Comet-Seeded Alien Oceans Could Be Common

[American Patriot]

Comet-Seeded Alien Oceans Could Be Common


by Mike Wall, SPACE.com Senior Writer
Date: 20 October 2011 Time: 02:01 PM ET

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Artist's concept illustrating an icy planet-forming disk around the star TW Hydrae, located about 175 light-years away in the constellation Hydra. Astronomers found huge stores of cool water vapor (illustrated in blue) in the frigid outer regions of the star system, where comets will take shape. CREDIT: NASA/JPL-Caltech View full size image

A still-forming alien solar system has enough water in its outer reaches to fill Earth's oceans several thousand times over, a new study finds.
The discovery marks the first time astronomers have detected water in a dusty planet-forming disk so far from its central star, in the frigid region where comets are born. Scientists think comet impacts delivered most of Earth's water, and the new study hints that alien planets may commonly acquire oceans in the same way.
"We now know that large amounts of water ice are available in planet-forming disks, ready to be incorporated in comets," said Michiel Hogerheijde, of Leiden Observatory in the Netherlands, the study's lead author. "Ultimately, some of this water may end up on Earth-like planets that form completely dry but this way may end up with life-supporting oceans." [The Strangest Alien Planets]


A nearby star
Hogerheijde and his team made the find using the European Space Agency's Herschel Space Observatory. They trained Herschel on the appropriately named young star TW Hydrae, which is located about 175 light-years away in the constellation Hydra (the Sea Serpent).
TW Hydrae is an orange dwarf star, slightly smaller and dimmer than our sun. It's only about 10 million years old, and is still surrounded by a disk of dust and gas that should one day coalesce to form planets, researchers said.
Herschel detected huge amounts of water — thousands of times more water than is found on Earth — in the freezing-cold outer reaches of this disk, far from TW Hydrae itself. The water out there is likely ice coating the innumerable tiny dust grains that swirl around in the disk, researchers said.
Ultraviolet radiation from TW Hydrae knocks some water molecules free from these icy grains, allowing Herschel to spot the light signature from the resulting vapor.
Astronomers have found water vapor in the warmer, interior regions of other planet-forming disks before. So Hogerheijde's team wasn't shocked to find evidence of water farther out.
"We had actually always suspected that this much water was hiding out in the cold reaches of disks like these," Hogerheijde told SPACE.com in an email. Thanks to Herschel, he added, "we can now for the first time detect the water vapor, and infer the presence and size of the hidden ice reservoir." [Gallery: Views from the Herschel Space Observatory]
The team reports its results in the Oct. 21 issue of the journal Science.
Alien comets, alien oceans?
The TW Hydrae find suggests that ice-bearing comets may form commonly around other stars. The icy wanderers might thus have seeded oceans on many alien planets throughout the cosmos over the years, researchers said.
"It does seem likely that life-supporting environments can form easily around other stars, now that we have found sufficient water ice to seed Earth-like planets with oceans," Hogerheijde said.
The discovery could also help astronomers better understand solar system evolution and planet formation in a general sense, he added.
For example, large quantities of ice in a protoplanetary disk could serve as a sort of glue, Hogerheijde said, helping dust grains stick together and grow into planetesimals, the building blocks of planets.
Also, analysis of TW Hydrae's far-flung ice shows that it's significantly different than that found on comets in our solar system. This suggests that comets' ice comes from several different regions in the dusty disk, not just the freezer on its outer edge.
"We actually think that comets in our own solar system contain mixtures of ices from across the solar nebula, hinting at the presence of long-range transportation of material through planet-forming disks," Hogerheijde said. "This is a much more 'dynamic' picture of planet formation than previously imagined."
You can follow SPACE.com senior writer Mike Wall on Twitter: @michaeldwall. Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.

[Malsua]

One of the most common elements in the universe is water.

The plot device that aliens would come here to take it is pure fantasy from Hollywood types who live in the arid southern California.

[American Patriot]

One of the most common elements in the universe is water.

The plot device that aliens would come here to take it is pure fantasy from Hollywood types who live in the arid southern California.

I have doubts they'd come for water.

Iron, or other precious metals though, or biomass, yes.

[Malsua]

Precious metals are not so precious in space. Why would you come into a nasty gravity well when you can tow a free-floating hunk of iron a mile across anywhere you need to go?

You might come for radioactive elements or perhaps rare-earth elements but it can be expected that they exist in the various asteroids and such floating about the solar system.

I think the main reason would be biomass. It exists in one place. Here.

[American Patriot]

Well... we KNOW biomass exists here. We don't know about other places. But, if there are lively creatures out there plying space in space ships, you can bet your ass they aren't going to really be looking for a permanent home.

In fact the BEST "scenario" I can imagine wouldn't be a "Vulcan like race" but more like the race of creatures on Independence Day.

I'm not so sure about the race of creatures in "Battle: LA" - though it was an intense movie, I think the premise of collecting water isn't as great as collecting people, animals or other foodstuffs to feed a population of spacefarers. I also would think it more likely to get minerals (and yes, I do understand the size and density of the asteroid belt better than most folks)... But as pointed out, rare earth elements aren't found in any abundance in space, but on large planetary bodies simply due to the density of the minerals.

(More gravity, the more heavier stuff collects).