NASA confirms there's a global subsurface ocean on Enceladus T

[kpete]

Last edited Wed Sep 16, 2015, 10:07 AM - Edit history (1)

NASA confirms there's a global subsurface ocean on Enceladus
The more we study our Solar System, the more water we find
By Sean O'Kane on September 15, 2015 04:40 pm



We've known there is water on Enceladus for a while now, but NASA has just confirmed a more recent theory about the icy moon of Saturn: it has a subsurface ocean that spans the entire globe. The news comes just a handful of months after the agency discovered evidence of hydrothermal vents, which are believed to be integral to the formation of life here on Earth.

The confirmation was made using research from Cassini — a spacecraft that arrived at Saturn in 2004 and has spent the last decade studying the planet and its many moons. (It was launched in 1997.) The researchers used Cassini to measure the wobble in Enceladus' orbit of Saturn, something that "can only be accounted for if its outer ice shell is not frozen solid to its interior."

ENCELADUS HAS HYDROTHERMAL VENTS AND LOTS OF WATER

Enceladus is one of a handful of worlds in our Solar System where you can see liquid jets erupting from its surface, and it didn't take long after Cassini arrived before NASA was able to confirm that the moon was leaking liquid water. But while previous studies of Enceladus had hinted at a subsurface sea, it was thought that the body of water was lens-shaped, and perhaps only occupied a portion of Enceladus' underbelly.

http://www.theverge.com/2015/9/15/9333821/nasa-enceladus-subsurface-ocean

[brush]

1. That just about confirms life there

I'm betting that whole under-surface ocean is not just water. There have to be organisms there.

[Scootaloo]

2. There's something we can agree on!

[brush]

3. Well whadaya know!

[Wounded Bear]

4. Depends on quite a few factors...

but it certainly increases the probability of it. Given the proliferation of life on Earth, you would think so. However, we don't know if life began in single place on Earth and spread out, or if it sprang up in numerous and various locations. Thus, we still don't know the ideal situation for life to begin, or whether there are "ideal" conditions. Life might just happen wherever it can survive.

[brush]

5. Since it's consensus here that life evolved in the sea . . .

I would think that the life there is deeper in the ocean, away from the bitter cold surface.

[Warpy]

6. And considering that even the Marianas Trench is teeming with life

I find it equally likely that there is some form of life there, whether we recognize it as such or not.

[mhatrw]

7. What are the chances that in 4 billion years, no life from Earth has infected Enceladus?

Meteors have hit Earth over and over and knocked infested pieces off Earth for almost 4 billion years.

The idea that not a single Earth-microbe infested projectile has crashed into Enceladus in those 4 billion years is bizarre.

[Hortensis]

8. Just wow...!

[brush]

11. That may be how life got to earth.

[muriel_volestrangler]

12. Fairly low, I'd think, from that article

Since the moons of those giant worlds are relatively close to their planets, many of them might get peppered by these meteoroids as well. The researchers calculated that Saturn’s moons Titan and Enceladus and Jupiter’s moons Io, Europa, Ganymede and Callisto should each have received between one and 10 impacts both from Earth and from Mars.

These findings suggest the possibility of transfer of life from the inner solar system to the outer moons, although very rare, currently cannot be ruled out. “When planning missions to search for life on Europa or other moons, scientists will have to think about whether they can distinguish between life that is or is not related to that on Earth,” Worth said.

- See more at: http://www.astrobio.net/news-exclusive/life-could-have-hitched-a-ride-to-the-moons-of-jupiter-and-saturn/#sthash.Pu9diSBi.dpuf

between 1 and 10 impacts - and the life then has to get to the liquid - if one of those incredibly rare impacts happened before they froze. And note that life on earth has been inside bodies of water for most of the Earth's life - where, I'd think, it's very difficult for an incoming meteorite to hit rock so hard that it can eject another one at sufficient speed to escape Earth's gravity and make it all the way to Saturn. Before plants or cyanobacteria colonised the land, how many Earth bacteria would have been there?

[mhatrw]

13. Their model was incredibly conservative.

Impacts from Mars, had it ever been globally infected from microbes from the Earth would have been inevitable. And if any moon of Jupiter has ever been globally infested with Earthly microbes, then all the other Jupiter moons with water oceans would/will subsequently become infested as well. Because life can self-replicate, it only takes one healthy autochemolithotrophic (rock eating) space travelling microbe to populate an entire moon or planet.

Do you really think that after 4 billion years of life on Earth, no microbe from Earth has ever self-replicated in any environment beyond the Earth? None has ever hitched a ride on a passing comet, for instance? Just think about this for a second. How could this not have happened many, many times?

[muriel_volestrangler]

14. I feel very confident that no microbe has "hitched a ride on a passing comet"

Comets are tiny, and so unlikely to intercept any meteoroids struck from Earth - you're just adding a level of unlikelihood by invoking them. And they don't contain lots of reduced compounds suitable for metabolising, so they'd just be another inert body travelling in space. And just like the meteoroids, they're far more likely to themselves be intercepted by the large planets rather than moons.

[mhatrw]

15. LOL. I am adding an additional manner life could potentially be transported.

Even of the odds are small, these odds can only increase the overall odds that Earthly microbes have infected other bodies in our solar system.

Yes, comets are small. But there are hundreds of thousands, if not millions, of them. So together, they are anything but small. And since there are about 80 visible comets each century, over the last 4 billion years, billions of comets have traveled close enough to the Earth to become visible to the naked eye. Yes, playing the Superlotto has long odds, but if you buy a few billion tickets, you are bound to win something big.

And if the ones we have studied closest are representative, they are rife with water and organic molecules.

So you are just looking for reasons to cling to the old paradigm, the paradigm you are comfortable with. There is no reason to assume that microbial life, once started in a certain gravity well, will somehow stay perfectly contained in that gravity well over a period of billions of years. And there is every reason to believe that microbial life, once started in a certain gravity well, will spread to infest other nearby gravity wells (that contain the water and chemical energy that life needs to thrive) over a period of billions of years.

Is there anything about Earthly microbial life that leads you to believe it is incapable of undirected colonization? There are somewhere in the vicinity of 10^30 living microbes on Earth's surface and perhaps the same number or more under the surface. What are the chances that so many microbes, each a potential mother of an entire ecosystem, could have been perfectly contained by Earth's gravity after over 3 billion years of catastrophes? The only way this makes sense if you desperately need it to make sense because you are wedded to a dying paradigm that became dominant in a time when scientists wrongly assumed that unprotected space travel necessarily sterilized all life.

[muriel_volestrangler]

17. There's the calculations in paper that you linked to an article about

which says it's unlikely. 1 to 10 hits on a moon, most likely in the early stages of the solar system's existence (when bombardment itself made existence on the surface a problem), that would have to be taking the right kind of microbe that could thrive not only on the surface of Earth, but the very different surface of a liquid-covered moon.

[mhatrw]

18. An expected 1 to 10 hits makes it LIKELY not UNLIKELY.

It would have to be less than 1 expected hits to be unlikely.

And, as I said, we do not need a direct hit from Earth. They never calculated indirect hits. We would expect microbial life in the solar system to spread the same way life would spread in a giant petri dish that was very sparsely specked with agar. First to the closest agar speckles, then from there to more distant ones.

[muriel_volestrangler]

19. No, they did calculate it for the only reasonable intermediate 'speckle' - Mars

Getting to Venus and then a moon of Saturn is even more unlikely - more changes in the gravity well of the Sun, plus an atmosphere to burn the outside of a meteorite. And you'd be introducing yet another set of conditions for the microbe to survive on the way. They wouldn't get back out of Jupiter or Saturn, and they would land on a comet in the first place - there may be many of them, but their tiny gravity won't attract passing meteoroids like planets or major moons will.

And their calculation for Mars would have to assume it got fully covered by your migrating microbes to have any bearing on the final calculation.

You assume that every meteoroid from Earth will have microbes suited to a moon on or in it, wherever or whenever it was produced.

[mhatrw]

20. Yeah, I would assume that. Why would you assume otherwise?

The microbes most likely to survive the journey through space would be the same microbes most well adapted to the colonize other planets, moons, asteroids and comets.

[muriel_volestrangler]

22. To be on those meteors, the particular species have to present on the entire surface of the Earth

because so few meteoroids make it to a moon. So they need to be well adapted to the whole surface of the earth, able to survive in space, and well adapted to the moon destination.

[bemildred]

9. Yep, if there is liquid water, there is heat, and that should do it.

Unless something pretty nasty there prevents it.

[Orrex]

10. Has it been tapped for fracking yet?

[closeupready]

16. If there's liquid water there, then there's liquid water all over the universe.

Statistically speaking.

[Warren DeMontague]

23. There's water all over the outer solar system, so yes.

Europa has more water on it than any other body in the Solar System. Think about that.

[closeupready]

24. I didn't know that, but I'm astounded.

Wow. There must be life all over the place. Seems like an irrefutable truth.

[Warren DeMontague]

25. I think so, too.

Although we only have the sample of one to go on, so we don't know how inevitable it is or what variables are likely to be important. But liquid water seems a pretty big one, and we know life can exist around hydrothermal vents as an energy source so....

pretty cool stuff.

[Omaha Steve]

21. Thanks for posting

K&R!

OS