It takes a photon 170,000 years to travel from the core of the Sun to the surface, but only 8 minutes to travel the rest of the way to Earth.
6
If NASA sent birds into space they would soon die; they need gravity to swallow.
146
There are more nerve cells in the human brain than there are stars in the Milky Way.
349
Mars had an oxygen-rich atmosphere around 4 billion years ago
13