke, as a likely candidate for
such a smashup. Referring to Olbers calculations, Milne informs his readers that
this comet will come as close to Earth as the moon in 88,000 years, miss the
planet by 7,700 miles after 4 million years and finally hit with enough energy
to annihilate species in 219 million years. The way Milne ends this part of his
essay is rather prophetic:

"I have remarked, that Encke's Comet approaches nearer the
earth's orbit than any other yet discovered; and hence the
probability is, that the fate which is thus demonstrated to be
reserved for our globe, will be fulfilled by means of this
particular Comet. But such speculations, however striking the
results, conduce to no practical advantage, and contribute little
to the advancement of science. They afford astonishing proofs
of the energy of man's intellectual power, by which he extends
his vision to the horizon of the most distant futurity, and looks
forward, it may be, with a feeling of complacent assurance, to
those momentous events, which, from his knowledge of nature,
he is enabled to foresee. But let him not rest too confidently on
the verity of such anticipations. Astronomers have prophesied,
it is true, the collision of a Comet with the earth; an event that
will at once destroy the greater part of the human species: but
any slight attraction, which, in calculating the movements of this
comet, they have chanced to overlook, must invalidate all their
conclusions, and render the prediction at once vain and futile;
while, perhaps, some other comet, among the many thousands
traversing the system, and following an orbit to us unknown,
may, in the mean while, come in contact with our globe, and
thus, without any warning of its approach, produce the same
terrible effects, long before the expected period ha[s] arrived."

So there was within the public domain a very scientific demonstration,
based on observation and the "clockwork" laws of Newtonian
physics, that Earth could be hit by a comet, no divine hand had
designed this possibility out as Hutton and Playfair had maintained.

"The Author of Nature has not given laws to the universe,
which, like the institutions of men, carry in themselves the
elements of their own destruction. He has not permitted in His
works any symptom of infancy or of old age, or any sign by
which we may estimate either their future or their past duration.
He may put an end, as He no doubt gave a beginning, to
the present system, at some determinate period of time; but we
may rest assured that this great catastrophe will not be brought
about by the laws now existing, and that it is not indicated by
any thing which we perceive."

This statement first appeared in volume IV on page 55 of Playfair's
Works (1822) sans italics. The above quote is taken from "Principles" of
Geology (1850); the highlighting is Lyell's.

Quite likely Lyell never perused Milne's fine essay; from 1828 through 1831 he
was busy traveling about Europe gathering evidence for his own case, and he
spent a few more years completing "Principles." If Lyell was aware of Milne's
work he certainly gave it no credence for the concluding remarks of "Principles"
read very much like those of Hutton/Playfair quoted above.

So compelling was Lyell's stately view of nature that associations
between comets and meteor showers, combined with only nucleus size
limiting data from observing a few comets during solar transit,
sufficed to completely ephemeralize these hairy demons in the minds
of most scientists. The obvious crack in the very foundation of the
gradualist paradigm was thus quietly patched over. This is well
illustrated by a note which appeared in the February 15,1872 issue of
"Nature" (Vol. 5, pg. 310):

"We have reason to know that many weak people have been
alarmed, and many still weaker people made positively ill, by
an announcement which has appeared in almost all the
newspapers, to the effect that Prof. Plantamour, of Geneva,
has discovered a comet of immense size, which is to "collide,"
as our American friends would say, with our planet on the 12th
of August next. We fear that there is no foundation whatever
for the rumour. In the present state of science nothing
could be more acceptable than the appearance of a good
large comet, and the nearer it comes to us the better, for
the spectroscope has a long account to settle with the whole
genus, which up to this present time has fairly eluded our grasp.
But it is not too much to suppose that the laymen in these
matters might imagine that discovery would be too dearly
bought by the ruin of our planet. Doubtless, if such ruin were
possible, or indeed probable--but let us discuss this point.
Kepler, who was wont to say that there are as many comets in
the sky as fishes in the ocean, has had his opinion endorsed in
later times by Arago, who has estimated the number of these
bodies which traverse the solar system as 17,500,000. But
what follows from this? Surely that comets are very
harmless bodies or the planetary system, the earth
included, would have suffered from them long before this,
even if we do not admit that the earth is as old as geologists
would make it. But this is not all. It is well known that some
among their number which have withal put on a very portentous
appearance are merely the celestial equivalents of our terrestrial

By the way according to Milne:

". . . Kepler, who, though in some measure the father of
modern astronomy, . . . had very incorrect notions respecting
the system of nature in general. The planets he imagined to be
animals swimming round the sun by means of fins acting upon
the ethereal fluid; and, agreeable to this strange belief, he held
Comets to be also huge uncommon creatures, generated in the
celestial spaces, and that they "were made to the end, the
ethereal fluid might not be more void of monsters, than the
ocean is of whales, and other great thieving fishes; and that a
gross fatness being thus gathered together, as excrements into
an apostume, the ethereal medium might thereby be purged,
lest the sun should be obscured, as he was for a year together,
when Julius Caesar was slain; when being weakened by a
bloody colour, he cast but a dim and disdainful light!" He even
supposes that the faculty of the earth, which he fancied to be
animated like all the other planets, is so terrified at the
approach of a comet, that it "sweats out a great quantity of
vapour through terror, and that hence arise great rains and

Milne extracted this from Kepler's Harmonices Mundi, (1619 Tab. IV,
Cap.VII). Though Kepler's views were at odds with earlier thinkers such as
Lucretius of the Epicurean school they show the need people have to
rationalize what is observed. Comets appear animate therefore they are
alive, or as we have read above, the Earth does not appear to have been
harmed by a comet though many must have collided, therefore comets
cannot hurt Earth.

Bob Kobres

email= <>

phone= 706-542-0583

CCCMENU CCC for 1997