CCNet 97/2002 - 20 August 2002
"When the close Earth approach of a large NEA rises above the
background level (the Palermo Scale value is then greater than zero) we
know this event is out of the ordinary and hence of some concern."
-- NASA/JPL, Impact Risk website
"What do asteroid impacts have to do with the Gaia hypothesis?
Perhaps Gaia has gotten tired of being whacked by asteroids and
having to restart biological evolution over and over again. Perhaps
she evolved technologically sophisticated, big-brained mammals who can
travel in space as a way of protecting herself from asteroids. Like
antibodies that protect the body from invading disease organisms,
humans can defend our Earth Mother against extraterrestrial intruders.
Just a thought."
--Ronald Bailey, Reason Online, 31 July 2002
"Space Rock just misses" - or so said the headline on the article in
Saturday's Herald Sun on the recent passing by of asteroid 2002NY40. A few
days earlier, ABC Western Plains, the voice of Australia in rural NSW,
advised "Don't panic . . . yet" as they, too, discussed our looming
encounter with said space rock. Don't panic indeed. This near miss, the
latest in a long line of asteroid scares, may well have been a close thing
in astronomical terms, but to us on the ground, the fact that it missed
Earth by well over half-a-million kilometres hardly seems to justify
the use of the words "just misses" let alone the wastage of the
necessary column inches to do so. Asteroid near-misses are this year's Y2K
drama - promoted, hyped and blown out of all proportion by
bespectacled gents in white laboratory coats doing all they can to boost
their funding applications."
--John Weldon, The Age (Australia), 20 August 2002
(1) ASTEROID FLYBY SEEN WORLDWIDE
Sky & Telescope, 19 August 2002
(2) IMPROVED MODELLING OF ASTEROID TSUNAMI
Michael Paine <email@example.com>
**MORE COMMENTS ON 2002 NT7**
(3) DEFENDERS OF EARTH: ARE HUMANS GAIA'S IMMUNE SYSTEM?
Reason Online, 31 July 2002
(4) ARMAGEDDON: COULD IT BE CLOSER THAN WE THINK?
The Express, 2 August 2002
(5) ASTERODDS PLAYING UP?
The Mirror, 2 August 2002
(6) BEWARE OF BUSES FROM DEEP SPACE
Space Daily, 31 July 2002
(7) WHAT THE NT7 AFFAIR IS TELLING ME
Daniel Fischer <firstname.lastname@example.org>
(8) 2002 NT7 IN SOUTH AFRICAN MEDIA
Jon Richfield <email@example.com>
(9) A BIT OF NEO HISTORY: REVERSED ROLES AS BBC CRITCISE NASA OVER ASTEROID SCARE
BBC News Online, 4 November 2000
(10) AND FINALLY: WHY SMART PEOPLE BELIEVE WEIRD THINGS TOO
Scientific American, September 2002
(1) ASTEROID FLYBY SEEN WORLDWIDE
>From Sky & Telescope, 19 August 2002
By Paul Deans
>From Uzbekistan and the Crimea to the UK, across North America, and on to
Hawaii, amateur astronomers around the world had fine views of the close
flyby of asteroid 2002 NY40 last weekend.
The experience of David Nance (Huntsville, Alabama) was typical of the many
reports received at Sky & Telescope. He wrote: "I found 2002 NY40 easily and
followed it for about 30 minutes. It was very bright (I'd estimate it at
magnitude 9.5), and it was really spectacular sailing through the eyepiece,
changing the patterns I formed with it and the framework of stars. My wife
thought it was neat since it was so obviously not a 'fixed' star ... it
looked a lot like a slow moving satellite on a really weird trajectory."
Chris Stephan, an AAVSO observer in Sebring, Florida, used his 14.25-inch
reflector with a 32-mm wide-field Erfle eyepiece to find and track the
asteroid. "I found the object very quickly and was amazed at how fast it was
traveling. I was hoping to catch a chance stellar occultation, but during
the time period I observed, it just passed between stars with a few very
close appulses. Another interesting thing was that the asteroid seemed to
fluctuate slowly in brightness by about 0.2 magnitude within a 4 to 5 minute
Most observers were surprised by the rapid motion of the asteroid through
their field of view, and some also reported that 2002 NY40 had a definite
color. "I never anticipated how quickly the asteroid would sweep through the
field even though advanced planning revealed such," wrote Clay Sherrod who
watched from his observatory in Conway, Arkansas. "In the 4-inch guide
refractor of the scope, the motion of this object was just incredible, not
unlike that of a slow-moving satellite seen through the same telescope. The
Near Earth Object was distinctly reddish in color; this was unmistakable
when it passed very near similarly bright stars within the visual telescopic
field of view."
Not everybody employed a large-aperture telescope at high power to watch the
flyby. Becky Ramotowski of San Antonio, Texas, used her 80-mm refractor and
a 32-mm eyepiece to follow the asteroid. "I was able to find it easily after
picking out a star field and just waiting for it to pass through," she
wrote. "It was quite amazing to visually watch it zoom through space! I did
not take any images, I just enjoyed the 'ride', and was it ever a fast one!
It made for an exciting evening of viewing, especially since we had a nice
ISS and Hubble pass to get us warmed up!"
After observing 2002 NY40 with his 8-inch telescope, Timo Karhula (Sweden)
decided to try using binoculars. "At local midnight (22:00 UT), when the
asteroid moved into Vulpecula, I pointed my 20 x 100 binoculars towards it.
It took a couple of seconds to discern a change in its position, but then
the motion was obvious. Then I took out my 7 x 50 binoculars, targeted M71,
and waited. At 22:43 UT, I could just see the 10th-magnitude asteroid. With
the hand-held 7 x 50s I was not able to notice the immediate movement of
2002 NY40, but after a few minutes I could see the speck's motion."
The most remote observation report received so far comes from Tom Krajci in
Uzbekistan. "Several of us had a blast finding and tracking the motion of
2002NY40 the evening of August 17th in Tashkent, Uzbekistan. Our first
attempts at finding this fast mover were unsuccessful until we got more
methodical. Using JPL HORIZONS we generated accurate coordinates for every
five minutes. It was crucial to use the proper latitude and longitude of our
location. Next we plotted the expected locations of the asteroid on the
appropriate Uranometria chart, star hopped to that region (using my 10-inch,
f/7.2 home-made Dobsonian), and kept a patient watch for a moving
interloper. After two minutes we confirmed the asteroid and followed it for
about 30 minutes. The asteroid's motion was most obvious when it passed near
Thanks to everyone who submitted observing reports to Sky & Telescope.
Copyright 2002 Sky Publishing Corp.
(2) IMPROVED MODELLING OF ASTEROID TSUNAMI
>From Michael Paine <firstname.lastname@example.org>
In June Los Almos National Laboratories issued a press release
described new advanced modelling of tsunami generated when a large asteroid
strikes the deep ocean. The work is being conducted by Galen Gisler and Bob
Weaver from the LANL's Thermonuclear Applications Group
(!), and Michael Gittings from Science Applications International Corp. The
article stated: "The team's effort builds on the pioneering research of Los
Alamos' Charles Mader and Dave Crawford of Sandia National Laboratories.
More accurate models of tsunami behavior are now possible..."
I have since heard from Charles Mader, who has been using the new software.
He is excited about the improvement: "...to do the modelling with all known
Physics is a dream come true".
The big question is whether the modelling changes the estimates of tsunami
effects across ocean basins. It is too early to answer this question (which
in any case will no doubt be the subject of journal papers) but Charles
advises that the tentative results are that the water crater (cavity) from a
1km diameter asteroid is the same as previous work but the collapse of this
cavity is complicated by turbulent water motion and breaking waves. As a
result the maximum height of waves at the edge of the crater is about twice
that of the previous modelling work (by Crawford and Mader). However, the
waves have a shorter period than the previous work and will therefore
dissipate faster (the same general results have been obtained with 500m and
250m asteroids). The end result is that tsunami from a 1km asteroid "will
not present a significant hazard after they run across an ocean basin". This
is the same conclusion as Crawford and Mader reached previously. As I point
out on my tsunami web page
(http://www4.tpg.com.au/users/tps-seti/spacegd7.html) this differs from
modelling conducted by Ward and Asphaug.
I am looking forward to the release of some official results of the latest
work and hope that it will resolve some of the differences.
The Planetary Society Australian Volunteers
(3) DEFENDERS OF EARTH: ARE HUMANS GAIA'S IMMUNE SYSTEM?
>From Reason Online, 31 July 2002
By Ronald Bailey
The Gaia hypothesis, which holds that Earth is a living organism in its own
right, typically has been used to highlight man's role in messing up the
environment. But if the latest warning of a possible ecological catastrophe
turns out to be accurate, people could end up helping Gaia rather than
The Gaia hypothesis--named after the Greek word for the Earth goddess, also
translated as "Earth Mother"--was devised in the 1970s by atmospheric
chemist James Lovelock and microbiologist Lynn Margulis. In Gaia: A New Look
at Life on Earth, Lovelock and Margulis wrote, "The entire range of living
matter on Earth from whales to viruses and from oaks to algae could be
regarded as constituting a single living entity capable of maintaining the
Earth's atmosphere to suit its overall needs and endowed with faculties and
powers far beyond those of its constituent parts." They said Gaia could be
defined as "a complex entity involving the Earth's biosphere, atmosphere,
oceans, and soil; the totality constituting a feedback of cybernetic systems
which seeks an optimal physical and chemical environment for life on this
Most evolutionary biologists reject the Gaia hypothesis as an unscientific,
although poetic, metaphor. But let's not let such quibbles trouble us today.
According to the Gaia hypothesis, the history of life on Earth can be
regarded as a progressive modification of the planet's chemistry and
temperature by biological organisms acting in ways that enhance their own
flourishing. For example, Earth's atmosphere was modified over billions of
years by photosynthetic microorganisms from one that was predominantly
carbon dioxide and methane into its current oxygen-rich state. This
oxygen-rich atmosphere apparently set the stage for the evolution of
multicellular life that took off in earnest during the "Cambrian explosion"
some 540 million years ago.
In the millions of years following the Cambrian explosion, Gaia took out all
the stops, and the earth saw a vast diversification of life and finally the
colonization of land by plants and animals. Then, 250 million years ago, the
Permian party came to a catastrophic end in which 95 percent of Earth's
species were wiped out. Gaia picked herself up and started over. Dinosaurs
and flowering plants eventually evolved to dominate the landscape in the
Cretaceous Period (146 to 65 million years ago). At the time, our tiny
mammalian ancestors were scrambling about the leaf litter, trying to avoid
becoming dinosaur snacks. The cornucopia of Cretaceous life came to an
abrupt end 65 million years ago, when 70 percent of all species became
The leading explanation for these mass extinctions is the havoc caused by
asteroids slamming into the earth. The asteroid that brought the Cretaceous
Period to a close is thought to have been 10 miles wide, creating the
110-mile-diameter Chicxulub crater just off Mexico's Yucatan peninsula. The
massive Permian extinction is thought to have been caused by an asteroid 10
It's inevitable that Earth will be struck again. In 1908 a small comet or
asteroid, about 165 feet in diameter, exploded over the remote Tunguska
region of Siberia, releasing energy equivalent to 15 megatons of TNT, 1,000
times stronger than the atomic bomb dropped on Hiroshima. In 1989 an
asteroid measuring a quarter of mile in diameter missed Earth by just
400,000 miles. In 1994 the house-sized asteroid XM1 was spotted only 14
hours before passing within 65,000 miles of Earth, well inside the moon's
orbit of 238,000 miles. In June an asteroid the size of a soccer field
missed Earth by 75,000 miles.
Scientists estimate that an asteroid with a diameter of a kilometer (0.62
mile) could destroy civilization by drastically changing the earth's climate
after impact and kill one-quarter of the world's population. This disaster
scenario was popularized in 1998 by two mediocre movies, Deep Impact and
So far astronomers have identified over 26,000 asteroids in our solar
system. The 1,700 or so that regularly pass close to Earth's orbit are
designated Near Earth Objects, or NEOs. Six hundred NEOs measure more than a
kilometer in diameter. The National Aeronautics and Space Administration's
Jet Propulsion Laboratory helpfully lists more than a score of upcoming near
misses for those who have a morbid interest in such things.
The latest scare occurred last week with the detection of asteroid 2002 NT7,
which measures more than a mile in diameter. Initial calculations showed
that there was a small probability that it might hit the earth on February
1, 2019. Fortunately, subsequent analysis found that civilization will be
spared until at least February 1, 2060, when there is a very tiny chance the
asteroid will hit us. In the meantime, NASA and the European Space Agency
are increasing their monitoring of NEOs and thinking of ways to deflect or
blow up any asteroids that threaten to smash into Earth.
What do asteroid impacts have to do with the Gaia hypothesis? In Gaia: A New
Look at Life on Earth, Lovelock asked, "To what extent is our collective
intelligence also a part of Gaia? Do we as a species constitute a Gaian
nervous system and a brain which can consciously anticipate environmental
Perhaps Gaia has gotten tired of being whacked by asteroids and having to
restart biological evolution over and over again. Perhaps she evolved
technologically sophisticated, big-brained mammals who can travel in space
as a way of protecting herself from asteroids. Like antibodies that protect
the body from invading disease organisms, humans can defend our Earth Mother
against extraterrestrial intruders. Just a thought.
Ronald Bailey, Reason's science correspondent, is the editor of Global
Warming and Other Eco Myths (Prima Publishing) and Earth Report 2000:
Revisiting the True State of the Planet(McGraw-Hill).
Copyright 2002, Reason Online
(4) ARMAGEDDON: COULD IT BE CLOSER THAN WE THINK?
>From The Express, 2 August 2002
IT IS ONLY A MATTER OF TIME BEFORE OUR LUCK RUNS OUT, YET EXPERTS ARE
WARNING THAT WORLD LEADERS ARE NOT TAKING THE THREAT OF AN ASTEROID STRIKE
AS YOU read this, scientists are preparing to dive far below the surface of
the North Sea to explore an exciting discovery. It's not the elusive giant
squid, nor a mystical city. They are looking at a huge asteroid crater,
seven miles wide and 900 ft deep. Just off the coast of Scarborough, it is
thought to have been been caused 60 million years ago by an asteroid 1,500
ft wide. The impact rings around it have been unusually well-preserved by
sediment and geologists believe it could reveal vital information about
asteroids like the one thought to have wiped out the dinosaurs 65 million
Never has it seemed more important to discover everything we can about large
chunks of rock that hurtle towards Earth. Last week scientists revealed that
a mile-wide asteroid was heading towards us at more than 60,000mph.
Astronomers feared that on February 1, 2019, it would hit us with the
violence of a million H-bombs. Codenamed 2002 NT7, it is one of countless
mountain-sized bits of cosmic debris that circle the sun between the orbits
of Mars and Jupiter.
Luckily, it is now thought that 2002 NT7 will not hit us in 2019 - new
observations suggesting that it will, instead, blast through the Earth's
atmosphere on February 1, 2060.
It's too early to start panicking just yet. As astronomers pin down the
precise orbit of 2002 NT7, the chances are it will turn out to be on a
course that misses Earth - although it may be an uncomfortably close shave.
But it is not too early to start finding out exactly where all the other
thousands of Earth-crossing asteroids are - and to keep a very close watch
For this is just the latest of a series of alerts about this cosmic threat
to our planet.
The vast majority never come near us but there are many thousands that cut
across the orbit of the Earth, threatening to strike with devastating
consequences. In April, astronomers in America discovered another asteroid
on course for a possible collision in 2880. And only last month, a 100-yard
wide asteroid called 2002MN came within 75,000 miles of hitting our planet -
an astronomical hair's breadth. Worryingly, it was only discovered after it
had made its closest approach.
All the experts agree that it is only a matter of time before our luck runs
out yet governments around the world have so far spent only token amounts of
money on finding out more about this danger. Two years ago, the UK
Government set up a task force to decide what steps Britain should be taking
over these Near Earth Objects (NEOs). Its final report called for the
construction of sophisticated telescopes dedicated to tracking down NEOs and
co-operation with other countries in drawing up plans for dealing with the
Earlier this year Lord Sainsbury, the Science Minister, unveiled the
Government's response: an information centre in Leicester.
Such a reaction seems almost like a parody of the Government's penchant for
spin over substance. Earth under attack? No problem: just give a boffin a
desk in Leicester and a heap of glossy brochures to hand out.
Others will regard it as an appropriate response to a blatant attempt by
scientists to whip up funding with a ludicrous scare story.
After all, when did you last read of an asteroid devastating vast areas of
In fact, newspapers have unwittingly carried reports of just such events
many times in the last century. In July 1908, correspondents reported
spectacular scenes over Europe, with nights so bright people were playing
golf at two in the morning. At the same time, earthquake stations picked up
a massive disturbance from somewhere in Siberia. Years later, when Soviet
scientists finally reached the epicentre of the disturbance near the
Tunguska River, they found a scene of utter devastation.
Hundreds of square miles of trees had been flattened, their trunks scorched
and blackened. They also found a mile-wide crater.
THE so-called Tunguska Event of 1908 is now known to have been caused by a
200ft meteor crashing down with the violence of 20 H-bombs. No one was
killed, but had the impact occurred a few hours later, it would have struck
the heart of Europe, killing millions. Had it hit the sea - which covers two
thirds of the planet - it would have been no less devastating. The shock
wave or tsunami would have drowned whole cities on the Pacific coast from
Japan to California.
No astronomer seriously doubts that far bigger NEOs can and do strike the
Evidence for more than 200 impact craters has been uncovered around the
In 1978, a geophysicist working for the Mexican national oil company found
remnants of a colossal crater deep under the coast of the Gulf of Mexico.
Measuring 110 miles across, it was gouged out by a huge impact around 65
million years ago. Scientists now think that the six-mile-wide meteor that
formed the crater helped drive the dinosaurs into extinction.
Humans are not immune from the effects of NEOs. Evidence has recently
emerged of a devastating impact in the Middle East which may have triggered
the otherwise mysterious collapse of early civilisations around 2,300 BC.
Satellite images of southern Iraq have revealed a two-mile-wide circular
depression which bears the hallmarks of a fresh impact crater. If confirmed,
it would point to the region being hit by an NEO with the violence of
hundreds of H-bombs around 4,000 years ago.
What no one yet knows is how big a risk we face from NEOs today. Estimates
suggest that the risk of a devastating impact within the next 100 years
could be as high as one in 1,500.
The problem is that no one knows for sure. At the last count, around 2,000
NEOs had been identified and their orbits calculated. Around 350 of them are
potentially hazardous, following paths that bring them a little too close to
the Earth for comfort. Of these, about 100 are so big that their impact
would be equivalent to the explosion of around a million H-bombs.
Knowing if we are on course for an NEO collision is vital. Given enough
warning, it should be possible to deflect an asteroid off a collision course
and avert disaster - a scenario that was played out in the film Armageddon,
starring Bruce Willis. One way to do it is to send a rocket packed with
nuclear explosive to intercept it. The aim is not to blow the thing to
pieces: that would leave us facing multiple impacts. Instead, the idea is to
detonate the warhead and vaporise material off one face of the NEO. The
resulting jet effect would gently push it off its collision course. Done
early enough, the detonation of a single H-bomb would be enough to do the
Some objects could even be deflected by landing rockets on them and using
their engines to send them out of harm's way.
Science fiction? Not at all: last year, Nasa landed its Near Earth Asteroid
Rendezvous (NEAR) probe on a 21-mile-long chunk of rock known as 433 Eros.
In 2005, Nasa plans to carry out a similar mission to a comet, firing a
probe deep into its surface.
Some scientists think the time has come to begin practising the art of
saving the planet but most think the priority is to find out how many NEOs
are out there - and that requires a global network of telescopes powerful
enough to spot a hill-sized chunk of rock millions of miles away and track
it, so its orbit can be worked out. The task is about more than just
compiling a catalogue of every sizeable NEO.
Constantly jostled by gravity, even apparently harmless NEOs can drift on to
collision courses in as little as 30 years. Add in the danger of comets
wandering in from beyond our solar system and the need to set up a global
early warning system seems beyond argument.
With the impact threat, the price of security is constant vigilance. Yet
until now, the role of cosmic lookouts has fallen to a handful of dedicated
professionals and amateurs. The amount of sky they can cover is only a
fraction of the vast expanse of space, which means there are still some
asteroids we cannot see.
ONLY when governments take the NEO threat seriously will our planet get the
early warning system it needs and for that to happen, politicians need to be
convinced of the need for action.
With one globally devastating impact expected only every 100,000 years,
dealing with NEOs is not about to become an election issue but this
overlooks the appalling death toll predicted from such an impact - expected
to run into hundreds of millions. Cosmic impacts thus produce a long-term
average toll of around 1,000 deaths a year - several times the average
fatality rate for air crashes, which every government takes very seriously.
Responding to last year's task force report, Lord Sainsbury declared that
Britain could "take an lead" in dealing with the threat. So far, our
Government has followed everyone else in failing to take the issue
seriously. We must all hope that it won't take a 10 megaton impact to wake
governments up to the very real threat that lurks in the depths of space.
Robert Matthews is a physicist at Aston University, Birmingham.
Copyright 2002, The Express
(5) ASTERODDS PLAYING UP?
>From The Mirror, 2 August 2002
By Kevan Furbank
RELAX, folks. The asteroid threat has been downgraded. The chances of the
lump of celestial rock turning planet Earth into the shape of a lozenge have
been reduced to one in 250,000.
Most unlikely, you would have thought. But it is still 56 times more likely
than winning the Lottery jackpot, the odds of which I am sure you are
painfully aware are 14million to one.
Yet people do win, the most recent and close to home being Limavady feller
Stephen Boyd. He scooped pounds 1.5million but is not going to give up his
pounds 10,000-a-year fizzy drinks job.
Makes you wonder what's in his fizzy drinks.
Statistically, lucky Stephen should have been hit by 56 asteroids. To my
certain knowledge, however, he carries no asteroid-induced injuries.
But I would advise him to wear a hard hat from now on.
This leads me on to the bookmakers who have given a chap odds of 20million
to one that Elvis Presley will turn up riding Shergar and then play Lord
Lucan at Wimbledon.
Even less likely, you would have thought, than winning the Lottery. But the
bookies are not so sure - they've limited the size of the bet to 5p, just in
But even this scenario becomes a certainty compared to the odds against
being struck by lightning seven times on seven different occasions - and
It's about one to 165,000 to the power of 7, a figure so high I can't write
it out in full because our printing press would run out of zeroes.
Yet it happened - to American park ranger Roy Sullivan between 1942 and
The first strike shot through his leg and knocked his big toenail off. In
1969, a second strike burned off his eyebrows and knocked him unconscious.
Another strike just a year later left his shoulder seared.
In 1972 his hair was set on fire and Roy had to dump a bucket of water over
his head to cool off.
In 1973, another bolt ripped through his hat and hit him on the head, set
his hair on fire again, threw him out of his truck and knocked his left shoe
A sixth strike in 1976 left him with an injured ankle. The last lightning
bolt to hit Roy Sullivan sent him to the hospital with chest and stomach
burns in 1977.
Sadly, Mr Sullivan committed suicide on the reasonable assumption that God
had it in for him.
But he will be remembered for cheating fantastic odds equivalent to being
caught in a hailstorm of asteroids, winning every lottery draw until the
money runs out and Elvis getting the Wimbledon doubles title - partnered
The moral of this story is that statistics - like the drinks price list in a
lapdancing club - bear absolutely no relation to reality; that the most
unlikely occurrences are very likely to occur; and if an asteroid has got
your name on it, your number is well and truly up.
Copyright 2002, MGN Ltd
(6) BEWARE OF BUSES FROM DEEP SPACE
>From Space Daily, 31 July 2002
by Michael Paine
Sydney - Jul 31, 2002
There was a flurry of interest by TV news studios and newspapers last week
when it was realised there was a slight risk that a space rock, designated
2002 NT7, some two kilometres across might hit the Earth in 2019. As
expected, by the end of the week additional observations had pinned down the
orbit sufficiently for astronomers to rule out any possibility of an impact
A debate ensued about whether the initial, tentative calculations should
have been made available to the public and whether the media reporting was
When the dust settles, so to speak, there are a few points to be made about
Firstly, a 2km asteroid is something to be taken very seriously. The global
climatic effects of an impact anywhere on Earth would be devastating for our
civilisation and would probably lead to the death of more than a quarter of
the world's population. It would however, not be nearly as severe as the
impact 65 million years ago that is associated with the extinction of the
Secondly this object has an unusual orbit and it appears to be fortunate
that it was picked up by the LINEAR "Spaceguard" telescopes. With current
search efforts we can expect a large proportion, perhaps 80%, of Near Earth
Asteroids of this size to have been discovered to date so it was a bit of a
surprise that 2002 NT7 turned up.
Thirdly, a world-wide effort by astronomers, who were mostly amateurs, was
needed to track the asteroid so that calculations could be refined and the
object eventually declared "safe" (there is still a slight risk of an impact
in 2060, but once again further observations are expected
to eliminate that possibility).
Estimates of the average impact rate of asteroids vary considerably. During
the next 50 years there is perhaps a one in ten chance of an impact actually
occurring but this would likely be an airburst event such as the 60m
diameter asteroid that flattened 2000 square kilometres of forest in Siberia
Small asteroids collide with the Earth (or more correctly, the atmosphere)
much more frequently than large ones. They are not a threat to our
civilisation but could easily destroy a city with an explosion similar to
that of a nuclear bomb.
For now NASA has decided to concentrate on asteroids one kilometre and
larger that pose a global threat. It aims to have detected 90% by 2008. The
search effort also picks up many of the smaller asteroids so that after ten
years it is expected that about 20% of asteroids 200m or
larger will have been found.
Since an impact by an object this size could devastate a small country a 20%
completion rate is likely to be seen as inadequate by future generations and
the Spaceguard effort will no doubt be stepped up.
Up until 1996 Australia made a significant contribution to Spaceguard,
accounting for about one third of discoveries. In that year Australian
government funding stopped and the program closed down. In January this year
more than 90 scientists from around the world signed an open letter
to the Australian government supporting the revival of funding for
"Spaceguard Australia". Most were experts in the field of asteroid research
and the letter was a remarkable, spontaneous show of solidarity.
Nevertheless during a subsequent TV interview, Australian Science Minister
Peter McGauran dismissed the search for Earth-threatening asteroids as a
"fruitless, unnecessary, self-indulgent exercise".
Fruitless? Spaceguard is finding objects like Asteroid 2002 NT7, and can
provide decades of warning - sufficient time to nudge an Earth-threatening
asteroid into a safe orbit.
Unnecessary? Only if we take the gamble that an impact will not happen in
our lifetimes. Sadly it is all too easy for politicians to ignore our
responsibilities to future generations - the ones who would benefit most
from observations made today.
Self-indulgent? That is plain insulting to the many scientists who have
recognised that the Earth is at risk and who have dedicated much of their
career to addressing the hazard. It is also insulting to the hundreds of
amateur astronomers who donate their time to follow-up observations.
In fact, the letter arose from a statement by a spokesperson for Minister
McGauran who indicated that funding would be reconsidered, following another
asteroid "near miss" around Christmas time.
Clearly asteroids do pose a hazard to our civilisation. The Spaceguard
system has been shown to be effective in detecting objects like Asteroid
2002 NT7 but there are many more that we should be looking for. An
international effort is needed and, in particular, the current blind spot in
the southern hemisphere needs to be addressed.
Yes - there is an asteroid with our name on it. It might hit tomorrow or not
for a thousand years. Every telescope that is added to the international
Spaceguard program will reduce our chances of being caught with insufficient
time to avoid the collision.
By reviving the search for rogue asteroids, Australia would fulfill its
responsibility to protect its citizens, to help protect other citizens of
the world and to provide a possible gift of survival for future generations.
Michael Paine is a consulting mechanical engineer based in Sydney. He is a
member of the Planetary Society.
(7) WHAT THE NT7 AFFAIR IS TELLING ME
>From Daniel Fischer <email@example.com>
sent: 31 July 2002
The more I think about the "2002 NT7 affair", the more I am confused - not
least by your assessment of the events in CCNet of July 26, item 13, and the
quotes therein. There seems to be a widespread belief in the community that
2002 NT7 was unique (and thus newsworthy) as the first NEO in the history of
Sentry & Co. that reached a Palermo value of greater than zero or even
approached it. You quote a statement from the Sentry site that claims that
prior to NT7 "the risks posed by the potential impacts identified by Sentry
have all been well below the background level" - and this is simply not the
The exotic example of 1950 DA aside (because of the extremely long lead
time), there was at least one other case in which the impact probability of
an asteroid reached about half the background value - and stayed at that
"threat level" for several weeks: 2002 CU11. No IAU announcement was made
about it. On the other hand the IAU protocol *did* kick into action
pre-Sentry in late 2000 when the small NEA 2000 SG433 had reached an impact
probability of 1:500 for 2030 - which was (if one assumes an impact of a 50
meter object every 200 years) only 1/75 of the background, representing a
Palermo level of -1.9. Back then the media impact had been immense, as
reflected in CCNet of Nov. 7 to 9, 2000.
Who knows how many cases like 2002 CU11 have come and gone unnoticed, i.e.
were not picked up by the impactological media of record such as CCNet and
BBC Online, let alone given special treatment by the IAU? The growing list
of removed risks on Sentry does not mention what maximum Palermo value had
been reached nor any other historical data - an omission, in my opinion. The
whole issue also forces me to ask again (as I did a few months back on
CCNet, not receiving one useful reply): What *is* a clear criterion that
distinguishes a NEA with a high Palermo
value that disappears from the lists within days or weeks from a really
threatening one whose P value eventually takes off?
Or, put in a more practical way: what pattern of Palermo as f(t) do we need
to experience in order to raise a real justified alarm with the public at
large (and ourselves)? It would be great outcome of the NT7 saga if some
agreement on that could be reached by all official and not so official
bodies putting out alert messages. And here is a suggestion how to proceed:
Someone with enough knowledge of the population(s) of NEOs, the probability
of discovery and the precision of astrometry (and enough computing power, of
course) should run a really comprehensive Monte Carlo simulation. Have lots
of NEOs go around the Sun, approach Earth, be discovered by LINEAR and
friends, be followed-up and sometimes appear on (and in nearly all cases
disappear again from) Sentry and NEODyS!
Then we could see directly how a typical case of an erroneous threat (as one
might call 2002 NT7 and kin) develops as compared to a threat that stays
valid for a long time before vanishing - and compared, of course, to an actual
impactor. I recall from DPS Meetings in the 90s that simpler simulations *have* been
done, e.g. by Paul Chodas and Ted Bowell: They were watching how the
impact probability of a certain impactor would develop with time, given the
state of the art of astrometry then (and Paul even produced a pretty scary
movie with the error ellipse slowly closing in on the Earth). What I am
calling for would be a much more complex simulation, of course - but it may
be worth the effort.
The Cosmic Mirror
(8) 2002 NT7 IN SOUTH AFRICAN MEDIA
>From Jon Richfield <firstname.lastname@example.org>
Sent: 31 July 2002 16:18
FWIW: South African local newspaper reports on 2002 NT7 could have been
I saw reports in the English Cape Times, the Afrikaans Die Burger and a
brief quote in the Mail & Guardian. There were presumably others, but I am
not much of a news addict, so having dug up those after hearing a radio
comment about the Cape Times headlines, I left it at that. The
Cape Times had a front page report from Reuters heavily laced with your
quotes and explanations, and an explanatory graphic from an American web
site. Die Burger had briefer (translated) excerpts of the same report on
page fifteen, and the M&G had about one sentence in a quotes column. The
tone was generally cheerful and gee-whiz, but as well balanced as one could
expect from non-technical media.
One or two non-techs asked me to explain it to them and left me with the
impression that we need never worry about getting directly through to Mr
Clapham Omnibus. It won't happen. The most important thing then, is to get
through to the opinion formers, which usually is impossible until
after they have made up their minds.
I have not yet thought through the implications of that. What a Good Thing
that I am not a pessimist...
(9) A BIT OF NEO HISTORY: REVERSED ROLES AS BBC CRITCISES NASA OVER ASTEROID SCARE
>From the BBC News Online, 4 November 2000
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.
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
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
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
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
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
Benny Peiser of Liverpool John Moores University, UK, said it was "extremely
unwise, premature and alarmist".
Copyright 2000, BBC
(10) AND FINALLY: WHY SMART PEOPLE BELIEVE WEIRD THINGS TOO
Scientific American, September 2002
Smart People Believe Weird Things
Rarely does anyone weigh facts before deciding what to believe
By Michael Shermer
In April 1999, when I was on a lecture tour for my book Why People Believe
Weird Things, the psychologist Robert Sternberg attended my presentation at
Yale University. His response to the lecture was both enlightening and
troubling. It is certainly entertaining to hear about other people's weird
beliefs, Sternberg reflected, because we are confident that we would never
be so foolish. But why do smart people fall for such things? Sternberg's
challenge led to a second edition of my book, with a new chapter expounding
on my answer to his question: Smart people believe weird things because they
are skilled at defending beliefs they arrived at for nonsmart reasons.
Rarely do any of us sit down before a table of facts, weigh them pro and
con, and choose the most logical and rational explanation, regardless of
what we previously believed. Most of us, most of the time, come to our
beliefs for a variety of reasons having little to do with empirical evidence
and logical reasoning. Rather, such variables as genetic predisposition,
parental predilection, sibling influence, peer pressure, educational
experience and life impressions all shape the personality preferences that,
in conjunction with numerous social and cultural influences, lead us to our
beliefs. We then sort through the body of data and select those that most
confirm what we already believe, and ignore or rationalize away those that
This phenomenon, called the confirmation bias, helps to explain the findings
published in the National Science Foundation's biennial report (April 2002)
on the state of science understanding: 30 percent of adult Americans believe
that UFOs are space vehicles from other civilizations; 60 percent believe in
ESP; 40 percent think that astrology is scientific; 32 percent believe in
lucky numbers; 70 percent accept magnetic therapy as scientific; and 88
percent accept alternative medicine.
Education by itself is no paranormal prophylactic. Although belief in ESP
decreased from 65 percent among high school graduates to 60 percent among
college graduates, and belief in magnetic therapy dropped from 71 percent
among high school graduates to 55 percent among college graduates, that
still leaves more than half fully endorsing such claims! And for embracing
alternative medicine, the percentages actually increase, from 89 percent for
high school grads to 92 percent for college grads.
We can glean a deeper cause of this problem in another statistic: 70 percent
of Americans still do not understand the scientific process, defined in the
study as comprehending probability, the experimental method and hypothesis
testing. One solution is more and better science education, as indicated by
the fact that 53 percent of Americans with a high level of science education
(nine or more high school and college science/math courses) understand the
scientific process, compared with 38 percent of those with a middle-level
science education (six to eight such courses) and 17 percent with a low
level (five or fewer courses).
The key here is teaching how science works, not just what science has
discovered. We recently published an article in Skeptic (Vol. 9, No. 3)
revealing the results of a study that found no correlation between science
knowledge (facts about the world) and paranormal beliefs. The authors, W.
Richard Walker, Steven J. Hoekstra and Rodney J. Vogl, concluded: "Students
that scored well on these [science knowledge] tests were no more or less
skeptical of pseudoscientific claims than students that scored very poorly.
Apparently, the students were not able to apply their scientific knowledge
to evaluate these pseudoscientific claims. We suggest that this inability
stems in part from the way that science is traditionally presented to
students: Students are taught what to think but not how to think."
To attenuate these paranormal belief statistics, we need to teach that
science is not a database of unconnected factoids but a set of methods
designed to describe and interpret phenomena, past or present, aimed at
building a testable body of knowledge open to rejection or confirmation.
For those lacking a fundamental comprehension of how science works, the
siren song of pseudoscience becomes too alluring to resist, no matter how
smart you are.
Michael Shermer is publisher of Skeptic magazine (www.skeptic.com) and
author of In Darwin's Shadow and Why People Believe Weird Things, just
Copyright 2002, Scientific American
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