When I heard that NASA was having a press release about a new exoplanet discovery I assumed they found one Earth-sized planet that falls more snuggly in the habitable zone; as many of the previous discoveries were often on the edge of being habitable. My mind was blown when I listened to their announcement, not one but seven Earth-sized planets, three of which fall in the habitable zone. I’m sure you’ve heard all about it by now, but I’m far too excited to spare you from another rendition of this breaking news!
To give you some perspective, including the three new planets, we now have a total of 49 planets that are considered potentially habitable. Of those 49, only 12 of these planets are considered more likely to have a rocky composition and the ability to maintain liquid water on its surface. Included in this number is three of the seven newly discovered planets. Another factor to bear in mind is that we can only detect exoplanets that orbit directly between their stars and our line of site. If their orbits don’t block some of the light emitted from the star, then we cannot detect their presence. This means we are only seeing a fraction of the exoplanets that are out there. Just think, if you take into account how many we can see, just imagine how many stars have planets just likes ours captured in their orbit that we can’t see.
This newly discovered solar system is dubbed TRAPPIST-1. The sun at the center of this system is an ultra-cool dwarf. This sounds like something from the World of Warcraft, instead it is a star much smaller and cooler than our Sun. All seven of the planets orbit very close to one another and to their central star. All seven would fit between our Sun and Mercury, and still can maintain liquid water on their surface. From one planet you could gaze upon the neighboring one, like we do with our Moon.
The TRAPPIST-1 system is exciting because it is only about 39 light-years away, that’s about 235 trillion miles (no big deal, right?). Space is relative, so compared to 267 light-years, it’s not so bad. That’s close enough for other sensors to detect these planets, more specifically for the James Webb Space Telescope (JWST). I never miss an opportunity to gush about the JWST. I’ve been writing about it for years and now we are only about a year from its launch, in October of 2018. The telescope has a 6.5-meter primary mirror and will orbit outside the orbit of the Moon, cutting down on interference from the Earth’s atmosphere. Once operational it will turn its attention to the TRAPPIST-1 system to study the planets’ atmospheres and search for signs of water.
So stay tuned, there are more existing discoveries to come, it’s a brave new world out there.