Azernews.Az

By Bloomberg

European space scientists, whose probe is tracking a comet through the solar system at 11 miles a second, will have to look elsewhere to confirm the origin of Earth’s oceans.

In the first major finding from the European Space Agency’s Rosetta mission, researchers have determined that the 321 million cubic miles of water that make Earth’s life possible probably arose internally and from nearby asteroids, rather than from comets, according to a study published today in the journal Science. The research contradicts previous findings about comets as the source of Earth’s water.

The Rosetta probe is orbiting the comet as it moves through space, gleaning information about the mass of dirty ice, dust and gas. It has also dropped a probe called Philae onto the surface, a feat of engineering that researchers hope may eventually reveal secrets about the history of our planet and surrounding solar system.

Data from Rosetta shows that water on the surface of the comet is significantly denser than water molecules on Earth, suggesting that Earth’s oceans and other water may not have originated from the icy rocks from beyond Jupiter.

Rosetta was launched in March 2004 and has been orbiting the comet Churyumov-Gerasimenko, which is currently between Mars and Jupiter, since Aug. 6, gleaning information about the comet. The new study points to asteroids, which originate closer to the sun than comets, and internal Earth pools as the source of the oceans, said Kathrin Altwegg, its lead author.

Asteroid Bombardment

“The main reservoir is probably asteroids and, in principal, water in the Earth,” Altwegg, of the University of Bern in Switzerland, said in a phone interview. “What points to asteroids is this story with the late heavy bombardment, it’s craters on the moon, which showed that there was really a bombardment of the moon and of course also of the Earth.”

The craters on the moon and the first signs of water on the Earth date to about the same time, 3.8 billion years ago, Altwegg said. Scientists suspected comets could have been the source of the craters and of water after a 2010 probe revealed that another comet’s water was almost identical to that on Earth.

The latest study, which examined gas molecules being shot from the comet’s surface, suggests a different origin.

Rosetta’s next steps will be to look into the presence of organic molecules on the comet, as icy bodies like it may once have seeded Earth with the building blocks for life. To get the best glimpse of organic matter, possibly even amino acids, scientists will rely on the Philae lander. The craft is powered down after bouncing out of the intended, well-lit resting place it was to rely on for solar power.

Sideways in a Ditch

Philae has been spotted lying on its side in a ditch on the comet, according to Matt Taylor, a Rosetta project scientist, who said the craft was still in hibernation. Its exact location is still being determined, he said.

“Once we get the identification of where the lander is, it will give us a better fix on what we believe the illumination conditions are and a better idea of when we would expect the lander to have sufficient illumination to be able to start charging its batteries and come back online,” Taylor said at a Dec. 9 press conference.

He said that using “a kind of back-of-a-beer-mat calculation,” that would be “around May.”

The European Space Agency spent almost two decades building the Rosetta probe that carried the lander and maneuvering it 4 billion miles (6.5 billion kilometers) to the side of the comet, which is headed for the sun. The comet’s material is far older than the solar system, Altwegg said.