PLEASE NOTE:
*
CCNet DIGEST, 12 May 1998
-------------------------
(1) MINOR BODY PRIORITY LIST
Sormano Astronomical Observatory <sormano@tin.it>
(2) ON THE AIRBURST OF LARGE METEOROIDS IN THE ATMOSPHERE
Luigi Foschini <L.Foschini@fisbat.bo.cnr.it>
(3) DISCOVERY OF MAJOR IMPACT HORIZON AT THE EOCENE-OLIGOCENE
BOUNDARY
O. Pierrard et al., CEA, CNRS, France
(4) DIAMOND-BEARING IMPACTITES
V.L. Masaitis, KARPINSKY GEOLOGICAL INSTITUTE,
ST PETERSBURG
(5) THE LUNAR IMBRIUM IMPACT EVENT
L.A. Haskin, WASHINGTON UNIVERSITY
(6) SMALL IS BEAUTIFUL, OR HOW TO SURVIVE THE K/T IMPACT EVENT
H. Mai et al., UNIVERSITY OF BREMEN
(7) COMPARATIVE STRATIGRAPHY AT THE K/T/ BOUNDARY
Z.C. Song & F. Huang, ACADEMIA SINICA,
CHINA
(8) THE K/T BOUNDARY IN THE SOUTHERN PYRENEES (SPAIN)
N. Lopez Martinez et al., UNIVERSITY
COMPLUTENSE MADRID
========================
(1) MINOR BODY PRIORITY LIST
From Sormano Astronomical Observatory <sormano@tin.it>
Dear Dr. Peiser,
we include here a message that we would like to be distributed
through
your CCNet mailing list. Thank you for your attention and your
work.
Best regards
Piero Sicoli and Francesco Manca (sormano@tin.it)
-----
Subject: Minor Body Priority List
Within the framework of the activity that is performed in our
observatory in connection with The Spaceguard Foundation, we have
prepared a list of minor bodies for which observations and/or
identifications are most desirable, because hazardous close
encounters
with our planet can be predicted or at least (taking into account
the
present uncertainty of orbital elements) cannot be entirely ruled
out
(over a timespan of the order of one hundred years).
We have selected the objects on the basis of their MOID (Minimum
Orbital Intersection Distance) and have computed their close
approaches
with the Earth over a time interval spanning one century in the
past
and two centuries in the future.
The results are available at our homepage
(http://www.brera.mi.astro.it/sormano/mbpl.html)
Piero Sicoli and Francesco Manca
Sormano Astronomical Observatory (sormano@tin.it)
MPC code 587
=========================
(2) ON THE AIRBURST OF LARGE METEOROIDS IN THE ATMOSPHERE
From Luigi Foschini <L.Foschini@fisbat.bo.cnr.it>
Dear Friends and Colleagues,
I would like to inform you that at the xxx Eprint server
(http://xxx.lanl.gov/) a
preprint on a reanalysis of the "Lugo" bolide
of January 19, 1993, is now available:
L. Foschini: On the airbursts of large meteoroids in the Earth's
atmosphere, eprint astro-ph/9805124.
ABSTRACT: On January 19, 1993, a very bright bolide (peak
magnitude -23)
crossed Northern Italy, ending with an explosion approximately
over the
town of Lugo (Emilia Romagna, Italy). The explosion (14 kton)
generated
shock waves that were recorded by six local seismic stations. A
reanalysis of collected data allows us to hypothesize that the
meteoroid was a porous carbonaceous chondrite somehow like the
asteroid
253 Mathilde. (41kb)
Comments are welcome.
Thank you very much for your attention.
Cordially,
Luigi Foschini
CNR - Institute FISBAT
Via Gobetti 101, I-40129 Bologna (Italy)
tel. +39 51 639.9620/9622; fax +39 51 639.9654
E-mail: L.Foschini@fisbat.bo.cnr.it
WWW: http://www.fisbat.bo.cnr.it/homepp/dinamica/foschini.html
=========================
(3) DISCOVERY OF MAJOR IMPACT HORIZON AT THE EOCENE-OLIGOCENE
BOUNDARY
O. Pierrard*), E. Robin, R. Rocchia & A. Montanari:
Extraterrestrial
Ni-rich spinel in upper Eocene sediments from Massignano, Italy.
GEOLOGY, 1998, Vol.26, No.4, pp.307-310.
*) CEA, CNRS, LAB MIXTE, CTR FAIBLES RADIOACT, F-91198 GIF SUR
YVETTE, FRANCE
Evidence of a major cosmic event at the end of the Eocene is
given by
the finding of at least one, possibly two or more, impact
horizons
containing microtektites, microkrystites, shocked quartz, and
unusually high iridium concentrations. We report here the
discovery,
in the global stratotype of the Eocene-Oligocene boundary at
Massignano in Italy, of Ni-rich spinel, a mineral that forms by
the
interaction of meteoritic bodies with the Earth's atmosphere. A
maximum concentration of approximate to 800 crystals mg(-1),
corresponding to a flux of 2 x 10(7) crystals cm(-2), is observed
in
a well-dated layer (35.7 +/- 0.4 Ma) that also contains shocked
quartz and iridium. The crystals are found clustered in flattened
spheroids, the probable relic of their host bodies. The chemical
and
physical characteristics of the spinel crystals indicate that the
spheroids formed by interaction of dust particles in the upper
part
of the atmosphere rather than by ablation of large objects, as
proposed for the spinel-bearing spheroids found at the
Cretaceous-Tertiary boundary. The most likely explanation is that
the
dust particles were generated by a large cometary impact. Whether
this impact is the one that produced microtektites and/or
microkrystites, or another one that may have occurred shortly
after
or before, is still questionable. Additional searching for
Ni-rich
spinel at other upper Eocene sections may help to answer this
question. Copyright 1998, Institute for Scientific Information
Inc.
===========================
(4) DIAMOND-BEARING IMPACTITES
V.L. Masaitis: Popigai crater: Origin and distribution of
diamond-bearing impactites. METEORITICS & PLANETARY SCIENCE,
1998,
Vol.33, No.2, pp.349-359
KARPINSKY GEOLOGICAL INSTITUTE, SREDNY PROSPEKT 74, ST PETERSBURG
199106, RUSSIA
About three decades ago, a formerly unknown genetic type of
natural
diamonds was discovered in impact craters. Impact diamonds are
currently known from a number of impact structures in Europe,
Asia and
North America, and it's likely that the number of finds will
increase
with time. The Popigai crater, Northern Siberia, where impact
diamonds
were first found, was specifically Investigated in terms of
geology,
geophysics, petrography and mineralogy. Large resources of
industrial
impact diamonds were discovered, and these minerals were studied
in
detail. Authigenic impact diamonds occur in situ in shocked
graphite-
bearing gneisses that are found as inclusions in impact melt
rocks:
tagamites and suevites. According to the observed transformation
of
coexisting minerals, the lower estimated pressure of the coherent
martensite transition of graphite to diamonds is 35 GPa. Impact
diamonds inherit the original shape of graphite crystals and are
composed of a polycrystalline structured aggregate of cubic and
probably hexagonal carbon microcrystals 1-5 mu m across. Numerous
properties of diamonds depend on the high density of defects in
the
crystal lattice. Allothigenic impact diamonds occur in rocks
produced
by the homogenization and solidification of impact melt, which
originated from the complete fusion of graphite-bearing precursor
gneisses. These diamonds usually reflect the influence of the hot
melt
and are strongly corroded. Diamond-bearing tagamites and suevites
in
the Popigai crater interior occur as extended lens and sheets
bodies
and also as irregular small bodies. Diamond distribution depends
on the
original abundance of precursor graphite in the target rocks, on
the
superimposed shock-metamorphic zonation, and on the character of
the
ejection of shocked and melted material along different
trajectories
and azimuths. This has resulted in radial and concentric
inhomogeneities in diamond distribution in the crater interior.
On a
second order, the distribution depends on the scale of melt
contamination by clasts and fragments and by the duration of
cooling of
certain melt bodies and their constituents. Enrichment in
diamonds at
the margins of thick tagamite sheets is the result of rapid
cooling,
which prevents combustion of diamonds. A positive correlation
between
diamond content and the amount of phosphorus pentoxide in
impactites
indicates links to C and P probably in organic matter of the
primary
sedimentary rocks, which were subjected to granulitic
metamorphism 2.4
Ga ago and melted at the time of impact 35.7 Ma ago. Copyright
1998,
Institute for Scientific Information Inc.
========================
(5) THE LUNAR IMBRIUM IMPACT EVENT
L.A. Haskin: The Imbrium impact event and the thorium
distribution at
the lunar highlands surface. JOURNAL OF GEOPHYSICAL
RESEARCH-PLANETS,
1998, Vol.103, No.E1, pp.1679-1689
WASHINGTON UNIVERSITY,DEPARTMENT OF EARTH & PLANETARY
SCIENCES, CAMPUS
BOX 1169, 1 BROOKINGS DR, ST LOUIS, MO, 63130
Late in the Moon's heavy bombardment period, the impact that
formed the
Imbrium Basin excavated and melted a tremendous volume of
material that
was subsequently distributed over most of the Moon's surface. The
Apollo orbiting gamma ray experiments [Metzger et al., 1977] show
that
the Imbrium projectile struck in a Th-rich area, called the
High-Th
Oval Region here and regarded as a unique lunar geochemical
province.
Imbrium primary ejecta were thus probably rich in Th. It is shown
here
using ejecta deposit modeling that the distribution of Th in the
highlands surface along the ground tracks of the gamma ray
spectrometers is consistent with the distribution expected for
Imbrium
ejecta deposits. Deep basins other than Imbrium appear to have
excavated regions of lower crust that were mafic and Fe-bearing
but not
Th-rich. The possibility that the surface Th distribution arises
mainly
from Imbrium ejecta has implications for the nature of the Moon's
igneous differentiation and the nature of the proposed
'cataclysm' or
late bombardment with large meteoroids. Copyright 1998, Institute
for
Scientific Information Inc.
=========================
(6) SMALL IS BEAUTIFUL, OR HOW TO SURVIVE THE K/T IMPACT EVENT
H. Mai*), K.V. Perch Nielsen, H. Willems, T. Romein: Fossil
coccospheres from the K/T boundary section from Geulhemmerberg,
the
Netherlands. MICROPALEONTOLOGY, 1997, Vol.43, No.3, pp.281-302
*) UNIVERSITY OF BREMEN, DEPARTMENT OF GEOLOGY, KLAGENFURTER STR,
D-
283539 BREMEN,GERMANY
The recent discovery of well preserved, complete spheres of
Biantholithus sparsus in a clay layer from the K/T boundary
interval
in the Geulhemmerberg section resulted in a search for
coccospheres
of other taxa. Applying the same new preparation-and SEM
techniques,
coccospheres of over 30 Cretaceous and Tertiary species were
found;
they are illustrated and briefly described in this paper. Based
on
the excellent state of preservation of the coccospheres of
several
Cretaceous species it is suggested that they survived the K/T
boundary event(s). Copyright 1998, Institute for Scientific
Information Inc.
=============================
(7) COMPARATIVE STRATIGRAPHY AT THE K/T/ BOUNDARY
Z.C. Song & F. Huang: Comparison of palynomorph assemblages
from the
Cretaceous/Tertiary boundary interval in Western Europe,
northwest
Africa and southeast China. CRETACEOUS RESEARCH, 1997, Vol.18,
No.6,
pp.865-872
ACADEMIA SINICA, NANJING INSTITUE OF GEOLOGY & PALAEONTOLOGY,
NANJING
210008, CHINA
The composition of palynomorph assemblages from selected sections
through the Cretaceous/Tertiary (K/T) boundary interval in
Western
Europe, northwest Africa and China is discussed. Similarities are
emphasised and widespread trends noted, including the
evolutionary
development of the porate group of pollen grains, palynomorph
extinctions within the boundary interval, and links with a
climatic
cooling trend. The comparative analysis revealed numerous
taxonomic
and; nomenclatural problems, as a list of 71 forms recorded from
five
papers on European and North African topics demonstrates. These
taxa
are considered to be similar or identical to palynomorphs
documented
in four Chinese papers, despite the fact that almost all of the
identifications differ at either generic or specific level, or
both.
(C) 1997 Academic Press Limited.
======================
(8) THE K/T BOUNDARY IN THE SOUTHERN PYRENEES (SPAIN)
N. Lopez Martinez*), L. Ardevol, M.E. Arribas, J. Civis, A.
Gonzalez
Delgado: The geological record in non-marine environments around
the
K/T boundary (Tremp formation, Spain). BULLETIN DE LA SOCIETE
GEOLOGIQUE DE FRANCE, 1998, Vol.169, No.1, pp.11-20
*) UNIVERSITY COMPLUTENSE MADRID, DEPARTMENT OF GEOLOGY, E-28040
MADRID, SPAIN
In the Ager basin and Benabarre area (southern Pyrenees, Spain),
the
Cretaceous-Tertiary (K/T) boundary is recorded in a succession of
non-marine to coastal deposits (Lower Tremp Formation). Abundant
diverse dinosaur tracks have been found at two localities on top
of
an estuarine sandstone body. A few meters above, grey marls at
two
localities contain Palaeocene mammals and fish. Both levels are
correlated with the latest part of chron C29R. These data have
led to
the location of the K/T boundary within a 3 m thick stratigraphic
interval with no major breaks in the sedimentation. A rapid fall
in
delta(13)C content is recorded shortly after the KT boundary. The
delta(13)C curve does nor support the hypothesis of a gradual
shift
due to volcanic activity. Both fossil vertebrates and isotope
data
are compatible with an abrupt change in the continental
ecosystems
close to the K/T boundary. Copyright 1998, Institute for
Scientific
Information Inc.
----------------------------------------
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*
DEEP IMPACT SPECIAL: REVIEWS, COMMENTS AND SUGGESTIONS
-------------------------------------------------------
(1) NATIONAL SPACE SOCIETY AND CREATORS OF "DEEP
IMPACT" ANNOUNCE
CAMPAIGN TO COLLECT ONE MILLION NAMES FOR
COMET MISSION
Ron Baalke <BAALKE@kelvin.jpl.nasa.gov>
(2) ASTEROIDS, COMETS AND COSMIC DISASTERS IN GENRE FILMS:
1951-1998
Steve Koppes <SKoppes@aol.com>
(3) ONLINE REVIEWS OF DEEP IMPACT
Phil Burns <pib@nwu.edu>
(4) VARIOUS REVIEWS OF DEEP IMPACT [Morrison, Cowing, Chapman,
Durda]
David Morrison <david.morrison@arc.nasa.gov>
(5) ESTIMATED MAY 8-10 GROSS FOR DEEP IMPACT IN US CINEMAS
David Morrison <david.morrison@arc.nasa.gov>
(6) FIVE % OF DEEP IMPACT OFFICE TAKE SHOULD BE DONATED
FOR
IMPROVED NEO SEARCHES
Greg Bear <grbear@ix.netcom.com>
(7) A LETTER TO 100 NEWSPAPERS AROUND THE WORLD
Michael Martin-Smith <martin@miff.demon.co.uk>
(8) JUPITER SCIENTIFIC REPORT ON THREATS FROM HEAVEN
From Victor D. Noto" <vnn2@phoenixat.com>
=======================
(1) NATIONAL SPACE SOCIETY AND CREATORS OF "DEEP
IMPACT" ANNOUNCE
CAMPAIGN TO COLLECT ONE MILLION NAMES FOR COMET MISSION
From Ron Baalke <BAALKE@kelvin.jpl.nasa.gov>
Contact: Karen Rugg
National Space Society
202-543-1900, ext. 77
Warren Betts
Paramount Pictures
310-479-1305
NATIONAL SPACE SOCIETY AND CREATORS OF "DEEP IMPACT"
ANNOUNCE CAMPAIGN
TO COLLECT ONE MILLION NAMES FOR COMET MISSION
Public invited to go to <http://www.nss.org/impact>
to "Make an IMPACT"
(Washington, DC) -- May 7 -- The National Space Society, along
with
Paramount Pictures and DreamWorks Pictures, today announce a
joint
online campaign to collect one million names to be placed on
board a
spacecraft that will intercept an actual comet. The
campaign, "Make an
IMPACT," is being launched in time for tomorrow's nationwide
release of
the film, "DEEP IMPACT," and will continue through the
summer or until
the one million mark is met.
The spacecraft, STARDUST, is being prepared for launch by NASA
and the
Jet Propulsion Laboratory to intercept Comet Wild-2, collect
samples
and return to Earth. The names will be printed onto a microchip
to be
placed aboard the craft later this year. Already on the chip are
the
names of every member of the National Space Society, and the
names of
the cast and crew of "DEEP IMPACT." Names can be
submitted by going to
the National Space Society website at nss.org/impact or to the
film's
website at deep-impact.com.
"We are firm believers in the idea that, today, fact can be
as
spellbinding as fiction," said Ms. Pat Dasch, executive
director for
the National Space Society. "In this case, a film tells a
fictional
story of an impending comet collision while, in fact, NASA and
JPL are
preparing a craft to intercept a comet and learn more about it.
We are
very pleased to be partnering with Paramount on this project;
with a
one million name goal, we're committed to making a real
'impact.'"
The National Space Society is also producing a slide set for
educators
on comets and asteroids, featuring text prepared by leading
scientists.
The set will include several images from "DEEP IMPACT."
The National Space Society, founded in 1974, is an independent,
nonprofit space advocacy organization headquartered in
Washington, DC.
Its 23,000 members and 90 chapters around the world actively
promote a
spacefaring civilization. Information on NSS and space
exploration is
available at <http://www.nss.org/>.
"DEEP IMPACT" is a contemporary action thriller about
the chaos that
ensues when it is discovered that a comet is on a deadly
collision
course with the Earth. DreamWorks Pictures and Paramount Pictures
present "DEEP IMPACT," a Zanuck/Brown production,
directed by Mimi
Leder. The executive producers are Oscar-winner Steven Spielberg,
Joan
Bradshaw and Walter Parkes. The film is written by Michael Tolkin
and
Bruce Joel Rubin. DreamWorks SKG is a multi-faceted
entertainment
studio formed in October 1994 by Steven Spielberg, Jeffrey
Katzenberg
and David Geffen. Paramount Pictures is part of the
entertainment
operations of Viacom Inc.
======================
(2) ASTEROIDS, COMETS AND COSMIC DISASTERS IN GENRE FILMS:
1951-1998
From Steve Koppes <SKoppes@aol.com>
On this opening weekend for "Deep Impact," I'd like to
take a few
moments to remember some of the more obscure movies of the genre.
Last week David Morrison gave us a technical-accuracy appraisal
of "A
Fire in the Sky" (1978), "Meteor" (1979),
"Asteroid" (1997), "Deep
Impact" (1998) and "Armageddon" (1998), while also
mentioning "When
Worlds Collide" (1951). And last summer Phil Burns reviewed
"Doomsday
Rock" (1997) for us. But I know of at least six other movies
of this
type: "The Day the Sky Exploded" (1958), "On the
Comet" (1970), "Night
of the Comet" (1984), "Without Warning" (1994),
"Within the Rock"
(1996), and "Falling Fire" (1997).
"The Day the Sky Exploded" was a French-Italian
production. This is the
darkest film I have ever seen (I'm talking lighting here, not
mood).
The first man in space, riding a nuclear-powered rocket to the
moon,
experiences a malfunction. He aborts his mission and ditches his
rocket, which blows up, sending a cluster of asteroids toward
Earth.
The Earth is saved when, in an international, coordinated effort,
all
the militaristic nations of Earth destroy the oncoming asteroid
swarm
in a barrage of nuclear (and conventional!?) missiles.
I haven't seen "On the Comet," but it is based on Jules
Verne's "Off On
a Comet" (1877). In this one, a comet explodes on the shores
of
northern Africa, knocking a substantial chunk of land and its
surviving
inhabitants into space.
"Night of the Comet" is one of my all-time favorite
films. It's a
comedy that can get away with all kinds of absurdity because it
obviously doesn't take itself seriously. If I remember correctly,
the
comet doesn't actually collide with Earth. Rather, the Earth
passes
through its tail, which reduces those not properly protected into
a
dehydrated pile of chemicals. Among the survivors are two sisters
in
Los Angeles, valley girls, who prevail over zombies, evil
scientists,
and then, apparently, live happily ever after with their
new-found
boyfriends.
"Without Warning" was a TV movie that aired the night
before Halloween,
1994. The movie was intended to have the same feel that led
millions of
people to believe that Orson Welles' "War of the
Worlds" radio
presentation on Halloween, 1938, was real. Real-life TV reporter
Sander
Vanocur appears in this one, along with Ed Marinaro, the former
NFL
football player who also would star in "Doomsday
Rock." Also appearing
briefly was U.S. Representative George Brown of California, the
chairman of the House Science, Space and Technology Committee.
This
time it's asteroids, not comets, raining down on Earth. I rather
enjoyed this one until it turned out that aliens were sending the
asteroids as part of their strategy to take over the world.
"Within the Rock" aired on the Sci-Fi Channel. Again my
memory may be a
bit hazy, but an asteroid is headed for Earth. A crew of miners
are
sent to remove enough of the asteroid's mass to deflect its
course.
Their mission is complicated by a predatory creature from another
galaxy who millions of years ago was subdued, encased in some
solid,
high-tech material, then launched into space. Over the millennia
the
creature's prison accretes an asteroid around it. The
miners have the
misfortune of exhuming and releasing the creature, which somehow
revives after millions of years encased in the rock. I rate this
film
quite highly for its suspenseful plot. The miners have a deadline
to
meet, but the creature keeps killing them off. Aside from the
creature,
it's fairly accurate (as far as I can tell -- I'm a science
writer, not
a scientist).
I can't say much about "Falling Fire" because I haven't
seen it. It
appeared on the Movie Channel a few months ago. The newspaper
listing
said it was about a spaceship officer who seeks a killer who is
murdering his crew and causing an asteroid to speed toward Earth.
By my count that's 13 movies, and I haven't even mentioned the TV
shows
(Rocky Jones, Space Ranger: "Crash of the Moons"
(1953), and "Bobby's
Comet (1954?), and Star Trek: "The Paradise
Syndrome" (1968).
Happy viewing.
Steve Koppes
=======================
(3) ONLINE REVIEWS OF DEEP IMPACT
From Phil Burns <pib@nwu.edu>
I have not yet seen DEEP IMPACT but there are a few reviews of
the
movie's science now available online. David Morrison provides one
at:
http://impact.arc.nasa.gov/news/1998/may/05.html
Morrison's sobering observation that
"It is interesting that the complete Spaceguard
survey could be
accomplished for the cost of either one of
these films: Deep Impact or
Armageddon."
should give everyone pause.
Randall Brooks, curator of physical sciences and space for the
National
Museum of Science and Technology in Canada, offers another review
at:
http://www.ottawacitizen.com:80/entertainment/980508/1696666.html
Brooks ends his review by stating:
"Fortunately, we will have to wait millions or
tens of millions of
years to get first-hand experience of the
psychological and physical
effects of an impending impact of the scale
depicted in Deep Impact."
with which I would disagree. While the average time between
impacts of
1-2 km objects may be a few hundred thousand (not millions) of
years,
there is no reason why such an impact could not happen tomorrow,
or next
week, or at any other time. This seems to me to be one of the
most
difficult ideas to get across to the general public. That the
-average-
elapsed time between impacts of a given size is a few hundred
thousand years,
does not mean that the -actual- elapsed time between any two
specific
impact events of a given size will ncessarily be a few hundred
thousand
years.
-- Phil "Pib" Burns
Northwestern University, Evanston, IL. USA
pib@nwu.edu
http://pibweb.it.nwu.edu/~pib/
==========================
(4) VARIOUS REVIEWS OF DEEP IMPACT [NEO NEWS 5/11/98]
From David Morrison <david.morrison@arc.nasa.gov>
I saw Deep Impact twice this weekend, and I think it is terrific!
Unfortunately the two reviews I read were not very favorable, and
both
took the position that the movie was too thoughtful and didn't
have
enough action and special effects. I suppose those critics will
prefer
Armageddon, which makes no sense but spent twice as much ($130M
versus
$60M) on the production. This week I was filmed by ABC for a show
they
will show in July dealing with the reality (?) behind Armageddon,
and
they commented that the special effects were much better in
Armageddon.
I can believe it. The special effects in Deep Impact are pretty
good in
terms of realism, but probably below state-of-the-art in a purely
technical sense. For example, some of the computer-generated
images
have slightly lower resolution that the photographic images. And
I felt
the water often didn't look right; the big breaking waves are
terrific,
but the water sloshing about over the landscape doesn't look much
better that the "crossing the red sea" scene from The
Ten Commandments
in the pre-computer age.
NASA supported Armageddon, which asked to film at Kennedy Space
Center,
but the Agency had little to do with Deep Impact. Former Johnson
Space
Center Director Gerry Griffin is credited with technical advice
and
appears briefly in the film, however. Deep Impact uses stock
footage of
a Shuttle launch, and the mission control room set looks just
right --
small and high-tech, consistent with current Agency efforts to
shrink
operations staff and depend more on modern information technology
in
running flight missions.
One can always nitpick the science, but in my opinion there is
not one
serious error in this film -- nothing that damages its basic
credibility. There is a great deal left unsaid, and this is in
fact an
understated film, so the audience is free to fill in the details
in
part according to how much you know. For example, it seems as if
the
astronauts get instantly to the comet, but it is entirely
consistent
with the film to imagine that several months have passed -- they
simply
don't say how long this flight takes. And the President uses some
loose
language in describing the origin of the comet in terms of
billiard-balls in the Oort cloud, but in fact we can all easily
imagine
a public official not quite getting it right technically. At
least no
scientists or NASA officials in this film say anything incorrect.
(Actually they don't say much at all). Probably the most
questionable
science comes at the beginning and the end. At the beginning the
comet
is discovered with a small amateur telescope at a star party, but
then
apparently not seen again for several months. This could be
explained
in terms of the comet moving into the daylight sky, except for
the
little matter of it appearing at discovery in Ursa Major, a north
circumpolar constellation. And at the end the 8-km diameter comet
is
blown to smithereens by a nuclear charge of a few megatons that
seems
way too small to do the job. The one other problem takes place on
the
surface of the comet itself, which comes to life with strong
outgasing
entirely too quickly after local sunrise. The idea is fine but
the
realization greatly exaggerated. Other aspects of the comet are
good,
especially the use of anchors to hold the spacecraft down in the
ultra-low gravity of the surface. And the overall framework of
the film
is entirely plausible, from the perspective of planetary science
as
well as the impact hazard.
Certainly this is much better science that any of the previous
impact
films -- there is no idiocy of a comet knocking an asteroid into
an
impact trajectory, or of small fragments getting through the
atmosphere
and hitting individual buildings, or of impacts targeted
precisely at
cities such as New York, Phoenix, or Dallas. The Deep Impact
film-makers took the trouble to find out what the real impact
danger is
-- both from a tsunami due to a mile-wide impact into the ocean,
and an
Extinction Level Event from a 10-km land impact. And the two-year
lead
time for a comet discovery is also just about right. Gene and
Carolyn
Shoemaker are listed as technical advisors in the credits, and
they
should be proud!
I found that Deep Impact is very impressive, thoughtful, even
moving.
It focuses in the entire middle section of the film on the
reaction of
people to impending doom. The approach is often subtle, based on
a
closeup of fingers nervously tapping, or an exchanged glance, or
an
involuntary head movement. Morgan Freeman gives a sensitive
portrayal
of the President, Tea Leoni draws our sympathy as a young
reporter in
way over her head, and Robert Duval turns in one of his finest
performances as the old astronaut -- a hero without the
histrionics.
One reviewer refers to Duval's projection of "simple
goodness -- an
unclouded spirit". Unfortunately, it is the subtlety of the
film that
was criticized in the reviews I read. I am reminded of last
year's
Contact, which was also criticized as too cerebral by many
reviewers,
who perhaps wanted to see aliens from Central Casting. One critic
of
Deep Impact wrote that "director Mimi Leder focuses on the
anguish,
fear and overwhelming grief that's provoked by an approaching
cataclysm. She couldn't have picked a harder trajectory for a
season
when people mainly want to see things that go boom . . . maybe
people
go to cataclysm movies for the cataclysm . . . the tidal wave
seems
welcome when it arrives." Another review concluded as
follows: "When
the tidal wave comes, its not a moment too soon. Still, when the
comet
enters the atmosphere -- a yellow fireball across the sky -- its
hard
not to feel just a bit excited that its coming. That they're all
coming. Armageddon, Godzilla, all of them".
See this film. It may do more to alert the thinking public to the
impact hazard than anything else in the past. And its images may
even
keep you up at night wondering if we are doing enough to protect
our
planet against this threat.
-------------------------------------------------------------------
From Keith Cowing:
This movie deals with two impacts - the slow-to-build human
impact of
realizing that immutable oblivion will happen at a set date
and time
and the swift and awesome impact which occurs when planets
and comets
collide.
Despite the blockbuster hype which "Deep Impact"
is being given, it is
actually a rather small story set against a huge backdrop - not
unlike
"Titanic". Take the technology out of the picture and
alter the source
of the impending disaster and the plot would still work. This
movie is
not about things being blown to smithereens but rather about the
choices you make when you have the power to save someone else's
life,
the way you spend your remaining days when the exact time of your
death
is a certainty, and the legacy you relay to those who will
survive.
Given Hollywood's chronic habit of violating the laws of physics,
this
movie is a rather notable exception. Speaking as a former
NASA rocket
scientist, the technology is portrayed quite realistically, the
celestial scenery is done very well, and the cataclysmic effects
of a
cometary impact are masterfully realized. This film also manages
to use
subtle means of conveying titanic events - such as a fleet of
ICBMs
exploding on a comet but having no effect on its
trajectory. You never
see it happen, you only see the disappointment on the president's
face
and in his voice as he goes on TV to relay the bad news.
This movie is about a devastating cometary impact - you know that
walking in the theatre. What amazes me is how a number of
movie
critics who profess to know and seek out good movies - and
good story
telling - are critical of this movie because it "waits until
the last
15 minutes" to deliver its punch. All I can say is that each
of these
critics is showing that they too are suckers for special
effects. For
me, the plot build-up is what makes this movie's
"impact" as powerful
as it is.
This movie is well worth seeing. It allows you to place
your own
existence in both a human and a cosmic perspective - something
far too
few films ever allow you to do.
---------------------------------------------------------------------
From Clark Chapman:
As a movie, we rate "Deep Impact" to be fairly
good...about 7.5 on our
scale of 0 to 10. Scientifically, it was fairly good. There were
essentially no "dumb" mistakes, like those that
proliferated during the
"Asteroid" miniseries. There were many things that
weren't right, but
can be generously chalked up to "artistic license".
Most seriously
wrong were:
* violent comet activity commences within seconds of
"sunrise"
* dispersal of the larger comet fragment that close to Earth is
represented
as a 4th of July-type fireworks display, rather than the deadly
holocaust
it would have been
* the two comet fragments are seen in broad daylight as bright
objects
weeks before impact
More forgivable, taking account of the simplification necessary
for a
plot in a reasonable length movie, is the sudden orbit
computation by
the astronomer in the dome (rather than Brian Marsden), omission
of
other effects (besides tsunami) of the impact, apparent discovery
of a
comet as bright as Mizar and Alcor that is then kept secret for a
year,
the extremely tangential angle (and long time to traverse the
atmosphere) of the impacting comet fragment (and its lack of
brilliance), apparent failures to predict locations of impact
earlier
(but after XF11, who knows?), and the extraordinary violence of
the
comet (spitting boulders) but then who knows what a comet really
looks
like?
Elements of the plot also strain credulity, from our informed
point-of-view. Especially, I mean keeping secret the comet,
the
construction of the space mission, and the construction of the
caves in
Missouri.
But the movie was at least 100 times better than
"Asteroid" and a
reasonable movie to watch by any standard. The Indianapolis
newspaper
reporter I talked with yesterday (who had seen the preview with
the paper's
movie critic) said "wait for the video". But the
special effects in the
final minutes are worth seeing on the big screen.
---------------------------------------------------------------------
From Dan Durda:
I enjoyed the movie as well. They got enough of the major science
so
right that I can overlook the nit-picky errors as dramatic or
artistic
license. I think it might be worth sharing with our colleagues
that we
might consider emphasizing the following as we talk with the
public
about the movie: for the price of making the movie, we could
survey to
completeness within a couple decades the near-Earth environment
for objects
which might pose a global catastrophe. (Granted, it wouldn't help
much
for the problem of long-period comets, presumably the scenario of
the
movie, but...) If people enjoyed the movie and were moved to
think a
little more about the scenario, would they be willing to spend
the
price of admission to better understand and prevent the real
thing?
=====================
(5) ESTIMATED MAY 8-10 GROSS FOR DEEP IMPACT IN US CINEMAS
From David Morrison <david.morrison@arc.nasa.gov>
The following information on Deep Impact is from Steve Ostro:
------------------------------------------------
Estimated May 8-10 gross in North American theaters:
1. Deep Impact $41.9 million (3156
theaters)
2. City of Angels 4.7 million
3. He Got Game 3.8 million
4.
Titanic 3.0
million
5. Les Miserables 2.7 million
Deep Impact posted the highest-ever pre-Memorial Day
single-weekend
gross, beating Twister ($41.1 million in 1996). It also accounted
for
more than half of the weekend's total.
------------------------------------------------
I (Morrison) note that this means nearly 7 million people have
already
seen Deep Impact. I wonder what impact it had on
them. Also I must
add that with a little extrapolation, the first week's gross from
Deep
Impact would be enough to implement the Spaceguard Survey
(detectors
and operations for 10 years), assuming availablility of the USAF
GEODSS
telescopes.
David Morrison
===========================
(6) FIVE % OF DEEP IMPACT OFFICE TAKE SHOULD BE DONATED
FOR
IMPROVED NEO SEARCHES
From Greg Bear <grbear@ix.netcom.com>
Just saw DEEP IMPACT with my son this morning. A very effective
film--beautifully made and at least acceptable on the technical
level.
(The last shotgun blast impact does seem extremely underrated, of
course, in terms of destruction--would probably cook one side of
the
Earth!)
I suggested in a NY NEWSDAY opinion piece last year that perhaps
Dreamworks SKG should donate five percent of the box office take
for
improved sighting and tracking... No announcement yet from them!
Greg Bear
========================
(7) A LETTER TO 100 NEWSPAPERS AROUND THE WORLD
From Michael Martin-Smith <martin@miff.demon.co.uk>
Meanwhile last night, Spielberg's DEEP IMPACT is opening, with a
piece
on News at Ten last night, featuring an interview with
Spaceguard-UK's
founder, Jay Tate. Trevor MacDonald, although anxious not to be a
scare
monger, gave due weight to the magnitude of the disaster which
would
result from an actual hit. I have sent a letter to 100 newspapers
world
wide, in severral different languages, making the case that the
true
lesson form this newly discovered thrweat is NOT counter attck
with
nuclear weapons, but orderly human dispersal into Space
utilizing these
same potential inpactors to our own profit
For the moment a radical idea, but one which I intend to make
widely
accepted within 10-15 years . The exploration of Space is a
matter of
scientific and intellectual interest- its development and
colonization
is an evolutionary necessity! If we work to put communities into
Space,
the space probes will come easily and cheaply enough. The
Lifespan of
an advanced civilization is now beyond doubt inversely
proportional to
the cost of Space travel! For interst, my letter appears below!
Re:- "Deep Impact"
Dear Editor,
Mr Spielberg's film, "Deep Impact", shows the
disastrous potential of
an impact on Earth by a comet or asteroid - indeed, it is most
likely
an understatement. The end of civilization, perhaps Humanity,
would
most likely result. Events like "Deep Impact", or
greater, have
occurred often in Earth's history, and will happen again.
Detection by dedicated telescopes and compositional study
by space
probes is essential reconnaissance and should be
established without
delay. Despite this, some will give us months' warning at best,
and so
are not amenable to Earth based nuclear strikes. Lunar based
lasers
could react more rapidly , but the only true insurance for
Humanity is
the timely development and settlement of Space by self
sustainable
populations, supported from these same threatening asteroids and
comets. It is wiser to consume an enemy for profit than to
destroy him.
Impact is the only disaster threat offering such a huge potential
pay-off!
We can and should move out into the new ecological niche before
us.
Those who question the value of Human Intelligence and science
now
have a clear answer; we exist to take Life and Mind out
into Space, as
surely as lions exist to eat wildebeestes - or face deserved
extinction!
Yours sincerely,
Dr Michael Martin-Smith,BSc,MRCGP,FBIS President, Space Age
Associates,
http://www.astronist.demon.co.uk/index.html
Spaceguard-UK http://dspace.dial.pipex.com/town/terrace/fr77/
=========================
(8) JUPITER SCIENTIFIC REPORT ON THREATS FROM HEAVEN
From Victor D. Noto" <vnn2@phoenixat.com>
Jupiter Scientific Reports on Threats from Heaven: Dangers to
Earth
from Solar System Debris at
http://ajanta.sci.ccny.cuny.edu/~jupiter/pub/sciinfo/impact.html.
Foregoing is an Interesting read. Would like your opinion on this
report.
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