Earlier this month, astronomers revealed they’d discovered another Earth-like planet that is almost 100% capable of sustaining life as we know it.
The planet (named Gliese 581g); which is 20 light years from us in the constellation of Libra; orbits its star Gliese 581 every 37 days and is around 3 to 4 times the mass of Earth.
6 planets have been spotted so far in the Gliese planetary system – more than we’ve discovered around any other stars so far.
These exoplanets capture the imagination and, at the very least, heighten the sense that life simply must exist elsewhere in the Universe. Around 490 exoplanets have been identified so far and that number is rising. The first of them to be confirmed orbiting a main-sequence star was 51 Pegasi b back in 1995. This giant planet has a four-day orbit of its G-type star 51 Pegasi (our own star, the Sun is also a G-type star).
Of course, spotting these planets against the background of their respective stars is no mean feat, though the steady increase in detection rates and the observation of smaller, Earth-like planets suggest that astronomers are honing their skills and techniques. Most have been found within about 300 light years of our own solar system.
The vast majority have been detected via indirect inference; noticing tiny changes in observations of their star and as a result mostly large planets (often referred to as ‘hot Jupiters’ because of their size and closeness to their star) have been found. It’s reckoned though that it’s likely to be more common to find smaller planets on larger orbits and so the chance for many more Earth-like discoveries seems to be high.