Washington, Sep 26 (IANS): Up to half of the water on Earth is likely to be older than the solar system, a study says.
The study published in the US journal Science Thursday raises hope that life could exist on exoplanets, the planets orbiting other stars in our galaxy, because all life on Earth depends on water, Xinhua reported.
According to the study, water is found throughout our Solar System, not just on Earth, but on icy comets, moons, and also on Mercury.
But it was unclear whether the water was there with the solar system itself, in the planet-forming disk of dust and gas that circled the young Sun 4.6 billion years ago, or whether water originated even earlier in the cold, ancient molecular cloud that spawned the Sun and the planet-forming disk.
Identifying the original source of Earth's water is the key to understanding how likely is the possibility of finding it elsewhere, the study added.