I joined Google+ Hangout on Air with NASA today. Special appearances in this session are by two austronauts on the ground and three in Space Station, all to answer public questions. Most of their answers are worth sharing. Here are some that I can recall:
(when asked how they know when to sleep and wake up)
Dark and bright sky aren't available in space, but biological circadian rhythm still works well. It also helps to pay attention to time. Rooms are also lit with specific setting for visual cues --dim for nighttime and bright for daytime.
(when asked how they were able to take good pictures with different light condition from earth)
Lighting is extremely different in space so different technique is a must. Good thing trainers back on earth prepared them well. Funny note: in weightless space, there is no worry about getting tired holding heavy cameras.
(when asked which historical scientist they would take up to space, if possible)
Newton! Back in his time Newton figured out all this gravity-no-gravity experience by sheer imagination. It would be awesome to take him up and let him know that he was right on the matter (Strike 1: this answer gave goosebumps)
(when asked if they can see man-made object on earth from space)
Contrary to what rumors say, astronauts cannot see Great Wall of China from space. Other kinds of man-made are visible. The exhaustions of forests in any part of earth is hard not to notice. The view breaks their hearts (Strike 2)
(when asked how it feels experiencing gravity again after weightless experience)
They say the body adapt to home very quick. Speaking of "home", space experience changes one's perspective on the word. One astronaut claimed, landed on Kazakhstan, he said to himself, "Good to be home." After space, home is Earth. (Strike 3: and if that didn't get you, you are one cold zombie)
Another session of NASA Hangout is coming up, in case you're interested.