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TheNocturnalEgyptian
26th November 2010, 10:59 AM
Nasa's Cassini probe has scooped oxygen from the thin atmosphere of Rhea – the first time the gas has been detected directly on another world


http://static.guim.co.uk/sys-images/Guardian/Pix/pictures/2010/11/25/1290710089277/Saturns-moon-Rhea-007.jpg


A spacecraft has tasted oxygen in the atmosphere of another world for the first time while flying low over Saturn's icy moon, Rhea.

Nasa's Cassini probe scooped oxygen from the thin atmosphere of the planet's moon while passing overhead at an altitude of 97km in March this year.

Until now, wisps of oxygen have only been detected on planets and their moons indirectly, using the Hubble space telescope and other major facilities.

Instruments aboard Cassini revealed an extremely thin oxygen and carbon dioxide atmosphere that is sustained by high-energy particles slamming into the moon's surface and kicking up atoms, molecules and ions.

Astronomers have counted 62 moons orbiting Saturn. At 1500km wide, Rhea is the second largest and is thought to be made almost entirely of ice.

"This really is the first time that we've seen oxygen directly in the atmosphere of another world," said Andrew Coates, at UCL's Mullard Space Science Laboratory, a co-author of the study published in the journal Science.

"Active, complex chemistry involving oxygen may be quite common throughout the solar system and even our universe," said team leader Ben Teolis of Southwest Research Institute in San Antonio, Texas. "Such chemistry could be a prerequisite for life. All evidence from Cassini indicates that Rhea is too cold and devoid of the liquid water necessary for life as we know it."

Rhea's atmosphere makes it unique in the Saturn system. Only Rhea and Titan, the largest Saturnian moon, have enough mass to hold on to an atmosphere with their gravity. Titan, however, has a very thick nitrogen and methane atmosphere, with very little carbon dioxide and oxygen.

Astronomers have previously used telescopes to detect oxygen in the atmospheres of Jupiter's moons Europa and Ganymede, but similar searches drew a blank on Rhea because the concentration of the gas was so low.

According to instruments aboard Cassini, every cubic metre of Rhea's atmosphere contains around 50bn oxygen molecules and 20bn carbon dioxide molecules.

The carbon dioxide may come from dry ice trapped within the moon, or be produced by high-energy particles striking water ice on Rhea. Another source could be carbon-rich materials deposited by tiny meteors that have bombarded Rhea's surface.


50 billion oxygen molecules per cubic meter! And 20 billion CO2 molecules! Wow! That's 7E10 molecules per thousand litres, or 0.000000000000000005 atmospheres. This article doesn't give you the context. (This was taken from the article comments)

What I find amazing is that Rhea has any atmosphere at all. Small moons usually have so little gravity that the velocity of gas molecules reach or exceed escape velocity. Is the oxygen on Rhea being rejuvenated by geological or chemical processes inherent to the planet?


And of course Rhea is the mother of the Gods... http://en.wikipedia.org/wiki/Rhea_(mythology)

Do with this what you will....Exciting time to be alive....Hurry it up space explorers! Let's get this in gear before I'm old!

Horn
26th November 2010, 12:12 PM
It doesn't get any weaker, than gravitational theory.

Awoke
26th November 2010, 01:13 PM
So when are we moving?

TheNocturnalEgyptian
26th November 2010, 03:01 PM
When we learn how to breath a tiny fraction of our own atmosphere. But this is the first time oxygen has been detected off Earth so I'm psyched.

Glass
26th November 2010, 03:24 PM
an extremely thin oxygen and carbon dioxide atmosphere that is sustained by high-energy particles slamming into the moon's surface and kicking up atoms, molecules and ions

And yes confirming there is oxygen on another planet-oid is impressive. Now they just need to confirm it on the other planets/moons where they have also detected it.

Neuro
26th November 2010, 03:35 PM
What I find amazing is that Rhea has any atmosphere at all. Small moons usually have so little gravity that the velocity of gas molecules reach or exceed escape velocity. Is the oxygen on Rhea being rejuvenated by geological or chemical processes inherent to the planet?
Rhea has a much lesser energy input from the sun, compared to our moon for instance, thus the gas molecules are moving much slower. Saturn is almost 10 astronomical units from the sun, or 10 times the distance of earth, which means that the intensity of solar radiation is a little more than 1/100th than the earths moon receives. Thus the smaller Rhea can hold on to an atmosphere better than earths moon...

Neuro
26th November 2010, 03:41 PM
When we learn how to breath a tiny fraction of our own atmosphere. But this is the first time oxygen has been detected off Earth so I'm psyched.
Well you could compress it and breath it.

I am opening an oxygen bar at Rhea... You are all welcome for a gulp of fresh air, if you are passing by!

mrnhtbr2232
26th November 2010, 03:45 PM
If only Arafat had lived long enough to see this new Palestinian homeland.

Buddha
26th November 2010, 05:57 PM
If only Arafat had lived long enough to see this new Palestinian homeland.


Nah, it's my new bug out location.

Horn
26th November 2010, 06:51 PM
What I find amazing is that Rhea has any atmosphere at all. Small moons usually have so little gravity that the velocity of gas molecules reach or exceed escape velocity. Is the oxygen on Rhea being rejuvenated by geological or chemical processes inherent to the planet?
Rhea has a much lesser energy input from the sun, compared to our moon for instance, thus the gas molecules are moving much slower. Saturn is almost 10 astronomical units from the sun, or 10 times the distance of earth, which means that the intensity of solar radiation is a little more than 1/100th than the earths moon receives. Thus the smaller Rhea can hold on to an atmosphere better than earths moon...


You're smokin the good shit!

TheNocturnalEgyptian
8th February 2011, 10:51 AM
Bump b/c the board seems interested in this stuff today.

kregener
8th February 2011, 11:36 AM
Hurry it up space explorers! Let's get this in gear before I'm old!

Get the government out of it, turn in into a for-profit deal, and we would be visiting Mars by now.