Cassini Finds Ice Volcanism on Saturn's Enceladus

Lord Zentei · Post by **Lord Zentei** » 2005-07-30 07:12am

SpaceRef wrote:NASA Cassini Spacecraft Finds an Active, Watery World at Saturn's Enceladus

Saturn's tiny icy moon Enceladus, which ought to be cold and dead, instead displays evidence for active ice volcanism.

NASA's Cassini spacecraft has found a huge cloud of water vapor over the moon's south pole, and warm fractures where evaporating ice probably supplies the vapor cloud. Cassini has also confirmed Enceladus is the major source of Saturn's largest ring, the E-ring.

"Enceladus is the smallest body so far found that seems to have active volcanism," said Dr. Torrence Johnson, Cassini imaging-team member at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Enceladus' localized water vapor atmosphere is reminiscent of comets. 'Warm spots' in its icy and cracked surface are probably the result of heat from tidal energy like the volcanoes on Jupiter's moon Io. And its geologically young surface of water ice, softened by heat from below, resembles areas on Jupiter's moons, Europa and Ganymede," Johnson added.

Cassini flew within 175 kilometers (109 miles) of Enceladus on July 14. Data collected during that flyby confirm an extended and dynamic atmosphere. This atmosphere was first detected by the magnetometer during a distant flyby earlier this year.

The ion and neutral mass spectrometer and the ultraviolet imaging spectrograph found the atmosphere contains water vapor. The mass spectrometer found the water vapor comprises about 65 percent of the atmosphere, with molecular hydrogen at about 20 percent. The rest is mostly carbon dioxide and some combination of molecular nitrogen and carbon monoxide. The variation of water vapor density with altitude suggests the water vapor may come from a localized source comparable to a geothermal hot spot. The ultraviolet results strongly suggest a local vapor cloud.

The fact the atmosphere persists on this low-gravity world, instead of instantly escaping into space, suggests the moon is geologically active enough to replenish the water vapor at a slow continuous rate.

"For the first time we have a major clue not only to the role of water at the icy moons themselves, but also to its role in the evolution and dynamics of the Saturn system as a whole," said Dr. Ralph L. McNutt, ion and neutral mass spectrometer-team member, Johns Hopkins University Applied Physics Laboratory, Laurel, Md.

Images show the south pole has an even younger and more fractured appearance than the rest of Enceladus, complete with icy boulders the size of large houses and long, bluish cracks or faults dubbed "tiger stripes."

Another Cassini instrument, the composite infrared spectrometer, shows the south pole is warmer than anticipated. Temperatures near the equator were found to reach a frigid 80 degrees Kelvin (minus 316 Fahrenheit), as expected. The poles should be even colder because the sun shines so obliquely there. However, south polar average temperatures reached 85 Kelvin (minus 307 Fahrenheit), much warmer than expected. Small areas of the pole, concentrated near the "tiger stripe" fractures, are even warmer: well over 110 Kelvin (minus 261 Fahrenheit) in some places.

"This is as astonishing as if we'd flown past Earth and found that Antarctica was warmer than the Sahara," said Dr. John Spencer, team member of the composite infrared spectrometer, Southwest Research Institute, Boulder, Colo.

Scientists find the temperatures difficult to explain if sunlight is the only heat source. More likely, a portion of the polar region, including the "tiger stripe" fractures, is warmed by heat escaping from the interior. Evaporation of this warm ice at several locations within the region could explain the density of the water vapor cloud detected by other instruments. How a 500-kilometer (310-mile) diameter moon can generate this much internal heat and why it is concentrated at the south pole is still a mystery.

Cassini's cosmic dust analyzer detected a large increase in the number of particles near Enceladus. This observation confirms Enceladus is a source of Saturn's E-ring. Scientists think micrometeoroids blast the particles off, forming a steady, icy, dust cloud around Enceladus. Other particles escape, forming the bulk of the E ring.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington.

Post by **Surlethe** » 2005-07-30 11:37am

Does this mean there could possibly be life in the interior?

CaptainChewbacca · Post by **CaptainChewbacca** » 2005-07-30 04:37pm

Surlethe wrote:Does this mean there could possibly be life in the interior?

Yes. Warm (liquid) water is the key.

Enforcer Talen · Post by **Enforcer Talen** » 2005-07-30 08:16pm

Time to go fishing.

Admiral Valdemar · Post by **Admiral Valdemar** » 2005-07-30 08:27pm

Aquatic missions are already on the drawing boards at NASA and ESA. The potential for new data from a mission to Neptune and related worlds with a submersible able to dive kilometres down into the unfrozen waters of such areas like the Deep Flight sub would be priceless. Remember, life very likely evolved first around the black smokers of our own deep oceans. If the waters of Enceladus are already ambiently warm, then the chances are even better.

Patrick Degan · Post by **Patrick Degan** » 2005-07-30 09:03pm

To quote Lucky Jack Aubrey: "What a fascinating modern age we live in."

Enforcer Talen · Post by **Enforcer Talen** » 2005-07-30 11:39pm

Admiral Valdemar wrote:Aquatic missions are already on the drawing boards at NASA and ESA. The potential for new data from a mission to Neptune and related worlds with a submersible able to dive kilometres down into the unfrozen waters of such areas like the Deep Flight sub would be priceless. Remember, life very likely evolved first around the black smokers of our own deep oceans. If the waters of Enceladus are already ambiently warm, then the chances are even better.

I wonder how much that would cost. Id find it more worth while then the ISS.

Erik von Nein · Post by **Erik von Nein** » 2005-07-31 02:21am

I've said before and I'll say it again; this is truly one of the greatest moments to be alive. Between this, the Saturn Ring finds, the giant, solid core planet, the Kuiper Belt planet (possibly) and dozens of other, fascinating finds this is truly an age of wonder for astronomy.

VT-16 · Post by **VT-16** » 2005-07-31 05:38am

It´s true, for the past ten years and especially the last few month, we´re discovered some incredible neato stuff in the universe:

- A particle accelerator 20 LY in diameter.
- A planet with it´s atmosphere trailing it like a veil.
- A planet in a tri-solar system.
- Kuiper-belt objects on the same size-scale as Pluto.
- Hot Jupiters and Earth-size planets.
- Giant rocky world.
- Several candidates for life, in our own backyard.
- Possible life-bearing planets in other systems, waiting for a closer examination.

It´s like the universe is a big freakshow and we´ve just paid the ticket and gone through the entrance.

Plushie · Post by **Plushie** » 2005-07-31 10:42am

VT-16 wrote:It´s true, for the past ten years and especially the last few month, we´re discovered some incredible neato stuff in the universe:

- A particle accelerator 20 LY in diameter.
- A planet with it´s atmosphere trailing it like a veil.
- A planet in a tri-solar system.
- Kuiper-belt objects on the same size-scale as Pluto.
- Hot Jupiters and Earth-size planets.
- Giant rocky world.
- Several candidates for life, in our own backyard.
- Possible life-bearing planets in other systems, waiting for a closer examination.

It´s like the universe is a big freakshow and we´ve just paid the ticket and gone through the entrance.

=O

Got any links for some of those? I've only heard of 4 of 'em...

VT-16 · Post by **VT-16** » 2005-07-31 01:03pm

Cosmic particle accelerator:

http://www.universetoday.com/am/publish ... tml?842005

Veil-planet:

http://www.extrasolar.net/

(In the 'planets' section, scroll down till you reach "Osiris".)

wolveraptor · Post by **wolveraptor** » 2005-07-31 01:25pm

Any idea of how dense the trail of gasses are? A while ago, I had an idea for a binary planet system that had a linkage of atmospheres, so life could travel between. It turned out that was too unstable. I was wondering if something similar between a moon and said planet could occur.

Vanas · Post by **Vanas** » 2005-07-31 03:56pm

Isn't Venus' atmosphere doing much the same, but on a much, much smaller scale?

More on-topic, at a balmy 110 Kelvin, I dunno about life on the inside. Europa, maybe, because that's got the rest of the big moons and Jupiter doing interesting things to it's insides, but Enceladus just seems to be oddly warm/unimaginably cold in a warm way on the bottom. Odd, yes, but I don't think it's life sustaining.

Erik von Nein · Post by **Erik von Nein** » 2005-07-31 07:36pm

Vanas wrote:More on-topic, at a balmy 110 Kelvin, I dunno about life on the inside.

Why not? In the undersea vents in Earth's oceans it's as hot as 673.15 and life still persists there. Thrives there, in fact. Sure, the tube worms, clams and shrimp as well as the bacteria that does all the chemosynthesis aren't exposed to the hottest temperatures it's still well above 110 Kelvin. It's certainly possible that life exists there, though, I don't know how probable that is.

Plushie · Post by **Plushie** » 2005-07-31 10:19pm

Erik von Nein wrote:
Vanas wrote:More on-topic, at a balmy 110 Kelvin, I dunno about life on the inside.
Why not? In the undersea vents in Earth's oceans it's as hot as 673.15 and life still persists there. Thrives there, in fact. Sure, the tube worms, clams and shrimp as well as the bacteria that does all the chemosynthesis aren't exposed to the hottest temperatures it's still well above 110 Kelvin. It's certainly possible that life exists there, though, I don't know how probable that is.

Isn't 110 Kelvin -163C?

Post by **Surlethe** » 2005-07-31 10:31pm

Plushie wrote:
Erik von Nein wrote:
Vanas wrote:More on-topic, at a balmy 110 Kelvin, I dunno about life on the inside.
Why not? In the undersea vents in Earth's oceans it's as hot as 673.15 and life still persists there. Thrives there, in fact. Sure, the tube worms, clams and shrimp as well as the bacteria that does all the chemosynthesis aren't exposed to the hottest temperatures it's still well above 110 Kelvin. It's certainly possible that life exists there, though, I don't know how probable that is.
Isn't 110 Kelvin -163C?

-162.85C, actually.

Close enough.

Erik von Nein · Post by **Erik von Nein** » 2005-07-31 10:34pm

Plushie wrote:Isn't 110 Kelvin -163C?

Errr ... right. I got confused. Don't mind me.

wolveraptor · Post by **wolveraptor** » 2005-08-01 03:34pm

I think his use of the world "balmy" threw you off. How the hell is 110 Kelvin "mild"?

What I don't understand is how the temperature is that low, and yet is still producing water vapor and melting the surface. Hell, to create vapor, you need to have boiling temps, right?

wautd · Post by **wautd** » 2005-08-02 02:26am

wolveraptor wrote: What I don't understand is how the temperature is that low, and yet is still producing water vapor and melting the surface. Hell, to create vapor, you need to have boiling temps, right?

boiling temperature also depends on the atmospheric pressure. Also, iirc water is prone to sublime at low temperatures

Erik von Nein · Post by **Erik von Nein** » 2005-08-02 03:54am

wolveraptor wrote:I think his use of the world "balmy" threw you off. How the hell is 110 Kelvin "mild"?

That's mostly it. That and I got the converstions screwed up in my head. Oie.

outcast · Post by **outcast** » 2005-08-02 06:11am

Admiral Valdemar wrote: The potential for new data from a mission to Neptune and related worlds with a submersible

except Neptune is a gas-giant, not a water-giant.

spikenigma · Post by **spikenigma** » 2005-08-02 06:18am

Admiral Valdemar wrote:Aquatic missions are already on the drawing boards at NASA and ESA. The potential for new data from a mission to Neptune and related worlds with a submersible able to dive kilometres down into the unfrozen waters of such areas like the Deep Flight sub would be priceless.

unfortunately there's a big gap between " being on the drawing boards " and deployment. Normally wonderful things are proposed and detailed but end up being scrapped due to "budget constraints" or "new priorities". The only upcoming missions (I know of) to the Icy Jovian/Saturian moons are:

* Promethius (2010)
This future mission will orbit three planet-sized moons of Jupiter -- Callisto, Ganymede and Europa -- to make extensive investigations of their makeup, their history and their potential for sustaining life.
link

Jupiter Icy Moons Orbiter (JIMO) (2012)
The Jupiter Icy Moons Orbiter (JIMO) is a proposed mission to orbit three of the Galilean satellites, Europa, Ganymede, and Callisto, which may have subsurface oceans and possibly the ingredients for life. The spacecraft will be launched by a conventional chemical rocket, but once in space will be driven by an ion propulsion system. The system consists of electric thrusters powered by a small nuclear reactor. *snip
link

so approximately 7 - 10 years to wait until we get a few orbiters, but no subsurface diggers/landers/swimmers to hear of...

Hawkwings · Post by **Hawkwings** » 2005-08-02 12:23pm

yay for Cassini, the monster space probe that's powered by n00ks and is the size of a school bus!

So NASA had that "Faster, cheaper, better" motto?

GrandMasterTerwynn · Post by **GrandMasterTerwynn** » 2005-08-02 12:28pm

Hawkwings wrote:yay for Cassini, the monster space probe that's powered by n00ks and is the size of a school bus!

So NASA had that "Faster, cheaper, better" motto?

And they still will. In fact, they're liable to go to "Space exploration? What's that? We've got an ISS to complete, a Shuttle to scuttle, a Shuttle-replacement to design and test, and a manned Mars mission that won't happen for thirty years (at the rate we're going) to hype up!"