Mars' Rotation Is Speeding Up, Puzzling Scientists

NASA's InSight lander collected multi-year data showing Mars' days are getting shorter.
Scientists learned about Mars' interior and rotation through InSight's instruments.
Mars wobbles due to its shape, allowing precise measurement of its spin.
Melting ice and crustal rebound may be causing Mars' rotational speedup.
The reasons behind Mars' changing spin remain unclear to researchers.