Rosetta - Early Orbital Operations at Comet 67P C-G, August 6, 2014 - November 13, 2014 Options

[Ant103]

Hello everyone !

I didn't stopped imagery processing, because I'm playing with the astounding images that Rosetta are sending us.

The last one was amazing, but very hard to processe. Here is the result

(Check out the bottom)

[SpaceScout]

Great mosaic Ant103!

If there is fine-grained loose material on the surface of the comet, could the gases ejected around perihelion act as a kind of "wind", moving the grains around and shaping them into ripples?

there was already a discussion of very speculative wind-like formed ridges and ripples few posts ago. Question remain whether the smooth material is hard (e.g., duricrust) or loose.

[climber]

Nice to see you're still around Damia
The crack on the right end side of the neck is clearly visible. Hope C-G will stay together. If not, the GC will change...

[nprev]

Thank you, Damia. Astonishing work as always!

Those features on the 'sand' really do look like dunes. I agree with charborob's 'vent wind' conjecture as well. In fact, such 'winds' would presumably have a major role in distributing the fine material in the first place.

Lots of interesting questions arise here. What is the composition of the fines? Can we measure the rate of vent outflow to determine how much force was exerted to form the dunes, thereby setting constraints on both grain size & composition? How exactly was the fine material even formed in the first place?

[ngunn]

If there is fine-grained loose material on the surface of the comet, could the gases ejected around perihelion act as a kind of "wind", moving the grains around and shaping them into ripples?

I'm highly sceptical on this. Dune or ripple formation as we understand it involves gravity controlled saltation and a reasonably steady horizontal wind. Saltating grains on the comet would have to be moving extremely slowly to avoid being blown away altogether. 'Winds' associated with cometary activity are presumably highly variable throughout each orbit and, on the evidence of the jets we see here, near vertical in direction. I agree the visual similarity to Martian dunes is uncanny and may well indicate some underlying connection at a mathematical level, but I think the physical process is likely to be very different.

[algorithm]

I think these two are taking 'Extreme Ironing' a bit far!

[dvandorn]

Excellent work, Damia! I can't tell, of course, how much of this might be some kind of image artifacting, but in this image you posted it almost looks like sheets of dust are being ejected -- very fine sheets.

It's a real imaging challenge to show the surface details of the nucleus and also see the jet and dust action. You *really* captured that with this one!

-the other Doug (With my shield, not yet upon it)

[foxfire]

It is amazing how much this looks like snow to my eyes, particularly given its bright contrast in the black and white photos and the way it seems to drape over the landscape. Not knowing enough about the physics/physical chemistry involved, i would be interested to know if is there any possibility that a volatile substance (as opposed to a "dust") could be emitted and subsequently deposited (or perhaps directly sprayed onto the landscape, or recaptured by the comet's gravity) and survive any sublimation into "free" space?

[elakdawalla]

It looks like snow because the contrast in the images has been stretched -- there is an excellent blog post on the ESA website about this. The comet is actually extremely dark, about 5% reflective, darker than charcoal. Its surface is definitely covered in dust (that's an early reported result of the mission) and much of the surface is actually too warm for water to be stable, though it's much much colder just below the surface (as reported by Sam Gulkis to the NASA Social held at JPL last week).

[foxfire]

Thank you, Emily.

[vikingmars]

The last one was amazing, but very hard to processe. Here is the result

Thanks a lot Damia !
It really looks like a view that could have inspired a painting from Chesley Bonestell...
Enjoy !

[djellison]

Oct 18th Navcam 4 frames from http://blogs.esa.int/rosetta/2014/10/22/co...ops-neighbours/

Attached thumbnail(s)

 

[jasedm]

Nice work!

Some of these structures are reminiscent of fumaroles, with encrustations around the edges.

BTW has anyone spotted any potential impact structures yet?

[Explorer1]

There was one way back during the first big OSIRIS release. It was a small dust-covered bowl (a third of the way down here: http://www.planetary.org/blogs/emily-lakda...around-cg.html).

Nothing confirmed, of course.

Ed:Fixed misplaced bracket...

[centsworth_II]

Edit: To add the pertinent image from Explorer1's link to Emily's blog.


And a crop from that image. That crater sits in the center of a raised mound. Coincidence?