What, or when, would aliens see, if they looked at the earth?
Answers to Physics Questions
Physics, cosmology, astrophysics, electricity, energy, forces, gravity, light and maths...
20 April 2008
Should you unplug your TV in a thunderstorm?
13 April 2008
How much air does the average car hold? If it were perfectly sealed, how long could you keep driving for without...