PLEASE NOTE:
*
CCNet 115/2002 - 4 October 2002
-------------------------------
"I believe there is considerable synergy between national
security
requirements related to man-made satellites and global security
requirements related to NEO impacts."
--Brigadier General Simon P. Worden, 3 October 2002
"Residents of the town of Bodaibo in the Irkutsk region
witnessed
the fall of a large celestial body. Scientists suggest that it
might
have been a meteorite. Scientists said that Bodaibo residents
could see the
fall of a very large luminous body, which looked like a huge
stone. The
unidentified object fell in the woods. The site of the fall is
situated
very far from any settlements, but locals felt a strong shock,
which could
be comparable to an earthquake. In addition to that, the people
also
heard a thunder-like sound. Flashes of bright light could be seen
above the
site of the meteorite's fall."
--Pravda, 3 October 2002
(1) EARTH PLAYING COSMIC ROULETTE WITH ASTEROIDS
Andrew Yee <ayee@nova.astro.utoronto.ca
<mailto:ayee@nova.astro.utoronto.ca>>
(2) LARGE METEORITE FALLS ON THE IRKUTSK REGION
Pravda, 3 October 2002
(3) A NEW RUSSIAN METEORITE?
NEO Information Centre, 4 October 2002
(4) ASTEROIDS MAY BE MISTAKEN AS NUCLEAR ATTACK OFFICALS SAY
The Associated Press, 4 October 2002
(5) SMALL ASTEROID COULD BE MISTAKEN FOR NUCLEAR BLAST
Reuters, 3 October 2002
(6) TRACKING EARTH-BOUND ASTEROIDS COULD NEED AMATEUR HELP
Scripps Howard News Service, 3 October 2002
(7) WE NEED MORE TELESCOPES NEO HUNTER TELLS CONGRESS
Space Daily, 4 October 2002
(8) AND FINALLY: ASTEROID PROBE KIT TO FIGHT TERRESTRIAL CRIME
New Scientist, 3 October 2002
============
(1) EARTH PLAYING COSMIC ROULETTE WITH ASTEROIDS
>From Andrew Yee <ayee@nova.astro.utoronto.ca
<mailto:ayee@nova.astro.utoronto.ca>>
Committee on Science
U.S. House of Representatives
SHERWOOD BOEHLERT, CHAIRMAN
Ralph M. Hall, Texas, Ranking Democrat
Press Contacts:
Heidi Mohlman Tringe, Heidi.Tringe@mail.house.gov
<mailto:Heidi.Tringe@mail.house.gov>
Jeff Donald, Jeffrey.Donald@mail.house.gov
<mailto:Jeffrey.Donald@mail.house.gov>
(202) 225-4275
October 3, 2002
107-295
EARTH PLAYING COSMIC ROULETTE WITH ASTEROIDS
WASHINGTON, D.C. -- Scientists are making progress in cataloguing
and
tracking large near-earth objects (NEOs), but a serious threat
still remains
from smaller objects, an expert panel told the Space and
Aeronautics
Subcommittee today.
These smaller asteroids (200-500 meters wide) could potentially
demolish a
city with a direct hit or cause a tsunami capable of wiping out
entire
coastal areas if they land in the ocean. NASA has catalogued
nearly 50
percent of asteroids 1 kilometer wide and larger. Astronomers
estimate that
between 900 and 1300 of the larger asteroids exist while there
could be as
many as 50,000 in the smaller range.
Subcommittee Chairman Dana Rohrabacher (R-CA) stated, "The
threat posed by
incoming asteroids and comets is a serious, potentially
life-threatening
topic. Given the number of near-earth objects in space, it is a
matter of
time before we are faced with an event unparalleled in human
history.
I hope that my legislation, H.R. 5303
[ http://www.house.gov/science/press/107/107-286.htm
], passed by the House on
Tuesday will strengthen existing government capabilities for
tracking
natural space objects by encouraging private citizens to observe
asteroids
and comets."
Subcommittee Ranking Member Bart Gordon (D-TN) added,
"NASA's Mission
Statement says that part of its mission is '... to protect our
home planet.'
I hope NASA will heed the message of today's hearing and work
with other
agencies of the U.S. government to craft a timely, cost-effective
plan to
detect and catalog as many as possible of the Near-Earth
asteroids and
comets that could potentially threaten our population. We cannot
afford to
be complacent."
Dr. David Morrison, senior scientist at the NASA Ames Research
Center,
discussed NASA's goals and accomplishments in monitoring NEOs
through the
"Spaceguard" program. Morrison noted that Spaceguard
was halfway to its goal
and he expected that by 2008 NASA will have 90 percent of large,
kilometer-sized threatening asteroids catalogued. Morrison added,
"Our
objective should be to find a large impactor far in advance, and
thus
provide decision-makers with options for dealing with the threat
and
defending our planet from cosmic catastrophe."
NEOs also pose a serious concern for the military, Brigadier
General Simon
P. Worden testified. Worden told of an asteroid that entered the
atmosphere
and exploded above the Mediterranean during last year's
India-Pakistan
conflict. U.S. satellites detected an energy release and
shockwave
comparable to the Hiroshima bomb, and Worden explained that had
the event
taken place at the same latitude two hours earlier and mistaken
for a
nuclear detonation it could have had devastating consequences.
Worden added,
"I believe there is considerable synergy between national
security
requirements related to man-made satellites and global security
requirements
related to NEO impacts."
Witnesses also debated the merits of continuing the cataloging
effort on
smaller NEO's once the Spaceguard program is completed. Dr. Brian
Marsden,
Director of the Minor Planet Center of the Smithsonian
Astrophysical
Observatory, testified that handling the large amount of data
from surveys
of smaller NEOs would be a challenging, but feasible, task. Dr.
Joseph
Burns, a member of the Solar System Exploration Survey Committee
of the
National Research Council, testified that NASA should partner
with the
National Science Foundation to build and operate a large
ground-based survey
telescope because of NSF's expertise in ground based astronomy
and NASA's
traditional support of ground-based solar system observations
that support
space missions.
Dr. Ed Weiler, NASA Associate Administrator for Space Science,
disagreed
saying, "I feel that it is premature to consider an
extension of our current
national program to include a complete search for smaller-sized
NEOs." He
also noted that NASA did not feel the agency "should play a
role in any
follow-on search and cataloging effort unless that effort needs
to be
specifically space-based in nature."
Rep. Anthony Weiner (D-NY) said, "For too long we've assumed
that the worst
asteroid risk would come from Hollywood -- in the form of a
sequel to flops
like Deep Impact or Armageddon. But the threat posed by Near
Earth Objects
is real, and if we can plow $100 million into a summer flick, we
can
certainly give NASA the means to make us safer from real life
blockbusters."
Witness testimony and an archived web cast of the proceedings can
be found
at <http://www.house.gov/science/>
==========
(2) LARGE METEORITE FALLS ON THE IRKUTSK REGION
>From Pravda, 3 October 2002
<http://english.pravda.ru/main/2002/10/03/37698.html>
Locals say that it was huge
Residents of the town of Bodaibo in the Irkutsk region witnessed
the fall of
a large celestial body. Scientists suggest that it might have
been a
meteorite.
This was reported by the regional department of the Russian
EMERCOM. They
added that they received the information from the Institute of
Solar and
Earth Physics of the Siberian division of the Russian Academy of
Sciences.
Scientists said that Bodaibo residents could see the fall of a
very large
luminous body, which looked like a huge stone. The unidentified
object fell
in the woods. The site of the fall is situated very far from any
settlements, but locals felt a strong shock, which could be
comparable to an
earthquake. In addition to that, the people also heard a
thunder-like sound.
Flashes of bright light could be seen above the site of the
meteorite's
fall.
Translated by Dmitry Sudakov
Copyright 2002, Pravda
===========
(3) A NEW RUSSIAN METEORITE?
>From NEO Information centre, 4 October 2002
<http://www.nearearthobjects.co.uk/news_display.cfm?code=news_intro>
On Thursday 3 October, residents of the village of Bodaibo in the
Irkutsk
region of Siberia witnessed the fall of a large glowing object
from space.
Witnesses saw a large fireball in the sky, followed by a
thunder-like sound,
a flash of light, and a small earth tremor.
Scientists from the Institute of Solar and Earth Physics of the
Russian
Academy of Science suspect the object is a large meteorite. It
landed in the
hills between the villages of Bodaibo and Balakhninsky. Early
reports
suggest there were no casualties or damage to property.
Siberia is no stranger to visiting rocks from space. Back in
1908, a near
earth object detonated in the atmosphere above the Tunguska
region,
flattening 2000 square kilometres of forest. More recently, in
February
1947, a large iron meteorite, estimated to weight 1000 tons,
landed in the
Sikhote-Alin mountain range.
Around 30,000 meteorites of varying sizes fall to Earth each
year, but the
vast majority fall in the oceans and deserts that make up the
majority of
the Earth's surface. If pieces of this new fall can be recovered,
it may
give scientists valuable insights into the nature of these rocks,
which are
remnants from the formation of our Solar System.
A group of scientists from the Institute of Solar and Earth
Physics is to
head for the new fall-site as soon as possible.
===============
(4) ASTEROIDS MAY BE MISTAKEN AS NUCLEAR ATTACK OFFICALS SAY
>From The Associated Press, 4 October 2002
WASHINGTON (AP) - At least 30 times a year, asteroids smash into
the Earth's
atmosphere and explode with the violence of a nuclear bomb. Now
some
officials are worried the natural explosions could trigger an
atomic war.
Air Force Brig. Gen. Simon P. Worden told members of a House
Science
subcommittee that the United States has instruments that
determine within
one minute if an atmospheric explosion is natural or manmade.
But none of the other nations with nuclear weapons have that
detection
technology, and Worden said there is concern that some of those
countries
could mistake a natural explosion for an attack and immediately
launch an
atomic retaliation.
Worden, deputy director for operations of the U.S. Strategic
Command, said
there was the risk of such a mistaken atomic exchange last August
when
Pakistan and India, both with atomic bombs, were at full alert
and poised
for war.
Not far away, a few weeks before, Worden said, U.S. satellites
detected over
the Mediterranean an atmospheric flash that indicated ``an energy
release
comparable to the Hiroshima burst.'' Air Force instruments
quickly
determined it was caused by an asteroid 15 feet to 30 feet wide.
``Had you been situated on a vessel directly underneath, the
intensely
bright flash would have been followed by a shock wave that would
have
rattled the entire ship, and possibly caused minor damage,''
Worden said in
his testimony.
Although the explosion received little or no notice, the general
said it
could have caused a major human conflict if it had occurred over
India or
Pakistan while those countries were on high alert.
``The resulting panic in the nuclear-armed and hair-triggered
opposing
forces could have been the spark that ignited a nuclear horror we
have
avoided for over a half-century,'' he said.
Worden said the Air Force's early warning satellites in 1996
detected an
asteroid burst over Greenland that released energy equal to about
100,000
tons of explosives. He said similar events are thought to have
occurred in
1908 over Siberia, in the 1940s over Central Asia and over the
Amazon basin
in the 1930s.
``Had any of these struck over a populated area, thousands and
perhaps
hundreds of thousands might have perished,'' he said.
Worden said early warning satellites do a good job of detecting
asteroid
bursts in the atmosphere and that new equipment will be even
better. He said
the Air Force is working on an asteroid alert program that would
quickly
send information from the satellites to interested nations.
He said the Air Force is studying the establishment of what he
called a
Natural Impact Warning Clearinghouse that would be part of the
North
American Aerospace Defense Command communications center in
Cheyenne
Mountain near Colorado Springs, Colo.
NASA is in the midst of a 10-year program to find and assess
every asteroid
six-tenths of a mile or more in size that could pass close to the
Earth and
might pose a danger to the planet.
Such asteroids or comets are called ``near earth objects'' and if
one struck
the planet it could wipe out whole countries. An asteroid 1 mile
across
could snuff out civilizations, while one that is 3 miles across
could cause
human extinction, experts say.
Edward Weiler, head of NASA's office of space science, told the
House
committee that his agency has detected 619 near earth objects and
is finding
about 100 new ones each year. None poses a danger to the Earth.
Worden and others said that smaller asteroids also can be
destructive. For
instance, if an asteroid the size of a cruise ship smashed into
the ocean it
could cause huge waves, called tsunamis, capable of drowning
coastal cities
on two continents.
Worden called for a system of instruments and telescopes on land
and in
space that could scan the sky to find asteroids down to the size
of 300
feet. He said telescopes and instruments weighing less than 150
pounds could
easily be launched to establish an observing network.
Copyright 2002, AP
===========
(5) SMALL ASTEROID COULD BE MISTAKEN FOR NUCLEAR BLAST
>From Reuters, 3 October 2002
< http://www.reuters.co.uk/newsArticle.jhtml;jsessionid=U30IR321ZQRLKCRBAELCFFA?type=scienceNews&storyID=1531650
By Deborah Zabarenko
WASHINGTON (Reuters) - Even small asteroids that never hit Earth
could have
deadly consequences, because they might be mistaken for nuclear
blasts by
nations that lack the equipment to tell the difference,
scientists said on
Thursday.
One such asteroid event occurred June 6, when U.S. early warning
satellites
detected a flash over the Mediterranean that indicated an energy
release
comparable to the atomic bomb dropped on Hiroshima, U.S. Brig.
Gen. Simon
Worden told a congressional hearing.
The flash occurred when an asteroid perhaps 10 yards in diameter
slammed
into Earth's atmosphere, producing a shock wave that would have
rattled any
vessels in the area and might have caused minor damage, Worden
said.
Little notice was taken of the event at the time, but Worden
suggested that
if it had occurred a few hours earlier and taken place over India
and
Pakistan, the outcome might have been horrifying.
"To our knowledge, neither of those nations have the
sophisticated sensors
that can determine the difference between a natural NEO (Near
Earth Object,
such as an asteroid) and a nuclear detonation," Worden said.
"The resulting panic in the nuclear-armed and hair-triggered
opposing forces
could have been the spark that ignited a nuclear horror we have
avoided for
over half a century," he told a committee investigating the
risk posed by
asteroids and other objects that might collide with Earth.
SHOCK WAVES AND TSUNAMIS
Astronomers have long been concerned about damage from asteroids,
meteors
and comets, and since 1998 NASA has worked to identify 90 percent
of all
large near-Earth objects -- those with a diameter of .6 miles or
more -- by
2008.
NASA's head of space science, Ed Weiler, told the committee that
scientists
have identified 619 of the suspected big, dangerous asteroids,
which is
about half the number astronomers believe are out there.
This kind of large asteroid hits Earth a few times every million
years, and
when it does, causes regional calamity. By contrast, a so-called
doomsday
asteroid 3 miles across -- like the one believed to have wiped
out the
dinosaurs -- hits once every 10 million years or so.
The one that caused the flash over the Mediterranean in June was
probably
about the size of a car, and was harmless to Earth. Such
asteroids hit the
atmosphere twice a month.
However, asteroids ranging from about 100 feet to hundreds of
yards can
cause serious damage, including spawning a powerful shock wave or
a tsunami
if it lands in an ocean, causing widespread catastrophe if the
tsunami
occurs near a populated shore.
These smaller bodies are not part of NASA's survey, and Worden
suggested
there might be an Air Force role in tracking these smaller
objects, and also
the potential for sharing early warning of incoming celestial
objects with
other countries that lack the technology.
Worden said the United States is unique in the world in being
able to
determine whether an incoming object is an asteroid or a bomb in
less than a
minute.
The United States spends about $4 million a year to track
asteroids and
comets, but very little on strategies to get them out of Earth's
way,
scientists said last month.
Copyright 2002, Reuters
============
(6) TRACKING EARTH-BOUND ASTEROIDS COULD NEED AMATEUR HELP
>From Scripps Howard News Service, 3 October 2002
<http://www.knoxstudio.com/shns/story.cfm?pk=ASTEROIDS-10-03-02&cat=AS>
By LEE BOWMAN
WASHINGTON - NASA, the U.S. Air Force and the Smithsonian all are
searching
for "planet-killer" asteroids that might be on a path
to hit Earth.
But some in Congress are concerned that the pace of the search
isn't brisk
enough, and are promoting a plan that would reward amateur
astronomers for
their efforts in finding doomsday rocks.
NASA officials told the House Science Committee on Thursday that
they're
actually ahead of schedule with a 10-year search that aims to
find 90
percent of near-Earth asteroids - those on an orbit that could
put them in
our planet's path - larger than about a half-mile in diameter.
David Morrison, a senior scientist at NASA's Astrobiology
Institute and
founder of the search effort, said the Spaceguard Survey has so
far
catalogued about 600 of the large asteroids. Scientists believe
such huge
objects hit Earth on average about every 100 million years - the
last time
being an impact of a 10-mile-wide asteroid off the Yucatan
Peninsula 65
million years ago that scientists believe helped drive dinosaurs
to
extinction.
"We can already state with assurance that there are no
asteroids this large
with orbits that could pose a threat to us," Morrison said.
"But there is
still a risk from objects down to 1 mile in diameter that could
perturb the
climate on a global scale and possibly collapse
civilization."
Still more likely to cause trouble are space rocks the size of a
city block
or football field. An asteroid of that size exploded more than a
mile above
a remote section of Siberia in 1908, devastating a 40-square-mile
zone on
the ground but causing few deaths.
So far, the National Aeronautics and Space Administration and
several
international partners aren't even deliberately looking for
objects that
small, although they'll note them as they're found. The Minor
Planet Center
at the Smithsonian Astrophysical Observatory in Cambridge, Mass.,
has
records of about 1,800 near-Earth objects as small as 600 feet or
so across.
An asteroid roughly that size passed within 75,000 miles from
Earth just
last summer, but wasn't detected until it was already moving
away. Morrison
and others said that such objects are capable of regional
devastation and
even wider damage if they fall into the ocean and generate
tsunamis that
could swamp cities on distant shores.
"Something that size could wipe out Southern California. I
don't take a lot
of comfort that an object like that missed us by an astronomical
hair, and
we didn't see it coming," said Rep. Dana Rohrabacher,
R-Calif., who heads
the House space subcommittee.
Rohrabacher has concerns that NASA's $1 million-a-year search
effort isn't
enough, and wants to encourage amateur astronomers to get more
involved. The
House this week approved his plan for a set of three $2,000
awards, named
after the late Apollo 12 commander Charles "Pete"
Conrad, that would
recognize amateur stargazers who "discover new and track
previously
identified large asteroids, particularly those that threaten
close approach
to the Earth."
Sen. Bill Nelson, D-Fla., a space advocate and one-time space
shuttle
passenger while in the House, has told Rohrabacher he'll
introduce a
companion bill in the Senate.
Brian Marsden, director of the Minor Planet Center, said amateur
astronomers
"occasionally" are the first to report a new near-Earth
object, "but where
they really contribute is with the necessary follow-on
observations that
must be done and reported to the database to establish the path
the object
is taking," he said. "Certainly encouraging them in
these contributions is
worthwhile."
But even with dedicated backyard astronomers, experts worry that
there's no
national plan for tracking down the other mid-sized asteroids,
let alone
even smaller chunks that could still be dangerous.
"There's no coordinated national policy, no one agency
responsible for
addressing this issue," Rohrabacher said, nor any planning
for how to divert
or otherwise protect Earth from impact if an asteroid on a
collision course
is found.
On the Net: <http://cfa-www.harvard.edu>
Copyright 2002, Scripps Howard News Service
=============
(7) WE NEED MORE TELESCOPES NEO HUNTER TELLS CONGRESS
>From Space Daily, 4 October 2002
<http://www.spacedaily.com/news/asteroid-02g.html>
Washington - Oct 04, 2002
A Cornell University astronomer told a House of Representatives
space
subcommittee today that Washington should spend $125 million for
a new type
of ground-based telescope that could detect hundreds of asteroids
and
numerous comets that pose a potential threat to the Earth from
space over
the next century.
Reporting on a government-commissioned review of solar system
exploration by
some of the nation's leading scientists, he said that the new
wide-field
telescope is needed to produce a weekly digital map of the
visible sky in
order to track space rocks called near-Earth objects (NEOs), the
great
majority of which have yet to be discovered.
There is, he said, a 1 percent probability of an impact with
Earth by a
300-meter-diameter (350 yards) body in the next 100 years,
resulting in many
deaths and widespread devastation.
The astronomer, Joseph Burns, the Irving Porter Church Professor
of
Engineering and professor of astronomy at Cornell, in Ithaca,
N.Y., is a
member of the Solar System Exploration Decadal Survey's steering
group.
His comments to the House Science Committee panel came during his
presentation of a small portion of the findings of the survey,
which had
been commissioned by the National Research Council (NRC) at the
behest of
NASA.
The impact of an object of this size, he said, would deliver a
thousand
megatons of energy and (assuming an average population density of
10 people
per square kilometer) result in a million fatalities. The damage
caused by
an impact near a city or into coastal water would be "orders
of magnitude
higher."
As of November 2001, he said, 340 objects larger than a kilometer
had been
cataloged as "potentially hazardous asteroids," and the
number of new comets
with impact potential "is large and unknown."
Burns quoted a section of the survey report (titled New Frontiers
in the
Solar System): "Important scientific goals are associated
with the NEO
populations, including their origin, fragmentation and dynamical
histories,
and compositions and differentiation.
"These and other scientific issues are also vital to the
mitigation of the
impact hazard, as methods of deflection of objects potentially on
course for
an impact with Earth are explored.
"Information especially relevant to hazard mitigation
includes knowledge of
the internal structures of near-Earth asteroids and comets, their
degree of
fracture and the presence of large core pieces, the fractal
dimensions of
their structures, and their degree of cohesion or friction."
However, Burns said, a survey for potentially threatening NEOs
"demands an
exacting observational strategy," and to locate most of the
objects with
diameters as small as 300 meters requires a capability a hundred
times
better than that of existing survey telescopes.
Because NEOs spend only a fraction of each orbit in Earth's
neighborhood,
"repeated observations over 10 years would be required to
explore the full
volume of space occupied by these objects."
Such a survey, said Burns, would discover NEOs at the rate of
about 100 per
night and obtain astrometric information on the much larger, and
growing,
number of NEOs that it had already discovered.
(Astrometry is the technique used to calculate the orbits of NEOs
and assess
the hazard that each poses to Earth.) "Astrometry at weekly
intervals would
ensure against losing track of these fast-moving objects in the
months and
years after discovery," said Burns.
To do this, he said, requires construction of an entirely new
type of
telescope, the large-aperture synoptic survey telescope (LSST)
"to survey
the entire sky relatively quickly, so that periodic maps can be
constructed
that will reveal not only the positions of target sources, but
their time
variability as well," the Cornell astronomer said.
The LSST would be a 6.5-metre-class, very-wide-field (3 degrees)
telescope
that would produce a digital map of the visible sky every week,
and carry
out an optical survey of the sky far deeper than any previous
survey.
Such a telescope, he said, "could locate 90 percent of all
near-Earth
objects down to 300 meters in size, enable computations of their
orbits and
permit assessment of their threat to Earth. It would discover and
track
objects in the Kuiper Belt, a largely unexplored, primordial
component of
our solar system."
A previous NRC astronomy and astrophysics survey also had
recommended the
building of an LSST. The new survey, however, recommends that
NASA and NSF
pay equally for the telescope's construction and operations, said
Burns.
The new survey, he said, projects the costs of the LSST at $83
million for
capital construction and $42 million for data processing and
distribution
over five years of operation, for a total cost of $125 million.
Routine
operating costs, including a technical and support staff of 20
people, are
estimated at approximately $3 million per year, he said.
The construction of the LSST, Burns told the legislators,
"would provide a
central, federal-sponsored location" for tracking the
potentially
threatening objects.
Copyright 2002, Space Daily
=============
(8) AND FINALLY: ASTEROID PROBE KIT TO FIGHT TERRESTRIAL CRIME
>From New Scientist, 3 October 2002
<http://www.newscientist.com/news/news.jsp?id=ns99992869>
Technology inspired by a NASA space probe will soon be helping
detectives
solve gun crimes and murder cases far faster. A simple handheld
device that
instantly confirms whether a suspect has recently fired a gun
means lab
delays will not allow suspects time to get away.
The idea for the device was hatched under a new collaboration
between NASA
and the US National Institute of Justice. The plan is to adapt
taxpayer-funded space research to fight terrestrial crime.
Jacob Trombka, a physicist at NASA's Goddard Space Flight Center
in
Greenbelt, Maryland, set the ball rolling. He believes X-ray
fluorescence
(XRF) could be a key crime-fighting technology. It was used by
NASA's Near
Earth Asteroid Rendezvous (NEAR) probe, which touched down on the
asteroid
Eros in February 2001.
X-ray fluorescence spectrometry can identify the chemical
elements in a
substance by measuring the wavelengths it emits when exposed to
X-rays.
NEAR's sensors simply recorded cosmic X-rays bouncing off the
asteroid and
beamed the details of the emissions back to Earth.
Trombka believes a handheld forensic tool could work along
similar lines,
taking X-ray fluorescence readings at the scene of a crime and
beaming them
to a computer for instant analysis. This way, forensics experts
could
quickly detect traces of blood, semen or gunshot primer on
suspects' hands.
Gunshot primer is a chemical that converts kinetic energy from
the gun's
hammer into heat to ignite the gunpowder.
Non-destructive
One benefit of this approach is that measuring X-ray emissions
would not
destroy the physical evidence, as analysing a swab can often do.
"Right now we have no method of doing this," says Carl
Selavka, from
Massachusetts State Police Crime Laboratory, who has been working
with
Trombka on this research. "It could also be quite helpful in
investigating
suicides," he says, because roughly half of all murder
investigations turn
out to have been suicides. If there is gun residue on the
victim's hand,
it's likely they fired the fatal shot.
Unlike NEAR's XRF system, the portable unit has to have its own
diminutive
X-ray source.
The device will compare its spectral readings with an onboard
database, or
failing that beam the information back to a forensics computer
for more
detailed analysis. Either way it should only take a few minutes
and give
crime teams reliable enough feedback to arrest a suspect - or
not.
Gunshot primer or solder?
Trombka found XRF particularly useful for identifying residue
from gunshot
primer, which can be difficult to detect, even in the lab. Traces
of
antimony and barium can come from gunshot primer, but may also be
found on
the hands of people working in jobs where they come into contact
with brake
fluid or solder.
However, Trombka found that these elements bind together with the
rapid
temperature changes they undergo when a gun is fired. So he can
identify the
residues as gunshot primer by checking if the barium and antimony
are bound
together. "It's a fingerprint of the high-temperature
process," he says.
But the real triumph could be XRF's ability to detect substances
without
destroying the samples. It might even spot blood or semen on
walls that have
since been painted over. However, the device still needs to be
made smaller,
he says. "But by 2003 we should be testing it in real
situations."
Duncan Graham-Rowe
Copyright 2002, New Scientist
--------------------------------------------------------------------
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.
----------------------------------------------------------------------------