& SCIENCE NEWS: May 2002
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& science news > space & science news: May 2002
Vast amounts of subsurface water-ice found
(May 26, 2002)
The Mars Odyssey probe has found compelling evidence for huge quantities
of water-ice on Mars just below the surface. What may prove to be
one of the most dramatic breakthroughs in astrobiology will be officially
announced by NASA on Thursday (May 30) shortly before its publication
in the journal Science. The Odyssey data provide a clear answer
to the long standing mystery of what happened to all the water believed
once to exist on the Mars – it is apparently mixed in with the
regolith, the layer of broken rock and dust at and near the surface.
The accompanying picture is an example of the images that have been
returned by Odyssey; the area in blue shows hydrogen detected by the
probe's gamma-ray spectrometer less than one meter below the surface
of Mars-hydrogen that is almost certainly locked into crystals of
water-ice. A neutron spectrometer, also onboard the spacecraft, has
provided spectacular confirmation that water-ice is present in abundance.
This new discovery will boost the argument for an early sample-return
probe and for a manned Mars expedition; the case for Martian life,
past and possibly present, now seems stronger than ever.
For more, go here
| To the stars via quantum wormholes
(May 23, 2002)
A New Scientist article this week begins:
us are tiny doors that lead to the rest of the Universe. Predicted
by Einstein's equations, these quantum wormholes offer a faster-than-light
short cut to the rest of the cosmos – at least in principle.
Now physicists believe they could open these doors wide enough to
allow someone to travel through.
"Quantum wormholes are
thought to be much smaller than even protons and electrons, and until
now no one has modelled what happens when something passes through
one. So Sean Hayward at Ewha Womans University in Korea and Hisa-aki
Shinkai at the Riken Institute of Physical and Chemical Research in
Japan decided to do the sums."
For more, go here.
Asteroid death of the dinosaurs –
(May 20, 2002)
It's now mainstream knowledge that a large asteroid impact at the
end of the Cretaceous Period, some 65 million years ago, put paid
to the last of the dinosaurs. But now an international group of scientists
has claimed that another such cosmic collision, may have played a
major role in the rise of the giant reptiles at a much earlier date.
Evidence from 70 different sites in the United States, the team suggests,
shows that the larger of the ancient reptiles began to proliferate
at the beginning of the Jurassic Period, a little more than 200 million
years ago, just after the time when geologists think life on Earth
experienced a mass extinction. The great loss of species – a
little under half disappear from the fossil record – just over
200 million years ago would have opened up ecological opportunities
for surviving dinosaurs to exploit. A key finding of the team, published
in Science, centers around the discovery of an iridium "spike" in
rocks laid down at the time-a known extraterrestrial signature. The
transition from Triassic-type to Jurassic-type footprints occurred
within an extremely short period of just 50,000 years. The theory
is that an asteroid or comet struck, wiped out much of the existing
competition, and enabled the rapid rise to power of the new big carnivores
(just as the mammals benefited from the eventual demise of the dinosaurs).
But others will need some convincing. The iridium anomaly is only
a thousandth as strong as that at the end of the Cretaceous Period,
so the size of any impacting body must have been much smaller. Other
factors, such as climate change and widespread volcanic activity,
may also have helped trigger the mass extinction at this time. However,
there's no doubt that random extraterrestrial catastrophes have influenced
evolution on Earth-and presumably on other worlds – far more
than anyone previously suspected.
For more, go here.
Possible meteorite from Mercury unveiled
(May 16, 2002)
We have meteorites that are known to have come from Mars and the Moon.
Now, it looks as if a chunk of the planet Mercury has conveniently
come into our possession. Found in the Sahara in 1999, NWA011 shows
obvious signs of having been molten in the distant past but is composed
of unsually light materials, suggesting that it came from a parent
body larger than an asteroid. The dynamics of getting a rock from
the surface of Mercury to Earth are tricky but not out of the question.
If this really is a piece of the innermost planet it will receive
intense scrutiny and be of particular interest to those involved in
future Mercury probes, such as MESSENGER.
For more, go here
Martian magnetite and biogenicity: the
(May 15, 2002)
Tiny grains of magnetite, an iron
oxide mineral, from a Martian meteorite are markedly similar in size,
shape, and composition to the little oxide magnets used by bacteria
on Earth and different from other naturally formed magnetites. Is
this good evidence for life on Mars? Or did the Martian magnetite
grains form by another process? Our studies reveal that the planes
of atoms in the Martian magnetites are aligned with atomic planes
in the carbonate in which the magnetites are embedded. This shows
that the magnetites formed in the rock and not inside microorganisms.
To read this new report by Edward R. D. Scott (Hawai'i Institute of
Geophysics and Planetology) and David J. Barber (University of Greenwich,
University of Essex, UK), go here.
Riding the light to distant encounters
(May 13, 2002)
The first spacecraft to be propelled by solar light pressure is due
to set sail this autumn and mission planners around the world will
be watching keenly to see if it succeeds. The mission, known as Cosmos
1, is being privately sponsored by the Planetary Society and Cosmos
Studios (a group of film-makers and writers set up by Carl Sagan's
widow, Ann Druyan), and relies on an ultra-thin, highly reflective
sail to trap individual particles of light from the Sun. Eventually,
such technology could be used to propel lightweight spacecraft to
Mars and the outer solar system. Beyond Jupiter, sunlight would start
to become too weak but, at this point, powerful space lasers in Earth
orbit, accurately directed onto the sail, could take over. An off-board
laser propulsion could eventually propel probes to other stars. Cosmos
1 will begin its journey aboard a rocket fired from a submarine in
Russian waters. If all goes well, it will then separate from its booster,
unfurl its sail, and fly for a few weeks or months around the Earth
pushed by the Sun.
For more, visit the Planetary Society's Cosmos
Return of the Death Star
(May 8, 2002)
Forget the Attack of the Clones, it's the Death Stars we need to worry
about. That's the conclusion of astrophysicist Arnon Dar, of the Technion
Space Research Institute, Israel, who reckons that the explosion of
a supermassive star (such as that which resulted in the Crab Nebula,
shown here), followed by the collapse of its dead core to a black
hole, would unleash a barrage of gamma rays and cosmic rays lethal
to anything in its path. He estimates that every life-bearing planet
in the Galaxy will be virtually sterilized in this way every 100 million
years or so – a figure that tallies roughly with the rate of
mass extinctions on Earth (though some of these extinction events
were almost certainly tied to asteroid impacts and other phenomena).
If you want the gory details of how Dar thinks terrestrial life would
perish in the radiation blast from a nearby supernova, go here
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