"I think I've found a track, what do you think?" A

[Snoopy]

Hi there, i did sleep it over and couldnt get it out of my mind because im really curious about this:)
So i just try to figure what will make sense to look for. Please comment and correct me

I'm referring to what is said in the about section of the Stardust site and to (what's there linked) the JPL Site about stardust especially the section 3.1 about aerogel there ( http://stardust.jpl.nasa.gov/science/de ... #interdust)

So what is this dust like? NASA got its knowledge about it from the missions ulysses and galileo. These are probes fitted with some sort of dust detector. As this detector couldnt be analyzed because these probes never return, i assume its some kind of collision detection. What leads me to the conclusion that relevant particles must have a determined minimum kinetic energy (speed,size) to produce a detector "hit".

Additionally they know about interstellar dust from optical observations during which they measured some apparent spectral anomalies which they ascribe to interstellar dust particles.

Then they think they found interstellar dust on meteorite samples they collected, and some other strange sources (a U2 aircraft?)

However, NASA expects the particles of a size from 0.01 to 20 micron.

The Stardust Team says, that they expect around 45 particles of interstellar dust in the size of 1 micron in the total collector.

In laboratory and in Space they tested how to catch particles in the aerogel and what this would look like. A 10 micron particle would leave a carrot-shaped trail of 1500 micron at a speed of 6km/s. ( http://stardust.jpl.nasa.gov/science/sd-particle.html) According to this image i estimate the diameter of the trail at 50+ micron at the top.
(It seems like the particle did not leave any trail in the last part before the ball at all. May the aerogel have melted together there due to the lack of deformation?)

But if the particle is just 1 micron, as the energy is dependent linear from the mass and the mass is cubic from the diameter, it would have 1/1000th the energy of a 10 micron particle. (But hopefully its faster )

I do not know how the energy relates to the resulting shape in the aerogel, but i think it will be small. But not so small it would make only 1,5 micron i hope .
If I consider now the resolution of the microscope samples, i assume that the focus distance changes several ten microns for all positions. So it would be a tiny little spot to look for.
The calibration movies seem to be from particles above 5 micron i guess.

Then again it would still be a carrot shaped trail. So these "Halos" that collapse if you go deeper (in 42381 and 41640), probaply will be inclusions . The halos are probaply caused by the optical fraction around this dirt as seen with the dirt on the surface. ( http://stardustathome.ssl.berkeley.edu/ ... .php?t=504)

On the other hand it might be possible that a very small particle would leave no trail if like aforementioned the aerogel would melt back in place? But i guess it would then be that small, it couldnt be seen at all.

But in http://stardustathome.ssl.berkeley.edu/ ... e_id=41778 there is in the low left a small hole which ends in a ball. Resembles me of the aforementioned pic of the trail just much smaller and from above - though the ball is quite big in relation to the depth.

So i will be looking for something like that.

[Orion_0169]

I'm becoming less and less sure of that, given some of the things that are being flagged.

[Jeff]

Only one other person has flagged this one...
http://stardustathome.ssl.berkeley.edu/ ... e_id=43986

I think I see two(maybe three) seperate extra small tracks. Just curious if anyone else sees them.

[Sharqua]

I see three specks and one possible track. The track is nearly invisible, though, so I can't be sure. It's below the surface and its focus doesn't change, but it's so close to the shade of the aerogel itself as to be effectively invisible. There's nothing above it (on the surface) to provide a shadow at that point, so it's not a blurred object.

To locate the potential track, look just slightly north of center. There is a pair of specks at the surface, slightly apart (the right one is north of the left one). They are in alignment with the "b" of "bars" and the "s" in "focus" of "focus up."

Now sweep slowly up and down through the words "focus down" (ie, the lower half of the focus bar). If you look carefully enough, you'll see a slight out-of-focus blur moving right to left just above the right-hand of the pair of specks I described above.

-Shar

EDIT: Nevermind. I looked at it with a magnifier. It's a speck, though a really hard to see one. It loses focus at the very bottom focus bar.

[dannyzs]

On my one movie that I was the first person to click on the dust track, there are now 21 agreements

Movie ID : 42477

What ya think?

[ethicalpaul]

I think you should post the link to your movie, not just the number because I don't know where to go to look up a movie number.

I also think you love attention

[dannyzs]

lol

http://stardustathome.ssl.berkeley.edu/ ... e_id=42477

[ethicalpaul]

Thanks!

Do you mean the very small thing 1/2 way down near the right edge? It is too small for me to say anything about it, it's smaller than any calibration image I've seen, but maybe.

[Orion_0169]

If you mean the out of focus ring that darkens to a focussed point. This is the stuff I've been talking about. The fact that it isn't in focus AS the layers go down would indicate it is something in the gel already. Not something that has entered the gel.

[Sharqua]

I see one definite inclusion (it is going out of focus at the bottom two bars), plus two likely inclusions coming into focus near the bottom of the focus bar. One is upper right hand corner, one is middle left just below the elaborate dustbunny.

I wouldn't call any of them a track because of the even nature of the focus change.

-Shar

[PocketLint]

Even though it comes into focus below surface, it does not stay in focus. so I have to say this is not a track.

A true track should have a few frames at least where it stays in focus below surface.

This seems to be an artifact where it is already existed in the gel.

Remember, the idea here is that as a particle pushes it's way into the gel, the displaced gel builds up along the 'tunnel' that it makes on it's way in.

The higher density of gel along the displaced tunnel wall should show up as a darkened ring along the 'tunnel' sides. The size of the ring will change slightly through the layers.

Because of the different entry angles the particle could make it's way into the gel, different tracks could be seen. That is the point of the initial testing. To get one to visualize the resulting tracks.

With that said, If a possible track comes into focus just in the last few frames of a movie, and there are really no other targets that are also coming into focus then it might be a track and worth marking as such. If however more then one possible target is coming into focus at the same rate/time then it most likely will not be a track as the odds are against two or more particles being in the same movie.

The test movies have rather large examples for tracks. The calibration movies have some better examples of smaller tracks but I think you could expect a real track to be smaller than the test movies.

Just the way I look at things.

[Koliedrus]

If you mean the out of focus ring that darkens to a focussed point. This is the stuff I've been talking about. The fact that it isn't in focus AS the layers go down would indicate it is something in the gel already. Not something that has entered the gel.

AH! I didn't get that during the web training. After looking at the movie, I would have tagged it as well. I've marked a few tiny potentials today that seem to enter at an angle. So far, the calibration movies seem to be way too obvious but I've only been through 20 so far.

I'm going to take the advice that if I'm not having fun, I'm doing something wrong. Reporting something that (to me) might be a track will only be done after I've looked long enough for it to be a "maybe"; something that requires the eyes and attention of others.

This one would fit into my self-defined "maybe" category.

Much respect for sharp eyes and patience,

Kol

[Snoopy]

I'd consider this as an inclusion. I saw some like this, but it's missing a tunnel. Of cours it might turn out, it was a slow one and didnt blow a tunnel (in those example pics there is a slight zone where the aerogel seemed untouched between the particle ball and the impact tunnel). So it could be one, but i don't think so.
Nevertheless you're the best

[jsellers]

This thread has so far been a great read...Firstly, congrats dd and thank you cthiker for revising your position. I too have a similar movie that I tagged and would love anyone here to let me know what they think of it:

http://stardustathome.ssl.berkeley.edu/ ... e_id=35086

It has many of the same characteristics of dd's movies but has an even clearer focus on segments of the trail--giving a clue to the angle. I sure hope it's not just an inclusion. It does, however, lack the trail length of dd's find, so please let me know what you think. Also, because I flagged this movie and it appears on my events page, does this necessarily mean that I was the FIRST to flag it?? I wasn't sure if I was just agreeing with an earlier flag.

[PocketLint]

if more than one come into focus, at any below surface ranges, then I would have to say no.