For the first time ever, the finding of water in an asteroid sample by Japan’s Hayabusa2 space mission sheds light on how the Earth’s oceans may have originated.
On Thursday, research teams from Tohoku University, the Japan Aerospace Exploration Agency, and other institutions published their findings in the journal Science. Samples from the Ryugu asteroid, which the Hayabusa2 sent, were examined by scientists.
The tiny amount of water was found in a depression in an iron sulfide crystal that was several microns wide in size. It is believed to be from around 4.6 billion years ago, shortly after the solar system originated. While on Ryugu, the water doesn’t seem to have been frozen but was likely in liquid form. The water was carbonated and contained salts, organic matter, and carbon dioxide.
Although water had previously been discovered in a meteorite, its introduction from a terrestrial source could not be completely ruled out. Additionally, even though a Ryugu sample’s prior examination had suggested the existence of water, this was only discovered after a chemical interaction with minerals.
Asteroids Contain Water and Organic Material
Tomoki Nakamura, a professor of earth sciences at Tohoku University, confirmed that an asteroid that impacts the Earth and contains water also contains organic material. “This is evidence that directly ties into the origins of oceans and organic matter.”
The discovery was praised by Kensei Kobayashi, a non-member of the research team and an expert in astrobiology and professor emeritus at Yokohama National University.
Given its fragility and the likelihood that it will be destroyed in space, “the fact that water was discovered in the sample itself is surprising,” Kobayashi said.
“It does suggest that the asteroid contained water in the form of fluid and not just ice, and organic matter may have been generated in that water,” he added.
The Ryugu samples are still being examined in Japan by eight research teams. More information on the make-up of organic matter, including the twenty-three amino acids that have already been identified, is expected to be discovered.