Boost to Chances of Life on Europa?

Gavinsblog writes "New Scientist is reporting that scientists have found that electricity is produced when aluminium bullets are fired into a block of ice. This raises the chances of finding life on Europa, as eletrical shocks of this kind could cause complex molecules to form. An electrifying discovery? :-)"

Comments

Title?

[Sepper]

I read the title really fast and thought it said: "Boost to Chances of Life in Europe?"

Elecrifying discovery

[BornInASmallTown]

An electrifying discovery?

I'm shocked that someone would say that.

Re:Elecrifying discovery

[objekt404]

Seems to be a charged subject.

hrm

[GoRK]

Yeah you know with all of those aluminum bullets shooting at that stupid moon over the last few billion years, it's bound to have created something!!!!!

~GoRK

Just like humanity...

[Lord Bitman]

To start shooting bullets at something just because it might be inhabitted.

Over-hyping?

[CheshireCatCO]

This result is certainly interesting, but I don't think it really pushes the case of organics on Europa much farther than it already was. I'm a little skeptical that electric sparks in an ice matrix will do a lot to generate organic molecules, for starters. (With compounds in the ice, there is very limited mobility, so that chemical reactions just don't occur very often. My guess is that you can spark it all you like, but in most case, nothing will happen.) Research needs to be done on that problem before they have much of a case.

Even then, this is hardly ground-breaking. Electric sparks are not the only way to generate organics. Urey and Miller also showed that UV light can do the same thing. All you really need is a high-energy source to break up some bounds and allow new ones to form. Heck, even the particle radition in Jupiter's magnetosphere can probably do some of that. The UV flux is down by a factor of 27 from that at Earth (top of the atmosphere, now at the surface where ozone and other molecules have attenuated it), but I'd bet you can provide more activation energy that way than with little electric shocks from impacts.

That said, it's a damn cool result without all the "Life on Europa" hype.

Re:Over-hyping?

[Bowling Moses]

Well I have to agree with it being a little over the top in hype, but if you want to get ahead in science not only do you have to do good work you also gotta have a little PT Barnum in you. However, the sparks don't have to produce many new organic molecules in order for things to get interesting. They just have to produce enough to outweigh their degredation so you have a net buildup. Over a long period of time things might get very interesting and Europa's no spring chicken.

Take this example of mine: I work on an enzyme that I have to store some samples of at -80 C for later experiments. I found that if it had been stored at -80 C for a long time (1-2 years) the enzyme is inactivated, but this is not due to the freezing process itself so some chemical change is occuring in ice at -80 C over a months to years timeframe. Pretty "cool" eh?

That damn dog!

[RealErmine]

Evidence for the presence of the molecular building blocks for life comes from the yellow-brown stains seen on the ice by the Galileo probe.

Newer images reveal evidence that these stains may have been left after a recent pass of Pluto.

Miller-Urey is pointless

[young-earth]

Miller and Urey's experiment is highly misrepresented in the textbooks of today. Among other things, it was based on a completely bogus set of assumptions. Such as the atmosphere being C02, CH4, H20, NH3 with no free 02. At our distance from the sun, this atmosphere is absurd. Why? Because the hard UV that would be coming in without any ozone layer (no O2 in the atmosphere, no ozone layer) would dissociate the NH3 rapidly into N2 and H2, as it would CH4 into more complex oils. But if there were 02 in the atmosphere, their experiment would fail miserably as the oxygenation would be the dominant reaction. All of which makes their experimental conditions irrelevant.

Additionally, they only made a tiny fraction of the amino acids necessary for life. Those that were made were racemic, while life is universally homochiral in proteins (the tiny number of exceptions are in things like bacterial cell walls).

And the sludge they did produce was mostly tar (a term used by organic chemists to mean the sludge left behind when you can't extract anything useful from it). In fact it was 85% tar, 13.0% carboxylic acids (many of which would destroy life before it could get started), 1.05% glycine (the simplest amino acid) and 0.85% alanine (the second simplest amino acid). There were also trace amounts of glutamic, aspartic, valine, leucine, serine, proline, and treonine.

If you want to understand the problems with the chemistry of the origin of life, there's a good paper that's pretty readable for those with a bit of exposure to chemistry.

Re:Miller-Urey is pointless

[CheshireCatCO]

The point of the Urey-Miller experiment wasn't to show the way organics were produced, it was to demonstrate that they CAN be produced by such methods. Similar experiments have been run with dozens of permutations on the atmosphere and energy sources, and they generally produce organics. In fact, a range of different experiments with a variety of catalysts, like some clays, have also been performed, with similar results. A quick literature search would have told you that.

The point of these experiments is not to reproduce the early-Earth conditions exactly. We still don't know what those are. But the fact that such a wide variety of conditions produce organics is an indication that the goop is easy to form and probably did so on the early-Earth, regardless of the conditions.

(Your point about the chirality of the amino acids is a red herring. There is no reason to think that life was formed in a soup of only one chirality. All we know is that somehow life on Earth has evolved to use only one of those. It isn't hard to imagine that one or the other might have a slight advantage or even that life had to - at some early stage - chose just one and use it. Dealing with both L and D forms all the time would probably require a lot more effort than it's worth.)

Re:Miller-Urey is pointless

[young-earth]

I made specific reference to how it's treated in textbooks; that was the point. Current textbooks claim it [Miller-Urey] shows how abiogenesis occurred, it does nothing of the sort.

It's a nice hand wave to say

somehow life on Earth has evolved to use only one of those. It isn't hard to imagine that one or the other might have a slight advantage or even that life had to - at some early stage - chose just one and use it.

Yet you are attributing purpose to "life", as when you say "chose". Yet evolution is supposed to happen by random changes, not by direction.

And you point about creating organics is quite true, heat carbon, hydrogen, and oxygen under a bit of pressure and you'll get all kinds of things. But those are immersed in a toxic soup that would annihilate any peptide bonds.

Re:Miller-Urey is pointless

[DuckDuckBOOM!]

DDB sighs, as he is wont to do in such circumstances, and wonders where to start...

Controversial? Certainly. Pointless? Hardly.

First of all, your criticism of M-U's experimental conditions is straw-man logic - you damn them for not using free O2, then promptly turn around and demonstrate the unlikeliness of free O2 in the primordial atmosphere - as you point out, it would have oxidized practically everything in reach. Despite recent evidence that the early Earth's atmosphere wasn't completly reductant after all, there's still little reason to think that free O2 in significant amounts was present before life came along. Also, please note that a typical electric discharge emits more than a little ultraviolet. Not nearly as much as solar UV flux, but let's be reasonable - their apparatus didn't simulate asteroid impacts, lava flows, or full-scale lightning strikes either.

Second: Okay, fine - a week-long experiment intended to loosely approximate conditions on Earth over the first billion-odd years of its existence didn't end with lizards crawling out of the flask. The significance of M-U isn't that it generated every chemical necessary for life, but that it managed to generate any at all. (Even if you factor in the amino acids found in meteorites, etc., those amino acids came into being somehow.) Tell you what - I'll start up an M-U-like experiment, let it run for a few million years, and let you know what happens.

Third: I rather hope Cremesti didn't pull better than a C-minus on that paper. It continually amazes me how creationists (one of which I am not necessarily assuming Cremesti is) continue to hammer away at the random-chance argument of life's origin / evolution, when I don't think there's a single evolutionary biologist out there who accepts it. Darwin didn't accept it. (It's rather a tickle to read about how this theory, such as it is, was demolished by computer analysis; with what was essentially a primordial ecological simulator. Run on "high-speed computers". In 1966. Project headed by Dr. Forbin, I assume.)

The rest of the paper is crap, full of bandwagon assertions ("Many authors believe..."...so it's obviously true. Would've been nice if he'd cited some of them.) and silliness like invoking the Second Law of Thermodynamics to show that "...[chemical evolution] will not occur in isolated or closed systems near equilibrium" when it's arguable that none of these conditions obtain even on a planetary scale, and glaringly obvious that they don't on a local scale. (Fun experiment: Hold up a tall metal pole in the middle of a thunderstorm, and determine how long your local environment remains in equilibrium.)

When we research things that occur on a time/space scale as grand as this, imho one of the biggest obstacles is the limits of human imagination. Can you picture - really grasp emotionally - intervals longer than your own lifetime? Or distances further than those you've actually traveled? I disagree with Cremesti in that I do not believe that chemical evolution is not falsifiable. I'm not so sure that it can be done by human beings, at least not for a very long time to come. Given a problem with thousands of variables, many unknown, whose domain is an entire planet (or many planets, if you accept panspermia) and hundreds of millions of years, can even the most knowledgable scientist state with confidence that any plausible event did or did not happen? No matter how fast the computer or how sophisticated the methods, is it possible to analyze such a problem and get results better than a coin flip? Again, not now, and imho not for a long time to come. The value of M-U is not that it showed the mechanism by which life originated on Earth, but that it showed a part of a plausible mechanism.

The first step is always important, even if it turns out to be in the wrong direction.

DDB (having a slow day at work)

Re:Miller-Urey is pointless

[spike hay]

Wow you're full of shit. Let's deconstruct this piece by piece.

Such as the atmosphere being C02, CH4, H20, NH3 with no free 02. At our distance from the sun, this atmosphere is absurd. Why? Because the hard UV that would be coming in without any ozone layer (no O2 in the atmosphere, no ozone layer) would dissociate the NH3 rapidly into N2 and H2, as it would CH4 into more complex oils.

Yeah, except that H2O, CH4, and NH3 block UV light. CH4 is a very stable element. It's methane. It is in the atmopheres of several planets. Ammonia is also stable. It can only be cracked into H2 and N2 with very high temperature furnaces, typically.

And the sludge they did produce was mostly tar (a term used by organic chemists to mean the sludge left behind when you can't extract anything useful from it). In fact it was 85% tar, 13.0% carboxylic acids (many of which would destroy life before it could get started), 1.05% glycine (the simplest amino acid) and 0.85% alanine (the second simplest amino acid). There were also trace amounts of glutamic, aspartic, valine, leucine, serine, proline, and treonine.

Laboratory simulations of primitive earth have produced all 20 amino acids used by life, as well as ATP and the 4 dna bases. If you have those 20 amino acids, you can form any protein in existence.

Of course you need to be able form something with all of those chemicals. Have you heard of protocells? These are structures that can be formed very easily with a few amino acids. In fact, if you have a few chemicals, you can make them quite easily at home. Anyway, they don't have DNA, but are capable of budding, metabolizing, using ATP, and non-darwinian chemical evolution.

As for your link to to Cremesti. That's a well known very biased creationist site. And that essay took quotes by many scientists way out of context. The classic creationist tactic of making debate about the specifics of a theory sound like the scientist is attacking the entire general theory.

Re:Miller-Urey is pointless

[Alsee]

I see no puzzle there. It was random which chirality became dominant. Saying one was "chosen" is like saying a coin "chooses" to land on heads or tails when an earthquake causes it to fall off its edge.

Once life randomly tips chirality away from 50/50 it drives it all the way one way or the other. Life that happens to use more of one type will evolve to manufacture more of that type. That type falls back into the enviornment and makes that type more common as "food".

It's sort of like VHS vs Betamax :) Everyone manufactures VHS tapes because everyone uses VHS tapes. It was once 50% VHS and 50% Betamax. It could have just as easily tipped the other way.

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