Micro-organisms have been brought back to life after being frozen in perma-frost for three million years.

When Krakatoa erupted in 1883, its force was so great it could be heard 4,800 kilometres away in Australia.

The speed of light is generally rounded down to 186,000 miles per second. In exact terms it is 299,792,458 m/s (metres per second – that is equal to 186,287.49 miles per second).

Koalas sleep an average of 22 hours a day, two hours more than the sloth.

Quasars emit more energy than 100 giant galaxies.

A thimbleful of a neutron star would weigh over 100 million tons.

The Earth spins at 1,000 mph but it travels through space at an incredible 67,000 mph.

Males produce one thousand sperm cells each second - 86 million each day.