[Interview+] Phobos Might Already Be Destroyed and Reformed. Possibly Multiple Times

Rubble pile asteroids dominate the small asteroid population, having formed from reaccumulated debris after collisions, and their evolution is shaped by weak self-gravity, friction, and external forces like the Yarkovsky effect, which drives orbital migration. Phobos may have already been destroyed and reformed multiple times due to tidal forces from Mars, a process that could recur before its final disintegration. The Yarkovsky effect, driven by thermal radiation from asymmetric solar heating, plays a key role in moving asteroids from the main belt into near-Earth space via resonances with giant planets.

It reveals how thermal forces and gravity shape asteroid evolution, with implications for planetary defense and the fate of Mars' moon Phobos.

1. 01Most small asteroids are rubble piles—loosely bound debris held together by gravity, not solid rock.
2. 02The Yarkovsky effect, caused by thermal emission from solar heating, gradually alters asteroid orbits, enabling migration from the main belt to near-Earth space.
3. 03Phobos may have undergone repeated cycles of destruction and reformation due to tidal stresses, challenging assumptions about its current stability.