We love exoplanets here at DVICE. We just can't get enough of 'em. Over the last few years, astronomers have found a whole bunch of new worlds, some of which are potentially habitable by alien life, and a few of which may even be habitable by humans. But what exactly does "habitable" mean? What is it that we're looking for? The easy thing to say is that we're looking for a planet exactly like Earth, but really, it's a complicated question with a much more nuanced answer.

To date, the Kepler space telescope has probably identified at least 2,299 planets orbiting around other stars. 2,299 planets is a lot of planets, obviously, but this simulation that puts every single last one of them in orbit around the same star is a very visual, albeit very implausible, way of illustrating how many planets are out there.

We're big fans of the Gliese 581 system here at DVICE. It's been a treasure-trove of potentially habitable exoplanets, and the latest data boosts one of them, Gliese 581g, up to a whopping 0.92 on the Earth Similarity Index. Yes, we now have one of those.

The best looks that we've been able to get at exoplanets are when they pass in front of or behind their parent stars. When that happens, sometimes, if we're lucky, we can get a brief hint atmosphere. For the first time, NASA's Spitzer Space Telescope has managed to observe a "super-Earth" directly, watching it glow in the infrared.