CCNet 24/2003 -  3 March 2003

"I wonder what those conspiracy theorists will say a week or two
from now, when nothing has happened. Will they say NASA covered up the
destruction of the Earth?"
--Phil Plait,, 28 February 2003

"As the world becomes increasingly concerned about objects of mass
destruction, it is well to remember that most of them are natural
objects and that we have the technology needed to protect ourselves.
It's just that we are not placing enough priority, yet, on planetary NEO
defense. These extremely dangerous objects are already programmed to strike
our "little blue marble" and the challenge is to identify them,
determine their programs and prepare to deflect them, if possible,
or to survive their impacts, if we must. Fortunately, things are
improving, but we have a long way to go."
--Andy Smith, 1 March 2003

    SpaceWeather, 3 March 2003


    CNN, 28 February 2003

    CNN, 28 February 2003

    High Point Enterprise, 2 March 2003

    International Herald Tribune, 28 February 2003

    Michael Paine <>

    Andy Smith <>

    The Observer, 2 March 2003


>From SpaceWeather, 3 March 2003

METEOR UPDATE: A rare Antarctic meteor shower due on March 1st was
unimpressive. "We had all eyes out last night for the shower but saw only
one meteor," reports astronaut Don Pettit from the International Space
Station. Ham radio operators in Australia listened for 144 MHz echoes from
the shower; they heard nothing out of the ordinary. "In fact, signals were
poorer than usual," notes Rob Quick of Canberra. Stay tuned for further

ASTEROID FLYBY: A small 25-meter wide asteroid, 2003 DW10, is flying past
Earth today only 1.4 times farther from our planet than the Moon. John
Rogers of the Camarillo Observatory captured this image of the 17th
magnitude space rock on March 2nd. Rogers tracked the asteroid, not the
stars, so 2003 DW10 appears as a pointlike speck in the middle of the image.
The surrounding stars are streaked. [3D orbit] [ephemeris]

BIG SUNSPOT: The face of the Sun has been mostly blank for some weeks, but
now a large sunspot has appeared. Active region 296 stretches eight
Earth-diameters from end to end. It's easy to see, but never stare directly
at the Sun. Use safe solar observing techniques instead.

COMET NEAT: Last month Comet NEAT swung perilously close to the Sun--a
lovely event recorded by SOHO coronagraphs. Contrary to some internet
rumors, the comet's orbit was not altered by its apparent encounter with a
coronal mass ejection. Comet NEAT is not on a collision course with Earth.
The comet is now emerging from the Sun's glare into southern-hemisphere
skies. Ian Cooper of New Zealand took this picture of Comet NEAT at sunset
on Feb. 28th. "The tail was 5 degrees long in 10 x 50 binoculars," says Ian.
"The coma was about as bright as a 2nd or 3rd magnitude star." Photo
details: 50mm lens @ f/1.4, 12 sec. exp. on Fuji XTRA 400 film. Glen Oroua,
Manawatu, North Island, New Zealand. [sky map]


>From, 28 February 2003

By Robert Roy Britt
Senior Science Writer

Alleged NASA Cover-up of Menacing 'NEAT' Comet Threat is Pure Bunk, Experts

Internet accounts of a comet, supposedly bigger than Jupiter and possibly
bearing down on Earth, have concerned citizens e-mailing astronomers and
journalists worldwide asking if the end is finally nigh. True to form, the
rumors also include allegations of a cover-up by NASA.

Scientists say there is absolutely no danger and call the suggestions of
cover-up false and even silly.

The inaccurate portrayals on various Internet sites range from suggestions
that the comet's electromagnetic field will drastically alter Earth's
weather in coming days to even wilder notions that it is not a comet but
instead the long-missing and hypothetical "Planet X." In some accounts the
object is destined to fulfill dire Biblical prophecy. 

The rumors are all based on a comet called NEAT, discovered late last year
and imaged in mid-February by the SOHO spacecraft, which is operated jointly
by NASA and the European Space Agency.

Photos behind the rumors

SOHO took dramatic photos of the comet as it rounded the Sun. The spacecraft
has imaged more than 500 similar so-called sungrazing comets in the past.
NEAT was the brightest comet ever photographed by the observatory, but it is
not remarkable, size-wise, compared with comets in general.

Adding to scientific excitement during the comet's trip around the Sun was a
chance event in which a solar eruption, called a coronal mass ejection
(CME), appeared to hit the comet on Feb. 17. SOHO captured the interaction,
something scientists had not witnessed before. A kink appeared to propagate
down the comet's tail, which astronomers say is energized, or ionized.

Comets are chunks of ice and rock that form in the outer reaches of the
solar system and orbit the Sun. When they approach the inner solar system,
on elongated loops, solar energy boils material away. This gas and dust
shines with reflected sunlight, creating the telltale heads and tails that
make popular viewing targets out of the icy visitors.

NEAT (officially C/2002 V1) has already made its closest approach to Earth
and is now headed harmlessly to the outer solar system, where it will remain
for another 37,000 years before looping around the Sun again. It did not
break apart, as some have suggested. It will not change Earth's weather. It
will not hit the planet.

In fact NEAT turned out to be slightly disappointing, after some astronomers
had speculated it might become bright enough to astound nighttime
skywatchers and possibly even be visible during the day. Instead, few casual
backyard stargazers even noticed the comet's passage.

"The orbit of NEAT is pretty well understood, and it's on its way out, not
in," said Philip Plait, an astronomer at Sonoma State University in
California who writes about misinformation in astronomy in an effort to set
records straight. "The orbit of the comet doesn't bring it any closer to us
than 120 million kilometers [75 million miles], and that was two months ago.
So there's nothing to worry about."

Range of errors

The accusations of cover-up result, in part, from a few alleged missing
images, or images that NASA tampered with, in the series snapped over few
days by SOHO (Solar and Heliospheric Observatory).

Plait called the tampering suggestion silly.

Bernhard Fleck, a SOHO project scientist, said it is common for delays to
occur in posting images to the SOHO Web site, primarily because the public
release of the large number of photos is done without funding and on a
mostly voluntary basis. He said a heavy snowstorm in the Washington, D.C.
area on the days of NEAT's closest approach to the Sun prevented most
scientists from getting to the office and processing the images.

"I can assure you that nobody manipulated any data," Fleck said today in a
telephone interview. "All the images are there now." He called the
accusations of cover-up "pure nonsense."

One Web site,, misidentifies NEAT as a planet, saying it
formed only recently and has a nucleus the size of Mercury. The account
accuses NASA of covering up this "fact" and of hiding images from the
public. Another Web site,, fuels fright with more subtle language:
"Maybe it is nothing. Maybe it is something. If something, it could be the
most significant occurrence in recorded human history."

Plait, author of "Bad Astronomy" (Wiley & Sons, 2002) and founder of a web
site by the same name, told these latest conspiracy theories share
a common trait: "They all have the distinct disadvantage of not being based
on facts."

But conspiracy allegations spread rapidly in the Internet age, propagating
to other sites such as Rumor Mill News (perhaps there's a clue in that name,
for those trying to sort fact from rumor). Plait said his own inbox had been
"hit pretty hard" in recent days with questions about the alleged cover-up
and the safety of our planet.

Plait said the idea that NEAT is as big as a planet is just plain wrong.

"The actual comet itself, the chunk of rock and ice, is only a few miles
across," he said. "What we see in the [SOHO] images is the cloud of gas
surrounding the nucleus, evaporated off the surface by the heat of the Sun.
That cloud is huge, but the comet itself is tiny."

Consistent fodder

Plait said SOHO images have given fringe thinkers and writers plenty to chew
on for years now.

"According to them, SOHO images show UFOs, giant planets, the eye of God,
and probably even Bigfoot if you look hard enough," he said. "All of these
facts are based on these people not understanding how digital cameras work."

Many of the "sightings" claimed in SOHO images are the result of bright
spots generated when solar radiation hits the spacecraft's detector, Plait

Other claims result from artifacts, or flaws, known to exist in the camera.
SOHO engineers have detailed these shortcoming of digital imaging and have
even gone so far as to explain "how to make a UFO" out of a SOHO picture in
their effort to combat the conspiracy crowd.

Plait complains that the alleged cover-up is "insulting to NASA and the
astronomical community. These conspiracy theorists seem to forget that three
people can keep a secret only if two of them are dead. You can hardly ever
shut up an astronomer; how would you keep thousands of them quiet?"

He also points out that before the comet came into SOHO's field of view, and
since it has left that circle of electronic vision, it has been photographed
by several amateur and professional astronomers around the world. These
images and other observations were used to determine NEAT's trajectory -- a
path that is widely agreed upon.

Credibility issue

Benny Peiser, a social anthropologists at Liverpool John Moores University
in England, has also been fielding questions on the alleged dangers of comet
NEAT. Peiser studies "neocatastrophism" and press coverage surrounding
potentially threatening events.

In Peiser's view, the issue has become one of credibility for the science
community revolving around public perception of whether NASA could -- or
would want to -- hide knowledge of an impending impact.

Peiser and other analysts inside and outside NASA agree that secrecy is not
even possible given the number of non-NASA astronomers who have instant
access to the data and imagery.

"The conspiracy mania regarding comet NEAT is a reminder of just how
important a pro-active communication policy can sometimes be," Peiser told He said rumors need to be debunked quickly and squarely by
scientists so that public trust of science is not diminished.

"Regrettably, most in the scientific community ignore or underestimate these
developments that are often driven by political extremists," he said.

In a separate event now tied into the NEAT affair, graduate student Geoffrey
Sommer, speaking at a meeting of the American Association for the
Advancement of Science (AAAS) on Feb. 13, suggested that the government
might consider keeping secret information about an impending impact if the
result were to be global destruction and the end of civilization. A few
poorly conceived comments -- Sommer said he was misquoted in an AAAS press
release -- spun out of control and fueled conspiracy chatter around the
Internet earlier this month.

Peiser warned at the time that the Sommer comments might serve as supporting
"evidence" for future conspiracy allegations. That is one prophecy that has
come to pass as spoken, based on this reporter's survey of NEAT chatter on
the Internet.

The AAAS "blunder is now being flagged up as clear evidence that the alleged
cometary impact risk is covered up by NASA," Peiser said.

More doom

For those keeping track, comet NEAT is not the first space object purported
to present terrestrial doom in 2003. As early as last summer, Web
prognosticators said a Planet X would pass so close to Earth in May of this
year that its gravity would generate natural disasters and kill 90 percent
of the people on Earth.

That nonsense was based not on NASA images, but instead involved pure
efforts at prophecy led by people like Nancy Lieder, who says she "channels"
aliens called Zetans (from the star Zeta Reticuli) who've explained all this
to her.

(Given that comet NEAT's arrival is well ahead of Lieder's May timeframe, it
appears to represent a separate doomsday problem.)

Planet X is often discussed in conversations that include Nemesis, a
possible companion to the Sun that's sometimes also called the Death Star.
No real evidence for either of these objects exists, though real scientists
have put considerable effort into looking for them.

However, the possible presence of another object as big or larger than
Pluto, lurking somewhere in the fringes of the solar system, has not been
ruled out. If one exists, astronomers agree, it would not pose a threat to

Doomsday aficionados might also recall that a chance alignment of planets in
the year 2000 had been cited as a moment that would bring great
gravitational calamity to Earth. Nothing happened, just as reputable
scientists had predicted.

Plait predicts the same non-occurrence of the present prognostications.

"I wonder what those conspiracy theorists will say a week or two from now,
when nothing has happened," Plait said. "Will they say NASA covered up the
destruction of the Earth?"

Copyright 2003,


>From CNN, 28 February 2003
By Richard Stenger

(CNN) -- If scientists detect a killer asteroid shortly before it slams into
Earth, should the public be informed?

One researcher, Geoffrey Sommer of the Rand Corp., a Santa Monica,
California-based think tank, believes the best answer in some cases is no.

Should an alert come too late to make a difference in the outcome of a
global catastrophe, Sommer suggests governments should remain silent.

"If you can't do anything about a warning, then there is no point in issuing
a warning at all," Sommer said earlier this month at an American Association
for the Advancement of Science meeting in Denver.

"If an extinction-type impact is inevitable, then ignorance for the populace
is bliss," he said.

Other space researchers were highly critical of Sommer's views.

"I find Geoffrey's whole idea both irrational and unrealistic," said Benny
Peiser, a U.K. scientist at Liverpool John Moores University who monitors
asteroid threats.

"The advocated secrecy, far from being cost-effective as Geoffrey claims,
would most certainly preclude any attempt at impact mitigation," he told

Regardless, Peiser said, any attempt to keep a killer asteroid quiet would
be futile.

"Professional and amateur astronomers from around the world can easily
access and confirm observational data and calculations of any discovered
NEOs [Near Earth Objects]," he said.

Scientists estimate more than 1,000 asteroids 1 kilometer (0.6 miles) in
diameter or larger -- big enough to cause global devastation -- lurk near
the Earth's orbital path.

NASA expects to finish a census of the so-called NEOs in 2008 and has
already identified more than half of the predicted population.

One particularly sizable space boulder is thought to have unleashed global
climate changes that hastened the end of the dinosaurs 65 million years ago.

Yet collisions with such monster rocks are rare. They take place about only
once every 1 million years or so.

Smaller asteroids the size of whales collide every few centuries. Most plunk
in oceans, but they could spark regional disasters if they were to hit near
a populated area, according to astronomers.

Copyright 2003, CNN


>From CNN, 28 February 2003

If astronomers detect a planet-killing asteroid right before it hits Earth,
do you want to know? 

Yes, I would like to be able to prepare for the end.    
70%  (51,395 votes)
No, I would rather enjoy the last minutes without knowing.    
30%  (22,173 votes)
Total:  73,568 votes 
This QuickVote is not scientific and reflects the opinions of only those
Internet users who have chosen to participate. The results cannot be assumed
to represent the opinions of Internet users in general, nor the public as a
whole. The QuickVote sponsor is not responsible for content,
functionality or the opinions expressed therein. 


>From High Point Enterprise, 2 March 2003
By Ronda Cranford, STAFF WRITER March 02, 2003
If terrorism alerts aren't enough to worry you, just think about asteroids.
It only takes one really big one to ruin everybody's day, according to
Anthony Crider. He said there are other dangers lurking out in space, too.
"The universe is a dangerous place," said Crider, an Elon University science

Crider was one of four experts who spoke at the Tri Star regional gathering
for amateur astronomers held at Guilford Technical Community College Friday
and Saturday.

Crider's talk, "It's the End Of The World As We Know It," was the first
presentation of the day.

Standing in front of a projected image of a mushroom cloud, he said he would
not be discussing any of the numerous ways that life as we know it could end
because of causes that originate on the Earth.

He said that when it comes to large space objects falling out of the sky,
"the thing that's most probably going to kill you is most probably going to
kill all of us."

It's true that tornado and air crash victims are more common than victims
hurt by space objects, Crider said, so people don't really worry as much
about that.

He said there's a one in a billion chance that something could fall from
outer space and strike a single individual.

But it all depends on the size of the falling object. If something bigger
than a mile square hit the Earth, the chances are much greater that more
people would die directly or indirectly as a result of the impact.

So, according to Crider's computations, people "should probably, in your
day-to-day life, worry about asteroids just as much as airplanes or

Crider said an asteroid which caused the Chicxculub crater in Mexico's
Yucatan Peninsula is what scientists believe caused the extinction of

But asteroids aren't the only potential problem. Other suns in the galaxy
sometimes end their lives in hypernovas, Crider said. If the Earth is close
enough and in the path of gamma rays created in the explosion, those rays
could deplete the ozone layer, allowing our own sun to fry us, he said.

And there are other ways life on Earth could become extinct. In about a
billion years, the sun will get so much hotter it's doubtful life on the
Earth can continue.....

İHigh Point Enterprise 2003 


>From International Herald Tribune, 28 February 2003

Kathy M. Kristof Los Angeles Times 

With the United States on the brink of war in Iraq and North Korea
test-firing missiles, State Farm Insurance Cos. is issuing a timely, if
chilling, notice to customers: It will not cover auto damage caused by
nuclear blasts or radioactive fallout.

"No insurance company could withstand the financial impact of insuring a
nuclear accident," Bill Sirola, a spokesman for the largest U.S. automobile
insurer, said Wednesday.

Never mind that filing an auto insurance claim may be the least of people's
worries should a nuclear strike occur.

Since the terrorist attacks on the United States on Sept. 11, 2001, most
insurance companies have been reassessing their exposure to potential losses
from terrorism, including the possibility of an attack using a nuclear
device or radioactive materials.

Nuclear exclusions have been an insurance industry standard since the end of
World War II, when the Soviet Union and the United States found themselves
locked in a nuclear standoff, said Pete Moraga, spokesman for the Insurance
Information Network of California.

But State Farm executives said they noticed during their post-Sept. 11
review that although the company's homeowner policies clearly excluded
damage from nuclear blasts, accidents and fallout, its auto policies
appeared ambiguous.

Most state insurance regulators have barred companies from dropping coverage
for terrorist acts from personal policies, said Robert Hunter, director of
insurance for the Consumer Federation of America, although terrorism losses
can be excluded from commercial policies.

Copyright 2003, International Herald Tribune



>From Michael Paine <>

Dear Benny

Mark Kidger raises some important points about the impact threat. The risk
to society is explored in our (Paine and Peiser) paper prepared for the 2002
Bioastronomy Symposium. A copy is online at It was when I prepared
Figure 4 *Estimated frequency of fatal events on a populated Earth* that the
seriousness of the issue struck me. In
particular the annual risk of a 1 MILLION fatality event is about 1 in
6,000. That is a much higher risk than society would be prepared to accept
for any man-made risk (other than war, it seems).

There seems to be too much emphasis on deflecting incoming NEOs - a
technically challenging and costly exercise. IF Spaceguard detects a NEO
that will impact in, say, the next century the most likely scenario is local
or, maybe, regional devastation (say a NEO with a diameter between
200 and 500m - smaller ones are too hard to detect and larger ones are much
less likely). In this case evacuation of the impact region would be possible
and many lives could be saved - for relatively small cost.

In other words a reasonable Spaceguard program (finding a good proportion of
NEOs down to 200m) will improve odds of a 1 million fatality event to,
perhaps, 1 in 12,000 (ie half the risk). As Duncan Steel has often pointed
out, and Mark Kidger raised again, this is an absolute bargain and is like
being offered car insurance for $10 a year.

Michael Paine


>From Andy Smith <>

Hello Benny and CCNet,

The third Space.Com Debate (25 Feb 03...ID-3) was interesting and a cause
for mild concern, because it seemed to play-down the NEO danger. It is at:

Tunguska Destructive Energy

First, Alan Harris seemed to be comparing the Tunguska impact with Hiroshima
("The nature of the destruction is pretty much the same as the
Hiroshima-style nuclear air burst...") and we wanted to be sure the readers
recognize that both Tunguska and Arizona (Barringer) were almost a thousand
times bigger than Hiroshima.

That means that the smallest NEO in our population of orbiting bombs
(300,000 or so), has the destructive potential of a large hydrogen bomb
(10-20 megatons) and would totally destroy any metropolitan area on the
planet, if it hit at or near that area.

Objects of Mass Destruction (OMD)

As the world becomes increasingly concerned about objects of mass
destruction, it is well to remember that most of them are natural objects
and that we have the technology needed to protect ourselves. It's just that
we are not placing enough priority, yet, on planetary NEO defense.

These extremely dangerous objects are already programmed to strike our
"little blue marble" and the challenge is to identify them, determine their
programs and prepare to deflect them, if possible, or to survive their
impacts, if we must.

Fortunately, things are improving, but we have a long way to go. Perhaps the
increased concern about the prevention of mass destruction will help us to
get higher priorities and funding...and our friends in the U.S. Congress,
the UK Parliament and in other governments may be able to help. They have
already done a lot and we appreciate it.

Relative Hazards

Another group of statements that caused us some concern was related to the
assessment of the NEO hazard. Clark Chapman stated that, "Roughly 80 percent of the impact hazard
is due to asteroids between 1 and several kilometers in diameter. About 10 percent is due to an
asteroid smaller than a kilometer striking the ocean and causing a tsunami.
Roughly another 10 percent is due to comets, and less than 1 percent is due
to small asteroids striking the land."

First, it was not clear how "impact hazard" is defined. Certainly the impact
risk is due largely to the objects smaller than a kilometer that constitute
more than 90% of the threat population. And these all could do serious
damage to any coastal city they impacted near...because the effective
coastal city target areas are so much larger than the effective inland city
target areas). Also, the heat and blast effects from these
hydrogen-bomb-equivalent impactors make them very hazardous to cities near
their impact points (effective target areas, again).

We prefer to define NEO impact hazards in the same way that we define them
for other impactors (automobiles, etc.). We first define the risk of the
impact, as a function of applicable variables. Then, we define the risks of
the various impact consequences...given the impact. This approach works well
for us, in explaining the NEO dangers to both informed and uninformed
groups...because it uses a familiar approach. This approach is also used by
most of the groups concerned with accident and disaster prevention.

We think it is extremely important to focus our initial planetary protection
efforts on the identification of the large number of unidentified NEO or OMD...and this
means getting the next generation of asteroid telescopes on-line and
increasing our annual discovery rate by another order-of-magnitude (from
about 500 per year to more than 5,000). Fortunately, the development
programs for these new systems are underway and we may have at least one of
them operational by mid-decade.

It is also very important to continue efforts aimed at the capability to
intercept and deflect these smaller (and much more likely)impacts. Programs
related to this capability are also, fortunately, underway.

In addition, we must continue to upgrade our civil impact emergency
preparedness programs... especially for the coastal cities.

Thanks Again to NASA and Space.Com

We are looking forward to the final part of this debate and we appreciate
the efforts responsible for making it happen. We hope there will be others,
in the coming months. We also appreciate all the work Benny and his
associates devote to our vital CCNet. May God bless you all.


Andy Smith


>From The Observer, 2 March 2003,5673,905653,00.html

Putting death off until we're older hasn't helped us cope better with the
here and now

Phil Hogan
Sunday March 2, 2003
The Observer

In common with the rest of the unscientific community, I don't really know
what to make of the latest doomsday scenario of an asteroid crashing into
the Earth and causing no end of weather problems and chaos on the roads.

The obvious idea of blowing it up with a weapon of mass destruction has been
pooh-poohed because it turns out that asteroids might not be just lumps of
rock as previously assumed (assumed, that is, by people we hoped had moved
beyond the assuming stage and on to the slightly more useful knowing one),
but rather like large Maltesers, the sweet you can eat between meals without
ruining your appetite for mad Dan Dare ideas, the latest one being to wait
in a spaceship until the asteroid comes past and then poke it out of orbit
with a giant pole, a solution with all the hallmarks of having been dreamed
up by someone with no GCSEs.

'Actually, that's Milky Ways,' my wife says. 'Maltesers are the sweet with
the less fattening centre.'

Right. Even better. Maybe we could just get everyone to blow at the same
time until it's out of our lane. Anyway, we might not need to worry,
according to a spokesman for a prominent American 'think tank' who is
advising the US administration that the best thing to do, come the day of
cosmic Armageddon, is not to tell anyone about it, thus at least avoiding
the prospect of millions of citizens running amok in town centres and
looting shopping malls and clubbing neighbours who play their music too loud
while the police are busy dealing with people running across the road when
the green man isn't lit up.

I'm not sure I'm entirely in favour of this. If, for example, the asteroid
came heading for east Herts, some of us might like a bit of time to make our
peace with God or, even better, take advantage of Ryanair's no-frills,
no-manners services out of nearby Stansted Airport (which by then could
feasibly have the extra runways that the government has been threatening us
with) and get a flight for £8.99 to, say, the Himalayas or somewhere else
unlikely to be affected by tidal waves. Obviously this is not a course of
action open to most Americans, who famously don't have passports and might
understandably go out and trash a few shops in their final hours as a
freedom-loving people.

Having acknowledged which, there's something to be said for not knowing what
hit you. Much was made of the shocking fate that befell the crew of the
Columbia space shuttle but, given the choice, I think I'd rather be atomised
instantly in a flaming ball of rocket fuel than, say, eaten slowly away by
an unglamorous wasting disease, the sort of ordinary death that lends itself
well to pain and long goodbyes, but offers little to the public imagination
in the way of grace or poignancy. The point is, though, you don't get the
choice, and wouldn't it spoil the surprise of sudden death if you did?

On the whole, though, science has become too good at giving us a fighting
chance: to kill the rogue asteroid before it kills us; to battle against
cancers. We acknowledge that in the great march to oust inevitability and
replace it with hope, we have lost our capacity to ruminate properly on
life's biggest question, to turn death round in our heads until we get to
know what it looks like.

Obviously, there are social benefits to finding new ways of putting death
off until we're older, but improving our moral fortitude isn't one of them.
As a result we have become useless at conveying and receiving all the lesser
sorts of inconvenient news. For example, when was the last time you went up
to someone at a cocktail party to quietly point out the bogey hanging out of
their nose?

I remember my wife once managing to get all the way to work on the Tube
without a single member of the public telling her she'd got yesterday's
balled up knickers protruding from the bottom of one trouser leg. She won't
thank me for mentioning it now, but I do feel we have to start somewhere.

And it's not as if it's the end of the world.

Copyright 2003, The Observer

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>From AstroBiology Magazine, 3 March 2003

Summary: Our "Great Debate" series brings together a group of scientists who
are experts on asteroids and comets. This final debate concerns how we could
respond to the threat of an asteroid heading for Earth, and what sort of
projects would best serve future NEO goals.


Clark Chapman - scientist at the Southwest Research Institute's Department
of Space Studies, in Boulder, Colorado. Member of the MSI/NIS
(imaging/spectrometer) team of the Near Earth Asteroid Rendezvous (NEAR)
mission to Eros.
Alan Harris - senior research scientist at the Space Science Institute, an
affiliate of the University of Colorado at Boulder.
Benny Peiser - social anthropologist at Liverpool John Moores University in
the UK. He has written extensively about the influence of NEO impacts on
human and societal evolution.
Joe Veverka - professor of astronomy at Cornell University in Ithaca, New
York. Principal Investigator for NASA's Comet Nucleus Tour (Contour)
Don Yeomans - (debate moderator) - Senior Research Scientist at NASA's Jet
Propulsion Laboratory in Pasadena, California, and manager of NASA's
Near-Earth Object Program Office.

Don Yeomans: As mentioned in last week's debate, an asteroid or comet larger
than a kilometer colliding with the Earth would be a very rare event. One
would only expect a collision of this type to occur every several hundred
thousand years. Nevertheless, it has happened before and it could happen
again in the near future. In the unlikely event that a sizable near-Earth
object (NEO) is found to be on an Earth-threatening trajectory, would we
have the technology to deflect the object in time so that it would pass
harmlessly past the Earth?

Clark Chapman: I think pieces of the technology are there. We have rockets
that can launch the deflection hardware, and there are well-tested means to
deliver and operate this hardware in the vicinity of a low-gravity body. In
fact, one spacecraft already has landed on an asteroid - the NEAR-Shoemaker
spacecraft landed on the asteroid "Eros" on Valentine's Day, 2001.

What has not been done is to put all the technological tools in our toolbox
together and make them work in the strange, unintuitive physical world of an
asteroid. Also, much more thinking is necessary about the diversity of
asteroid properties. We have sufficiently energetic tools to push on an
asteroid and move it, but we need to consider how we might attach any
deflection mechanism to an NEA and push it in the direction we want.

Not every one-kilometer NEA will be easy to divert. Such a body is very
massive, and a long lead-time of perhaps decades would be necessary to
succeed, even without employing new or potentially dangerous technology.
But, fundamentally, we probably could do it, provided there was sufficient
motivation: namely, an asteroid headed our way, destined to collide with
Earth some years or decades hence.

Joe Veverka: I believe that we currently are not in a position to protect
Earth from impacts by one kilometer-sized objects. The technology required
to carry out such a task exists, or it can be developed, but the effort
would be colossal by any standards.

I would argue that the question, while of academic interest, is not very
relevant from a practical point of view. In such a discussion, it is
essential to define a "horizon of concern." In other words, how far into the
future does it make sense to worry about something and take precautions?

The answer might depend on where and when we live, but right now any
planning that society does hardly extends more than a few decades into the
future, and at most perhaps to a few centuries. Planning for events that
occur on time scales of hundreds of thousands to a few million years just
doesn't make practical sense. Nor is it necessary to expend resources to
protect ourselves against events that occur on time scales of a million
years. For instance, few of us lose sleep over the fact that the sun will
turn into a red giant some 5 billion years from now.

It is only when we get down to impacts that occurred early in the 20th
century that it makes sense to discuss mitigation - for example, the
Tunguska explosion of 1908 that has been attributed to a meteoroid 60 meters
in diameter. But even for these events, which might occur every few hundred
to a thousand years, the cost of a mitigation policy must be weighed against
the likely benefit.

We have to keep in mind all of the other ways resources could be used to
benefit society in preserving and improving life. Even in the case of
Tunguska-type events, there are far more urgent and potentially more
beneficial uses of our resources than developing a system to protect us from
impacts by bodies a hundred or so meters across. Almost certainly more
people will die from wars, cancer, and even traffic accidents during the
next few hundred years than are likely to die from the next Tunguska.

Clark Chapman: Joe Veverka makes a major error when he compares the time
scale for a large asteroid collision with the time scale for the sun turning
into a red giant. There is ZERO chance that the sun will turn into a red
giant during the next century, or even the next billion years, according to
our robust understanding of the physics of stellar evolution. But asteroids
strike AT RANDOM. If asteroids struck like clockwork, a kilometer-sized body
every few hundred thousand years for example, then the analogy might work.
But there is roughly a one-in-several-thousand chance that a kilometer-sized
asteroid will strike during the 21st century. One could even strike

One might well question what level of risk we are willing to accept by doing
nothing about one-kilometer asteroids. Joe should argue that he's willing to
accept the risk, given other higher priority concerns. But he's wrong, and
he hurts his case, to make the classic error people make about lightning
strikes and hundred-year floods: "the next one can't happen again soon." It
has nothing to do with a "waiting time" or being "over the event horizon."

Given that civilization might hang in the balance, we really should think
about this issue, despite the low probability that we will have to meet this
challenge during our lifetimes. Of course, until such an asteroid is
discovered, there certainly are weightier threats facing society, as Joe
Veverka argues.

Benny Peiser: In contrast to other, more frequent natural disasters such as
earthquakes, volcanic eruptions, tropical storms, tsunami, etc., we have
very little understanding of or experience with NEO impacts. Thus, we can
only speculate about the effectiveness of planetary protection. The question
as to whether or not we have the technology necessary for effective NEO
protection ultimately depends on the warning time we are granted by an
asteroid or comet on a collision course with Earth.

At present, we do not have any protection against a NEO about to collide
with Earth in, say, one or two years time. Estimates for the time it may
take to assemble an operative deflection system currently range from 30 to
70 years. With ongoing advancements in space and defense technologies, I am
confident that this estimate will gradually come down further.

But the real problem, as I see it, is not so much whether we have the
theoretical know-how for NEO deflection. Instead, the key challenge we will
face at some time in the future is when a NEO is found to have a significant
chance of hitting Earth. In the absence of any experience, we will be
confronted with an unprecedented crisis situation. Such an impact crisis
could happen tomorrow or it could occur in 300 years time. It could be a
small asteroid, a medium-sized comet, or an even larger object. Happily,
chances are extremely small that this will happen soon. Nonetheless, such an
event will transpire one day. And when it happens, it will be unprecedented.

By contemplating what may happen in the event of a small impact, we need to
recognize the psychological and social implications of traumatic events and
the emotional and irrational reactions they can activate. The social effects
of an impact are all too often ignored or underestimated, but they could be
extremely grave. Such effects perhaps could be even more disruptive than the
physical damage and economic costs. Some people may experience problems
dealing with even a small impact due to its totally random and "terrorizing"
nature. It will certainly stir up anxieties - not least because the impact
is likely to be blown out of proportion by the mass media. Some people will
blame their governments, space agencies, and astronomers for failing to
protect them from cosmic disaster. Then it will not be sufficient to issue
the mantra of 'statistical risk estimates.'

Don Yeomans: If you were given the means, what scientific or engineering
project (or any other endeavor) would be highest on your list to better
understand these near-Earth objects, or to possibly reduce the threat that
these objects pose to Earth?

Clark Chapman: The theme of NEO impacts with Earth and other planets has a
strong scientific legitimacy, even if dangerous impacts in our lifetimes are
unlikely. I believe that asteroids and comets are of exceptional importance
in the scientific understanding of the solar system. Yet it took 25 years
from the first asteroid mission study before the first dedicated asteroid
mission (the NEAR Shoemaker mission to Eros) was accomplished.

I believe future studies of NEOs should combine the purely scientific
interest in these bodies with the public interest of impact hazard
mitigation, as well as the potential utilization of asteroid materials. This
includes theoretical studies, Earth-based telescopic observations, and
space-based missions of increasing sophistication.

Joe Veverka: To assess the risk that NEOs pose to Earth, we not only need to
know how many there are and how big they are, but we need to know what they
are made of and how they are put together. Telescopic observations have done
a splendid job in finding what's out there, and a pretty decent job in
determining how big these bodies are. The next important step is direct
exploration by spacecraft of carefully selected NEOs to determine their
precise geochemistry and internal structures. Missions are needed to return
a sample from each of these bodies for detailed geochemical analyses and to
determine the average density of each object. Such samples would give us
accurate data on what these bodies are made of and how they are put
together. This information will be essential for evaluating the risk and
planning a mitigation strategy, if needed.

Alan Harris: I have always felt that, given the very low chance that
anything out there "has our name on it," we should not expend resources on
impact mitigation unless we discover something to mitigate against. However,
I would soften this position in the same way that one might buy a "whole
life" insurance policy rather than term life insurance, so that even if you
don't die in the prescribed term of the policy, you at least have something
like a savings account in return. Therefore I think we might favor research
programs that have intrinsic scientific interest and that also contribute in
some way to potential mitigation, if that should ever come to be necessary.
The landing of NEAR-Shoemaker on Eros already is in this category: a
valuable practice exercise for something almost certainly necessary if we
were to need to deflect an asteroid, and also scientifically valuable in

Another example could be a rendezvous and landing mission to an asteroid to
probe the interior structure of an asteroid - rubble pile, monolithic rock,
or what? This exercise would give us further insights into possible modes of
deflection. Or perhaps we could implant transponders on an asteroid in order
to practice precision orbit tracking, making sure we could monitor the
progress of a deflection maneuver. The scientific payoff, even if the
deflection technology were never needed, would be to look for wobbles in the
asteroid rotation that could help probe the interior of the body. We also
could look for very slight variations in the orbit, perhaps due to radiation
pressure, and that would help us understand the evolution of small bodies
into Earth-crossing paths.

I remain opposed to major defense programs to protect against an
undiscovered "enemy" asteroid that has only a one in ten thousand chance of
existing. I believe that the danger of having such a "defensive" system,
which almost certainly would involve rockets and nuclear bombs, exceeds the
security it provides. However, any part of the preparation that can be
accomplished at modest cost might be justified, so long as it will yield a
scientific return as a side benefit.

Benny Peiser: I'm glad to hear that Al has softened his position on future
efforts to boost the study and our understanding of impact mitigation. I
have always been skeptical of the customary NASA view that no funds should
be provided for impact mitigation research until we are faced with an
impending impact threat. This sounded too unreasonable to me. Traditionally,
the main argument has been that no supplementary resources should be
allocated to examine a highly implausible scenario. But nobody is asking for
additional funds.

Space agencies around the world are already spending billions of dollars
each year on space exploration and scientific research. As Al points out,
the landing of the NEAR-Shoemaker spacecraft on Eros shows that scientific
space missions easily can be designed so they include mitigation aspects
without the need for additional funding.

Future missions should progressively incorporate NEO and impact mitigation
components. This would ensure that we gradually learn to decode and handle
the multifaceted compositions of asteroids and comets. Such a policy would
be the best remedy to reassure an increasingly concerned public that the NEO
and space communities are taking adequate steps to take control of our
cosmic environment.

In the next twenty-five years, I would like to see the first space mission
aim to nudge an asteroid out of its orbit. After landing a spacecraft on an
asteroid (NEAR-Shoemaker), striking at a comet (Deep Impact) and bringing
back samples from an asteroid (MUSES C), the most captivating, and certainly
the most popular NEO mission ever would be an attempt to shift a
medium-sized space rock out of its orbit. In many ways, this would be the
first attempt in all of history to change the course of cosmic nature.

Clark Chapman: A NASA-sponsored workshop on "scientific requirements for
mitigation" last autumn went a long way towards demonstrating that there is
great similarity between the kinds of missions one would fly to study the
nature and origin of NEAs, and those that one would fly to learn how to push
on an asteroid, if it were ever necessary to do so.

A focused motivation to try to move a small NEA in a controlled manner in
the next dozen years, as advocated by the B612 Foundation, could reap an
enormous scientific pay-off as well as take a major step toward
understanding the practicalities of how to move a such a body. If the
endeavor involved "bombs in space," as Al Harris fears, then I would be
hesitant too. But last autumn's workshop made it clear that the appropriate
technology in most instances involves long-acting, low-thrust propulsion.
This is in order to move the asteroid gently, in a controlled fashion, and
not risk breaking the body up into a dangerous swarm of pieces. I don't see
such technology as being especially dangerous, although international
oversight of such endeavors will always be the prudent way to go.

CCCMENU CCC for 2002