Question: who first realised space existed. specific name please. :D

Sam Connolly answered on 23 Jun 2014:

That’s a bit of a hard question really, because it depends what you mean by space. People have thought that there is space outside the Earth, which contains the planets and the stars, for thousands of years. The first person who proposed that the Earth goes round the sun, instead of the other way around, was a Greek philosopher called Hipparchus, who was alive over two thousand years ago. It wasn’t really accepted until about 400 years ago though, when Galileo saw Jupiter’s moons with one of the first telescopes and saw it as proof that it wasn’t necessary for everything to go around the Sun. But if you’re talking about space as all the space in between stars and galaxies, the answer is a bit different. Because stars are so far away, it’s very hard to measure how far away they are, so no one managed to do it very accurately until about 200 years ago, when Friedrich Bessel made the first decent measurement, and realised just how far away the stars are! He used a method called ‘parallax’, where you watch how a star moves as the earth goes around the Sun. It works in the same way as how your thumb moves compared to things behind it if you hold it in front of your face and close one eye at a time. The further away it is from your face, the less it moves, so you can work out how far away it is. But it wasn’t realised how huge space was and how big the distances between galaxies are (millions of light years!) until just under a hundred years ago, when Edwin Hubble found the distances to other galaxies. Before that, it was thought that our galaxy, the Milky Way, made up the entire universe. So once it was discovered that other galaxies, which at the time they couldn’t see that well because telescopes weren’t as good, were actually huge collections of stars like our own galaxy, we really had an appreciation of how big (and empty) space is. So hopefully one of those people is the person you were looking for!