illuminating science

It’s funny isn’t it, how quickly we become accustomed to things? A few years ago, discovering an extrasolar planet (i.e., a planet orbitting around a star that wasn’t our sun) was pretty incredible - and yet now, with dozens already discovered, it’s nothing to write home about. However, there’s always something new on the horizon. So far, all the planets that have been discovered have been big planets - a thousand times the size of Earth, objects, a bit like Jupiter, that aren’t quite suns but are pretty close. This is because they’re the only ones big enough to see, or to have a significant gravitional effect that we can detect. And while these are interesting, they couldn’t support life (as we know it, anyway) - they’re gas giants, with no solid surfaces!

So, how could we detect Earth sized planets, ones like ours? Well, one technique is to look for gravitational lensing effects (specifically microlensing), where the planet’s gravity literally bends the path of the light around it in a way that we can detect. And the planet recently discovered (in part by an Australian team!) was found using this technique. Again, it’s a big planet, but it means that this gravitational lensing technique is a realistic possibiliity.