PLEASE NOTE:
*
CCNet SPECIAL - 2000 SG344: RETRACTIONS & REACTIONS
---------------------------------------------------
(1) STATEMENT BY THE NASA NEAR-EARTH OBJECT PROGRAM OFFICE
Ron Baalke <baalke@jpl.nasa.gov>
(2) SCIENTISTS REVISE ASTEROID WARNING
BBC News Online, 4 November 2000
(3) ASTEROID THREAT DOWNGRADED
MSNBC.COM, 4 November 2000
(4) MEDIA COVERAGE OF THE 2030 "IMPACT THREAT"
Michael Paine <mpaine@tpgi.com.au>
=====
(1) STATEMENT BY THE NASA NEAR-EARTH OBJECT PROGRAM OFFICE
NEW RESULTS OF OBJECT 2000 SG344
From Ron Baalke <baalke@jpl.nasa.gov>
New Results for Object 2000 SG344
November 4, 2000
On the afternoon of November 3, Carl Hergenrother of the Catalina
Sky
Survey (CSS) near Tucson, Arizona, obtained and made available
additional observations of object 2000 SG344 from the CSS image
archives. These pre-discovery observations significantly improved
the
certainty of the object's position in 2030 and effectively ruled
out the
chance of an Earth impact in that year. As explained in the
earlier release
from the International Astronomical Union (IAU), this was the
most likely
outcome of the continuing investigations. With the new
data, we can say
that the closest the object can approach the Earth in 2030 is 11
lunar
distances on September 23. These results are in agreement with
those of Andrea Milani at the University of Pisa, Italy.
The earlier announcement of a possible Earth impact in 2030 made
by
the Technical Review Team of the IAU followed the recently
established
process for reviewing Torino Scale 1 impact predictions. In
the first
use of this procedure, the Team formed a consensus opinion and,
following the IAU mandate, made their results public within 72
hours.
While the new orbital calculations have ruled out the 2030 event,
they
have also increased the likelihood of encounters in years after
2030.
For example, for the date September 16, 2071, current
computations
indicate roughly a 1 in 1000 chance of an Earth impact. However,
these
calculations assume that object 2000 SG344 is asteroidal in
nature.
There remains the significant possibility that this object is a
spacecraft booster rocket from the Apollo era and studies are
continuing to assess this possibility. Additional observations of
the
object will be possible in the coming months and these should
further
refine the calculations and conclusions.
NASA Near-Earth Object Program Office, Jet Propulsion Laboratory
Don Yeomans
Paul Chodas
Steve Chesley
============
(2) SCIENTISTS REVISE ASTEROID WARNING
From the BBC News Online, 4 November 2000
http://news.bbc.co.uk/hi/english/sci/tech/default.stm
Warnings of a devastating impact of an asteroid in 2030 were
exaggerated
-it will miss the Earth by millions of kilometres.
By BBC News Online science editor Dr David Whitehouse
Astronomers say reports that the Earth could be struck by a small
asteroid in 2030 are wildly exaggerated.
Less than a day after sounding the alert about asteroid
2000SG344, a
revised analysis of the space rock's orbit shows it will in fact
miss
the Earth by about five million kilometres (three million miles).
However, astronomers will continue to monitor the asteroid, which
was
picked up in September and thought to be 0.6 km (one mile)
across.
Some scientists have criticised the way the information was
released to
the media before it had been thoroughly confirmed.
Threat rating
Asteroid 2000SG344 is the first object to have a threat rating of
greater than zero on the 0-10 Torino scale of dangerous objects
from
space.
It was spotted on 29 September by astronomers David Tholen and
Robert
Whiteley using the Canada-France-Hawaii 3.6-metre telescope on
the
island of Hawaii.
Shortly thereafter, pre-discovery observations taken in May 1999
by the
Linear sky survey were also identified.
On Friday, the International Astronomical Union issued an alert
saying
that the object had about a 1-in-500 chance of striking the Earth
on 21
September, 2030.
No object has ever been rated with so high a chance of impact.
Were it to strike our planet, the results would be devastating,
with an
explosion greater than the most powerful nuclear weapon.
Sky survey data
But after the announcement, astronomers began looking at sky
survey data
to see if the object had been picked up but not recognised in
earlier
observations.
This turned out to be the case and these past observations
allowed a
more accurate calculation of the asteroid's orbit to be made.
The result: in 2030, the space rock will miss us by about five
million
kilometres, or 12 times the distance from the Earth to the Moon.
The new orbit reveals a slight risk of a collision with the Earth
about
2071, but it is thought that when the orbit is better known this
risk
will disappear as well.
Currently, asteroid 2000SG344 is about 15 million kilometres
(nine
million miles) away and getting more distant.
'Premature and alarmist'
Because 2000SG344 is in a similar orbit to the Earth, it has been
suggested that it might be an old Saturn upper-stage rocket of
the type
that was used in the early Apollo Moon missions.
If it is manmade and did strike Earth, the effects would be very
local
and limited.
Some scientists have criticised the IAU and Nasa for releasing
warnings
about the asteroid only for those warnings to be rescinded less
than a
day later.
Benny Peiser of Liverpool John Moores University, UK, said it was
"extremely unwise, premature and alarmist".
Copyright 2000, BBC
===========
(3) ASTEROID THREAT DOWNGRADED
From MSNBC.COM, 4 November 2000
http://www.msnbc.com/news/485240.asp
Astronomers eliminate chance of collision in 2030 thanks to
additional data,
but say 'we're still watching it'
By Alan Boyle
MSNBC
Nov. 4 - One day after sounding an alert, astronomers said
additional data
had eliminated any chance that a recently discovered space object
would
collide with Earth in 2030. The revised forecast shows the object
passing no
closer than 3 million miles. "We're still watching it, but
the 2030 event is
not a concern anymore," the head of NASA's asteroid-watching
project told
MSNBC.com Saturday.
THE FAINT OBJECT, dubbed 2000 SG344, was the first celestial body
to merit a
rating higher than zero on the zero-to-10 Torino scale of impact
threats.
That made the risk more significant than past real-life asteroid
scares but
far less threatening than the scenarios depicted in movies like
"Armageddon"
and "Deep Impact."
On Friday, NASA and the International Astronomical Union said the
object had
a 1-in-500 chance of hitting Earth on Sept. 21, 2030. That may
sound like a
slight chance by terrestrial standards, but it was a biggie for
asteroid-watchers. In comparison, the "background risk"
that an object
bigger than 0.6 mile (1 kilometer) in diameter would hit Earth in
a given
year has been estimated at somewhere between 1 in 500,000 and one
chance in
a million.
The estimate released Friday was based on observations made in
September
using the Canada-France-Hawaii 3.6-meter telescope, plus a review
of 1999
data from the Massachusetts Institute of Technology's LINEAR
team.
But late Friday, even more "prediscovery" data on SG344
came in from the
Catalina Sky Survey. That gave scientists such a good idea of the
object's
orbit that they could see it would miss Earth in 2030.
"The new solutions rule out the 2030 [collision]," said
Don Yeomans, manager
of NASA's Near-Earth Object Program Office at the Jet Propulsion
Laboratory
in Pasadena, Calif., "but it just pushes it out 40 years or
so."
He said there was still a slight risk of collision in the 2071-73
time
frame. However, additional observations of SG344 between now and
then could
rule out even those possibilities, he said.
A picture taken in the wake of the Tunguska Meteorite explosion,
which
occurred over Siberia in 1908, shows the devastation that even a
"small"
asteroid or comet can produce.
PLAYING 'WHAT IF...'
Even if the object were to hit Earth, it would be no
"Armageddon"-style
mass-extinction event. Based on its brightness, astronomers are
guessing
that the object is 30 to 70 meters (yards) wide. The upper end of
that range
would put SG344 on the level of the Tunguska Meteorite, which
flattened a
wide swath of Siberian forest in 1908. That blast was thought to
be the
equivalent of 15 million tons of TNT - compared with a 20,000-ton
yield for
the Hiroshima atomic bomb.
An impact involving SG344 could be the equivalent of 100
Hiroshima bombs,
scientists said.
"You certainly wouldn't want to be at the impact point,
because there's a
good chance it would make it through the atmosphere ... but at
most we would
have really local consequences," said astronomer Paul
Chodas, a colleague of
Yeoman's at the Near-Earth Object Program Office.
From Earth's perspective, SG344 is slowly receding in an orbit
very close to
our own and getting fainter every night. Gareth Williams of the
IAU's Minor
Planet Center said that the object, currently 8.4 million miles
away, is
"beyond the range of all but the largest telescopes on the
planet."
Within months, it will disappear from view until the 2020s.
That's why
astronomers were anxious to check their data records to see if
SG344 showed
up but went unnoticed. As in past cases involving asteroid
alarms, such
"prediscovery observations" were key to eliminating the
perceived risk of a
collision with SG344.
The fact that the object follows an orbit so close to Earth's
raised the
possibility that SG344 is actually a rocket booster that was sent
out from
Earth years ago, Chodas said. The IAU pointed out that the S-IVB
rocket
stages used for Apollo 8 through 12 missions, for example, could
have
followed paths similar to the newly found object's orbit.
If SG344 is a rocket booster, the threat posed by any re-entry
into the
atmosphere would be far less than if it were an asteroid, Chodas
said. He
drew a parallel to NASA's Skylab space station, which dropped
through the
atmosphere in 1979 and broke into fragments that fell harmlessly
into the
Indian Ocean and onto Australia.
QUESTIONS IN THE AFTERMATH
Benny J. Peiser, an anthropologist at Liverpool John Moores
University who
specializes in the social implications of impact threats,
criticized the way
the SG344 incident unfolded.
In a posting to his widely respected Cambridge Conference e-mail
list,
Peiser said Saturday that "it was extremely unwise" for
astronomers to rely
on such limited data when they made their initial 1-in-500 impact
assessment, and that Friday's announcement by NASA and the IAU
was
"premature and alarmist."
Yeomans, however, said that he and other astronomers were trying
to follow
guidelines dictating that announcements about asteroid risks
should be made
within 72 hours after the risks are detected.
"It's just that at 80 hours we got this data" from the
Catalina Sky Survey,
he said.
Copyright 2000, MSNBC
============
(4) MEDIA COVERAGE OF THE 2030 "IMPACT THREAT"
From Michael Paine <mpaine@tpgi.com.au>
Dear Benny,
I thought you might be interested in the way the media have
picked up on
the 2030 "threat'. Here is a snapshot of Excite's astronomy
news page
this morning. I have never seen most of these newspapers on this
"science" page before. I wonder if they will appear
with the follow-up
story of "no threat"?!
regards
Michael Paine
Excite News Tracker:Astronomy Discoveries
http://nt.excite.com/topics/science/astronomy_discoveries
Last Updated 01:33 PM ET November 4, 2000
SPACE OBJECT MAY HIT EARTH IN 2030
Source: Los Angeles Times First Found: 4 Nov 2000
There is a small but significant chance that an asteroid
will strike Earth in 2030 with a force up to 100 times the
Hiroshima
bomb, an international team of astronomers concluded ...
SPEEDING OBJECT MAY HAVE A DATE WITH EARTH
Source: Washington Post First Found: 4 Nov 2000
Astronomers announced yesterday that they had spotted an object
speeding through space that has a 1-in-500 chance of colliding
with
Earth on Sept. 21, 2030.
SPACE OBJECT MAY HIT EARTH IN 2030
Source: San Jose Mercury News First Found: 4 Nov 2000
WASHINGTON -- The odds are 500-to-1 against its hitting Earth,
but a space object the size of an office building appears to be
on a
crash course with our planet, the ...
SPACE OBJECT IS HURTLING TOWARDS EARTH
Source: Edmonton Journal First Found: 4 Nov 2000
Scientists have spotted a small asteroid or a piece of space junk
that they say has a 1-in-500 chance of hitting the Earth in 30
years,
far greater odds than any ...
SCIENTISTS SEE SLIGHT CHANCE OF ASTEROID ....
Source: Kansas City Star First Found: 4 Nov 2000
Date: 11 03 00 22:15 WASHINGTON -- The odds are 500-to-1 against
a collision with Earth, but a space object the size of an office
building
appears to be on a ...
WHATEVER IT IS, IT MAY HIT THE EARTH IN 2030
Source: Seattle Post-Intelligencer First Found: 4 Nov
2000
OK, folks, this one is for real: A small, recently discovered
asteroid is on a path that gives it a 1-in-500 chance of striking
the
Earth in the year 2030 -- ...
ASTEROID GIVEN 1-IN-500 ODDS OF HITTING EARTH
Source: Salt Lake Tribune First Found: 4 Nov 2000
By Seth Borenstein Knight Ridder
Newspapers WASHINGTON -- The
odds are 500-1 against it hitting Earth, but a space object the
size
of an office building appears to be on ...
UNKNOWN SPACE OBJECT HEADING TOWARD EARTH
Source: Philadelphia Inquirer First Found: 4 Nov 2000
INQUIRER WASHINGTON BUREAU WASHINGTON - The odds are 500-1
against its hitting Earth, but a space object the size of an
office building appears to be on a potential crash course ...
----------------------------------------
THE CAMBRIDGE-CONFERENCE NETWORK (CCNet)
----------------------------------------
The CCNet is a scholarly electronic network. To
subscribe/unsubscribe,
please contact the moderator Benny J Peiser <b.j.peiser@livjm.ac.uk>.
Information circulated on this network is for scholarly and
educational use only. The attached information may not be copied
or
reproduced for any other purposes without prior permission of the
copyright holders. The fully indexed archive of the CCNet, from
February 1997 on, can be found at
http://abob.libs.uga.edu/bobk/cccmenu.html
DISCLAIMER: The opinions, beliefs and viewpoints expressed in the
articles and texts and in other CCNet contributions do not
necessarily reflect the opinions, beliefs and viewpoints of
the moderator of this network.