Slashdot Mirror
Meteorites May Have Delivered Seeds of Life On Earth
esocid writes "At the national meeting of the American Chemical Society, scientists presented evidence today that desert heat, a little water, and meteorite impacts may have been enough to cook up one of the first prerequisites for life. The result of that brew could be the dominance of "left-handed" amino acids, the building blocks of life on this planet. Chains of amino acids make up the protein found in people, plants, and all other forms of life on Earth. There are two orientations of amino acids, left and right, which mirror each other in the same way your hands do. These amino acids "seeds" formed in interstellar space, possibly on asteroids as they careened through space. At the outset, they have equal amounts of left and right-handed amino acids. But as these rocks soar past neutron stars, their light rays trigger the selective destruction of one form of amino acid."
We discussed something similar to this here where they found organic molecules in a Canadian meteor.
My work here is dung.
It's the "Invasion of the left handed amino acids" - Ahhhhhhhhhhh
It means that there is only a 50% chance we are edible for aliens!
I have a feeling a creation vs. evolution flamewar is about to start. Creationists will be creationists, but everyone else just think for a second:
If you were an average joe, not even a stupid joe but an average joe, which honestly sounds more convincing: 1) A supreme being did it, or 2) blah blah amino acids blah blah meteorites blah blah neutron star light rays blah blah?
So y'know, take it easy on the creationists. They may not understand how science works, but when faced with an article like this, can you really blame them?
The United States of America: We do what we must because we can.
The idea of panspermia and exogenesis has been around since 1743. Scientists have only found circumstantial evidence rather than empirical proof that life does get spread throughout the universe by tenaciously clinging to rocks which may or may not survive re-entry.
Nope, I'm pretty sure that was John Holmes. Next question?
Makes sense in a way: the meteors are sperm, the Earth the egg, the orbital bombardment the BDSM.
Hail Eris, full of mischief...
E pluribus sanguinem
It sure sounds like it.
Interesting read. It has been one of the more pressing questions of the theory of biogenesis: where did the first organic matter come from? I have always found chirality and the left-handed nature of Earth's proteins to be more than mere coincidence.
It is strange that our location in the galaxy led to a slight imbalance in the amount of gravitationally polarized light striking chunks of rock and metal floating in a cosmic dance 4 billion years before I was born....yet that combination of factors resulted in the alanine in my body to contain only the left-handed chiral.
Studies like this are the cause of my personal religious dilemma. Most of the major religions came about 1500-5000 years ago...and at the time they were conceived, they convincingly explained every natural occurrence well enough to placate the masses. I wonder what the Pope would have to say about this study...was God a southpaw??
khasim (12/9/06): In a blind taste test, more people preferred Coke over the Pepsi that I had previously pissed in.
Wow, the farmers must have had a gala time back then, trying to figure out how to sow the new seeds :D
Mother Earth, you ignorant slut, you obviously picked some bad seeds.
No comprende? Let me type that a little slower for you...
This is what happens when you push your Ph.D so far into one direction that you lack basic understanding of other fields. Symmetry-breaking happens all the time in non-linear systems, it doesn't require an external mechanism.
The fact that meterorite showers brought life to our planet is no mystery to me. See, I lived in Smallville for a while and I've seen things you wouldn't believe.
- Chloe Sullivan
On a chemical level, life is mostly a whole mass of chemical chain reactions that form closed loops of events that (directly or indirectly) spread into multiple copies like glider-replicators in a game of life. A right-handed compound and a left-handed compound won't interact the same way ... so as the chain reaction "replicates", only one form gets passed on. That there would be a chirality bias is not surprising. On the contrary, I would say that it is the expected situation.
.. reminded of how Tiberium arrived on Earth?
"Money shot" joke goes here.
Have gnu, will travel.
"All earthbound meteors catch an excess of one of the two polarized rays." [which are generated by neutron stars]
Doesn't this imply that there is a neutron star somewhere in the immediate vicinity of Earth that's zapping all our incoming meteors? Wouldn't we, um, notice?
I mean, neutron stars are pretty rare things (~2000 known in our galaxy, nearest known is 280 lt/yrs away). I find it improbable that a significant majority of the incoming material has passed by one at some point in its life.
How did life start is the key question, not where. The earth is an ideal place, lots of water and a long-lived sun. Why left-handed, maybe the just one first "living thing", molecule, whatever started it all. In a similar vein, why matter not anti-matter universe I believe is still up in the air.
Now that we know that life as we know it sprang from meteorite-sperm, we owe it to the rest of the Universe to immediately deploy Dyson condoms.
Someone correct me if I'm wrong, but I was under the impression that the left-handed chirality bias had already been explained by the non-conservation of parity in the electroweak force. The L enantiomers have a slightly lower binding energy, so in any mole of racemic amino acids you'll have about a million excess on the L side, which is enough to tip the balance.
-- Insert witty one-liner here. --
Is this science or fantasy? Am I to believe that amino acids somehow formed on an asteroid (magic must happen) then, within the vastness of space, managed to soar passed some neutron stars without getting sucked in, and then, found its way to Earth, survived entry into the atmosphere and produced life?
Gravity polarized light? You need to shut up and do some research.
Debian FTW
This gives the expression "You're out of this world" a new meaning.
This is only "evidence," of course, and evidence can be brought on both sides of any case.
On the other hand (perhaps I should read the article, correct me if I'm wrong), it does not appear to mention the huge step between having amino acid chains laying around and having them actually form a living cell organism. There's a huge difference between a pile of blocks and an actual functioning structure. Which is why, in old times, if your city got conquered, they "leveled" it. They knocked everything over. A pile of amino acids is like a pile of rocks...
Try this: age of universe - age of earth / chances of amino acids surviving cosmic rays X when life began on earth = earth is probably the one spreading amino acids.
Agreed - delivery of aminos is not delivery of life. I was going to make that point, but I gave the Slashdot crowd the benefit of the doubt that they would see it that way too. +1 to you, good sir.
khasim (12/9/06): In a blind taste test, more people preferred Coke over the Pepsi that I had previously pissed in.
Cumshot by meteorite. What a way to die. I am pretty baked still..
Orbis terrarum est non altus satis
OK, gotta bare my soul on this one (and luckily that's all I'm baring...).
The thought that some meteorite from a distant star seeded life on earth just kicks me. A few days ago the Discover channel aired a documentary about black holes and supernovas. At some point it mentioned that our Sun too would eventually go boom and swallow the earth as some guy sips a drink at a Restaurant at the End of.. no never mind... OK, maybe it will go dark and the earth freezes over. Robert Frost is somewhere chuckling I'd guess...
Now maybe it's all been misinterpreted. Maybe life began here as the product of some freak lightning striking the just-so-right soup of chemicals. Among billions of worlds, maybe life is not the exception but the rule.
But I can't get over the idea of this lone meteor crossing these IMMENSE GULFS OF TIME AND SPACE (said in the best Marlon Brando rumble I could command)... Maybe some alien civilization realized that their world was doomed and they sent this rock across the galaxy to find Picard and whisper to him secrets of a lost world.
Maybe it's a code from some godlike programmer... the Great Woz in the Sky.. The unchanging midichlorians.. sorry.. mitochondria actually some code to unlocking the secrets of the 'Verse.
Or Verse.. like in some Holy Book verse.. Could be a secret code... oh wait sorry, about 4.6 billion years too late...
Sh*t. All I really wanted to say was that I wish I had a space ship.
A space ship with laser cannons.
And photon torpedoes.
And a holodeck. Yeah, can't forget the holodeck.
I love these far-thrown theories.
Personally, I think it is turtles. Yup, all the way down.
This issue is a bit more complicated than you think.
Now shut up or I will kill you and declare jihad on your family for a thousand years!
Coincidently, written records go back to ~5000-6000 years ago, and the world is a red state.
XML causes global warming.
Where did those amino acids come from?
Engineering is the art of compromise.
something Mr. Roddenberry should consider polishing/updating in his original "star trek" series...the title sequence narration......from "Space the final frontier" to "Space hello honey I'm home"
Don't you know that ITT people who aren't creationists disprove creationism to other people who aren't creationists?
I'm not sure left handedness needs such a far fetched explanation. It makes sense for cells to pick one handedness or another, otherwise they need twice the machinery. And there are plenty of pathways that connect different amino acids and other compounds, so if one of them is left handed, chances are most of the rest are as well. And which handedness it ended up being may just have been chance.
I have long been a fan of the ideas presented in the book Genetic Takeover, but it always seems the science media is all about meteorites and Mars; I'm not sure if this is a product of the book being dated or the science media being no better than the regular media.
However, "where did the first organic matter come from" is a no brainer. There are what, 6 * 10^23 carbon atoms in a mole (roughly 16g) of methane, the simplest organic, so imagine the number in the atmosphere of the early Earth because I can't be bothered to extrapolate to billions of tonnes. We already know that graphite spontaneously occurs in nanotubes, buckyballs and now graphene, so suitable structures for collecting random small molecules by hydrogen bonding already exist. (Add many similar structures that occur in clays.) So we have an enormous number of potential small molecules getting together on substrates that will tend to align them under the wide variety of conditions of the early earth and, initially, no predators to eat them up as soon as they appear. Given this almost infinite improbability drive, the appearance of more complex organics is hardly surprising.
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
So I'll guess at the scientific origin of life: take the two most organic, chemically active elements and collide them. A meteor hit into the ocean and landed against an undersea volcanic vent. Even if we have no evidence that this is how life formed, just imagine all the chemical reactions and elements that came together when this (statistically likely) happened (at some point in the past).
stuff |
I don't see much discourse on that subject in the scientific media.
You mean in popular scientific media. The origin of the first life is a very hot topic amongst those in biological disciplines, and there are several competing theories. I suggest you start with a bit of reading on Abiogenesis on Wikipedia. You'll find quite a few relevant citations as well as a discussion of past and current models.
It is strange that our location in the galaxy led to a slight imbalance in the amount of gravitationally polarized light striking chunks of rock and metal floating in a cosmic dance 4 billion years before I was born...
That's great for you, but what about the rest of us?!
Comment of the year
Earth may have delivered death to meteorites.
I've often heard it joked about when discussing what a proper religion would be, some saying "Ok, now this is a religion I as an atheist could believe in." There's the old scifi story about the super-computer built to answer the ultimate question. They power it on and ask it "Is there a God?" It whirls and chirps and in a thundering voice replies "There is now." If we survive the next hundred years and keep up our pace of technological advancement, we could well see something like the technological singularity. I could well imagine scientists of the future shaking their heads at the continued lack of evidence for a God or gods and decide to step into the void themselves, ending hunger, death, and suffering. A post-scarcity economy, they would call it. It remains to be seen whether we'd get fluffy cloud heaven as the Christian religion postulates or asshole jerk-god heaven such as with Olympus and Asgard.
Kwisatz Haderach
Sell the spice to CHOAM
This Mahdi took Shaddam's Throne
You're right: this topic has been kicked around for a while. I remember as a grad student listening to talks about parity-violating energy differences between enantiomers "explaining" why biomolecules have one handedness over the other.
It occurred to me at the time that the handedness of life doesn't need an explanation. It had to be one handedness or the other; there's no way for a symmetric system to function, and no way for two systems of opposite handedness to coexist. One would always outcompete the other for resources, if not through physical advantage, then through contingency.
So do we really need to have a dynamical explanation of a binary outcome with (at worst) a 50-50 probability, when the symmetry would break spontaneously in any case? Is it useful to say that the reason a one-time coin flip was tails is because the coin was ever so slightly weighted to favor that outcome?
You were born 0.6 billion years ago? What's the secret to such a long life?
Sorry, couldn't resist...
They still can't explain, and can't even understand or decode (yet) the operating system with error correction and compression, and the instruction sets for life. Without that, all you have are raw materials.
religious imagery? to me it would appear more like fractal imagery. A pattern in nature is replicated all the way up from a biological viewpoint to an astronomical viewpoint.
http://pdphoto.org/PictureDetail.php?pg=8232
You've missed the bigger problem: if this is a scientific experiment, where's the control? It's not proper application of the scientific method unless she isolated a variables using a control. Unless she had a second jar, and prayed for her deity to create life there, and life was created for her, I'm not buying it.
I would make her repeat the experiment with a control. Then when she got back I'd ask her how one designs a double-blind experiment when God is involved.
This does not conflict with my belief in Pastafarianism. What you call a "meteorite", I call a spicy meatball of life. What you call "amino acids", I call blessed noodles.
Even the picture in TFA resembles Him in all His noodley goodness!
Indeed, about all enzymes are chiral, and if a living creature produces an amino acid, enzymes are likely to be involved. So why would amino acids be racemic?
The effects of competition are even more pronounced in the case of RNA versus DNA: though both make viable self-replicating independent biopolymers, and even though (we think) RNA was the first one found in life on Earth, DNA out-competed it and became the dominant life form. (In this case though, the competitors were not mutually exclusive as with molecular chirality, but compatible and largely redundant. Modern life forms use DNA and RNA, but this isn't strictly necessary.)
Where do people come up with this sh**?!