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

[Ron Baalke]

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