[meteorite-list] Water Found in Stardust Suggests Life is Universal

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 20 Jan 2014 21:38:58 -0800 (PST)
Message-ID: <201401210538.s0L5cwJ2022133_at_zagami.jpl.nasa.gov>

http://www.newscientist.com/article/dn24907-water-found-in-stardust-suggests-life-is-universal.html

Water found in stardust suggests life is universal
by Catherine Brahic
New Scientist
20 January 2014

A sprinkling of stardust is as magical as it sounds. The dust grains that
float through our solar system contain tiny pockets of water, which form
when they are zapped by a blast of charged wind from the sun.

The chemical reaction causing this to happen had previously been mimicked
in laboratories, but this is the first time water has been found trapped
inside real stardust.

Combined with previous findings of organic compounds in interplanetary
dust, the results suggest that these grains contain the basic ingredients
needed for life. As similar dust grains are thought to be found in solar
systems all over the universe, this bodes well for the existence of life
across the cosmos.

"The implications are potentially huge," says Hope Ishii of the University
of Hawaii in Honolulu, one of researchers behind the study. "It is a particularly
thrilling possibility that this influx of dust on the surfaces of solar
system bodies has acted as a continuous rainfall of little reaction vessels
containing both the water and organics needed for the eventual origin
of life."

Dust rain

Solar systems are full of dust - a result of many processes, including
the break-up of comets. John Bradley of the Lawrence Livermore National
Laboratory in California and his colleagues inspected the outer layer
of interplanetary dust particles extracted from Earth's stratosphere.

Ultra-high-resolution microscopy allowed them to probe the 5- to 25-micrometre
specks of dust to reveal small pockets of trapped water just beneath the
surface.

Laboratory experiments offer clues to how the water forms. The dust is
mostly made of silicates, which contains oxygen. As it travels through
space, it encounters the solar wind. This stream of charged particles
including high-energy hydrogen ions is ejected from the sun's atmosphere.
When the two collide, hydrogen and oxygen combine to make water.

As interplanetary dust is thought to have rained down on early Earth,
it is likely that the stuff brought water to our planet, although it is
difficult to conceive how it could account for the millions of cubic kilometres
of water that cover Earth today. "In no way do we suggest that this was
sufficient to form oceans," says Ishii.

Universal water

A more likely origin for the huge volume of water on our planet is wet
asteroids that pummelled early Earth. Comets are also a candidate: the
European Space Agency's Rosetta spacecraft, due to send a lander to a
comet later this year, is tasked with probing their role.

However, the Bradley team's results are relevant to the quest for life
on other planets. The water-producing reaction is likely to be universal,
and to happen in any corner of the universe with a star, or even a supernova,
says Ishii.

What's more, interplanetary dust in our solar system - and in others 0
contains organic carbon. If stardust contains carbon and water, it means
the essentials of life could be present in solar systems anywhere in the
universe and raining down on their planets.

"These are the types of processes that we expect to occur in other planetary
systems," says Fred Ciesla of the University of Chicago in Illinois, who
was not involved in the work. "Water and organics are not uncommon."

Journal reference: PNAS, DOI: 10.1073/pnas.1320115111
Received on Tue 21 Jan 2014 12:38:58 AM PST