However, according to a recent study, a little-known planet approximately 111 light-years away could perhaps be the first real testament to intelligent life beyond our tiny ball of blue and green.
Previously, researchers were unsure if K2-18b was a super-Earth - meaning it is slightly larger than our planet, but mainly rocky - or a mini-Neptune composed mostly of gas.
"Being able to measure the mass and density of K2-18b was tremendous, but to discover a new exoplanet was lucky and equally exciting", Ryan Cloutier, a doctoral student at the University of Toronto, Scarborough, said in a news release.
While K2-18b and its newly discovered super-Earth nextdoor, K2-18c, are both roughly the same mass as Earth, their similarites may end there.
Please Wait while comments are loading. "But with the James Webb Space Telescope we can probe the atmosphere and see whether it has an extensive atmosphere or it's a planet covered in water".
The researchers surmised that K2-18b has a mass between six and 10 times that of Earth, making it either mostly rocky with a small gaseous atmosphere or a mostly water planet with a thick layer of ice on top. At that time they noticed that the super-Earth was orbiting the dwarf-star within its habitable zone.
"With the current data, we can't distinguish between those two possibilities", Cloutier added.
Humans originated here on planet Earth and, all things considered, it's a mighty nice place to be, but we won't be able to stay here forever. "Once all the boxes were checked it sunk in that, wow, this actually is a planet", said Ryan Cloutier, who had the target of finding at least one new exoplanet during the course of his Ph.D. It couldn't maintain orientation as well as before, but it's "K2" phase still allowed it to spot many exoplanets like K2-18b.
The Canadian-made Near-InfraRed Imager and Slitless Spectograph (NIRISS) is specifically created to probe the atmospheres of exoplanets, and Doyon said that K2-18 is at the top of the list. "But whether or not there is surface water, we're going to have to do some follow up observations to figure that out for sure, because right now we just don't know".
"You have to ensure the signal isn't just noise, and you need to do careful analysis to verify it, but seeing that initial signal was a good indication there was another planet".
Other researchers on the team are affiliated with the Geneva Observatory in Switzerland, France's University of Grenoble, and the University of Porto in Portugal.