21 Science Facts You Won't Believe Are True

20. The Photons From Stars Could Be Older Than The Human Race When They Hit Your Eye

The photons, or "light particles" from stars rain down on us from space, and have literally travelled astronomical distances.

The Andromeda Galaxy, for example, is just over 2.5 million light years away and is the most distant object that can be seen with the naked eye. This means that the photons coming from it first set off when the Homo genus, from which all modern humans are descended, first emerged in the form of Homo hablis.

19. A Cubic Meter Of Neutron Star Weighs More Than All The Water In The Atlantic Ocean

Neutron stars are made when stars collapse under their own gravity and form incredibly small, dense objects, mostly made up of neutrons. They can have the mass of two of our suns packed down into a radius of just 30 kilometres.

This means that, if you somehow got some of it back to Earth (which would be tricky as the escape velocity from your average neutron star is about a third of the speed of light), then a block about the size of a washing machine would weigh approximately 400 billion tonnes. You wouldn't have long to appreciate the effect, however, as the gravitational tidal forces would likely rip you apart.