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dartmanx
2007-Sep-23, 04:56 PM
Are there any estimates of how much water is contained on Europa? I'm curious how it compares to estimates of water in other places in the Solar System.

Jason

01101001
2007-Sep-23, 05:19 PM
Wikipedia: Europa (moon) (http://en.wikipedia.org/wiki/Europa_(moon)):


[...] it is predicted that the outer crust of solid ice is approximately 1030 kilometers (520 mi) thick, including a ductile "warm ice" layer, which could mean that the liquid ocean underneath may be about 100 km (6065 mi) deep. This leads to a volume of Europa's oceans of 31018m3, slightly more than two times the volume of Earth's oceans.

But, it's a rough estimate. The depth is yet unknown.

KaiYeves
2007-Sep-23, 06:09 PM
On Earth, hydrothermal vents are found at about 7,000 feet. Can we safely say that Europa's ocean is deep enough for black smokers and tube worms?

01101001
2007-Sep-23, 06:21 PM
Can we safely say that Europa's ocean is deep enough for black smokers and tube worms?

I don't think so, safely, for we don't know for certain there is an ocean of liquid water under the ice. If there's no liquid water, there's no circulation for smokers, and certainly no tube worms.

It's all very tentative and hypothetical at this time. Europa is barely examined, barely explored.

m1omg
2007-Sep-23, 06:50 PM
Well, I heard estimates around 100 km deep...

01101001
2007-Sep-23, 06:56 PM
Well, I heard estimates around 100 km deep...

Sure, there are estimates of deep liquid water, and liquid water is very likely, to match the evidence, but in the question about black smokers I saw the word "safely", implying certainty, and as far as I know we don't have certainty about the existence of liquid water under Europa's ice.

Planetary Photjournal: PIA01669: Model of Europa's Subsurface Structure (http://photojournal.jpl.nasa.gov/catalog/PIA01669)

http://photojournal.jpl.nasa.gov/browse/PIA01669.jpg (http://photojournal.jpl.nasa.gov/catalog/PIA01669)

Emphasis mine:


These artist's drawings depict two proposed models of the subsurface structure of the Jovian moon, Europa. Geologic features on the surface, imaged by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft might be explained either by the existence of a warm, convecting ice layer, located several kilometers below a cold, brittle surface ice crust (top model), or by a layer of liquid water with a possible depth of more than 100 kilometers(bottom model).

dartmanx
2007-Sep-23, 07:26 PM
Okay, so what is a future mission going to need to do in order to determine what is really the case with Europa?

Neverfly
2007-Sep-23, 07:49 PM
Okay, so what is a future mission going to need to do in order to determine what is really the case with Europa?

We can attempt no landings there.

Ronald Brak
2007-Sep-24, 02:56 AM
An ice slushy Europa is still a Europa that can support life. But I don't know if Europa's rocky core will produce much in the way of black smokers as there might not be enough heat energy for large thermal gradients to form. It has been suggested that Europa's oceans or refreshing ice slushy layer will be very nutrient and energy poor. This suggests that any life may have a very laid back lifestyle, perhaps similar to deep rock dwelling bacteria on earth with incredibly slow metabolisms.

Scattering some seismographs on Europa would be a good way to determine what it is like under the ice crust. They might need to be located on the trailing side of Europa as it orbits Jupiter as the radiation isn't so intense there.

m1omg
2007-Sep-25, 08:23 AM
We can attempt no landings there.

Why not?

Ronald Brak
2007-Sep-25, 08:35 AM
It's a joke, quote from the movie/book 2010. "All these worlds are yours except Europa. Attempt no landing there."

KaiYeves
2007-Sep-27, 12:57 AM
An ice slushy Europa is still a Europa that can support life. But I don't know if Europa's rocky core will produce much in the way of black smokers as there might not be enough heat energy for large thermal gradients to form.
Rats! I'd love if Robert Ballard actually got known for something other than the Titanic.