Stardust Comet Particles Tell Tales of Fire and Ice
Thursday, March 16 2006 @ 03:20 pm EST
Contributed by: bobmoody
The wonderfully successful Stardust mission to retrieve cometary and interstellar dust grains is now beginning to reveal to scientists the secrets it was sent to find. It re-entered Earth's atmosphere at a near-record speed of almost 30,000 mph on January 15, 2006, with the pristine dust particles of comet Wild 2 (pronounced 'Vilt 2') as well as other particles gathered from between the planets on its way to the comet safely packed away deep inside.
Once it had landed at the Dugway Proving Grounds in Utah, it was recovered, transported to a special lab at a NASA facility in Houston, and research is now underway on the first of these exciting never-before-seen-particles.
|Brilliantly illuminating the countryside over the Pacific Northwest and Northern Nevada and Utah, Stardust announces its return to Earth after a spectacularly successful cometary material return mission.|
Early reports from Stardust mission scientists reveals that there are materials found within the dust grains gathered from Comet Wild 2 that had to have formed in very high-temperature conditions, namely, the mineral olivine. This was totally unexpected as Stardust Principal Investigator Donald Brownlee of University of Washington at Seatlle explains."The interesting thing is we are finding these high-temperature minerals in materials from the coldest place in the solar system." Most AOAS club members will remember some of the meteorites that I've brought to club meetings from time-to-time, and olivine is a common ingredient in meteorites and in many Earth minerals. Another well-known name in meteoritical research is Michael Zolinsky who happens to be the curator and a co-investigator on the Stardust team says, "[finding] high-temperature minerals...supports a particular model where strong bipolar jets coming out of the early sun propelled material formed near to the sun outward to the outer reaches of the solar system."
Olivine is one of the most common minerals in the universe. It's the primary ingredient in the green beach sands found on some Hawaiian beaches, and they are, of course, formed from volcanoes. Quite surprising to find such a mineral within cometary dust.
|Tiny fragment of the high-temperature mineral olivine found as one of the comet dust grains imbedded within the aerogel material on the Stardust mission.|
While olivine is a component of iron and magnesium, as well as other elements, the olivine in the dust taken from the Wild 2 samples is also rich in calcium, aluminum, and titanium.
The remarkable material which performed the task of capturing these dust grains and interstellar particles is called Aerogel, and is about 1000 times less dense than glass. To look at it, one can easily see where it gets the nickname "solid blue smoke".
Click "read more" for an image of Aerogel, more images of cometary particles, and links to websites to learn more about Stardust
The Stardust website is loaded with many of the early release photos of the work done so far. In addition to the images, there are several movies available, which, unfortunately, I'll never be able to see due to our super-slow connection speeds up here on the ridge at Coleman Observatory.
|Solid blue smoke, more widely known by it's commercial trade name - "Aerogel"|
Website visitors will also be able to learn more about the Stardust@Home program which will allow a few lucky people to actually participate in the research! If you are selected from a list of applicants through the website above, you'll receive a download that will allow you to search through small chunks of images that will be sent to you from the research lab. Your computer will be turned into a "virtual microscope" and allow it to search for the sometimes unimaginably small particles that could be held within the chunk of image you've been sent to search through.
In this image we see at least two good impact tracks from dust grains that have been captured in the Aerogel. The "tadpole" shaped objects are somewhat deceiving. The "head" is wide indicating where most of the energy was released when the particle first struck the aerogel at several thousand miles-per-hour. the "tail" points towards a tiny almost invisible speck which is the object that made the track, and is still intact and virtually unchanged from the experience.
|Multiple tracks from cometary dust grains imbedded in aerogel. Even though the tiny black specks may be no more than a few hundredths of a millimeter in diameter, they can still be sliced so thin that more than 100 scientists can study one speck!|
According to the scientists on the Stardust project, the number of particles gathered surpassed their wildest expectations and yielded a virtual gold mine of material for study. That's just the cometary dust particles, too! The interstellar dust grains haven't even been opened yet, but it's expected that they too will be far more numerous than expected. If all goes as planned, the Aerogel tray with the interstellar grains should begin study by mid April.