Grooves

[mmcirvin]

Parallel grooves on Phobos.

Parallel grooves on Lutetia.

Parallel grooves on Vesta, in the July 9 picture I've linked before.

There are a lot of theories about these things and it seems to be a rapidly developing mystery. The research mentioned in the top link suggests that the grooves on Phobos are not related to the giant crater Stickney, but it's tempting to link them. They're not necessarily radial to Stickney.

But look closely at the new Vesta picture: the grooves appear to be mostly inside the giant southern-hemisphere crater (which is hard to identify as a crater in the photo), but they're running across it from side to side. Again, it's tempting to link them to the crater but it's hard to say what the relationship is. They probably wouldn't be chains of secondary impacts. Are they cracks in the underlying rock?

Vesta and Lutetia are the two largest asteroids imaged up close. So you might imagine that would be significant, but, then again, Phobos is a much smaller body.

Comments

[autopope.livejournal.com]

Don't worry, they're just bulldozer tracks left by the mining robots from the Von Neumann probes.

[mmcirvin.livejournal.com]

And there's also grooved terrain on Ganymede, but it looks different and is probably something else entirely.

[skapusniak.livejournal.com]

Grooves also in the 'saddle' on Eros

[skapusniak.livejournal.com]

Looking at that, how about impacts that are less 'bullet hits target' but more 'sideswiped by another vehicle'?

One asteriod drags across another at an oblique angel, but both keep chugging along their orbits digging grooves in each other.

[urbeatle.livejournal.com]

Asteroids are just groovy.

[cshalizi.livejournal.com]

Claws.

[mmcirvin.livejournal.com]

The Cassini Titan radar imaging team initially referred to the parallel marks in Titan's infrared-dark regions as "cat scratches". It eventually turned out they were dunes of stuff with a sandy consistency.

These asteroid grooves look to me sort of like the features on the Moon that geologists say are chains of collapse pits over a deeper fissure or collapsed lava tube. But I don't know if you would get something looking just like that on a small body.