Physics in free fall. Dropping supercold atoms may prove useful for understanding general relativity. Share this: Email; Facebook; Reddit; Twitter; Print; By Laura Sanders. June 17, 2010 at 1:49 pm.

Using a box with a candle and GoPro inside, Physics Girl tests a candle in free-fall. Slow-motion fire experiment in microgravity done by dropping a box with a GoPro and candle inside.

The universality of free fall is a consequence of the equivalence principle, which lies at the heart of Einstein’s general theory of relativity. It states that inertial and gravitational mass are ...