Monday, February 3, 2014

Life from space: UH researchers

The stuff of life is blowing in the interplanetary winds.

A remarkable paper by University of Hawai`i researchers and others has been underreported. It suggests that in both our solar system and others, interplanetary dust carries both water and organic materials. That dust rains down on Earth and the other planets. 

(Image: Tiny interplanetary dust particles mix hydrogen from the solar wind with oxygen from the weathered rims of the dust to create water. This mechanism of water formation almost certainly occurs in other planetary systems with potential implications for the origin of life throughout the galaxy. The little bits of blue on the dust particles are water. Credit: John Bradley, UHM SOEST/ LLNL.)

It’s not going too far to say this suggests life on Earth came from space. But also, that this same mechanism could deliver the building blocks for life to any habitable planet in the galaxy.

The work was published in the Proceedings of the National Academy of Sciences by scientists at the University of Hawai`i-Manoa (UHM) School of Ocean and Earth Science and Technology (SOEST), Lawrence Livermore National Laboratory, Lawrence Berkeley National Laboratory, and University of California-Berkeley.

The University of Hawai`i’s press release on the study is here. The paper abstract is here.

Not to get too breathless about this, it’s a finding that has fascinating feed-ins to discussions of life on other planets, life on Earth, how water got to the Moon, and, of course, religion.

“It is a thrilling possibility that this influx of dust has acted as a continuous rainfall of little reaction vessels containing both the water and organics needed for the eventual origin of life on Earth and possibly Mars,” said study co-author Hope Ishii, an associate researcher at the University of Hawai`i Institute of Geophysics and .Planetology.

Scientists already knew that interplanetary dust, left over from the formation of the solar system, contains carbon compounds that have been identified as a possible source of organic life. The addition of water to carbon compounds adds another necessary component to the mix.

“Interplanetary dust, especially dust from primitive asteroids and comets, has long been known to carry organic carbon species that survive entering the Earth’s atmosphere. We have now demonstrated that it also carries solar-wind-generated water. So we have shown for the first time that water and organics can be delivered together,” Ishii said.

The water on dust particles only forms in thin rims at the surface, and older analytical techniques were unable to locate it. The research team was able to use the latest high-tech tools to detect water on space dust.

“By exploiting the high spatial resolution of transmission electron microscopy and valence electron energy-loss spectroscopy, we detect water sealed in vesicles within amorphous rims produced by (solar wind) irradiation of silicate mineral grains on the exterior surfaces of interplanetary dust particles,” the authors say in the paper.

The team was also able to repeat in the laboratory the mechanism for its creation. Laboratory-irradiated materials, like materials in space that are pounded by the solar wind, develop similar surface characteristics—characteristics that allow hydrogen ions in the solar wind to combine with oxygen in silicate minerals to make water.

The process clearly did not deliver all the known water on Earth, but delivered those seminal packages, the authors say. “The relevance of our work is … that we have shown continuous, co-delivery of water and organics intimately intermixed.”

Citation: Detection of solar wind-produced water in irradiated rims on silicate minerals, John Bradley, Hope Ishii, Jeffrey Gillis-Davis, James Ciston, Michael Nielsen, Hans Bechtel, Michael Martin. Proceedings of the National Academy of Sciences, doi: 10.1073/pnas.1320115111.

© Jan TenBruggencate 2014

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