The water that covers two-thirds of the Earth may be much older than scientists previously believed, according to new research.

During Earth’s early years it was not possible for water to stay on the planet’s surface, as temperatures would have been much too hot and solar winds would have blasted water vapor to the edges of the solar system. However, scientists have found evidence that rocky bodies near the young planet stored the ingredients for water, and perhaps Earth itself contained those ingredients, according to the study, which was published in the journal Science.

If that is true, water has been hanging around the inner solar system 135 million years earlier than perviously believed.

Scientists made the discovery by examining meteorites that came from the asteroid Vesta — chunks of which have been found in Antarctica. At first, there was no evidence of water in the meteorites, but when scientists looked at the molecular contents of the rocks, they discovered trace amounts of hydrogen-oxygen molecules.

This is the only way water could have existed in the inner solar system during the early years, as any water vapor would have resided on the edge of the solar system due to the extreme conditions.

Scientists believed that when the Earth formed 4.6 billion years ago, high-energy impacts created a dry planet with a molten surface, and it wasn’t until hundreds of millions of years later that comets and asteroids delivered water to the Earth. However, the new research suggests that water has been here all along.