Just how big is the universe?

LET us ponder, for a moment or two, the size of the universe.

As the wonderful, much-missed Douglas Adams wrote in his first novel, The Hitch-Hiker’s Guide To The Galaxy: “Space is big. You just won’t believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space.”

Man I miss him. (If you haven’t read any Douglas Adams yet, what the hell have you been doing with your life? Go and get some, NOW! No, hang on, come back – wait until you’ve read this Blog first, then go…)

Anyway, he was right, space IS big. And since Douglas wrote that back in 1979, when most of you reading this didn’t even exist, we’ve found out even more about just how big it is.

Advances in science such as the amazing Hubble Telescope (which took the amazing picture at the top of this page) have enabled us to evaluate its size and shape in ever more detail. We now, naturally, know far more than we used to know about what it consists of and how far away everything is. But we still don’t know everything.

OK, so let’s try to get a grip on size. Do you know how far a mile is? That’s about 1.6 kilometres, for those of you using metric.

It takes an average person around 20 minutes at normal walking speed to go a mile. It may be how far it takes you to walk to the local shops, say. Or, if you’re American, it may be the length you drive to the local shops in five minutes. (I know most Americans don’t do walking, which is fine… just don’t come driving to me when your arteries clog up and you can’t see your toes anymore).

Where was I? Oh yeah, space. So you know how long a mile (1.6km) is. Well, our own sun, which you appreciate makes quite a big impact on our world, is a staggering 93 million miles away. That’s 93 MILLION MILES away (don’t bother converting it into kilometres; it’s still a bloody long way). It would take rather a long time to walk there, if truth were told (or drive, if you’re American).

Our nearest planet, Venus, is, at its closest, 25 million miles away. The furthest ‘planet’ in our Solar System, Pluto, (yeah I know, it’s now officially a rock, but give it a break) is 2.6 BILLION miles away when it’s closest to us.

By now, I expect you’re beginning to get the idea. Our own bunch of planets is huge. Far beyond what our tiny brains can comprehend. So anything outside of that – the Milky Way, say – is mind-bogglingly big, as Douglas so aptly put it.

We know that the Milky Way – our own galaxy of stars – is so huge that even if we could travel at the speed of light it would take 100,000 years to get across it.

That’s why the development of speedy inter-stellar travel, a staple of so much science fiction, is so important to that genre. If you head off in a traditional space rocket, you’ll die long before you get to meet anyone interesting.

We actually don’t know how big the universe is. How can we? We know we can see light that’s travelled for 14 billion years to get to us. But there could easily be galaxies or whole universes further away than that. So, is your mind boggled yet?

Leave a Reply

Your email address will not be published. Required fields are marked *