Water discovered for first time in atmosphere of habitable exoplanet

Water has been discovered for the first time in the atmosphere of an exoplanet with Earth-like temperatures that could support life as we know it, scientists revealed Wednesday.

Eight times the mass of Earth and twice as big, K2-18b orbits in its star's "habitable zone" at a distance -- neither too far nor too close -- where water can exist in liquid form, they reported in the journal Nature Astronomy.

"This planet is the best candidate we have outside our solar system" in the search for signs of life, co-author Giovanna Tinetti, an astronomer at University College London, told AFP.

"We cannot assume that it has oceans on the surface but it is a real possibility."
"K2-18b is not 'Earth 2.0'," he said. "However, it brings us closer to answering the fundamental question: is the Earth unique?"
"This is not only because super-Earths like K2-18b are the most common planets in our galaxy, but also because red dwarfs -- stars smaller than our Sun -- are the most common stars."