How Big is The Universe?

It’s absolutely massive! It’s infinite. It’s mind-blowing. 

To try and put some perspective on this in the observable universe (the area of the universe that can be seen from earth using all our technical wizardry) there are an estimated 200 billion galaxies. 

Our very nearest galaxy neighbour, Andromeda, is 2.5 million light years away and hurtling towards the Milky Way at 402,000 kilometers per hour. Even at this immense speed it will take a further four billion years before they collide, head-on. This will not be an epic, fiery, cosmic explosion but rather a billion years dance as the 2 slowly settle into a new merged elliptical galaxy with new constellations and a new name. (Name ideas welcome) 
 
And that is our nearest neighbour. Barely visible with the naked eye on particularly clear nights. 

Did Copernicus realise the fuss he would cause while arguing that the earth isn’t the centre of the Solar System? Probably. But although he put the Sun at the centre of the Universe (His catchily titled “On the Revolutions of the Celestial Spheres” was published just before his death in 1543) he had set in motion a quest to discover just how big this Universe of ours really is. 

It turns out there is an answer. A definitive one. Who knew! 

Save the Multiverse for another Day 

I don’t want to complicate things, so I’m saving the existence of an infinite number of universes co-existing in parallel worlds for another post when I’m less tired.