I think the angle of the image makes them look steeper, most of the fine material is on slopes less than 30 or 40 degrees (see Groussin 2016 if you're interested) but the cliffs are indeed vertical, sometimes even overhanging!
That is cool, and thanks for the reference. I've been interested in non-spherical gravitational fields on asteroids (we have a code to calculate that), and the influence on landform shapes. But 30 deg is pretty unremarkable.
Angles of repose of sand on Mars looks to be identical to those on Earth, even under 38% gravity. So probably grain shape (and electrostatic forces) are the dominant factors, with gravity playing much less of a role.
Also, there are *ripples* of sediment on 67P, which basically has no atmosphere.
Vibration ripples? Cohesion dominated systems in lower g seem reasonable. I was more interested in variations on slope on non-spherical bodies as a marker of internal gravity tensor orientation and thus internal density distribution.
Comments
Nice beach!
Where's the lake?
The image resolution is approximately 15 centimetres per pixel.
Credit: ESA/Rosetta/MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Also, there are *ripples* of sediment on 67P, which basically has no atmosphere.
Checkmate