Walkabout The Galaxy

We think of aurora as an atmospheric phenomenon, but what happens when high energy particles from the Sun directly impact a planetary surface? Mercury reveals another cool planetary twist with auroral-like emission from its surface. Meanwhile, Jim and and Josh are gobsmacked by the old news of a big gravitational potential hump in the Indian ocean caused by upwelling of low-density magma far below. Catch up on all the cool space news with the astroquarks.