Can I have some geology-knowledgeable people look at this thread?

[Ediacara]

Without right clicking, I'd like some ideas as to what the striations are on this body. I already have some ideas myself, but I'm wondering if others see what I'm seeing.

I'll reveal what this is in a few days, I just want people to look with a blank slate. Thanks!

[Fox Mulder]

1. Without right-clicking, I already know what that picture is.

Maybe I shouldn't answer...

(I went to college for geology, btw :hi:)

[Ediacara]

2. I did too

Which is why I find these features very weird.

[Dogmudgeon]

8. The universe is weird

Little wonder so many kooks have outlandish explanations for these things.

But, and not for the first time in history, the kooks are earning their keep. A lot of very ... interesting ... things have been found in the NASA photo archives. They may not all be UFO landing pads and extraterrestrial amusement parks, but they're interesting nonetheless, and the alien-hunters are good at finding them.

As to the striations, I don't have much of a clue; and I studied geology as a hobby when I was a kid. I was a "rockhound" with a couple of college textbooks from the 1960s. (Did they even have metamorphic rocks back then? :) ) But I think my years of playing in the snow provide more experience. Some of them look like the tracks of incoming meteorites that "skipped" along the surface of the body like rolling snowballs on a virgin field of snow. And since several asteroids have been discovered with smaller asteroid "satellites", the idea has a certain intuitive charm.

Or, have I overlooked something (other than half-built UFO landing strips) -- ?

--p!
Of Course, I Could Be Wrong™

[tocqueville]

3. they are not sedimentary

and regarding the position of the stripes which look more like channels, one explanation could be molten material that flowed on the surface after the big impact creating the major crater. It depends a lot of what the asteroid is made of, what kind of rocks, if it contains ice etc...

[htuttle]

10. Hmm...I'm not a geologist, but I was thinking it *was* sedimentary

The main reason I'd say so is in the second picture, on the far side of the large 'crater' on the left side of the object, it looks like at least two of the main 'scrapes'/lines are continued on the opposite wall of the crater, as though these lines go all through the object's cross section. It seems unlikely that any object that would scrape these lines would be able to follow the outside contour of the object on a 90+ degree corner.

But as I said, what do I know? :shrug:

[tocqueville]

15. if you know what the object is

it's made of the primordial elements of the solar system. It's a C-type asteroid made of chondrite. The big impact resulted in a flow of molten "tar".

[Viva_La_Revolution]

4. skid marks

from martian hot-rod landings. :popcorn:

[bananas]

5. Claw marks

Godzilla tried to hold on, but he couldn't.

[Kolesar]

6. First one looks like a bicycle helmet, heavy duty

What stands out in the second photo is how the biggest striation starts with a big indentation, then there is a continuing series of indentations. It looks like someone rolled a snowball across the surface

[whistle]

7. Striations such as these seen on earth would be caused by the

...scouring actions of glacier ice embedded with sharp rocks and gravel moving across the surface. This of course being an asteroid or possibly one of the moons of Mars it is not likely to be that.

In the bottom photo just to the right of the lip of the crater lower edge there appears to be a series of smaller impact craters along one of the deeper striations that appear to be in almost a perfect line. I count about a dozen. The top photo shows similar patterns of linear striations with impact craters lined up as well.

Very curious. I have no idea what these are. Better not be a potato photographed under some black light process.:crazy: :silly: Thanks

[Nihil]

9. Ejecta trails after impact?

From the photo I'd guess that this is a space object (asteroid/satellite)
so the larger items "splashed" from the impact would have longer and
apparently bouncier trails that you'd expect on a higher-gravity body
with an atmosphere.

Or am I trying to answer the wrong question here? :silly:

[mccoyn]

11. That was my thought, too.

The lines are densist near the crater and they run perpendicular to it. I'd be surprised if the two weren't related.

Before I saw the second picture all I could come up with was alien spaceport.

[HiFructosePronSyrup]

13. That's what I'm thinking.

[tocqueville]

16. try to fire a small "nuke" in a deep frozen aqueous tar pit

at perpendicular angle. Counting that the tar pit is moving in vacuum.



http://www.nasa.gov/mission_pages/deepimpact/media/deepimpact-090605.html

"In a couple of seconds the fast, hot moving plume containing water vapor left the view of the spectrometer, and we are suddenly seeing the excavation of sub-surface ice and dust," said Deep Impact co-investigator Dr. Jessica Sunshine, with Science Applications International Corporation, Chantilly, Va. "It is the most dramatic spectral change I've ever seen."

Phobos is probably much more compact than the Tempel comet and the impact was much more violent. But basically it's the same procedure.

sadly there no "after" pictures of the impact experiment

[Odin2005]

12. I'm assuming they have something to do with Stickney Crater (the big one)

http://en.wikipedia.org/wiki/Phobos_%28moon%29

"Phobos is highly nonspherical, with dimensions of 27 × 21.6 × 18.8 km. It is heavily cratered, and the most prominent surface feature is the large crater named Stickney, after the maiden name of Asaph Hall's wife Chloe Angeline Stickney Hall. Like Mimas's crater Herschel on a smaller scale, the impact that created Stickney must have almost shattered Phobos. The grooves and streaks on the surface were probably also caused by the Stickney impact. The grooves are typically less than 30 m deep, 100 – 200 m wide, and up to 20 km in length."

[Xithras]

14. Fracture marks

Big rock hits bigger rock. Bigger rock gets big crater and a series of radiating cracks away from the impact site (caused by impact force + super-heating from the strike). Over the ensuing billion years, the bigger rocks picks up many, many feet of dust, partially filling the cracks and making them appear as "grooves".

It's also possible that an extremely close call with a much larger gravitational body (like a moon) might have induced enough stress across the surface of the rock to crack it along a single plane. A large asteroid that missed a moon by only a few hundred meters or so would undergo massive stress as gravity tried to pull it down, and the combined inertial effect sling-shotted it into a new orbit. Again, those cracks could fill with dust over time, creating the effect you see here. We know that near misses like this have happened on Earth (someone actually filmed one back in the 1960's), so it's likely that the scenario has played out hundreds or thousands of times in the history of our solar system.

[Ediacara]

17. Thanks for all the input

It is indeed, Mars' moon Phobos as some posters have pointed out. The strong roughly parallel lineations across much of one side of the object are certainly very weird. I don't buy that they're all ejecta trails (they don't radiate from Stickney Crater and in fact many cross right over it), but it seems likely it's a body-wide fracture system (with other parallel, but differently oriented fractures visible on the north side), or less likely, bedding. It really looks like bedding to me, but the fact that it's a moon and is huge (18km is the shortest dimension) really makes that unlikely. Although maybe it's a piece of what used to be under Hellas Planitia before it was hit by a planetoid 4Ga....