Under The Martinborough Stars 

“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.” 

― Douglas Adams, The Hitchhiker’s Guide to the Galaxy

Space is massive, it is hard to even think about how big Space is, let alone comprehend it. How can we even begin to measure the size of the Universe when it is so enormous?

To measure all the objects in our Solar System, we can still use kilometres. The regular kilometres we use here on Earth. Easy. Our Sun is 150million kilometres away from the Earth.

The distance between the Earth and the Sun is known as 1 Astronomical Unit or 1 au.

However, once we leave our Solar System, everything is just so far away that we need to use a new unit of measurement- a light year (ly).

Astronomers aren’t great with naming things. Lots of things that they name is very much say what you see. A Black Hole (it’s a hole that is black) for example, or the Small Magellanic Cloud (it looks like a small cloud). A light year (ly) is just how far light can travel in one Earth Year, approx. 9.5trillion km or 300,000 km a second.

Our nearest star after our own Sun is fairly ‘close’ at only 4.3 light years away and called Proxima Centauri. That means its light left 4.3 years ago and so we are seeing it in 4.3 years in the past.

To give you an idea of how far away it really is, imagine we will send a person to our nearest star. For arguments sake, let’s send Elon Musk.

If he travelled the fastest we can at the moment, 20,000km per hour, Musk will take 80,000 years to get to Proxima Centauri. And that’s our nearest star after the Sun!

Moving further out, if you wanted to leave our galaxy, the Milky Way, you would have to travel a minimum of 30,000 light years.

But even a ly can only get us so far. For truly huge distances, we add up 3.26 ly’s to make a new measurement, a parsec.

Now if you think a parsec sounds familiar, you might be thinking of the classic Star Wars quote about the Millennium Falcon “making the Kessel run in 12 parsecs”. Unfortunately, a parsec is a unit of distance rather than time so this doesn’t make any sense at all (sorry all Hans Solo fans)

So next time you look up into our beautiful dark sky and realise that all those stars are actually shining from the past, and that beyond our galaxy there is a vast Universe, try not to get too concerned, Just pick up Hitch Hikers Guide to The Universe and Don’t Panic.

Becky Bateman runs the award-winning stargazing business Under The Stars