EARTH’S WATER may have originated from both asteroidal material and gas left over from the formation of the Sun, according to new research. The new finding could give scientists important insights about the development of other planets and their potential to support life.
In a new study in the Journal of Geophysical Research: Planets, a journal of the American Geophysical Union, researchers propose a new theory to address the long-standing mystery of where Earth’s water came from and how it got here.
The new study challenges widely-accepted ideas about hydrogen in Earth’s water by suggesting the element partially came from clouds of dust and gas remaining after the Sun’s formation, called the solar nebula.
To identify sources of water on Earth, scientists have searched for sources of hydrogen rather than oxygen, because the latter component of water is much more abundant in the solar system.
Many scientists have historically supported a theory that all of Earth’s water came from asteroids because of similarities between ocean water and water found on asteroids.
The ratio of deuterium, a heavier hydrogen isotope, to normal hydrogen serves as a unique chemical signature of water sources. In the case of Earth’s oceans, the deuterium-to-hydrogen ratio is close to what is found in asteroids.
But the ocean may not be telling the entire story of Earth’s hydrogen, according to the study’s authors.
“It’s a bit of a blind spot in the community,” said Steven Desch, a professor of astrophysics in the School of Earth and Space Exploration at Arizona State University in Tempe, Arizona and co-author of the new study, led by Peter Buseck, Regents’ Professor in the School of Earth and Space Exploration and School of Molecular Sciences at Arizona State University.
“When people measure the [deuterium-to-hydrogen] 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.”