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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