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An asteroid raid and a cosmic blast

A smash-and-grab probe is planned, while an explosion dazzles

LONDON: Under the gentle puff of its ion drive, a Japanese space probe is positioning itself for an extraterrestrial first: a smash and grab on a speeding asteroid. The Hayabusa (or falcon) probe has been chasing the asteroid since 2003 and has this week reached within tens of kilometres of its surface.

Scientists at the Japanese Institute of Space and Astronautical Science will spend the next few weeks using Hayabusa's cameras to build up a detailed map of the asteroid. The probe will close in on the asteroid and try to knock lumps of material from it to bring back to the earth.

Risky mission

"No one has ever tried this before and it is risky," said Mike Zolensky, an expert in cosmic dust at the National Aeronautics and Space Administration's Johnson Space Centre in Houston and one of the scientists working on the mission. "It's all new and there are no guarantees it'll work."

Asteroids, the cosmic leftovers from the formation of the solar system 4.6 billion years ago, are a mystery to scientists. "One thing we want to learn is just what they are made of, because then we can work out how best to mitigate against collisions from objects like these," said Dr. Zolensky. "No one knows if asteroids are like beanbags inside, or like travelling sandbanks, or if they are hard, solid objects."

One of the closest

Hayabusa is approaching the 600-metre long, potato-shaped Itokawa, one of the closest asteroids to the earth. Scientists will, for the first time, be able to study an asteroid that has not broken up into meteorites and been scorched as they penetrate the earth's atmosphere.

To grab material from the asteroid, the probe will drop a marker, which looks like a disco glitterball, on to the surface to help judge its approach. The silver ball, which will be left behind, has been etched with the names of 877,490 people who e-mailed the mission scientists.

A pellet will be fired into the asteroid's surface and fragments will be sucked up a tube and stored. When Hayabusa has collected all the material it can, it will return towards the earth, ejecting a capsule containing the fragments. If all goes according to plan, the capsule will land in the Australian outback, ending its 1,200-million-mile mission.

"Asteroids are the building blocks of the planets in our solar system," said Keith Yates at the British Government's Near Earth Objects Information Centre. "Around 50,000 meteorites, which are fragments of asteroids, fall to earth every year, but... this is the first time we'll have pristine asteroid material to investigate."

Cosmic blast

Meanwhile, elsewhere space and earth-based telescopes have detected the most distant cosmic explosion ever observed, opening a window onto the origins of the universe and the formation of stars, U.S. astrophysicists said. The Swift satellite, launched by NASA last year, and terrestrial telescopes detected and measured the powerful explosion and its afterglow of gamma rays on September 4, charting new scientific territory.

The explosion of a massive star in the farthest reaches of the cosmos occurred at a distance of about 12.6 billion light years, Don Lamb, an astrophysicist at the University of Chicago, said on Monday. Until now, the most distant explosion recorded was 12.2 billion light years. A light year corresponds to the distance that light travels in a year.

Gamma ray emission

Mr. Lamb and his colleague Daniel Reichart of the University of North Carolina have anticipated since 1999 that the Swift space telescope, launched by NASA in November 2004, would break new ground by capturing the emission of gamma rays from explosions dating back to the beginning of the universe. "We are finally starting to see the remnants of some of the oldest objects in the universe," Mr. Reichart said. © Guardian Newspapers Limited 2004

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