New Evidence Points To Icy Plate Tectonics On Europa (gizmodo.com) 67
According to new research published today in Journal of Geophysical Research: Planets, Europa has what it takes to support plate tectonics. "Using computer models, a team lead by Brown University planetary scientist Brandon Johnson was able to demonstrate the physical feasibility of icy plates driving deep into the icy interior in a processes similar to what's seen on Earth," reports Gizmodo. "Excitingly, this same process could be delivering important minerals to the ocean below, heightening the moon's status a potentially habitable world." From the report: Europa has surface features reminiscent of Earth's mid-ocean ridges. For astronomers, this hinted at geological processes akin to subduction zones, where, on Earth, tectonic plates slide underneath another, sinking deep into the planet's interior. Several years ago, researchers Simon Kattenhorn and Louise Prockter posited this explanation when they noticed that a 20,000 square-kilometer (7,722 square-mile) chunk of ice had mysteriously disappeared from Europa's surface. Their explanation was that Europa's surface, like a gigantic jigsaw puzzle, is composed of tectonic plates, and that occasionally a plate of ice will sink beneath the other into warmer layers below. But this observational evidence of extension and spreading needed to be supported by geophysical reality. To that end, Johnson's team ran a computer simulation to see if it was possible for ice to sink in this way.
On our planet, subduction is primarily driven by differences in temperature between a descending slab and the surrounding mantle. Dense crustal material features a negative buoyancy that drives it down into the mantle. The Brown University scientists figured a similar thing happens on Europa, but with ice. In the case of Europa, the researchers surmised that the moon has two frozen layers -- an outer lid of very cold ice that sits above a layer of slightly warmer convecting ice. Their models showed that subduction is indeed possible in this alien environment, but only if the outer shell contains varying amounts of salt. This added ingredient provides the necessary density differences for a slab to conduct.
On our planet, subduction is primarily driven by differences in temperature between a descending slab and the surrounding mantle. Dense crustal material features a negative buoyancy that drives it down into the mantle. The Brown University scientists figured a similar thing happens on Europa, but with ice. In the case of Europa, the researchers surmised that the moon has two frozen layers -- an outer lid of very cold ice that sits above a layer of slightly warmer convecting ice. Their models showed that subduction is indeed possible in this alien environment, but only if the outer shell contains varying amounts of salt. This added ingredient provides the necessary density differences for a slab to conduct.
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Aren't you glad you're not a niiger?
Sharing DNA with a mouth-breather like you is definitely a sad and sobering realisation.
By the way, it's two Gs. One I. You stupid cunt.
Life we know it. (Score:3)
*Habitable worlds for life as we know it.
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You're so smart.
Joke aside, "as we know it" is implied because at this point we only know one way.
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Most people who feel the need to add, 'for life as we know it' when the subject comes up seem to be ignorant of the reasons we have for believing it is probably very safe to say 'life' instead of 'life as we know it'.
No, Si can't replace C as a backbone for complex molecules. Yes, you need a liquid in which chemistry can happen. And a (fairly gentle) energy gradient - enough to help chemistry along without breaking molecules apart before anything interesting happens with them.
There aren't any plasma being
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What about machines driven by strong AI built by some advanced life-as-we-know-it kind of civilisation, though?
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I think that one is possible. I can see that being humanity's legacy - creating such a 'species'.
I also think the fact that we've never found any evidence of such is probably a pretty good indication that the difficulty of traversing the void between stars is likely insurmountable even if you're an AI in radiation-hardened hardware.
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I also think the fact that we've never found any evidence of such is probably a pretty good indication that the difficulty of traversing the void between stars is likely insurmountable even if you're an AI in radiation-hardened hardware.
I'm not sure that's right -- on a cosmic scale we really haven't been looking for all too long yet, and we're such a small target to hit - or put differently, the universe is so huge - that even with a viable means of bridging those distances, it wouldn't seem all too likely to be run into just by chance (especially not in the short timespan in which we could actually tell what's going on). For all I know, the various stories about gods and angels and whatever might as well be based on such encounters ;)
Re:Life we know it. (Score:4, Insightful)
Unfortunately, the math says otherwise.
The Earth - the one example of intelligent life in the Milky Way known to humanity - is ~4.5 billion years old, and it's taken ~4 billion years of that time to have us evolve on it to the point we can post about it on Slashdot. We don't know, however, if that's an unusually long time, or an unusually short time.
Hopefully it's long or average, because our star is near the end of it's current Earth-supporting phase. If you assume you need a Sun-like star (smaller gets you a longer-lasting star, but the habitable zone gets closer to requiring planets to be tidally locked, and stellar temperament becomes a problem, too), then you pretty much want to know people can pop up on an orbiting rock in less than 4 billion years.
Anyway, at speeds we can reach with our technology, it would take around 5 million years to cross the galaxy. 5 million years is peanuts compared to the 4 billion years life has been on Earth so far. Now consider there are probably ~10 billion potentially habitable worlds in the Milky Way based on our current models.
Only ONE of those 10 billion worlds has to have intelligent life begin to colonize the galaxy a mere 5 million years before we started talking about it to arrive by tea time tomorrow.
And the Sun wasn't the first star of its class to be born. There's at least one similar star we know of that's over 11 billion years old, which potentially means there's an extra 7 billion years of leeway for aliens to set up shop everywhere. Well, not everywhere - obviously if they were zipping around the Milky Way more than 4 billion years ago, Earth would just have been a hot damp rock. On the other hand, you'd expect that with the extra lead time, they'd be around pretty much every star in the sky and we'd have seen SOMETHING by now.
Re: Life we know it. (Score:2)
That assumes that we know what to look for.
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Of course we do - anything we can't explain as a natural phenomenon.
The real (and immense) difficulty is in getting enough photons into our detectors, because the distances are vast and unless you have some silly dream of planet-sized megastructures... anything we'd look for would be tiny.
Re: Life we know it. (Score:2)
That assumes we know everything about the universe and can tell the difference between natural and artificial and that time hasn't eroded the evidence.
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Sorry, gmail keeps locking me out so I miss/get delayed a lot of reply notifications these days.
Anyway, at speeds we can reach with our technology, it would take around 5 million years to cross the galaxy.
I guess this is true when only considering speed. I think there's a lot more to crossing the galaxy in 5M years than velocity alone.
Only ONE of those 10 billion worlds has to have intelligent life begin to colonize the galaxy a mere 5 million years before we started talking about it to arrive by tea time tomorrow.
Dunno. This is based on the assumption that galactic colonization is a) desirable and b) happens in a von Neumann probe sort of way, which would be a different matter altogether.
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> I think there's a lot more to crossing the galaxy in 5M years than velocity alone.
Agreed. But humans have gone from banging rocks together to the space and information age in 200,000 years. That's basically 'from scratch'. Now imagine you've arrived at a new planetary system having foreknowledge of the available resources, and brought all your tech know-how and a 'starter kit' with you.
I think you'd have to agree that the amount of time required to jump off to the next candidate planetary system wou
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I bet you would like "The Vital Question" by Nick Lane. It's a very recent book that brings together quite a lot of phylogenetic, chemical, and geophysical evidence to show how like likely arose on Earth - the first plausible explanation of abiogenesis I've ever seen. Also, by his reasoning, the origin of life might not have been a fluke, but the first eukaryote - that's possibly a great filter.
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Story Is Incorrect (Score:1)
New Evidence Points To Icy Teutonics On Europa
Not in the summer. It's too warm in Germany then.
Incorrect moderation (Score:1)
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Minerals? (Score:4, Interesting)
Where from? The amounts of rock minerals from space dust and organics from reactions on the surface are probably minute. I suspect any significant minerals come from the moons core which AFAIK is thought to be made of rock.
Anyway, we have no idea what conditions are required for life to start. There may well be a minimum energy requirement which europa doesn't even get close to. Also you need some kind of energy gradiant. In an ocean sealed off dozens or even hundreds of km below the surface I suspect that gradient is shallow in the extreme.
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Well if you consider numerous articles I've read on the subject and a science background nothing, then sure. But feel free to elaborate your ideas, if you have any and you're not just another A/C troll.
Re:Minerals? (Score:5, Interesting)
Well, then, since you feel qualified to weigh in on the amount of rocky mass recycled from the icy crust, off the top of your head you should be able to tell us the mass flux from impactors and space dust at Europa. What is it?
Because I guarantee you, people who study these things don't need to google it.
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Very little I should think given the amount of ice still visible on calisto and ganymede especially in craters, which almost certainly don't have any kind of crustal convection. If it was any significant amount then these moons would be jet black after 4 billion years. So go ponder that one you smug bastard.
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"Very little I should think" - Fail
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So you don't read, you just make it up. Got it. Glad we cleared that up.
Re:Minerals? (Score:4, Interesting)
I have no specific knowledge either, but I know Rei is highly intelligent and from past posts probably works in the field, even if this subject is not his direct area of study.
All that bitching aside, here is a paper with some numbers for you: http://people.virginia.edu/~re... [virginia.edu]
If Io were the only source of non-ice material to Europa’s surface and no loss occurred, then using the flux values from Table 1, sulfur compounds could be present on the surface at ~7% (molar abundance) relative to H2O, while Na and Cl could reach 0.3%. Silicon and magnesium could be comparable or slightly less than Na and Cl. These estimates assume uniform mixing and ignore hemispherical flux and gardening rate differences, which can produce surface concentrations that are a factor of 10 or more different between the leading and trailing sides (see Fig. 2 and caption).
Seems to me that there could be quite a bit of material present. Much from Io outgassing and 'splash' from impactors to IO settling on Europa, not even counting direct impacts to Europa.
Science.. try it sometime.
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You have a go at me for saying "I should think" , then you say "Seems to me".
On your bike you hypocrite.
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"You on the other hand seem to want to be acknowledged as an expert"
Seriously? Which part of "I suspect" and "There may well be" in my original post do you have a problem comprehending, because its seems like simple fucking english to me. If english is your second language I'd suggest learning it a bit better, if not then
buy yourself a nice spade for christmas, it'll help you did that hole even faster.
Re:Minerals? (Score:5, Insightful)
Re:Minerals? (Score:4, Informative)
Io is right next door (so to speak), and spews forth a lot of material from its volcanoes. Some of that material makes it into the Jovian space between the moons. Jupiter's magnetic field is a transport mechanism.
Also: we know that tons - literally, tons [iflscience.com] - of extraplanetary material rains down on the Earth each day. Jupiter, being as massive as it is, probably sucks up a lot more. Europa is a small target, but is traveling through this inward flux of material and is sure to pick some up.
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Some sure, but the other moons of jupiter would be jet black even in their craters if it was any significant amount. Since there're not, it obviously isn't.
Re: Minerals? (Score:2, Interesting)
Except the surface of Europa is red-brown specifically because something is accumulating. The two competing ideas are either it is organic compounds due to UV interacting with carbon and nitrogen coming from below the ice, or a combination of sulfur and magnesium coming from off the moon. Results of Galileo lean toward the latter. Depending on the geology of the rock below the ice and ocean, sulfur from rock may be very small compared to what hits the surface.
You can't just say the amount hitting the surfac
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Anyway, we have no idea what conditions are required for life to start. There may well be a minimum energy requirement which europa doesn't even get close to. Also you need some kind of energy gradiant. In an ocean sealed off dozens or even hundreds of km below the surface I suspect that gradient is shallow in the extreme.
Features such as Conamara chaos [wikipedia.org] show extensive melt-through and rafting. That does not happen with an icy crust hundreds of kilometres thick.
The ice shell is probably less than 10km thick in most places and occasionally much thinner. Gives ample opportunity for surface materials (irradiated by the sun and radiation from jupiter) to be recycled into the subsurface ocean.
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One contribution on the possible source of minerals, if I may.
Jupiter is *the* gravitational trash compactor for the whole solar system. Earth collects around 50 tons of space dust a day, and that doesn't include the significant larger chunks of stuff that fall intermittently. We're in the kiddy pool version of gravitationally stretched space, at least compared to the Mariana Trench that that is Jupiter. I would imagine a commensurately greater amount of crap is swirling in the region of Jupiter and as a
Silly idea to name a moon like a continent (Score:4, Interesting)
The first picture that came to my mind were some giant ice sheets covering Europe doing some strange kind of tectonics.
Btw. I'm German, in which both items are spelled "Europa", and it took a few seconds to remember the moon and that the continent would be spelled "Europe" in English.
Of course in terms of Greek mythology it all makes perfect sense ...
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I vote for Iapetus being called America.
- A mix of black and white on the surface, but due to its history, they're mostly separated.
- The distribution of its "assets" (mass) is far from equilibrium.
- A violent history
- A bulging waistline (with a belt)
- Elected a mentally-challenged racist as its president (I assume based on no evidence)
Re: Silly idea to name a moon like a continent (Score:1)
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Europa the moon and Europe the continent are both named after the same mythical character
https://en.wikipedia.org/wiki/... [wikipedia.org]
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Zeus was beyond good and evil, in the Nietzschean sense. A bit like Trump!
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I had exactly the same mental image as you. In French, both the continent and the moon are spelled "Europe", which is as confusing. I had to read the summary twice to remember that Europa is the moon.
I suggest we add Europa as the newest 28th state of the EU (now that the brits are out).
Tidal Forces (Score:5, Interesting)
I don't see how this makes it more habitable however as large glacial tectonic forces, while similar is appearance to regulr tectonics don't seem to make life any easier on the surface. If anything it makes it more difficult to establish any kind of surface base given how quickly the ice can shift compared to normal mantle based tectonics.
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Who cares about the surface? We're talking about a subsurface ocean. Get over your "topdweller privilege", man. Subterranean lives matter!
We've been warned (Score:1)
Ah headlines, you got me again (Score:2)
Stay away from Europas (Score:2)
Of
Trouble
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Serious
Damn Colin Chapman!
Ugh. Science? (Score:2)
As par for the course I didn't RTFA. So I don't know if the title and summary have nothing to do with each other and follow the inflammatory trend of clickbait or not.
However I'm not sure what "New Evidence" they are referring to other than someone built a simulated model. A model demonstrating something isn't exactly evidence. Depending on the parameters, you can build a model to show just about anything you want to show. If you are trying to show ice tectonics by using a model, I'm pretty sure you can do