NASA Comet Chaser Finds 'Footprints' 2BN Miles Away (Stardust Mission)

The Telegraph (UK) ^ | 6-18-2004 | Roger Highfield

[blam]

Nasa comet chaser finds 'footprints' 2bn miles away

By Roger Highfield, Science Editor
(Filed: 18/06/2004)

Giant "footprints" measuring about a mile from heel to toe have been found on a comet.

The Stardust spacecraft reached comet Wild 2 in January after a six-year journey of two billion miles.

Scientists expected to see a big chunk of rock and ice around three miles across, liberally coated with dark dust, obscuring any interesting features.

Stardust flew less than 150 miles from the comet's heart and the first detailed analysis of the rendezvous, published today, describes the "feet" along with broad mesas, craters, pinnacles and canyons with flat floors and sheer walls, all sharply defined and covering the comet's surface area of about 20 square miles.

"It's completely unexpected. We were expecting the surface to look more like it was covered with pulverised charcoal," said Prof Donald Brownlee, Stardust's principal investigator and co-author of three papers published in Science.

The footprints, which are craters, have been named Right Foot and Left Foot. Left was 650 yards across and 140 deep, and right was 1,000 across and 200 deep, said Dr Simon Green of the Open University, one of the team.

The scientists found two kinds of craters, probably created when other space bodies slammed into the comet nucleus, he said.

One has a rounded central pit and a surrounding terrain that is rough, presumably because material was ejected upon impact. The other has a flat floor and nearly vertical cliffs.

The images also show that a popular notion of comet structure - a pile of rubble that is packed loosely - does not apply to Wild 2, said Prof Brownlee.

"We're sure this is a rigid material because it can support cliffs and spires."

Many features on the comet's surface probably are billions of years old, perhaps from around the time that life first arose on Earth, said Prof Brownlee.

If that is the case, the nucleus almost certainly carries evidence of how the solar system came together, evidence the scientists hope is contained in a sample now en route to Earth.

Today's studies describe jets on the comet's surface that spew material into space at supersonic speeds, the unexpectedly chaotic distribution of dust particles coming off the comet, and an analysis of the particles' composition.

Stardust, launched by Nasa in 1999, is returning to Earth with thousands of particles less than a millimetre in size captured during the flyby as they streamed from Wild 2 at more than 13,000 miles per hour.

A capsule carrying the sample will parachute into the Utah desert in January 2006.

Two swarms of microscopic cometary dust blasted Stardust, according to a University of Chicago instrument on board.

The materials range in size from particles that could fit on the head of a pin to boulders the size of a truck. Several particles larger than bullets struck the spacecraft.

[blam]

I want to see close-up pictures.

[Terpfen]

Uh-oh. Geological formations. I can hear the "comets and asteroids are the remnants of a destroyed planet" people rushing to the cameras.

[Lokibob]

2004 March 19

Going Wild
Credit: Stardust Team, JPL, NASA

Explanation: Dynamic jets of gas and dust surround one of the most active planetary surfaces in the solar system in this wild-looking picture of a comet nucleus. The comet's designation is 81P/Wild 2 of course (sounds like "vilt 2"), and the picture is a composite of two images recorded by the Stardust spacecraft's navigation camera during its January 2nd flyby. The composited images consist of a short exposure recording startling surface details of Wild 2's nucleus and a longer exposure, taken 10 seconds later, revealing material streaming from the surface. The left edge of the nucleus appears extremely jagged due to a strong shadow. Pitted and eroded after billions of years of outgassing and meteorite impacts, the nucleus pictured is only about 5 kilometers in diameter, while the jets of dust and gas ultimately leave trails millions of kilometers long. Stardust is scheduled to return samples of Wild 2's cometary dust, picked up during the flyby, to Earth in January 2006.

[Lokibob]

good enough???

[Unknowing]

It appears that comets are orders of magnitude more physically dynamic, and important for science, than we were taught in science courses years ago. And the return sample makes it appear that the operation was well considered.

[blam]

"good enough???"

You bet! Excellent, thanks.

[blam]

[Lokibob]

Crews are already practicing to catch the sample on Utah Test and Training Range.

[JennysCool]

Art Bell, white telephone please, Art Bell ...

[Terpfen]

LOL! Yeah... Coast to Coast is one hell of a nutty program.

Though I do admit, that show has served a purpose with me. Last summer, I worked at a job with a 12 hour shift: 3PM to 3AM. During the drives home, Coast to Coast provided me with endless amusement. Laughing at the oddball guests helped keep me awake.

[ngc6656]

When viewed stereoscopically, the comet is one rough looking piece of primodial space debri. The relief probably has been exaggerated by a factor of two or three to make details stand out better (a common trick of stereographers).

[ApplegateRanch]

It is for me! Thanks for posting it.

[Bloody Sam Roberts]

I can hear the "comets and asteroids are the remnants of a destroyed planet" people rushing to the cameras.

Well heck. Everyone knows they're actually remnants of the planets Krypton and Alderaan.

[LibWhacker]

That IS weird and unexpected. There goes the dirty snowball theory.

[ancient_geezer]

There goes the dirty snowball theory.

Nahhh, think Yeti,

one great BIG space alien Yeti practicing socker with a dirty snowball ;oP

[Lokibob]

I'm not a reg listener, but if I get up middle of the night, and the choices are 27 infomercials or coast-to-coast, Art wins.

The one thing I admire about Art Bell and George Norry is that they don't condemn anybody. Every caller or guest, no matter how nutty the subject they want to talk about, is treated with respect.

However, the one thing I have noticed is that Art Bell has taken a major swing to the left, politically. To a certain extent, so has Norry.

[TXnMA]

Thanks! That thing is really irregularly-shaped!

[RightWhale]

I want to mine the comet. It looks like a cinder.

[SunkenCiv]

Note: this topic is from June 17, 2004. Just adding, not pinging.

• Strange comet unlike anything known

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