Onward to other worlds

Astrobiology is celebrating its tenth anniversary, and is publishing a great deal of speculative reviews with it. Not that I want to imply something negative with the adjective "speculative" - good speculation is hard to do.

Here is an interesting paper on the future of exoplanet discovery and characterization. It's weird thinking how quickly this field has developed. I still remember reading, back when I was a kid, the idea that there weren't any exoplanets; now it looks like at least 30% of stars have them.

The principle problem facing their finding has been trying to distinguish the tiny dark spot from the mass of flaming plasma it orbits, which is why we've been finding so many super-Jupiters. I always thought that was a good indicator that there would be many earth-sized bodies around. All planets are just made up from the bits left over from star formation, and it seems reasonable that you'd end up with more small bits than big bits. However, I'm not an astronomer.

In addition to the usual ideas - improvements of telescopy and so on - the paper discusses something more interesting, namely the improved detection of exo-moons. I like the sound of this, especially given all the interest in what's below the Europan ice layer. However, the telescopes necessary to detect exomoons will have to be seriously huge, way bigger than even the ones we use to detect exoplanets at the moment, and it therefore seems reasonable to assume that what the paper calls the "ultimate step" - seeing continents and other planetary features - may be available either shortly before or shortly after we can see these moons in the first place, and we'll have found life on other planets long before we find them on other moons.

Towards the end of the paper it gets really speculative, discussing finding things like "technosignatures", an example of which would be artificial light. Given that human produced light on earth is only one thousandth of the light it reflects naturally from the sun, I wouldn't hold my breath on this one.