24 ağustos günü Avrupa uzay keşif aracı dünyaya benzer bir gezegen keşfetti.
As exciting as this potential discovery is, “Earth-like” carries a lot of caveats. The term is often bandied around to describe an exoplanet, of approximately Earth dimensions orbiting within a given star’s habitable zone. The habitable zone is the distance from a star where it’s not too hot and not too cold for water on a hypothetical rocky world to remain in a liquid state. On Earth, where there’s liquid water, there’s life, so finding an alien world in any star’s habitable zone is exciting for the possibilities of extraterrestrial biology.
But there’s a lot more to Earth than simply being in the right place around the sun that makes it habitable. Earth is also rocky, has a thick atmosphere, has a protective magnetosphere etc., all ingredients for a bona fide life-giving world. The only planet we know that is Earth-like is Earth.
Should there really be a world that approximates Earth mass/size at a distance that could allow water to exist in a liquid state on its hypothetically rocky surface, that’s all we’ll know. We won’t know whether it has an atmosphere or a magnetosphere. We won’t know if it possesses water.