Category Archives: planetary science

comet, Comet Tempel-1, jet Propulsion Laboratory, NASA, planetary science, stardust

The Face of a Comet

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Stardust-NExT Shows us Tempel-1

This view of Comet Tempel-1 was taken at 8:39 PST on February 14 when the comet and the spacecraft were about 200 kilometers apart. Click to enlarge for detail.

Well, the wait is over, folks. The close-up pictures are starting to make their appearance on the mission and NASA web pages.  As a former comet researcher, I find these quite compelling.  All my studies were done on the plasma tail, but the nucleus was always interesting, too. So, here’s one of the images of the comet’s nucleus returned from the mission.

Let’s do what scientists do when they look at these things: take a visual inventory. What leaps out at you?  Craters.  Yep. A lot of cratery-looking formations. Also some bumps and nodules. The nucleus of the comet itself has rounded edges, like a potato. It’s not perfectly spherical, and seems to have some flattish-looking plains at the upper right in this image.

There are some bright areas — I’m guessing they’re reflective material glinting in the sunlight.  Probably uncovered ice, maybe from some areas where material has recently outgassed and left fresh ice on the otherwise greyish surface.

Comet Tempel-1 as seen by the Stardust-NExT spacecraft on 8:39 p.m. (PST) on February 14, 2011. Click to see details.

This comet has been at its closest to the Sun since the last time a spacecraft (the Deep Impact mission) saw it in 2005.  The combination of increased solar radiation and heating has changed the surface ices.  The material underneath is more pristine — unchanged. What scientists want to know is the nature of those changes and the difference between the surface and the below-surface ices.  The pristine ices are likely unchanged from when they first formed in the early solar system, and that makes Tempel-1, and indeed — most comets — treasuries of information about conditions in the early solar system.

Okay, that’s some instant science. What do the experts have to say about these and images we haven’t seen yet?  We’ll find out later today (Tuesday, February 15, 2011) after the team members have had time to study the images.  It should be cool news! Stay tuned! If you want to watch the press conference, keep an eye out here for live streaming coverage of the press conference at NASA Jet Propulsion Laboratory.

Asteroids

All Hail Lutetia!

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Rosetta’s Closest Approach to an Asteroid

A closeup of the asteroid 21 Lutetia, taken by the Rosetta spacecraft on July 10, 2010. Click to massively asteroidinate.
21 Lutetia with Saturn hovering in the background.

It’s been a fascinating day today (Saturday, July 10) here at the hacienda — watching as images of Asteroid 21 Lutetia come pouring out across the IntarWebs from the European Space Agency’s Rosetta mission (which was built and is being run by a team of scientists from a consortium of 50 contractors in 14 European countries and the United States.

I was watching earlier today as the scientists sweated out the planned “loss of signal” from the spacecraft as it went through a maneuver.

It wasn’t long, however, before they were jubilantly reacting when the signal was reacquired. And, then just a few hours later, they were nearly weeping for joy as the first closeup images came streaming back from the spacecraft. It was a great moment for all the scientists and technical support staff who have worked on Rosetta for years.

The scene above is the closest approach image and, as you can easily see, 21 Lutetia is a battered worldlet, scarred with craters. If you enlarge the image, you’ll see evidence of boulders on the cratered surface, and in the central crater (middle of the image) it looks like there might be a little slumping along the crater wall

If you zoom in on the image above, you can see are grooves between the craters. They suggest some kind of action that has deformed the surface. Could they have been formed when the asteroid was whacked during an impact event?  How old are they? How deep are they? All these and other questions await answers from the planetary scientists on the Rosetta mission.

There are more images to come, so keep an eye out at the Rosetta Blog for details on these and the rest of the fascinating views of 21 Lutetia.  And, just to give you feel for the scale and distances involved, here’s a great view of the asteroid from a distance of 36,000 kilometers, with the planet Saturn in the background.

Woohoo!!! This is what the exhiliration of scientific discovery feels like.  It’s a process that wakes you up to the amazing things that exist throughout the cosmos — from our planetary back yard to the most distant reaches of the universe.  And, the good news is — there’s always more to discover! The next stop for Rosetta is a 2014 visit to comet 67P/Churyumov-Gerasimenko.  Stay tuned!