Oceans and asteroids share a similar chemical signature.
Cosmos Magazine has an article about the origin of Earth's water. A paper in the Journal of Geophysical Research: Planets challenges the widely-accepted ideas - maybe it didn't come from an asteroid impact.
Earth’s water may not have originated solely from material carried by asteroids, according to new US research.
A study in the Journal of Geophysical Research: Planets led by Steven Desch from Arizona State University challenges widely-accepted ideas about the asteroidal origin of hydrogen in the planet’s water by suggesting it came in part from the solar nebula – clouds of dust and gas left over after the formation of the Sun.
And the researchers believe their findings could provide new insights about the development of other planets and their potential to support life.
To date, many scientists have supported a theory that all of Earth’s water came from asteroids, primarily because the ratio of deuterium, a heavier hydrogen isotope, to normal hydrogen is similar in ocean and asteroidal samples.
Certainly the ocean chemical signature is close to what is found in asteroids, but that may not be the whole story, explains Desch.
“It’s a bit of a blind spot in the community,” he says. “When people measure the ratio in ocean water and they see that it is pretty close to what we see in asteroids, it was always easy to believe it all came from asteroids.”
