Where can life exist on Earth?
To host life, an exoplanet doesn’t necessarily have to be exactly like Earth. Even under very harsh conditions, some forms of life are able to survive, as evidenced by terrestrial extremophiles.
Many exoplanets look inhospitable to life – they are very cold or very hot, or they lack water or a breathable atmosphere. But that does not necessarily mean they are lifeless. After all, some lifeforms found on Earth, known as extremophiles, survive under the most extreme conditions: at the bottom of the ocean, high up in the atmosphere, under thick layers of polar ice, in acidic hot pools, and even in the Earth’s crust. Apparently, life can quite easily exist in harsh environments. Who knows what kind of organisms might thrive on exoplanets?
On Earth, life exists in some very strange places. Some bacteria can even survive without sunlight or water. So there’s no reason why life couldn’t exist on exoplanets that look horrible at first sight.