An Unexpected Discovery On The Surface Of Rosetta's Comet

Here's some cool news for the Spacce enthusiasts on ATS. Scientists have discovered sand ripples and dunes on Comet 67P/Churyumov-Gerasimenko. The surprising part is that Comets don't have the ffeatures necessary to create ripples and dunes such as an atmosphere or even wind.

Scientists have presented their initial observations of Comet 67P/Churyumov-Gerasimenko in seven articles published Thursday in the journal Science. Among the more surprising finds: images of ripples and dunes on the comet's surface, unexpected given that the comet lacks an atmosphere (and therefore wind) and experiences very little gravity.

Pretty cool, ATS?

io9.com...

a reply to: lostbook

Very interesting! Perhaps the comet was created originally from a planet that exploded or suffered some sort of impact that knocked 67p into another orbit.

a reply to: lostbook

From your article:

"Features in the Hapi region show evidence of local gas-driven transport producing dune-like ripples (left) and boulders with 'wind-tails' (right) – where the boulder has acted as a natural obstacle to the direction of the gas flow, creating a streak of material 'downwind' of it.

Sublimating gases can move material.

Cool and puzzling.

Van der Wall's force and gas emissions are the most plausible explanations according to the interviewed expert... I say it landed in Indonesia, gently, on a beach ...and was then blown back into space from the force of the Toba volcanic event... hey, that's "plausible," too!

a reply to: lostbook













cool thread, i'm going with exhaust from alien spaceship.

My vote is for alien rock gardeners!!!

(Isn't that the Japanese hobby where you rake sand around?)


Which by the way is PISSED we messed up his sculpture!!

#invadingrockgardeners

a reply to: lostbook

Yes it does have wind... solar wind.

The reader, I'm sure, is aware that sand dunes are huge. And we _are_ talking sand dunes here on the Comet surface. Massive piles of sand.



Space sand, which will probably be found to be much more abrasive than regular sand.








And boulders. Those are not little rocks, but massive bigger-than-a-house boulders. I'm just waiting for someone to point out that the only astronomers close to predicting this were the EU guys when they said water would never be found on any comet back in 08. But that is hardly the same thing as predicting actual sand dunes so, for now, the Electric Universe guys are not too active.


They only have the merit of being the least wrong.


Mike Grouchy

Maybe radiation pressure from solar wind?

How do they think sublimating gas in a perfect vacuum can create a wind at the head of the comet? The tails and jets are near the rear right? I personally vote for stellar wind and charge differential causing the effect.

a reply to: lostbook

Given that the emissions from the comet bodies are plainly evident as the comas, why would this be a surprising find? It seems to me that lacking an atmosphere and little gravity would be an aid in allowing clumping of charged particles that would remain undisturbed except for their own attractions and repulsions which eventually would result in discernible fields of action.

www.youtube.com... this theory is much more plausible than the conventional opinion of the origin of comets.


a reply to: olaru12

More like a result of static discharge than solar "wind".

a reply to: thishereguy

originally posted by: olaru12
a reply to: lostbook

Very interesting! Perhaps the comet was created originally from a planet that exploded or suffered some sort of impact that knocked 67p into another orbit.

I wonder if it could have been a volcanic island/solidified magma chamber that was blown up into space from a planet or even the Earth? There are some mountains that have been known to have completely disappeared after an explosive volcanic eruption.

a reply to: lostbook

Would you think these features could be caused my vibrations?
If you take a piece of plyboard or sheet of metal, put out a layer of sand and some small rocks on to it, then strick it several tmes, the loose material will move around and form similar features over time.
The comet is likely made up from a lot of similar materials held together by a very weak gravitional field. If, or when, it is struck by some other objects it would likely set up vibrations within the structure of the comet. This would make to loosest particles shift around and change positions.

a reply to: teamcommander

Would you think these features could be caused my vibrations?

Yes, by way of ion acoustic waves, which have been found to be very strong on and around some comets.

originally posted by: stormcell

originally posted by: olaru12
a reply to: lostbook

Very interesting! Perhaps the comet was created originally from a planet that exploded or suffered some sort of impact that knocked 67p into another orbit.

I wonder if it could have been a volcanic island/solidified magma chamber that was blown up into space from a planet or even the Earth? There are some mountains that have been known to have completely disappeared after an explosive volcanic eruption.

That is something i have always wondered about since looking on this as a child



What goes round

originally posted by: olaru12
a reply to: lostbook

Very interesting! Perhaps the comet was created originally from a planet that exploded or suffered some sort of impact that knocked 67p into another orbit.

I actually really liked what you said about this! Possibly from a planet? Perhaps sort of like what happened when the planet that hit the earth giving us the moon occurred! Great theory

Fascinating... I highly doubt it's due to solar wind or the like.. from what I just read on the subject,solat wind isn't felt like our wind on earth.. the other theorys "sound" good but.. it would have a larger impact.. such as blowing up from another planet.. wouldn't the ripples or waves been comet wide? How can you explain isolated areas? Same with the comet approaching the sun.. the head would blow everything back affecting the comet as a whole..

The scientists are still scratching their heads on this one and as much as I appreciate ATS armchair astrophysics department and as much as I loathe the official explanation.. I'll wai.

There are two hypotheses presented in the paper on the origin of the dune-like features on 67P.

High velocity jets of sublimating gases and electrostatic effects similar to those which may occur on the Moon's terminator.

Images acquired in the Hapi region of aeolian ripple structures, rocks with wind tails (fig. S4), and rocks with moats provide further support for localized gas-driven transport. To initiate saltation, the surface shear stress from the gas expansion of a vent must overcome the gravitational force and interparticle forces (14). Although the gas densities are low, following (15), velocities on the order of 300 m/s appear to be sufficient to move 100-μm particles and may be generated by localized sublimation. Electrostatic levitation in combination with horizontal electric fields across the terminator, as proposed for the Moon and 433 Eros, may be an alternative mechanism, although this may only be effective for smaller particles (16).

www.sciencemag.org...

Really interesting reading. That comet is a weird place.

There are three areas characterized by extremely smooth material with no obvious impacts or circular flat-floored depressions and a paucity of boulders (Imhotep, Anubis, and Hapi). The Imhotep region is morphologically remarkable. It is dominated by a smooth surface that covers an area of >0.7 km2 (Fig. 3). At its margins, the smooth material gives the impression that it is layered. Unlike the airfall deposits, the smooth material appears to be enclosed by more-consolidated material that surrounds it [consolidated cometary material (CCM) (21)]. The smooth material thins to one side and gives way to a terrain dominated by circular filled and unfilled structures.