[meteorite-list] Rosetta Discovers Haunting Beauty in Deep Space (Asteroid Lutetia)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 15 Jul 2010 14:10:28 -0700 (PDT)
Message-ID: <201007152110.o6FLASj4022689_at_zagami.jpl.nasa.gov>

http://science.nasa.gov/science-news/science-at-nasa/2010/14jul_rosetta/

Rosetta Discovers Haunting Beauty in Deep Space
NASA Science News

July 14, 2010: The European Space Agency's Rosetta spacecraft has
beamed back close-up photographs of asteroid Lutetia, an ancient,
cratered relic from the dawn of the solar system. Scientists are abuzz
about the stunning images, which reveal a worldlet of haunting, alien
beauty.

"I've never seen anything like it," says Claudia Alexander, project
scientist for the U.S. Rosetta Project. "It looked as though it could
have been fractured off of a mother asteroid - it was all angles and
flat planes, ancient impacts overlaid by newer ones, covered by dust of
some kind."

She is particularly intrigued by a giant dent in the asteroid's side.

"My first guess would be that it's the remnant of a giant collision that
occurred sometime in the distant past," says Alexander. "The edges look
shallow rather than sharp and deep as might be the case with a fresh
crater. I'm sure there will be much more analysis of that feature in the
weeks to come."

And then there's the perplexing appearance that boulders rolled down
Lutetian slopes at some point.

"If that is indeed what we're seeing, the question becomes 'what could
have caused the rolling? Perhaps the asteroid spun-up, spun-down, or
experienced some orbital irregularity. It's not clear right now that the
asteroid is subject to the forces that could cause these things. This is
another issue for further study."

"Right now we have more questions than answers," Alexander continues.
"We can only speculate at this point about what we're seeing in the
pictures."

Asteroid Lutetia has been a target of interest among astronomers for
many years. It is one of the largest asteroids in the solar system and
has a strange spectrum of reflected light that doesn't look quite like
any other asteroid. When the opportunity presented itself for Rosetta to
pay a visit en route to its prime target, comet
67P/Churyumov-Gerasimenko in 2014, mission planners couldn't pass it up.

Now that Alexander has seen the images, she can't help but wonder what
it would be like to have a walk around.

"Astronauts would have a hard time walking on Lutetia -- the gravity is
likely to be much less than that of the moon," she says. "Also, the
surface regolith looks very powdery, so astronauts might find themselves
sinking in maybe a half-inch or so as they walked."

NASA's MIRO (Microwave Instrument for the Rosetta Orbiter) instrument
will help determine whether the surface layers are powdery or rocky. As
scientists analyze data from Rosetta's other instruments, they'll be
able to determine Lutetia's mass and density, thus revealing more about
the asteroid's composition and helping solve the riddle of its origin.

Is Lutetia a 130-km fragment from a planet that broke apart billions of
years ago? Or is it one of the original planetary building blocks
astronomers call "planetesimals" that has remained the same because no
planet sucked it in during the solar system's formative years?

As scientists begin to answer these questions with the Rosetta data,
they'll gain new insights into the origin and history of asteroids, and
also learn more about the evolution of the solar system itself. An
asteroid's contents can reveal something about the conditions and makeup
of the solar nebula where the asteroid formed.

"Rosetta took measurements with 17 different instruments," says Rita
Schulz, ESA Project Scientist for the Rosetta Mission. "When all the
data are analyzed, Lutetia will be one of the best known asteroids out
there."

"These spectacular images," she says, "are just the beginning."


Author: Dauna Coulter
Editor: Dr. Tony Phillips
Credit: Science at NASA
Received on Thu 15 Jul 2010 05:10:28 PM PDT