What do we do with structures beneath the surface???

Discuss your experiences with and ideas about Stardust@home here.

Moderators: Stardust@home Team, DustMods

Post Reply
Posts: 9
Joined: Thu Aug 03, 2006 10:49 am
Location: Heidelberg, Germany

What do we do with structures beneath the surface???

Post by afwxgeek »

I've seen various movies with tiny structures beneath the surface of the aerogel. It may just be contamination that somehow found its way down there. Or maybe it's a miniscule track. I've seen these in a couple calibration movies and I've been marked wrong. I've already pointed them out in various real movies and if they're not what we're looking for then I'll back off a bit.

What's the official word on these? Should we mark them or not?? :?

Posts: 23
Joined: Tue May 23, 2006 9:44 am
Location: Berlin, Germany

Re: What do we do with structures beneath the surface???

Post by Sebastian »

For me the answer depend on how clearly you can tell that you are beneath the surface.

Take a look at this movie
http://stardustathome.ssl.berkeley.edu/ ... e_id=41978

You can recognize the surface beeing right at or slightly above the topmost image. If you dive deeper into the gel you see all particles on the surface go out of focus. For small particles, this is a circle widening the deeper you go into the gel.

But very soon you will recognze that there are four circles narrowing and getting more and more contrast. Finally you might recognize three small spots in focus.

Maybe these spots are just bubbles in the aerogel. Or maybe they are slow particles and not the ones we are looking for. But who of us can know that just by viewing the movie?

Remember the motto: "Expect the unexpected"
Whatever you have seen in the training and in the calibration movies is not what the real thing will look like.

So you definitely should mark these tracks to allow further investigation.

Now imagine the surface would not have been right on top of the movie. You would only see some narrowing circles and you would never reach the actual focus point. Should you mark these findings? I think, you should.

On the other hand, there is a large number of movies that show an uneven surface only next to the bottom of the movie and you cannot dive deep enough into the movie to tell the difference between particles on an uneven surface and particles inside the aerogel. If you acually can see the particle, it is very unlikely that you have found a high speed interstellar particle since they are expected to be much smaller and faster than that..

But if it looks really unusual and you think it should be further investigated, you should mark it. It´s up to you to decide.

Posts: 9
Joined: Thu Aug 03, 2006 10:49 am
Location: Heidelberg, Germany

Post by afwxgeek »

Yeah, those are almost exactly like the ones I've been marking. I just don't appreciate the calibration movies telling me that they're wrong. I'm coming up on 1000 movies and I've only had two calibration movies marked wrong for that very reason.

Strangely, I was marked off once for sensitivity and the other time for specificity. I'd think they would have been the same type of movie since I clicked on an alleged dust particle each time. But that's another issue.

Posts: 14
Joined: Sat May 27, 2006 5:11 pm
Location: Malden, The Netherlands

Post by mover »

I've marked a similar case in which there are 4 or 5 bright things way beneath the surface:
http://stardustathome.ssl.berkeley.edu/ ... e_id=44993
Could be particles, could be defects in the aerogel, at least it is something unusual that catches the light :wink:
See the universe in a grain of dust...

Posts: 9
Joined: Thu Aug 03, 2006 10:49 am
Location: Heidelberg, Germany

Post by afwxgeek »

That's a pretty cool movie. Thanks for the link.

Posts: 1253
Joined: Sat May 20, 2006 8:47 am
Location: Hampton, SC, US

Guns and knives

Post by fjgiie »

I saw a knife blade. I marked it just because the Stardust scientist told us to look for something unusual. We should not mark these structures. I only did it one time.

I wonder if these bright reflections are the microscope light reflecting off of real glass? I believe Aerogel is silica made in a different way.


Posts: 694
Joined: Wed May 17, 2006 8:12 pm
Location: Horsetown, USA

Post by DustBuster »


This is being discussed elsewhere. here is the word:

from this thread http://stardustathome.ssl.berkeley.edu/ ... .php?t=427

Hopefully this will clear things up a bit.
I exchanged email with Dr. Butterworth on this specific subject, and this was her response:

"I've reviewed the movies you sent. 41798 does show something below the surface. To me it looks like an inclusion in the aerogel (part of the manufacturing process), not a track. For sub-surface particles, the focus comes to a point and then diffuses out again. Tracks tend not to come to a dark point. Saying this, it is not wrong to click on something curious in a movie. Going through some of the first cut of movie "hits" we have kept several movies we think are probably inclusions, but will need the high resolution checks to verify."

So, bubbles? Maybe. There's no way to tell until a good review can be made- but it has to be clicked for them to even consider looking-[/url][/i]
No dessert for you- ONE MONTH!

Post Reply