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Posted by: djellison Jul 18 2005, 12:24 PM

I made this during a debate with a conspiracists anomalist loon on a forum elsewhere...but I thought I'd share it here just because..well..it's cool

http://www.unmannedspaceflight.com/doug_images/near_feature.gif

Doug

Posted by: Marcel Jul 18 2005, 12:43 PM

Waaah ! That's pretty cool indeed ! What's the scale we're looking at here ?

I have 2 horizontal "seams" in the images in the end of the animation though.
Is that me, or your "Gericom" ? I often wondered, would it be possible to fill in the images in between, so that it runs smoothly, without shocks ? Is there any software that can generate these "gaps", so that it runs at 24 images a second ?

Posted by: djellison Jul 18 2005, 12:48 PM

I think the seams are a result of stuttering on playback - sometimes I get it - sometimes I dont

I wouldnt want to really go and fudge frames inbetween the ones that were taken - it wouldnt tell us anything new

I was inspired to go find more based on this

http://near.jhuapl.edu/iod/20000503/index.html

The f.o.v. is about a mile

Doug

Posted by: Marcel Jul 18 2005, 12:57 PM

I agree. But i thought it might be more easy (and comfortable) to follow a particular feature then, because it isn't "jumping", but "flowing".....but hell: it;s a great sequence and there's always something to comment on. You can hate me now

Posted by: edstrick Jul 19 2005, 09:50 AM

You don't have to interpolate frames in coarse time-step movies if the object imaged isn't changing much between frames.. you basically have to make short mosaic segments and steadily pan the reconstructed field of view along the sequence, going from perfect registration with one image's center to the next image's center and so on.

Posted by: Chmee Jul 19 2005, 12:45 PM

Would that be Space.com's forum *cough*

Posted by: djellison Jul 19 2005, 12:56 PM

Nope - somewhere else

doug

Posted by: ljk4-1 Jul 22 2005, 08:50 PM

NEAR mission images give clues to composition of asteroid Eros

July 22, 2005

Writer: Lauren Gold
Phone: (607) 255-9376
E-mail: lg34@cornell.edu

Media Contact: Press Relations Office
Phone: (607) 255-6074
E-mail: pressoffice@cornell.edu


ITHACA, N.Y. -- An asteroid's external features, when analyzed carefully, can say a lot about its interior. So it was while he was mapping the surface of the asteroid 433 Eros that Peter Thomas, a senior research associate in astronomy at Cornell University, found a simple solution to an earlier puzzle about the asteroid's composition.

Thomas was using images collected by the Near Earth Asteroid Rendezvous mission in 2001 to create a digital map of Eros. On the asteroid's surface, predictably pock-marked with thousands of craters accumulated from impacts over its lifetime, he saw a feature first noticed by Cornell graduate student Marc Berthoud: that a few particular patches were inexplicably smooth. That observation had led to various theories -- but none that seemed completely satisfying.

In a letter appearing in the current issue of the journal Nature (Vol. 436, No. 7049, p. 366), Thomas and Northwestern University geologist Mark Robinson show that the asteroid's smooth patches can be explained by a seismic disturbance that occurred when the crater, known as the Shoemaker crater, was formed.

The fact that seismic waves were carried through the center of the asteroid shows that the asteroid's core is cohesive enough to transmit such waves, Thomas says. And the smoothing-out effect within a radius of up to 9 kilometers from the 7.6-kilometer Shoemaker crater -- even on the opposite side of the asteroid -- indicates that Eros' surface is loose enough to get shaken down by the impact.

Asteroids are small, planetlike bodies that date back to the beginning of the solar system, so studying them can give astronomers insight into the solar system's formation. And while no asteroids currently threaten Earth, knowing more about their composition could help prepare for a possible future encounter.

Eros, whose surface is a jumble of house-sized boulders and small stones ("what geologists call 'poorly sorted,'" says Thomas), is the most carefully studied asteroid, in part because its orbit brings it close to earth.

Thomas and Robinson considered various theories for the regions of smoothness, including the idea that ejecta from another impact had blanketed the areas. But they rejected the ejecta hypothesis when calculations showed an impact Shoemaker's size wouldn't create enough material to cover the surface indicated. And even if it did, they add, the asteroid's irregular shape and motion would cause the ejecta to be distributed differently.

In contrast, says Thomas, the shaking-down hypothesis fits the evidence neatly. "The classic light bulb goes on in your head," he says; the crater density of small craters increases with the distance from the Shoemaker crater. "Simple geometry says something like a simple seismic wave."

The NEAR mission, in which a NASA spacecraft landed on the asteroid's surface in 2001 after orbiting it for a year, yielded more than 100,000 images of the small asteroid. (Eros is about 33 kilometers long, 13 kilometers wide and 8 kilometers thick). Since the mission's conclusion 16 days after the landing, scientists from institutions around the world have been sorting through the data.

That process is expected to continue for years. "Careful mapping of things on the surface can give you a good clue as to what's inside," says Thomas. "And in one sense, we've barely begun."


Related World Wide Web sites:

Cornell University Department of Astronomy:

http://www.astro.cornell.edu/

Seismic resurfacing by a single impact on the asteroid 433 Eros (Nature)

http://www.nature.com/nature/journal/v436/n7049/full/nature03855.html


-30-

The web version of this story, with accompanying photos, is available at

http://www.news.cornell.edu/stories/July05/Thomas.Eros.lxg.html
--

Cornell University News Service
312 College Ave.
Ithaca, NY 14850
607-255-4206
cunews@cornell.edu
http://www.news.cornell.edu

Posted by: ElkGroveDan Jul 22 2005, 10:09 PM

OK now that you've piqued our interest, can we have a hint as to what the conspiracists loons were alleging?

Posted by: djellison Jul 22 2005, 10:12 PM

That the feature about 75% across, 30% down was artificial

Stop laughing.

I explained that the CCD pixels were non square so a small feature could appear stretched after processing. I explained that deconvolution would artificilaly enhance features like that....and I showed the orig raw imagery and the re-sized imagery, yadda yadda yadda - but you know what these loonies are like, once they latch onto something...


I say debate...they proposed a quite rediculous theory - I counter it with evidence - they ignore the evidence and carry on. It's totally futile to be honest, but it's good 'sport' if nothing else

To give you an idea - the same person suggested that there are hangers on the moon, glass worms on mars, that he KNOWS Mars had a civilization in the past etc etc etc...

Doug

Posted by: Bob Shaw Jul 22 2005, 10:44 PM

Doug:

Please don't go into *too* much detail, or else Google will lead the sods here! It's one thing having a gentlemanly discourse regarding impact vs uplift as the origin of the Columbia Hills (even if it sometimes degenerates into discussions of the geology of Benny Hill, the Phil Monty, et al) but if the green ink brigade start haunting our discussions we'll pass from the highly speculative to the merely laxative...

Bob Shaw

Posted by: ElkGroveDan Jul 22 2005, 11:13 PM

OK I jumped on my Web Surfboard (they call me the Big Kahuna) and went looking for your debate, and found it. You're right. Those folks are what we call "whackjobs" in my business.

I will admit though that it does look a bit like an Imperial Walker from Star Wars

Posted by: djellison Jul 23 2005, 08:35 AM

Oh - Bob - have no fear - I have a special administrating/moderating hat just for net kooks It comes with a large bat marked "ban"

They all know about this place but they've never come in here....because they know their arguments would be smashed to pieces.

Doug

Posted by: ljk4-1 Jun 19 2006, 03:37 PM

Near Earth Asteroid Rendezvous Guide

http://near.jhuapl.edu/media/NEARoverview.pdf

Posted by: AlexBlackwell Jun 19 2006, 06:03 PM

I'm just curious: Is there any particular reason that you're reviving a thread that's been dormant for nearly a year by posting a bare link to a document that's nearly ten years old?

Posted by: ljk4-1 Jun 19 2006, 06:22 PM

Hi Alex,

I already explained my actions to Doug, but: I thought people on this
forum particularly might find a document on NEAR of interest that had
not been available online before (after all, I see plenty of info and talk
on space probes far older than that one) and I wanted to put it in a
thread relevant to NEAR, and this was the closest one I could find.

But if people don't want it and aren't interested, then feel free to get
rid of it. I have no personal attachment to it and certainly did not intend
to turn it into the big deal it apparently has become.

Posted by: AlexBlackwell Jun 19 2006, 06:33 PM

I believe that document has been online since before NEAR entered orbit around Eros. In fact, I remember downloading it from the NEAR site years ago. I could be mistaken, though. At any rate, a few words explaining why the post is relevant (as you do above) probably would help.

I only bring this up because I'm "guilty" of the same thing. Over the past couple of months I've tried to stop bombarding the forum with posts, especially those that are only peripherally related to a thread. Given the amount of postings one has to wade through, self-restraint would really be appreciated. Don't take it personally, though. Those words (or something close to them) have been said to me in the past.

Posted by: ljk4-1 Jun 19 2006, 06:41 PM

Yes, I will try to be more verbose in the future, and no, I was not aware
the document was online before. I admit I didn't do a deep search, either,
but usually the list I found this on only posts things that are new to the Web.

And maybe some people think the info you provide is too much, but I have
found it to be immesurably valuable, especially as you find it from sources I didn't
even know about, let alone read on a regular basis. And I bet I am not the only
one who agrees with this. With all the real crap on the Web, it is refreshing to
see an article of real depth and substance on a subject of interest here.

But Lord, if it helps, just say "Look at this really neat article!"