Scientists theorize new origin story for Earth's water

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 proposes a new theory to address the long-standing mystery of where earth's water came from.

The new study challenges widely-accepted ideas about hydrogen in Earth's formation, called the solar nebula.

To identify sources of water on earth, the results of this study are more important than those of hydrogen, because they are more abundant in the solar system.

Many scientists have historically supported the theory of all of the earth's water 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 whole 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] in water and they see it as much as we like in asteroids, it was always easy to believe it all came from asteroids. "

More recent research suggests hydrogen in Earth's oceans does not represent hydrogen throughout the planet, the study's authors said. Samples of hydrogen from deep inside the earth, have the advantage of less deuterium, indicating this hydrogen can not come from asteroids. Noble gases helium and neon, with isotopic signatures inherited from the solar nebula, have been found in the Earth's mantle.

In the new study, researchers developed a new theoretical model of Earth's formation and explained it to the world.

Modeling Earth's beginning

According to their new model, several billion years ago, large waterlogged asteroids started developing while still in the sun. These asteroids, known as planetary embryos, collided and grew rapidly. Eventually, a collision was introduced enough energy to the surface of the largest embryo into an ocean of magma. This largest embryo would eventually become Earth.

Gases from the solar nebula, including hydrogen and noble gases, were drawn in by the broad, magma-covered embryo to form an early atmosphere. Nebular hydrogen, which contains less deuterium and is lighter than asteroidal hydrogen, dissolved in the molten iron of the magma ocean.

Through a process called isotopic fractionation, hydrogen was pulled towards the Earth's center. Hydrogen, which is attracted to iron, has been delivered to the core by the metal, while much of the isotope hinder, deuterium, remained in the magma which has been cooled and has become the mantle, according to the study's authors. Impacts from smaller embryos and other objects then continued to add water and overall mass

This new model would leave Earth with noble gases deep inside its mantle and with a lower deuterium-to-hydrogen ratio in its core than in its mantle and oceans.

The authors used the model to estimate how much hydrogen came from each source. They were most asteroidal in origin, but some of Earth's water came from the solar nebula.

"For every 100 molecules of earth's water," said Jun Wu, assistant research professor at the School of Molecular Sciences and School of Earth and Space Exploration at Arizona State University and lead author of the study. .

An insightful model

The study also offers scientists new perspectives on the development of other planets and their potential to support life, the authors said. Earth-like planets in other solar systems. The new study suggests these exoplanets could be obtained through their own solar nebula system.

"This model suggests that the inevitable formation of water would be likely to occur in a broad rocky exoplanet in extrasolar systems," Wu said. "I think this is very exciting."

Anat Shahar, a geochemist at the Carnegie Institution for Science, who was not involved with the study, noted the hydrogen fractionation factor, which describes how the deuterium-to-hydrogen ratio changes when the element dissolves in iron, is currently unknown and difficult to measure. For the new study, this property of hydrogen had to be estimated.

The new model, which fits in well with current research, could be tested once again revealing hydrogen fractionation factor, Shahar said.

"This paper is a very creative alternative to what is an old problem," Shahar said. "The authors have done a good job of estimating what these different fractions would be without having the experiments."

Research paper

Related Links

American Geophysical Union

Water News – Science, Technology and Politics

Thanks for being here; We need your help. The SpaceDaily news network continues to grow. With the rise of Ad Blockers, and Facebook – our traditional revenue sources through quality advertising continues to decline. And unlike so many other news sites, we do not have a paywall – with those annoying usernames and passwords. Our news coverage takes time and effort to publish 365 days a year. If you find our news sites and make a contribution.
SpaceDaily Contributor $ 5 Billed Once credit card gold paypal		SpaceDaily Monthly Supporter $ 5 Billed Monthly paypal only

Poop in hand, Bill Gates backs China's toilet revolution

Beijing (AFP) Nov 6, 2018

The most active philanthropists, Bill Gates usually has his hands full. Just not with poop.

So it came as a surprise when the founder of Microsoft branded a jar of human waste at a forum on the future of the toilet in Beijing on Tuesday.

The stunt was an effort to draw attention to a problem affecting developing countries around the world: not enough toilets.

"In places without sanitation," said Gates, pointing to the feces … read more