HiRISE images of Phobos!, "images available NOW". Options

[Stu]

Can't wait to see these...!

MRO images Phobos

[Adonis]

Hi everyone,

Images from MRO are fantastic. I'd like to share some especulations about some Phobos features.

The bright zone at the rim of Stickney coincide perfectly with the point in Phobos closer to Mars (or the central point as seen from Mars). At the same time, it's also the point with more tidal effect in Phobos or less gravity in the surface. I guess both facts (brightness and less gravity) should have some kind of relationship. Same happens with the opposite side, in which tidal effect is also maximized.

Because of tidal effect of Mars, close to this area gravity forces are not normal to the surface, but with a small inclination in direction to Mars, that is, some very small drag forces are in Phobos's surface in the direction to that bright zone. In the images I can see some dragged terrain or small attempts of avalanches in that direction (could it be this effect?).

In case of a big impact that shakes Phobos, the preference point to loose material into space should also be that point (could it be the reason for the bright zone?).

Grooves have also the direction and seems to converge to the maximal tidal effect zones. Because of the elongated aspect of Phobos, just before it got tidally locked to Mars there should have been a period in which it swung over the actual equilibrium point. In that period, those swings surely produced short time variations of drag forces in the surface due to tidal effects (could this be a reason for the grooves?).

Thanks