Earth may not need it asteroid and comet strike to fill their oceans, reports a new study.
Conventional wisdom has long claimed that our planet was born dry because its building blocks were relatively close to the hot, scorching sun. Earth therefore received the vast majority of their water later, most scientists have thought, from influencing objects native to the cold and icy depths of the outer solar system.
In fact, researchers have been arguing for years about whether comets as asteroids were the primary aquifers.
Related: Earth quiz: Do you really know your planet?
But such debates can be mostly academic, suggests the new study, which was published online today (August 27) in the Journal of Science. Researchers analyzed 13 different meteorites of enstatite chondrite (EC), a class known for comparing the space rocks that coalesced more than 4.5 billion years ago to form the Earth.
They found a lot of hydrogen in the alleged drought meteorites – enough to imply that our planet was born quite wet. The team’s calculations suggest that the rocks that make up the earth have at least three times as much water as the planet’s current oceans.
“Our discovery shows that the earth’s building blocks may have contributed significantly to the earth’s water,” said lead author Laurette Piani, a researcher at the Center de Recherches Pétrographiques et Géochimiques in Nancy, France, in a statement. .
“Hydrogen-bearing material was present in the inner solar system at the time of the rocky planet formation, although the temperatures were too high for water to condense,” said Piani.
Piani and her colleagues “convincingly claim that water can come from enstatite chondrites,” wrote Anne Peslier, a researcher at NASA’s Johnson Space Center in Houston, in a statement. Plugin “Perspectives” in the same issue of Science.
Big questions remain about the timing of the earth’s water uptake, Peslier noted, as it is unclear if most of the water that sinks into our seas is actually going backwards completely. For example, if most of the Earth’s terrestrial water was taken up very early, it could have been boiled away by recent asteroid bombings and / or the formation of magma oceans. (In that case, the asteroid-against-comet debate would be very viable.)
“Yet the work of the authors brings a crucial and elegant element to this puzzle,” Peslier wrote. “Earth’s water can simply come from the nebulous material from which the planet deviates.”
Mike Wall is the author of “Out There” (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.
