“It isn’t only the beauty of the night sky that thrills me. It’s the sense I have that some of those points of light are the home stars of beings not so different from us, daily cares and all. who look across space with wonder, just as we do.” -Frank Drake
What is it that makes our Solar System special? It’s Earth, of course. A rocky planet of the right mass and composition, the right distance from our Sun, the right atmosphere, the surface oceans, and all the life that’s ensued is what makes us special. Not just special, but unique, at least among the planets we’ve found so far.
The orbits of the Galilean moons around Jupiter, the seven planets discovered around TRAPPIST-1, and the inner Solar System worlds, shown together for comparison of scale. Image credit: ESO/O. Furtak.
But there are other planetary systems out there with Earth-like worlds. Similar to Earth in mass, size, temperature and many other conditions, these might represent planets where life similar to what we find here arose. For the first time, we’ve found a planetary system with not just one Earth-like, potentially habitable world, but three!
This infographic displays some illustrations and planetary parameters of the seven planets orbiting TRAPPIST-1. They are shown alongside the rocky planets in our Solar System for comparison. Image credit: NASA.