Where are the big ones?

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Where are the big ones?

Post by dgloria »

Dear Dusters,

I'm amazed to find all these tiny things here and there, I cannot imagine how can that be, that by now I can tell the calibration movie from the real ones, because hours elapse till I find something that really looks like something. Where are the big rocks?

I must be late because missing phase1, I'd really like to think that this gel did found anything else than what I see on the surface (and as you say it is not what you guys are looking for).

All the best, :~)
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Post by Nikita »

Buried in the past under a totally different thread was this post from fjgiie:
Hi apollo13,
A brief answer or a long answer, according to how much you would like to read.
The shortest answer is that the particle that makes the track may end up deeper down into the aerogel than we look or can see with the virtual microscope. Deeper than 200μm. The scientist of the Stardust team will eventually get to see these particles, but we will need to find them first, from the tracks they make.

What size are these interstellar particles?
Before they can be studied, though, these tiny interstellar grains will have to be found. This will not be easy. Unlike the thousand of particles of varying sizes collected from the comet, scientists estimate that Stardust collected only around 45 interstellar dust particles. They are tiny-only about a micron (a millionth of a meter) in size! These miniscule particles are embedded in an aerogel collector 1,000 square centimeters in size. To make things worse the collector plates are interspersed with flaws, cracks, and an uneven surface. All this makes the interstellar dust particles extremely difficult to locate.

What we have learned about interstellar dust comes from remote observations of how the dust absorbs, scatters, polarizes, and even emits light. Also, some ancient interstellar dust has been identified in meteorites found on Earth. Interstellar dust is small, ranging in size from 0.01 microns all the way up to 20 microns. They are made of different minerals such as silicates, graphitic carbon, hydrogenated amorphous carbon, alumina, and even diamond carbon.

http://stardust.jpl.nasa.gov/science/de ... #interdust
...small (less than 0.01 micron-size) grains to explain the far-UV extinction; graphitic carbon to produce the 0.22 micron bump; and somewhat larger particles of size 0.1 micron, giving rise to the visual extinction. A spectral feature near 10 microns is evidence for small amorphous silicate grains.

How deep into the aerogel do they go?

Here is what is thought to be a lateral track only to get an idea of how long the tracks can be. This track may be from a slower moving interplanetary dust particle or idp.

This is a link that show photos of comet tracks. I believe you can see the particle down at the end of it's track on some of the pictures. (I looked and searched for a photo of an interstellar dust track but could not find one)

The particle that makes the interstellar dust track may end up well below the 10μm to 200μm depth that we can view at the VM.


ps: Oh, I forgot to say that this is new science and that we do not know what we are doing.
I popped this out quickly, but I think all the answers are completely covered here as far as size and frequency. fjgiie did a great job of combining them all together.

If that doesn't help, let us know and we'll blame fjgiie together! :wink:
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Post by GrahamGallagher »

Way to go Nikita, excellent thanks.
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