More than 20 million meteoroids enter Earth's atmosphere every day.
139
A comet's tail always points away from the sun.
2
The typical spec of dust that you see floating in the air is half way in size between the Earth and a subatomic particle.
131
The heart of an astronaut actually gets smaller when in outer space.
216
A lightning bolt generates temperatures five times hotter than those found at the sun's surface!
127
Saturn's rings are about 500,000 miles in circumference but only about a foot thick.
160
An organisation called Mars One is planning to establish a permanent colony of humans on Mars by 2023.
9
The population of the Earth has more than doubled since 1950.
151