PLEASE NOTE:
*
CCNet 138/2000 - 31 December 2000
-----------------------------------
"The Government is expected to approve construction of a
£10m telescope
early in the New Year which would be dedicated to finding comets
and
asteroids before they hit Earth. The Science minister, Lord
Sainsbury, is
expected to accept one of the main proposals in a Government task
force
report - to develop a telescope with European partners to track
"near-Earth
objects" that could threaten the planet. Scientists from the
Government's
expert team are now urging it to begin devising ways to deflect
the objects
when they have been identified."
-- Colin Brown and Sophie Goodchild, The Independent, 31 December
2000
(1) UK GOVERNMENT EXPECTED TO APPROVE CONSTRUCTION OF SPACEGUARD
TELESCOPE
The Independent, 31 December 2000
(2) 2001: A SPACE ANNIVERSARY
Andrew Yee <ayee@nova.astro.utoronto.ca>
(3) APPARENT METEOR FLASHES IN THE SKY OVER VERMONT
Rutland Herald (Vermont)
(4) NIGHT SKY BOOM RATTLES AUSTRALIANS, BAFFLES POLICE
Ron Baalke <baalke@jpl.nasa.gov>
============
(1) UK GOVERNMENT EXPECTED TO APPROVE CONSTRUCTION OF NEO
TELESCOPE
From The Independent, 31 December 2000
http://www.independent.co.uk/news/UK/Science/2000-12/space311200.shtml
SPACE WATCH FOR EARTH-BOUND ASTEROIDS
By Colin Brown and Sophie Goodchild
The Government is expected to approve construction of a £10m
telescope
early in the New Year which would be dedicated to finding comets
and
asteroids before they hit Earth.
The Science minister, Lord Sainsbury, is expected to accept one
of the
main proposals in a Government task force report - to develop a
telescope with European partners to track "near-Earth
objects" that
could threaten the planet.
Scientists from the Government's expert team are now urging it to
begin
devising ways to deflect the objects when they have been
identified.
Their report suggested detonating a nuclear bomb in space to
deflect
asteroids, using space craft to nudge objects out of their
orbits, or
erecting solar panels like sails on an asteroid, using the sun's
radiation pressure to change its course.
The ideas may sound like the script from the Hollywood
blockbuster Deep
Impact which is to be screened on BBC1 on Tuesday. However, the
scientists warned: "This is not science fiction."
An asteroid travelling at more than 20 miles per second missed
the Earth
by 480,000 miles last week, a near-miss in astronomical terms.
The
50-yard wide asteroid, called 2000 YA, appeared unexpectedly
above
London at midnight on Friday. Space experts said it would have
left a
crater about 20 times its size if it had struck.
Massive asteroid and comet strikes on Earth have been well
documented,
including one 50 yards across which exploded 15 miles above
Siberia in
1908. A comet hitting the Gulf of Mexico 65 million years ago is
thought
to caused the extinction of the dinosaurs.
Nasa will launch its own Deep Impact mission to the comet Tempel
1 in
2004. The probe will release a half ton lump of pure copper to
cause a
huge crater in the comet so that its composition can be studied
from
Earth.
The threat posed by the Mir Russian space station as it falls to
Earth
next week has also highlighted the real risks from impacts of
objects
from space.
Harry Atkinson, the chairman of the Government task force on
"near-Earth
objects," said: "We hope all our recommendations will
be taken up but
the telescope is the important one. We need to know where the
objects
are coming from. That is the high priority. It needs to be
dedicated,
working all the time."
Dr Atkinson said his three-man team began as sceptics but became
more
convinced of the need for action as they investigated the threat.
A telescope to hunt for objects in outer space on a path to Earth
could
be established in co-operation with European partners in the
inter-governmental European southern observatory in Chile, which
Britain
has recently joined.
While the chances of a direct hit on Britain are remote, an
object only
50 yards across hitting the mid-Atlantic would set up a shock
wave which
would cause devastation on the shores of the Continent, Britain
and the
eastern seaboard of the US.
Lembit Opik, the Liberal Democrat MP who led the successful
Parliamentary campaign to persuade the Government to take the
outer-space threat seriously, said a "sheath in space"
or "cosmic
condom" could be the best way of deflecting asteroids or
comets
comprising rocks and gas.
"You could have a big plastic cosmic condom or space sheath
to collect
near-Earth objects and tow them away to safety," he said.
Copyright, The Independent
=========
(2) 2001: A SPACE ANNIVERSARY
From Andrew Yee <ayee@nova.astro.utoronto.ca>
from The Guardian, 28 December 2000
[ http://www.guardianunlimited.co.uk/science/story/0,3605,415643,00.html
]
The first asteroid was discovered two centuries ago. Duncan Steel
reports on the fragments of the planet that never was.
There is another reason to celebrate this January 1. It is the
bicentenary
of the discovery of the first asteroid.
Astronomers keep a master list of asteroids with well-determined
orbits.
As new bodies are added, they get a number, and a name. So far
almost
20,000 are on the list, such as 1815 Beethoven, 2001 Einstein,
and
2985 Shakespeare. (Oh, and 4713 Stell.) But the first is 1 Ceres.
Ceres was found on January 1 1801, by an Italian astronomer named
Giuseppe Piazzi, from Palermo in Sicily. It was not an unexpected
discovery.
Late in the 18th century, astronomers had become convinced that
there
must be another planet, yet to be spotted, between the orbits of
Mars
and Jupiter. Their belief was based on a numerical relationship
known as
Bode's Law, which seemed to govern the distances from the sun of
the planets
Mercury, Venus, Earth, Mars, Jupiter and Saturn, but with a gap
between the
fourth and fifth. When Uranus was discovered -- in 1781, by
William
Herschel, from his observatory in Bath -- in a location
consistent with an
extrapolation of Bode's Law, astronomers were convinced that the
intermediate planet must soon be found.
Soon after Piazzi made his discovery, however, it was realised
that
Ceres was hardly big enough to deserve the accolade of
"planet". It is only
about 600 miles across, much smaller than our moon. Indeed, the
proper
astronomical term for an asteroid like Ceres is a "minor
planet."
The situation became more confused in 1802, when another minor
planet
was found between Mars and Jupiter, and shortly thereafter two
more.
These three are named 2 Pallas, 3 Juno and 4 Vesta.
Out of that confusion, another hypothesis was developed: perhaps
these
asteroids are simply the fragments of a large planet that, for
some
reason, had exploded? This idea held sway for some time, until it
was
eventually realised that the myriad bodies orbiting between Mars
and
Jupiter (in what is now called the main belt) are simply
primordial
debris that never managed to accumulate into the planet predicted
by Bode's
Law. The reason is the gravitational stirring imposed by massive
Jupiter, which keeps these objects dynamically agitated so that
collisions
between them result in their erosion and destruction, rather than
the
gradual agglomeration of a single large body.
The majority of the 20,000 asteroids in our data banks remain on
well-behaved paths forever circuiting the sun in the main belt.
In 1873,
however, one was found on a trajectory that brought it in to
cross the
orbit of Mars.
It was obvious that an asteroid-planet collision was possible.
Fundamentally this was not a new idea, because comets had been
known to have
planet-crossing orbits for some time. Even as far back as 1694,
Edmond
Halley (for whom the famous comet is named) had suggested that
impact-induced calamities and upheavals must have occurred in the
past.
But there are few comets, whereas 19th-century astronomers were
finding a host of asteroids. Comets are easy to find because they
are
bright, being surrounded by vast clouds of water vapour. The
recognition
of dark asteroids required the development of better telescopes,
and
then photography led to a blossoming of the discovery rate.
Astronomers' fears were confirmed when in 1898 the first
earth-approaching asteroid was spotted. This is 433 Eros. (For
the
past year, a NASA spacecraft has orbited around Eros, sending us
back
detailed images of its surface and other characteristics.)
Then, in 1932, the first possible Earth-impacting asteroids were
found.
Over subsequent decades several more were discovered, essentially
by
accident on celestial photographs obtained with powerful
telescopes. It
has only been in the past few years that dedicated search
projects in
the US have reaped a harvest of the skies.
Almost 1,000 small asteroids crossing our orbit are now known,
300 of
them found in the year 2000 alone. Many keep their distance, and
we
know -- from numerical experiments in which their paths are
followed
forward by computer for decades, while they loop around the sun
--
that they cannot hit our planetary home soon. By "soon"
I mean the
next century: the period of interest to you, your children, and
your
grandchildren.
We are all familiar with shooting stars. Tiny rocks from space,
the size
of a pea or a grape, cause these. Many of the known asteroids are
small
enough to blow up on meeting the atmosphere. They could still
make a
mess. The rocky asteroid that entered the atmosphere above
Siberia in
1908 was only about 60 yards across. When it exploded at a height
of
around five miles it released energy equivalent to about 15
megatons
of TNT, burning and flattening the largely uninhabited forest
over an
area of almost 1,000 square miles. Such an event over London
would
destroy most buildings out to the M25. About once per century is
our
best guess of how often a cosmic calamity like that must occur
somewhere on Earth. Fingers crossed, then.
The major hazard posed by asteroids comes from larger objects. A
one-mile asteroid would release energy equivalent to about a
million
megatons of TNT in a terrestrial impact. That is 80M times the
Hiroshima bomb, enough to cause a global catastrophe. No matter
where it hit, we would all be severely affected. There is about a
one
in half-million chance that such a disaster will occur next year
without any warning (we know that as of yet we've found only a
fraction of these cosmic projectiles). Compare that with your one
in
14 million chance of winning the Lottery.
Given the deadly potential of asteroids, should we celebrate the
anniversary of the first discovery? An optimist could point out
that
whereas an impact is unlikely, our exploitation of asteroids and
comets
as sources of the raw materials (rock, metal, water and oxygen)
we
will need for our future expansion into space makes them valuable
discoveries. As we map their orbits, we not only safeguard our
future
on planet earth, but also make feasible our conquest of the final
frontier. And that is worth toasting as January 1 properly begins
the
new millennium.
[Duncan Steel works at the University of Salford. His new book
Target
Earth is published next week by Time Life (£14.99). To order a
copy
for £11.99 freephone 0800 3166 102 or, send your order with a
UK cheque, payable to The Guardian CultureShop, to FREEPOST
Books,
LON3590, London, W3 6BR. Please add 99p UK p&p.]
© Guardian Newspapers Limited 2000
=========
(3) APPARENT METEOR FLASHES IN THE SKY OVER VERMONT
From Rutland Herald (Vermont)
http://rutlandherald.nybor.com/News/AtAGlance/Story/17567.html
December 28, 2000
The Associated Press
BURLINGTON - A bright object that raced across the Vermont and
was seen
by scores of people was probably a meteor, officials say.
"It was very green -- neon green -- streaking across the
sky," said
Donna Day of Essex. "It had an orange tail. It disappeared
behind the
horizon and there was a flash of light."
The object was bright enough to be seen clearly even under city
lights.
Full story here:
http://rutlandherald.nybor.com/News/AtAGlance/Story/17567.html
==========
(4) NIGHT SKY BOOM RATTLES AUSTRALIANS, BAFFLES POLICE
From Ron Baalke <baalke@jpl.nasa.gov>
http://www.cnn.com/2000/TECH/space/12/27/australia.spacejunk.reut/index.html
Night Sky Boom Rattles Australians, Baffles Police
December 27, 2000
SYDNEY (Reuters) - Australian authorities were baffled on
Wednesday by
overnight reports of bright lights and booming noises in the sky
which shook
some houses and prompted fears of falling space junk or
meteorites.
Police said they received numerous reports of
``explosions in the sky, sonic boom-type noises and
flare-type lights'' over a two hour period on Tuesday
night from residents along a 124 mile stretch of the
country's east coast.
Full story here:
http://www.cnn.com/2000/TECH/space/12/27/australia.spacejunk.reut/index.html
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