Science Questions

Could a distant habitable planet no longer really exist?

When we’re out looking for habitable planets in the universe, they’re always a long, long way away so isn’t it possible that by the time we actually see it or get to it – it might no longer be somewhere where it’s worth living? Daniel, USA

We put this question to Stuart Clarke, author of 'The Sun Kings":

Stuart - It’s certainly possible if you’re looking for planets in the whole galaxy you’ve got about 100,000 light years to imagine the size of telescope you’d have to build to actually see a planet 100,000 light years away is just so large. All the ones we’ll look at will be only a few tens of light years away.

Chris -  There is theoretically the possibility that we should pick up a star that turns out it should have some habitable planet around it but by the time we get to when we can see anything useful that star could have blown itself up.Stuart -  yes, the upside is that allows us to do cosmology because the farther we look into space the older the objects get we can do the archaeology of the heavens. Chris -  Are people looking at that?Stuart -  Exactly, that’s how you do galaxy evolution. You just look for galaxies farther and farther away and know that’s how they looked billions and billions of years ago.

April 2008