Using Light's Handedness To Find Alien Life 210
Rational Egoist writes "Scientists working at the National Institute of Standards and Technology have come up with a novel, easy way to detect life on other planets. Rather than try to measure the composition of atmospheres, they want to look at the chirality of light coming from the planet. From the article: '"If the [planet's] surface had just a collection of random chiral molecules, half would go left, half right," Germer says. "But life's self-assembly means they all would go one way. It's hard to imagine a planet's surface exhibiting handedness without the presence of self assembly, which is an essential component of life."' And they have already built a working model: 'Because chiral molecules reflect light in a way that indicates their handedness, the research team built a device to shine light on plant leaves and bacteria, and then detect the polarized reflections from the organisms' chlorophyll from a short distance away. The device detected chirality from both sources.' The article abstract is available online."
One problem (Score:5, Funny)
What if the aliens are ambidextrous?
Re:One problem (Score:4, Informative)
Then this scan won't find them and no preemptive Relativistic Kill Vehicle [wikipedia.org] will be dispatched to their planet.
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It worked on the Martians, didn't it?
Stupid native Martians. Always whining that people don't treat their ancestor's bones with respect.
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The problem is that anything above a certain cross-sectional are will probably just disintegrate at 0.99c. At a velocity like that, even the vaccuum of space suddenly becomes quite dense. Heck, you might even run into problems with vacuum energy.
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At a velocity like that, even the vaccuum of space suddenly becomes quite dense.
That's a plus point if you're using a Bussard Ramjet.
Actually consider the following scenario. You scan for planets with an oxygen atmosphere and then check for signs of a threatening civilisation.
You then launch a Bussard Ramjet to nuke the planet. The spacsehip builds a Krasnikov Tube as it goes. Then you have a route for ground troops or more likely bots to reach the planet quickly post explosion to mop up/enslave any survivors. Most likely humans would survive in shelters from a K-T type impact, but it
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You then launch a Bussard Ramjet to nuke the planet. The spacsehip builds a Krasnikov Tube as it goes.
Whoa, hold on for a minute. The energy required to distort space enough to form a Krasnikov Tube is _huge_. There's no way to accelerate something to 0.99c _and_ form a Krasnikov tube behind it using just a Bussard ramscoop. In fact, it might be impossible just to accelerate to 0.99c without a supplementary power source.
I think this is far too ruthless for humans to do and in any case the technology involv
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You then launch a Bussard Ramjet to nuke the planet. The spacsehip builds a Krasnikov Tube as it goes.
Whoa, hold on for a minute. The energy required to distort space enough to form a Krasnikov Tube is _huge_. There's no way to accelerate something to 0.99c _and_ form a Krasnikov tube behind it using just a Bussard ramscoop. In fact, it might be impossible just to accelerate to 0.99c without a supplementary power source.
I think this is far too ruthless for humans to do and in any case the technology involved is highly speculative and some parts of it are probably not possible, but who says we're the nastiest species out there? Maybe there are much nasier civilisations with the requisite technology.
Why should a species with access to technology like this limit itself to colonizing previously-inhabited planets? They don't have to care about less-developed civilizations - they could simply pwn the whole galaxy within a few million years or so.
Actually you'd don't need the Krasnikov tube. The whole civilisation could travel in Bussard Ramjets. Why do it? Why invade countries for gold, oil or slaves when you could stay home and live sustainably?
Everything is about resources. In my hypothetical planet hopping civilisation planets provide the resources to build more ramjets. You'd send down engineers and machines, they'd strip the planet and turn it into another ships. The reason you target planets with technically advanced civilisations is that the
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Why do it? Why invade countries for gold, oil or slaves when you could stay home and live sustainably?
The question is reversed in our case. Why go through all the trouble of exterminating less advanced civilizations, when the planet they're on only contains a tiny fraction of the "resources" in their solar system?
In my hypothetical planet hopping civilisation planets provide the resources to build more ramjets. You'd send down engineers and machines, they'd strip the planet and turn it into another ships.
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"se. Why go through all the trouble of exterminating less advanced civilizations, "
because they are competitors for resources.
If they are at a primate level, then fine, but if they are cusping on space technology then you ahve to do something.
Either kill them, or infiltrate them and co-op there society.
Also, have a habitable planet ready to go is nice.
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AS long as the disintegrated pieces(Atoms) hit the planet at that speed, the planet will still be dead.
Of course, at that speed, you really only need something the size of a softball to cause the atmosphere to explode and kill most, if not all life.
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The asteroid that killed the dinosaurs had an yield of 75 to 100 million megatonnes. So you'd need a 740 metric tonne projectile at 0.99c
So you need that much energy to set it on course. Any ideas? Blow up 1,5 million Tsar Bombas [wikipedia.org]?
Also, doesn't mass increase at non-relativistic speeds?
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Mass doesn't increase at *non*-relativistic speeds. At non-relativistic speeds, the conservation of mass applies.
Anyway, it wouldn't require anything like blowing up a giant bomb. You don't need to get the rate of acceleration of the projectile very high. You just need to accelerate it for a long time.
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Mass doesn't increase at *non*-relativistic speeds. At non-relativistic speeds, the conservation of mass applies.
Typo. I meant relativistic.
You don't need to get the rate of acceleration of the projectile very high. You just need to accelerate it for a long time.
Acceleration requires energy, no matter the rate. As you apply energy, the object's mass increases as well, not just its speed, though it's insignificant at low speeds, so you get Newtonian physics if you disregard it. At speeds comparable to c, however, the mass increases significantly, so you have to add even more energy to accelerate it further. This is why you can't reach light speed: at c, the mass, and thus the required energy would be infinite.
See here [wikipedia.org] and play it out as v
raise your hand... (Score:4, Funny)
if you had to google chirality
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Don't they cover this in the second semester of freshman chem?
Re:raise your hand... (Score:5, Funny)
if you had to google chirality
You know, it's when you open the door for ladies.
Quirks and Quarks Had a Good Story about This (Score:5, Informative)
CBC's science program Quirks and Quarks had an interesting story about the handedness of molecules [www.cbc.ca] that it played last month. (Audio available in Ogg Vorbis) It provides a nice, friendly introduction to this topic.
Aliens, we are coming! (Score:2, Funny)
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http://www.anythingleft-handed.co.uk/golf.html [anythingle...nded.co.uk]
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This sound very interesting. Maybe there are business opportunities with Aliens. What do you think they would be ready to buy from us?
Knowing us humans, we will probably be able to supply what they crave most: PORN. The interstellar DVD trade will flourish, with constant streaming of jellyfish polyps budding off, jellyfish polyps turning into medusae and for those real sickos, jellyfish catching and eating fish.
Hey I don't ask questions, I just sell it.
Very punny :P (Score:4, Funny)
Scanning for lifesigns (Score:2, Interesting)
One more trek concept brought to real-life, yay! (The other one being the communicators on TOS)
- AC, patiently waiting for warp drives
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Isn't science fun? In the meantime the religious crazies are still waiting on Jesus.... 2000+ years and counting... tick tock tick tock
Hmm? We waited 4000+ years the first time.
Kids these millennia, always in such a hurry.
Wow (Score:5, Insightful)
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Might take a gigantic telescope in outer space.
What would be really cool would be able to build one of those array type telescopes(really, outrageously Humongus sized) at one of the lagrange points.
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(really, outrageously Humongus sized) at one of the lagrange points.
No, please don't give them any more stupid ideas for what to call large telescopes [wikipedia.org]
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(really, outrageously Humongus sized) at one of the lagrange points.
No, please don't give them any more stupid ideas for what to call large telescopes [wikipedia.org]
Let's see...
Freakish Array of Radio Telescopes?
Stupidly Large Ultraviolet Telescope?
Binary Interferometric Narrowband Telescope?
Coordinated Unit of Networked Telescopes?
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This just might work. It'll take incredibly good optics, of course, and the chirality of the light from these distant planets might be lost when the light goes through the earth's atmosphere.
Then it'd also be lost going through the source planet's atmosphere.
I don't see the scheme working.
I'm sceptical.... (Score:5, Interesting)
The whole reason that life produced molecules of fixed chirality is that molecules precursing life are generated in cold gase nebulae that are often effected by radiation from young stars which have a particular chirality. That is to say, the cold nebulae that was the precursor of the Sol system, had light whose chirality precipitated right handed sugars and left handed amino acids.
A planet let's say, made of hydrocarbons and complex organic molecules that formed in such a cold dark nebulae, might have no life, but it's chemistry would in fact have fixed chirality. That is to say, someone needs to point the first instance of this instrument at Titan, a place where we are pretty sure no surface life (as we know it) might exist, but whose surface chemistry may very well have preserve some of the chirality of the nebulae that formed the Sol system. If we receive significant chirality frozen in the Titan surface, it would be a strong indicator that this test is less than optimal for finding earth like planets.
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Re:I'm sceptical.... (Score:4, Insightful)
Not all molecules are chiral. Simple molecules which form the raw materials for life forms are not themselves chiral because they are symmetrical (O2, H20, NH3, CO2, etc; chirality is only possible for asymmetric forms molecules). The simplest solution the problem you describe is to introduce simpler lifeforms from earth--bacteria or archaea to start producing organic molecules of the correct chirality from the raw material precursors.
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Or it might tell us that there's life on the surface of Titan...
Certainly not life as we know it. I can just imagine what would happen to all those algae once they manage to produce enough oxygen to - well let's say that's one world with the potential to eventually "go out with a bang". Hopefully for them any life there would use a different oxidizer...
Re:I'm skeptical.... (Score:5, Informative)
-most compounds are not chiral, so even if a dead planet had some pure enantiomers, they would be insignificant compared to one with life, life produces a crazy large amount of them
-no one has quite figured out why life has the handedness it does, some say it could be because of silicon catalyzing a certain handedness, others disagree, there is not an answer to this question yet, but it makes sense that life would evolve to have a specific handedness so all the parts could be interchangeable and we don't have bizzaro ecoli floating around that can exchange DNA with normal ecoli
-since when does polarized light catalyze chiral reactions?? UV light can catalyze reactions, and chiral molecules can cause a reaction to form with a specific handedness, but only chiral MOLECULES can catalyze reactions to cause a more enantiomericly pure product
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-since when does polarized light catalyze chiral reactions?? UV light can catalyze reactions, and chiral molecules can cause a reaction to form with a specific handedness, but only chiral MOLECULES can catalyze reactions to cause a more enantiomericly pure product
Not quite, IIRC, there are examples of some reactions with polarized light which gives ~1% excess of one enantiomer. It has been hypothesized to be the origin of the handedness of life. But in itself, it will not give enough of a excess to be meassured with this technique.
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-no one has quite figured out why life has the handedness it does
I recall a theory that it is due to the slight asymmetry in weak interaction, but I've forgotten the exact mechanism. This asymmetry exists basically everywhere in the universe, but as life is self-replicating, it can amplify the effect to a great extent. Here's the first reference found via quick googling:
http://www.springerlink.com/content/0743577n4716u23j/ [springerlink.com]
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I recall a story about it, someone in this thread linked to a Quirks and Quarks story where it turned out that comets have been shown to have a tendency to lean towards containing amino acids with a certain handedness. The thought is that life likely formed with that handedness because there were more amino acids to work from.
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Also, don't forget racemization (http://en.wikipedia.org/wiki/Racemization) - a lot of enantiomeric compounds can spontaneously switch chirality (it's actually a big problem for some extremophile bacteria - they replicate so slowly because they have to expend energy to repair damage from racemization).
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According to this article ( http://asunews.asu.edu/20080229_pizzarello [asu.edu]), an un-contaminated meteorite was was found to have amino acids with mixed chirality, but with a bias towards the left-handed (up to 15%), not the 50%-50% suggested in the article linked in the submission. So to some extent, this supports what you said.
Even so, the technique described in the submitted article could work. It's all about signal to noise. If some feature of a planet reflects vastly more chiral bias than a rocky moon or aste
Life Jim, but not as we know it! (Score:5, Informative)
First, for those who are wondering "What the heck is chirality?". So, you have left handed gloves and right handed gloves, and you can't transform one into the other without doing something like flipping it through a fourth spatial dimension (strangely, flipping it through the time dimension will result in an opposite handed glove traveling backwards in time that's made of antimatter) or turning it inside out. Proteins, also being three dimensional objects, are the same way. And there is a convention for deciding whether a given molecule is right or left handed. Chemical processes tend to produce equal numbers of left and right handed versions. Biological processes on earth tend to produce almost exclusively right handed molecules.
I didn't know this before reading the article, but it makes sense... the chirality of a molecule apparently affects the polarity of the light that is reflected from it or transmitted through it.
Now, to talk about what I think of the article...
Scientists make too many assumptions. Life requires self-replication... that's it. It doesn't require water and it doesn't require chirality. It doesn't require a whole host of things that scientists tend to assume it requires simply because it's a characteristic we've observed about life on earth.
But, I will agree that if they can detect the predominance of one particular chirality then that's a strong indicator of some life-like process at work.
That absence of chirality is no indicator that there isn't life. It just won't resemble the life we have here on earth.
It may be possible to prove that self-replication within a given system (like chemistry, for example) is very hard without certain conditions. I'm willing to believe, for example, that non-carbon based life that primarily functions chemically is highly unlikely because carbon is such a fantastically versatile atom chemically speaking.
Of course, there might be life based on nuclear processes [wikipedia.org] or, even farther fetched, life based on gravitational processes. As support for the second, galaxies have a very complex lifecycle in which supernovas and black holes play key roles. They eat the thin gas left over from the big bang, and metabolize it into new stars with supernovas and black holes. I'm not sure where self-replication fits into that picture so galaxies may just be metabolism absent a mechanism for self-replication (i.e. engines) and hence not really alive.
Life based on nuclear processes or gravity is certainly not going to exhibit any chirality signature, nor require water or even carbon.
But, as I said, I will agree that a chirality signature is strong evidence for chemistry based life. I just don't think its absence is strong evidence against life.
Re: Oops! (Score:2)
Further research shows that I'm wrong about the chirality of life on earth. Apparently left and right handed aren't used as such in biology. Amino acids, and hence proteins have L- chirality and sugars have D- chirality [wikipedia.org].
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In Latin, "left" and "right" are "laevus" and "dexter", hence the L and D for left and right handedness.
I think [s]he knew what the L and D stood for... the comment "I was wrong" referred to the statement that "Biological processes on earth tend to produce almost exclusively right handed molecules."
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I'll avoid the obvious pitfall of pointing out that we can't conclusively prove a negative. I think that, at any arbitrary point in the future, we'll either have found non-carbon life, or we'll still be arguing over it's existence. Science fiction of the thirtieth century should be an interesting read :-)
However, we need to look for the carbon-based life first, regardless. We currently have a sample size of one for livable planets, and that tells us next to nothing about the rest of the universe. Is our
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Spoiler Alert
An engineer gets exposed to an intense magnetic field during an accident in a power station. While recovering from his injuries it turns out that he can no longer extract energy from normal human food. The theory is that the field created a volume of four dimensional space within which he rotated before the power was removed. Faced with the prospect of starving to death he agrees to repeat the exposure in the hope that he will get rotated arou
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I disagree, enumerating and testing assumptions is at the core of their job description. They don't have any examples of "life as we don't know it" so they cannot make ANY TESTABLE ASSUMPTIONS about it, if scientists cannot test it then it's NOT science. This probably explains why your dragon's egg link is classified as fiction.
Life requires self-replication... that's it. It doesn't require water and it doesn't require chirality. It doesn't require a whole host o
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Crystals self replicate on the atomic scale so I think your definition requires some work.
This is true. I believe there is a more formal definition out there involving the ability to evolve [wikipedia.org]. But defining exactly what that means can be a bit tricky.
I disagree, enumerating and testing assumptions is at the core of their job description. They don't have any examples of "life as we don't know it" so they cannot make ANY TESTABLE ASSUMPTIONS about it, if scientists cannot test it then it's NOT science. This probably explains why your dragon's egg link is classified as fiction.
...
It's a shame you felt you had to take a poke at scientists since you are obviously an intelligent life form and the rest of your post contains some interesting speculation.
I disagree. For example, I think looking for chirality is a much more general, and a stronger test than looking for water. I think what you want to look for is evidence of complex self-ordered systems.
I do agree that looking for life that's like the life we already have first hand examples of is the easiest thing to do, and probably what we should
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I think you're arguing mostly about language. A scientist, speaking scientifically, uses constrained definitions of words. "Life" in the scientific sense is only what we know on Earth, since science requires evidence and all our evidence of life is here on Earth. And everything we know to be alive on Earth does in fact require water. Thus it is a scientifically supportable statement to say that "life requires water."
That does not make it true...science is not so much concerned with "truth," but with what it
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So, you have left handed gloves and right handed gloves, and you can't transform one into the other without doing something like flipping it through a fourth spatial dimension
Little known fact : that's actually how right hand gloves are made. Turns out that using a fourth spatial dimension is cheaper than machinery to build both types of gloves.
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Little known fact : that's actually how right hand gloves are made. Turns out that using a fourth spatial dimension is cheaper than machinery to build both types of gloves.
That "fourth spatial dimension" actually being kids in sweatshops in China and Malaysia?
This is all well and good, but... (Score:4, Interesting)
If we can't actually go visit any aliens we detect because they are light years away, it is just going to drive us batty.
And I don't really want the aliens coming to visit us either, because that would mean they were more technologically advanced than humans. And the inferior species always seems to end up as food or raw material. Come on, even Hollywood has figured this out!
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But if we detect they're right handed, we can at least be sure they won't eat us (or rather, won't get any nutritional value from eating us :-)
A sufficient, but not necessary condition for life (Score:3, Interesting)
I suppose that if you were to detect chirality bias in the light coming from a particular planet, that would probably be sufficient to conclude that there might be some form of life on that planet that was causing that particular bias. However, it doesn't seem that it's a necessary condition, i.e. not detecting chiral bias might mean that there might after all be some very strange life form on the planet whose chemistry made use of both left and right handed molecules. In fact, there are some strange life forms on Earth, notably archaea [wikipedia.org], that actually use right-handed proteins in some aspects of their biochemistry, quite unlike all other life forms found on earth, which use left-handed proteins exclusively.
Test it on Europa (Score:3, Insightful)
Surely this would be a good test to check out Europa?
Even though the ice crust might obfuscate things, if the light was from reflected from the area of a crevice/crack then there would be elements (or the lack thereof) in the frozen water that give some indication.
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Test it on earth first! Lots of chiral molecules on earth rotate light in one direction. Lots rotate it the other way. So the total rotation is going to be rather small. Furthermore, most molecules (including all of the atmospheric gases) are not chiral. The scientists should start by trying to detect life that's one meter away by measuring optical rotation. I doubt they'll manage. But if they do, then they can move on to longer distances.
For what it's worth, though, the scientists appear to be well aware o
Let Me Guess... (Score:2)
Based on the little-known work of Dr. Peter Pullet-Wildly, it should be possible to detect not just alien life, but alien intelligence. Because if you encounter left-handed rather than right-handed chirality, it feels like somebody else.
Unless you're a southpaw, of course.
Instructions on doing something similar at home... (Score:2)
By using a combination of rice paper and domestic household bleach you can detect if a planet is either Regular or Goofy footed...
A good tool for the toolbox. (Score:2)
I like the idea. It looks like an execellent tool to add to the toolbox for determining the probability of an extrasolar planet harboring an ecosystem.
Of course, an alien ecosystem could have evolved to use both handednesses, but the information that one handedness is predominant on the planet is a strong hint that there's something unusal going on there. Same goes for the detection of unusually large quantities of unstable substances (oxygen, halogens, etc) in the atmosphere of the planet.
Heavy handed approach not working (Score:2)
Using Light's Handedness To Find Alien Life
Because the heavy handed approach we've taken so far is not working?
Oh wait...
Rather thin (Score:2)
That is a very weak cup of tea. For one thing, I can't see what is new in this; we have been able to do this sort of thing for decades. Also, I don't think we would be able to detect life on Earth using this method, let alone another planet lightyears away. The biomass on Earth is actually rather minute compared to the whole of the atmosphere or the oceans, so the signals would be weak, even for our own planet; and there are many things between us and our neighboring stars that could both polarise and depol
The assumption here... (Score:4, Interesting)
...is that life forms a kind of amplification process.
If you have some random soup of molecules formed by abiotic processes then apart from some small biases brought about by parity-violating fundamental physics we expect complete symmetry between left- and right-handed molecules.
But life, arguably, forms a kind of amplification process. Competition between molecules with different chirality might serve to increase any initial small difference between one group and another. So what starts as almost exact symmetry results in a planetwide bias one way or the other.
But there are two issues.
(1) Could such a planetwide bias show up strongly enough in the polarisation of light reflected from the planet. It seems very unlikely given how messy a planet is. Let's say you pick a million different types of molecule than come in chiral pairs and for each molecule pick one of the pair, discarding the other. Now jumble up many different copies of each of these molecule types. Your chances of detecting chirality from afar is minimal even though, in some sense, the mixture is perfectly chiral, because of the overall randomness of the mixture.
(2) Could any other physical processes cause such amplification? The answer is yes. For example some kinds of crystal growth can result in homochirality.
So I'm pretty sceptical despite the idea being neat.
Meteorite organics show chirality (Score:2)
Material from space has already been shown to exhibit chirality. There's quite a nice review on...
http://scienceandreason.blogspot.com/2009/04/amino-acid-chirality.html [blogspot.com]
We do not know that this chirality comes from life. People have presented this as evidence that life exists in space, that life was seeded from space, and all sorts of other stuff. All we actually seem to know is that some stuff out there shows a handedness. If your light is passing through chiral material in space it will pick up a pola
Maybe on Nasa/Esa Darwin project? (Score:5, Interesting)
I requested the full paper but... as we are friday afternoon here in Europe I'll probably get it on Monday ;-)
In the meanwhile, from the abstract I feel this'll be more applicable to say checking remotely life hints in Jupiter's atmosphere here, than getting answers for remote stars tomorrow.
I for one highly doubt, for instance, that just analysing an exoplanet's transit onto its star will bring any measurable polarization. ;-) it'll be very difficult to detect the ppm of added polarization.
Just remember what you see is star light that passed through the planet's *atmosphere*, not reflected onto its ground (and grass/trees).
And as this specific light is moreover buried within the 99,99% of starlight that just didn't cross the planet at all, even with a specifically intense *atmospheric* life (a dense, GREEN atmosphere
Rather, I see this either for
a) a futuristic payload for the (too futuristic) Darwin project from Esa/Nasa ( http://www.esa.int/esaSC/120382_index_0_m.html/ [esa.int] ), when the dozen of years of development (and equal number of euro and dollar billions) will have been invested: if things go well, no more crises, etc., we then will have a way to just switch the starlight off (via destructive interferometry), and see only planet's light.
Then maybe you'll measure polarization. But then you'll also measure specific wavelength absorptions, so get directly to molecules (which is the raison d'être of the Darwin project)
b) as said earlier, maybe in nearer times a way to observe our neighboring planets atmospheres, and suddenly discover they may be polarized (or not, and that check will be quick).
If they were it'd definitely be fun.
In my space factory there is a breadboard of the Darwin nulling interferometric concept. Nifty. Representing maybe 1% of the required development work. But nifty, definitely: capable of switchig off a star light that is millions of times superior to the planet's reflected light and at the same time leave planet's light in, when planet is just the pixel against the star's one. As they say on Esa's site, capable of seeing a candle light stuck against a lighthouse firewindow, from 1000 km away.
Handedness (Score:2)
If we discover life that is of opposite handedness to the life on this planet, then they wouldn't be able to eat us. :(
On the other hand we wouldn't be able to eat them
but on the gripping hand thry could still hunt us for sport. (or we could hunt them for sport.)
Danger, Will Robinson?! (Score:2)
Handing Out Assumptions (Score:2)
"If the [planet's] surface had just a collection of random chiral molecules, half would go left, half right," Germer says. "But life's self-assembly means they all would go one way. It's hard to imagine a planet's surface exhibiting handedness without the presence of self assembly."
He's not talking about life, he's talking about Earth life. We have only one data point to go by, which is too little to draw generalities from.
It is perfectly plausible that a biosphere could be bichiral. There could be parallel
The joke is on you astronomers! says the Zorrans (Score:2)
But does self-assembly mean life? (Score:2)
I agree that chirality implies some kind of autocatalytic process to amplify weak natural chiral bias or statistical fluctuations, but I don't agree that it is diagnostic for life. After all, crystals self-assemble, so a planet dominated by large crystal structures could be highly chiral.
Self-assembly is only part of the definition of life--there also needs to be mutation, and the mutation has to affect the propagation of subsequent generations.
Re:How about earth? (Score:5, Informative)
What 'handedness' is earth? I think that because of the vast amount of life on our planet, the handedness would be (statistically speaking) about the same in both direction
As far as I know, all known life on earth is left handed (i.e. built from left handed amino acids)
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Oops, I've said too mu[NO CARRIER]
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As far as I know, all known life on earth is left handed (i.e. built from left handed amino acids)
When I read the GP, I jokingly thought to myself, we are inherently evil so we must follow the Left Hand Path.
Funny to see life on this planet is actually wired for evil.
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The other left, of course.
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[Laughs] Right, kick ass. Well, don't want to sound like a dick or nothin', but, ah... it says on your chart that you're fucked up. Ah, you talk like a fag, and your shit's all retarded. ...
Don't worry scrote! There are plenty of 'tards out there living really kick ass lives. My first wife was 'tarded. She's a pilot now.
I thought it was a hilarious movie : )
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What 'handedness' is earth? I think that because of the vast amount of life on our planet, the handedness would be (statistically speaking) about the same in both directions. According to the article, the handedness gets inherited from parents but it doesn't make clear whether or not it is the same for all life forms.
The last several articles that interested me also did a terrible job of actually explaining anything. It's surprising that some of the information omitted consists of very basic details that are directly related to the headline. I hope this isn't the beginning of a trend; infotainment and the average press release have done enough damage to journalism already.
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However, I'm surprised to learn we collect enough light from a planet to be able to aut
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Why is that obvious? It seems obvious that left and right handed molecules should be useful for different things like the Z and S blocks in Tetris, but why should one be discarded entirely?
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It's possible it arose twice and both happened to be left-handed, of course...
That's interesting. I wouldn't be too surprised to find a very localized think like Archaea that could be traced to a different source. (Well I would be surprised, but I wouldn't be "That's impossible surprised")
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The answer is that two mirror image mollecules won't necessarily fit into the same chemical receptor (think Tetris), and therefore have different biochemical effects.
Codene is actually the stereoisomer of heroin, but it doesn't fit most of our receptors so appears mostly inert.
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What 'handedness' is earth?
I have no idea. But I'm not sure it matters. Even if Earth was perfectly neutral the method still works. If the presumption is true then any planet significantly away from average would indicate life. Even if it wouldn't find planets with life that were average.
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I have no idea, but I'm not sure it matters. The method still works even if Earth is perfectly neutral--if the presumption is true then any planet that deviates significantly from the average must have life; although, those planets might not be typical of ones with life.
Re:How about earth? (Score:5, Informative)
Life on earth exhibits a specific "handedness" or chirality. All DNA twists the same way, for example. Apparently the term for this is homochirality.
http://en.wikipedia.org/wiki/Homochirality [wikipedia.org]
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Actually there are forms of DNA that twist in a right handed manner and a left handed manner [wikipedia.org]. But of course that has little to do with chirality.
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Life on earth exhibits a specific "handedness" or chirality. All DNA twists the same way, for example. Apparently the term for this is homochirality.
Sounds kinda gay to me.
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Think of the movie War of the Worlds. Dropping yourself into another inhabited planet would probably be a death sentence as your body would have no resistance to the kinds of viruses and bacteria that live there. But could having opposite chirality make you immune to their effects?
Re:How about earth? (Score:4, Informative)
This is the basis for creating artificial sweeteners. Sucralose contains mostly dextrose, which is a mirror image of glucose. They have the same chemical formula, but since it's of the opposite chirality of all the other structures in your body it's unable to be metabolized.
The body can metabolize dextrose (d-glucose) just fine (in fact, it's the l-glucose that the body cannot metabolize). Sucralose, on the other hand, is a different molecule since it contains chlorine atoms in some of the places where sucrose contains HO groups. Sucralose is also about 600 times sweeter than sucrose.
Evolution and Intelligent Design are both false? (Score:2)
If life evolved from simpler forms then one would expect each species to inherit the handedness of its ancestors, all the way to the very first living being.
OTOH, if life was designed by a creator, then one would expect that creator to have some preference for one handedness over the other.
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OTOH, if life was designed by a creator, then one would expect that creator to have some preference for one handedness over the other.
Why would you expect that?
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Converting food sources (proteins, molecules) from left-handedness to right-handedness and vice versa is going to take more energy than just having the same handedness as the food source. Whichever food source became dominant would eventually force everything else up the food chain to have the same handedness. In the end, everything would flip to one state or the other.
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Smells of a "fund me, or PhD me" non-story.
Also possible: "Buy my freaking huge flashlights!"
Anyway, I guess a star would work as a light source to.
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Actually, rough guess here of course (IANAPHD on the subject), I don't think that's the main problem.
Detecting light reflected from a planet at any interstellar distance is a bigger hurdle. We still mainly detect extrasolar planets indirectly, either by gravitational effects, or by occlusion. (For the curious, this is also where the bias in favour of detecting very large planets arises; the bigger they are, the easier these methods can be used to find them.)
Detecting light from a planet is a pain, since t
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Transit.
As a planet passes between us and the star some (very) small amount of light from the star passes through its atmosphere, including incident grazing of the surface. If/when the detectors on a space telescope are sensitive enough, then, during transit they may detect a change in the distribution of polarization. This may also be easier when the transit is either just beginning or just ending, since the main source of light will be mostly "to the side" of the planet.
As the sensor density increases,
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The habitable zone is not fixed in stone, we could perhaps find life outside of it. It would be worth examining chirality for any planet. Still, not much can be done until advances in astronomy let us get a decent view of these exoplanets.
Venus and Mars are 9 light years away? (Score:2)
When did that happen and why wasn't I informed about it?
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When did that happen
Yesterday.
and why wasn't I informed about it?
Well, if they're 9ly away, then the signal will take another years to get here, of course.
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It happened less than 9 years ago, which is also why you haven't been informed yet.
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Parent is abrasive, but I think his point is probably correct.
I'm not an astronomer - but I'm a biologist and we do circular dichroism measurements on biological samples (wikipedia article is good enough: http://en.wikipedia.org/wiki/Circular_Dichromism [wikipedia.org]).
The notion that you could detect these signals from an exoplanet lightyears away - given that we can't, at the moment, detect light from such planets at all - strikes me as somewhere between far fetched and complete bullshit.
On the
PSST! (Score:2)
Sounds little early to be news.
One of the points of "the news" concept is the delivery of the information as early as possible and as soon as it happens.
That is one of the reasons we call it "the news" and not "the olds".