Can you sneeze in your sleep?

Why do some things dissolve but others don't, what are the stains on the towels at the gym and how do astronauts keep their balance in the absence of gravity? Also, what causes meteor showers, can you sneeze in your sleep, what's the best way to dislodge a foreign body in the eye, what is pancreatic cancer and what causes sweaty hands and feet? The answers to this lot, plus news of how Earth came by its water and a chemical to keep unblocked arteries clear...