Are we aliens? This question has come up due to a new result from studying meteorites, and is getting a lot of web-chatter. I figure I’d better get on this sooner rather than later!
First, the science. Then the chatter. Finally, the caution flag. 
The Science:
Some meteorites have been found to contain some relatively complicated organic compounds, including molecules that are components of amino acids, the building blocks of life. For example, the Murchison meteorite, which fell on Australia in 1969, has been found to contain purines and pyrimidines, which are crucial to a large number of biological molecules like DNA, RNA, and ATP (adenosine triphosophate, a chemical our cells use for fuel).
Now, you have to be careful. A meteorite might have had these molecules in it before it slammed into the Earth, or it may have absorbed them from the ground after impact. One way to tell the difference is to look at isotopes of the elements. An element like carbon usually has 6 protons and 6 neutrons in its nucleus, but an isotope is when the number of neutrons is different. Carbon 13, as an example, has 6 protons and 7 neutrons in the nucleus (the number of protons determines the chemical properties, so carbon 13 is still like carbon, though a tad heavier).
The ratio of isotopes in a sample can be different for objects in space versus on Earth. Various process can change the ratio, so that’s a good way to find out if these molecules are native to a meteorite, or if it was contaminated after it fell.
OK, that’s the primer. Now the good part: scientists studying the Murchison meteorite have determined that the purines and pyrimidines — specifically, uracil and xanthine — have a non-terrestrial origin. In other words, the molecules in this meteorite, so crucial for life, were actually formed in outer space and fell to Earth.
That is very, very cool.
So this means that the some of the basic building blocks of life formed out in space, and came to Earth via meteorites and, presumably, comets.
Note that "some of". That’s important. Because…
The Chatter:
This news is being picked up all over the blogosphere and news sites, of course. We’re aliens! lots of people are saying. I’m quite sure the panspermia folks are having nerdgasms over this news as well.
Well, I hate to throw some cold H2O on all this, but I’m gonna. Just a little, a few drops. I think this is big news, and extremely awesome, but I want to make sure people don’t take it farther than the evidence suggests.
The Caution Flag:
Let’s take a step back and see what this new finding really tells us. First of all, I have little reason to doubt the results — of course as a scientist I reserve some skepticism, but let’s assume the team was on the money and the results are accurate. (I don’t have access to the journal paper, sadly, but I’ll dig around and see if anyone else does) (I have the paper now; thanks to Preston Hart and Stan Gunn!).
So the Murchison meteorite has native chemicals in it that are the basis for life. Obviously, since they were found at all, that means they survived entry into our atmosphere and impact. This in turn means that in the distant past, when the Earth was bombarded by such rocks, these chemicals were scattered across the planet, where they could be incorporated into ever more complex molecules, which eventually became life. And, well, us.
Well, cool. And even, wow! It’s been hypothesized for years, decades, that the basis of organic chemistry may have fallen to Earth from space. And now we know that it’s true.
However, that does not mean that all of these chemicals came from space! Transport yourself back a few billion years. The Earth has just suffered a several hundred million year bombardment period, getting the crap pummeled out of it by impacts. But that finally ended, and the crust started to cool. The trickle of impacts that continued — some of which contained the organic compounds — fall to Earth. If they fall into a hostile environment, they’ll get destroyed, of course? But if the environment is not hostile to them, then it’s also possible these compounds could have formed right here, on Earth! It may be easier for them to form in space, where conditions may have been better, but that doesn’t preclude them forming here.
So it’s still possible that even though these compounds fell to Earth after the Earth settled down, it’s also possible the majority of such compounds formed right here, in situ. The original molecules are long, long gone, so we cannot test them for isotopes. There may yet be some way of determining if life actually formed from space compounds or from terrestrial ones, but right now I don’t think there is — I haven’t heard of one, at least.
So what these new results show is that life here might have formed from compounds that fell from space. It may even be likely. But it’s not rock-solid fact. As the scientists say on the abstract of their paper (emphasis mine):
These new results demonstrate that organic compounds, which are components of the genetic code in modern biochemistry, were already present in the early solar system and may have played a key role in life’s origin.
To be even more broad, and to stop any extrapolation here, this also does not mean that life itself formed in space and fell here. We’re only talking building blocks here, not viruses, RNA, DNA, or bacteria. Just chemicals.
There is a group of folks who claim that every unexplained molecule must have fallen from space. Panspermia is a cool idea, and may even be right — but the group at Cardiff (founded by Hoyle and Wickramasinghe) make outrageous claims about bacteria and viruses from space, with almost no real supporting evidence that I have seen.
So you have to be careful to not fall into a "God of the gaps" argument: because we can’t explain something now, that doesn’t mean it must be due to some supernatural (or extremely unlikely) cause. That’s a bad path to follow, because eventually someone will fill that gap with evidence, and then your supernatural cause gets squeezed out. For example, creationists say that the eye could not have evolved, therefore God did it. But now we understand pretty well how the eye evolved, and the creationist’s explanation looks silly. They found a gap in knowledge, proclaimed a supernatural explanation, and it turned out to be natural after all.
I put panspermia into that category for the moment. While there is some real science, and really interesting science, to pursue there, it’s not a panacea for all things biologica-ex-nihilo.
The Conclusion:
So here are the big points:
1) Researchers have found that some molecules which are the basis for life on Earth can have an extraterrestrial origin.
2) These molecules survived their impact with Earth.
3) These alien molecules may have been crucial to the development of life on Earth.
4) These needed building blocks of life may have also been formed right here on Earth, so we can’t fly off the handle.
5) Intact life from space — bacteria, viruses, and such — is still just an idea, with no credible supporting evidence.
But the really big point is that this is an amazing and wonderful discovery! It is entirely possible that life here — or at least the necessary components of it — began out there. This is one of those discoveries that makes you think, and sparks discussion, and also just happens to have some profound philosophical ramifications. I’m in favor of all three of those things!
So remember, when you go outside at night and look up, the sky is filled with far more than just the stars you see. Our future is up there, and our past. And, not incidentally, our present as well.
June 14th, 2008 at 1:15 pm
“It is entirely possible that life here — or at least the necessary components of it — began out there.”
Wow, I just had a childhood flashback of the original 1978 BSG…haha
June 14th, 2008 at 1:25 pm
Nerdgasm: Everytime a nerd goes, “Ohhhhhh cool!”
See also Galactigasm: Everytime a BSG fan says, Ohhhhhh Frak Me! Known to occur multiple times an hour during viewing.
June 14th, 2008 at 1:27 pm
Well, yeah.
June 14th, 2008 at 1:41 pm
That would explain this little guy, looking for his daddy:
moar funny pictures
June 14th, 2008 at 1:42 pm
I doubt it. I don’t see how meteorites could impart high enough quantities of essential chemical compounds.
Also, DNA bases are fairly simple compounds. They should be fairly often synthesized during lightning strikes and during cosmic ray impacts of nitrogen-rich materials.
June 14th, 2008 at 1:46 pm
Personally, I think the distinction is irrelevant. Whether life formed out in space or down on Earth, we’re still left with the question of how it formed in the first place.
June 14th, 2008 at 1:50 pm
An experiment on a Russian rocket was used to see if microbes could make it back to Earth. A paper was written. I’ve read it, I’m sure i got it on the web somewhere, but can’t locate it at the moment.
June 14th, 2008 at 2:00 pm
I honestly see this as a distinction without a difference. Earth was formed from raw materials from space. All the water on Earth likely came from comets and other water-bearing stuff crashing into us. We’re made up of that “alien” water, too.
June 14th, 2008 at 2:10 pm
ive never understood the claim to say life began “out there”. well duhhh, this whole planet “began” out there then more stuff fell on it, that stuff was rich in carbon compounds, then the energies of the early earth mixed it up into a self substaining chemical reaction we call life
or is it that they think life began in comets?!
who knows, but i think with the profusion of energy that molecules were subjected to on the earths surface it all began down here, or even subsurface with undersea vents.
though i have to nag jason on one thing “Earth was formed from raw materials from space”. the distinction that the earth is serperate from space is an all to common phrase, we are in and of space, just we think it being seperated cuase we have an atmosphere
June 14th, 2008 at 2:20 pm
OMG! You mean that life on this planet could be made out of stuff that wasn’t from Earth originally?!? We’re aliens!!!
June 14th, 2008 at 2:22 pm
Is it bad that I see the phrase “the group at Cardiff” and think, “Oh great, what’s Torchwood up to now?”
June 14th, 2008 at 2:30 pm
Oh marsh, I thought the same thing…
June 14th, 2008 at 2:41 pm
The full research paper is available, for a price, here … http://is.gd/xwF
Similar information is found in these papers, but they date back years … http://is.gd/xwo … http://is.gd/xwr
June 14th, 2008 at 2:43 pm
Bacterial spores can cross space and survive high impact events. This seems an unlikely trait for life that evolved here on Earth and a likely trait for life that spread here from beyond.
Anyways it makes scenarios like Star Wars, Star Trek and Farscape that much more likely – lots of compatible alien life. So panspermia gets my vote! …until more evidence comes in…
June 14th, 2008 at 2:48 pm
Well, the problem here is that the “origin of life” is not a problem but a sequence of problems. Or a sequence of questions-answers if you prefer:
1- pre-biotic origin of simple organic molecules such as adenin, ribose, aminoacids, etc.
2- pre-biotic ensamblage of simple organic molecules on polymeric macromolecules (peptides, nucleic acids).
3- adquisition of metabolism and evolutionary capabilities of macromolecule ensamblages: the origin of first proto-cells.
4- etc.
It’s not exactly to accept panspermia for the first step than accepting it for the third one.
And, obviously, panspermia does not solve the “origin of life” problem. Simply, it takes the question off the Earth to pre-existing planets.
Moreover, the “we” in the “are we aliens?” deserves consideration. For most people, we are “we humans” or, even, “we Americans”. But, for BABlogger “we” is “we earthlings” or “we living beings from planet Earth”. Anyway, if our chemical o biological origin is placed on the primeval Earth, we must not forget that the origins of Earth are literally “extraterrestrial”. Any nucleon we are made of has its ultimate origin in the Big Bang.
June 14th, 2008 at 2:50 pm
Ok, John.
But Star Trek scenarios do not only suppose “bacterial panspermia”. They suppose panspermia for primates, because Vulcanians, for example, are clearly an hominid lineage. And I think that “hominid panspermia” is a hard think if you lack of the proper technology to interstellar travel.
June 14th, 2008 at 2:51 pm
I think you’re point #4 is the most important one. I mean, if we find silica in a meteorite, does that mean that all of the silica on Earth came from space?
Oh wait, bad example.
But the real question is how much of the precursors of life were synthesized in space, and how much on Earth.
June 14th, 2008 at 3:06 pm
At the level at which it’s being reported, this story isn’t really news, either. Murchison has been well-studied, and of course that includes investigating the provenance of its organics. It was recovered quickly after its fall, and its stereoisomeric organics are in roughly (but, interestingly, not exactly) equal mounts of their enantiomers, implying a non-biological origin.
So this story ought to be something like “You know that meteorite, which contains organic molecules, including DNA bases, that we were pretty sure came from space? Well, scientists have done another test, which means that we are now even more sure that the DNA bases came from space.”
As to why it isn’t being reported that way, I leave to the black-stained conscience of academic press officers to explain.
June 14th, 2008 at 3:25 pm
First, you deserve epic kudos for the archaic BSG reference.
Second, that sound pretty interesing. It would open up some interesting options for life on other planets, as well as new ideas for abiogenesis. IANAB, but I’m guessing zero-g and such offer novel conditions for creating those first few chemical mixes.
And, if the chunk came from somewhere that had life, it eases the probability boundaries a little. If you have multiple planets “creating” life that can spread “by itself”, it increases the odds of life on any suitable planet.
And, there’s the extremely cool possibility of it being a “seed pod” for some alien race out there. It’s one way of spreading life, instead of a handful of ships with genes, send out a billion asteroids with potential genetic material. If you don’t want to be alone, spread some life.
June 14th, 2008 at 3:59 pm
This is not exactly news. Nor is Murchison the only carbonaceous chondrite to be intensively studied. The Orgueil meteorite is a carbonaceous chondrite that fell in France in 1864. It has been studied extensively. A 2001 study found that according to carbon isotopic data its carbon was extraterrestrial and nonbiological. Almost all of the amino acids were very simple ones like glycine and alanine.
http://www.spacedaily.com/news/life-01g.html
Panspermia is dead in the water and has been for some time.
June 14th, 2008 at 4:01 pm
All this is interesting, but not that notable. We’re from space no matter how you slice it. We’re IN space, just on the earth. People have been tossing around the “Heavy elements are created in supernovas – we’re starstuff” adage for years.
It’s equally plausible that an alien spaceship dumped their septic tank on the primordial earth and that’s what we came from – it’s crude, but isn’t that argument as to why we send our probes to space as clean as possible? Why we sent Gallileo into Jupiter rather than leaving it in orbit? And those were little microbes!
The big question is were does life originate in the first place – it doesn’t doesn’t matter how cells can be transported by asteroids or living creatures – how did the alpha call begin?
June 14th, 2008 at 4:02 pm
Above – “cell” not “call”.
June 14th, 2008 at 4:09 pm
One thing to add: Miller-Urey. Does this mean life was created or seeded by professors at the University of Chicago? Obviously not.
Sure, building blocks came from space, but if they form in space, they can form down here too. then there’s no guarantee that they will Perhaps in even greater quantities.
Don’t get me wrong, if life on earth was seeded by comets, great. This isn’t exactly definitive proof.
It’s all interesting from the scientific perspective of possibility, but before we accuse the media of mishandling things remember that the editors often write the headlines for sensationalism, but the story below may be perfectly accurate.
June 14th, 2008 at 4:20 pm
A good URL for Murchison is at:
http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=375
June 14th, 2008 at 4:35 pm
Here’s something cool I just realized.
Hard sci/fi authors now have material for panspermia-based story lines!
No really! This is great news! Hard sf needs new discoveries in order to appeal to their readership. Now it’s up to the wordsmiths to
1. create a hypothetical, NON-HUMAN (chrissake) civilization several billion years ago
2. who realize that the end of their star’s life cycle is about to end in a supernova
3. and have scattered themselves to the outermost reaches of their star system (no FTL stuff)
4. Those at a distance still die but their goop isn’t vaporized. Bodies torn apart, sure, but scraps trapped within melted chunks of Plutoids pushed into interstellar space by the shockwave along with material thrown out from their parent star to become
6. a stellar nursery billions of years later from which the Sun and its siblings are born.
Wouldn’t be that difficult to imagine those initial building blocks firing up the life systems of sibling stars scattered across the galaxy over time, their trials and tribulations as they encounter stuff that I’m guessing is in Phil’s next book and maybe one or two that figure out where they came from.
The most difficult part of making up stuff like this (for me anyway) is the biological component. Might as well try to describe an entire game of chess before the first piece is moved.
We’re all made of stuff that came from the inside of stars. That’s a given. Explosions, though, aren’t neat and clean. Maybe some body parts flew out in the form of a molecular mist.
Again, all that is fiction but fun to think about.
June 14th, 2008 at 4:36 pm
Awesome post.
June 14th, 2008 at 4:43 pm
I just popped a vein.
“CSI: Milkey Way”
June 14th, 2008 at 4:44 pm
All that the exams of minerals from Earth or from distant rock formations can do, is to give some background information on the origin to an individual’s physical Hosts and this is good, it teaches us a lot …. But no study of minerals of any kind, can by any means ever disclose the origin of that which is actually the individual … and that is the Complex ‘Designed Circuitry of Intelligent Energy’ no larger than the palm of an adult hand, and somewhat thinner than a sheet of paper; a living web-like fiber of a translucent and complex ‘Circuitry of Energy’ which in-takes and process thoughts in many ways similar to a computer chip, but an organic Plasma Chip … and that is an individual’s Mind-Soul … and this is from a High Celestial Region …
June 14th, 2008 at 4:51 pm
More details place:
What specific Carbon Isotopic ratio would indicate space borne molecules? I suppose it would be a greater amount of carbon 13 over carbon 12? Does anyone know what specific ratio indiciates extra terrestrial origins?
June 14th, 2008 at 5:17 pm
@Helioprogenus
If you want specific details that are more reliable than, say, Yahoo! Answers, I suggest trying to get in contact with one of the scientists who know how to give you an undiluted answer.
Check up there in the original post Phil made. The link credits everyone directly involved. Perhaps one of them will be kind enough to post here in a comments section of a blog but I’m guessing they’re pretty busy right about now, what with all the speculation.
And just to clarify my first post, I had my first and last bout of prosorinospentaphobia. It was a tough 55 seconds but I’m ok now.
June 14th, 2008 at 5:34 pm
This discovery generates interesting speculation about our origins, but I think an even better conclusion to draw from it, is that it increases the probability that life “very much like ours” exists elsewhere in the universe, and that such life may even be abundant.
June 14th, 2008 at 5:41 pm
Check this out.
Panspermia is more than a baseless hypothesis. There’s actual evidence.
http://www.space.com/searchforlife/seti_panspermia_030724.html
.
June 14th, 2008 at 5:42 pm
Interesting ideas explained with clarity. Thanks!
(You also realize I’m sure that it is a common assumption among many scientists that the cuisine known as “Swedish meatballs” likely originated on the Narn home world.)
June 14th, 2008 at 6:03 pm
Isn’t everything (even what the earth is made of) not from the earth? So everything is alien.
June 14th, 2008 at 6:19 pm
The reason that organic precursors are important is that they show that the building blocks for earthly life forms are prevalent in the solar system. This means that life that is made of nuclides and proteins has the potential to form in other parts of the solar system, as the precursors are available. So looking for those kinds of molecules is more useful than assuming that life could be made up of arbitrary molecules, whose detection and significance is hard to define.
So this sort of study makes exobiology more tractable, by giving us hints of what to look for.
June 14th, 2008 at 6:56 pm
Excellent analysis. Are you sure you shouldn’t move over to the geosciences ? We’re always looking for a few good men, you know.
June 14th, 2008 at 6:58 pm
@sam
“Isn’t everything (even what the earth is made of) not from the earth? So everything is alien.”
In a temporal sense, yes. Once you get a grasp of the quark’s evolution over time to the thing that is “you”, it isn’t as freaky as some would suggest.
June 14th, 2008 at 7:09 pm
Is it really *that* important? If you think about it, the entire mass of the Earth started “out there.”
The organic molecules form just about everywhere, it seems. I can’t think of a way we could ever tell if it was Earth based or “invader” molecules that got life started. Maybe it was both.
Seems almost like a *purely* philosophical question.
June 14th, 2008 at 7:35 pm
@Quiet Desperation
“Is it really *that* important?”
I don’t mean to come across as an ass but, yes, it really is that important.
Some of us are passionate about our origins.
June 14th, 2008 at 7:36 pm
The book Genesis Stone by Dr. David Seargent published in 1991 is a good report on the fall of the Murchison meteorite both trying to discover its possible parent body & the chemical analysis of the meteorite.
June 14th, 2008 at 7:40 pm
Panspermia?
Not to ask the obvious, but what does sperm in a pan have to do with life on earth originating in outer space?
*sarcasm*
June 14th, 2008 at 7:53 pm
@ KevinF: You said:”Why we sent Gallileo into Jupiter rather than leaving it in orbit?”
Nahhh, We sent Galelio into Jupiter to attempt to start a fusion ‘burn’ that would ignite Jupiter as a star… Haven’t you been keeping up with your “Enterprise Mission” reading assignments?
@ Nicole and Marsh – yep, I thought the same thing, I wonder how Gwen is getting along with Rhys?
June 14th, 2008 at 8:11 pm
@ KevinF: You said:”Why we sent Gallileo into Jupiter rather than leaving it in orbit?”
Nahhh, We sent Galelio into Jupiter to attempt to start a fusion ‘burn’ that would ignite Jupiter as a star… Haven’t you been keeping up with your “Enterprise Mission” reading assignments?
That’s one way to get a mountain-sized diamond out of a gas planet.
June 14th, 2008 at 9:13 pm
Sorry, just a minor correction, this is one of my pet peeves.
You say “an isotope is when the number of neutrons is different.” This is only half correct, an isotope is ANY form of the element, not just ones other than the most common one. So Carbon-12 is still an isotope, even though it is the most common.
June 14th, 2008 at 10:27 pm
http://www.space.com/searchforlife/seti_panspermia_030724.html
That’s really an embarrassing piece that Seth wrote there. Someone ought to slap him hard. So they find some kind of bacteria at an altitude of 41 km and therefore it must be extraterrestrial. Yep, I’m convinced. After all, it’s much easier for the little bugs to travel trillions of miles from the nearest star system than it is for them to travel a few dozen miles from the surface of the earth up into the atmosphere.
June 14th, 2008 at 10:31 pm
Ah, well that explains the crappy cover of “All Along the Watchtower” I’ve been hearing for in my head for a while now.
We’re aliens. And we always have been.
See you guys at the next meeting. I’m off to airlock those who annoy me.
June 14th, 2008 at 10:47 pm
” life here — or at least the necessary components of it — began out there. ”
Original Battlestar Galactica wants it’s theory back.
June 14th, 2008 at 10:49 pm
” life here — or at least the necessary components of it — began out there. ”
Original Battlestar Galactica wants it’s theory back.
June 15th, 2008 at 1:31 am
John Kennell wrote:
at 2:13 pm:
The universe, galaxy, solar system, planet, epoch, species, gameshow, is a distillation of matter.
Matter matters. Figure that one out.
John
+—-+—-+—-+—-+—-+—-+
at 2:15 pm:
Phil,
Are you a singulatarian, or what?
Pick sides.
+—-+—-+—-+—-+—-+—-+
at 2:38 pm:
all of this has happened before, all of this will happen again
John,
I’ve tried to do what you asked (”Figure that one out.”) w/o success. Do you suppose you could clarify the above posts?
June 15th, 2008 at 1:38 am
[...] Plait has a good writeup on some recent space news. He writes that the Murchison meteorite: …which fell on Australia [...]
June 15th, 2008 at 4:59 am
Space dust has lots more active surface area than earth rock- and all sorts of interesting nano effects would be possible at that size scale that are more difficult in a terrestrial environment. Add in extreme environmental contrasts again not present on earth, with bulk atmosphere, water, etc.
Some years ago I had this idea that the biopolymers originally had structural function in prebiotic constructs, rather than coding ones, which presumably evolved much later.
Perhaps the structural ‘function’ first happened beyond earth? As the goop which helps hold dust motes together to make bigger conglomerates. Space pre-life would live between the bits and pieces, protected by the volume versus surface area. When gravity hasn’t melted rock (but perhaps water ok) lifelike organization might get a foothold inside such flocks. All sorts of interesting energy sources, including radioactivity, present in newly made space junk. After all this time much of that is gone in remaining materials.
Finally: Panspermia is the euphemism animal ethologists use to refer to Bonobo social life……
June 15th, 2008 at 6:02 am
Well, we are all made of stardust, and while our evolution from inert matter to in-nerd matter is fascinating, I cannot see why a such a big emotional reaction should hang on where exactly life started.
June 15th, 2008 at 6:08 am
With primordial earth (and sometime prehistoric) earth getting bombarded by space debris, is it possible that some of these meteorites are bits of earth finding their way back?
Anything show up in lunar samples?
June 15th, 2008 at 7:56 am
This is a questin I have often pondered. Clearly we are not the ONLY ones out there, I mean space after all is infinite is it not?
JT
http://www.FireMe.to/udi
June 15th, 2008 at 8:25 am
Kol on 14 Jun 2008 at 4:35 pm :
In a way this was done a very long time ago (1930’s -40’s~ish) by the great Olaf Stapledon in the conclusion to ‘Last & First Men.’ In that epic novel story of all Humanity’s future incl. human successor species living on Venus and Neptune is the one deliberately spreading its seeds tothestars as our Sun dies …
(Apart from 1 although his “Humans’” were very distant and alien descendants of our first men species.)
Scarily enough Stapledon is right on the money in ‘L & 1st Men’ about a number of things from dead Princess hysteria (albeit more serious consequences) to China versus Amercia fighting for the future of our “first men” (& he goes through about 15-20 or so separate species of Humans) species …
Well worth a read still if you can find a copy – as are his novels “odd John” & “Sirius”
As for the panspermia theory – I’ve always kind of liked it although not 100 % convinced. Read and was impressed by Hoyle’s SF novels and his non-fiction on it with Wickramasinghe too.
June 15th, 2008 at 8:34 am
John T Rowlins on 15 Jun 2008 at 7:56 am :
Actually, no, I don’t think it is technically infinite although it is staggeringly, mind-bendingly, unfathomably, incredibly, colossally, amazingly, superhypercallafragillistically, incomprehensibly, B – I – G!!!
But, yes, I agree that given the size of the comos – & even just of our Milky Way Galaxy (which is something like 100 billionstars in 100 billion light years isn’t it?) we are not the only sentient species around.
Although I very, very, very much doubt they come round here in flying saucers peeking in bedroom windows and go abducting and probing drunken hicks!
June 15th, 2008 at 8:48 am
As I understand it, biologically produced chiral molecules convert over time to their enantiomers, so the proportion of a sample that is in the original configuration is a measure of how old a biological sample is. My recollection is that the proportions are equal after a few million years.
So if the D and L forms are about equal, that could mean they were abiotically produced, or that they are fairly old.
Does anybody know more about this?
June 15th, 2008 at 9:04 am
[...] Bad Astronomer explains why panspermia is not a given based on recent discoveries.read more | digg [...]
June 15th, 2008 at 9:17 am
Let’s not forget that astronomers have recently huge (>10 light years across) clouds of organic chemicals in the vicinity of ’stellar nurseries’ (Google: pillars of creation organic chemicals). Over 200 ’species’ of organic chemicals have been identified so far. There is no compelling reason NOT to think that this is exactly the same kind of environment in which our OWN solar system and planet evolved.
It could be that we have not been asking the right question. Rather that asking how life on earth arose, it might be that the better question is “When did conditions on earth stabilize sufficiently that life was able to take-hold?”
June 15th, 2008 at 9:58 am
[...] Bad Astronomer explains why panspermia is not a given based on recent discoveries.read more | digg [...]
June 15th, 2008 at 10:43 am
For everyone saying “what’s the big deal? Everything is from space” I’d agree on one level, but if a spacecraft landed in my backyard and a biped stepped out and tried to high-five me, I think I’d have a more profound reaction than “interesting… There’s a species of our common universe that I’ve never seen.” It matters where stuff is from within the universe too.
June 15th, 2008 at 12:15 pm
Regardless, a fine analysis.
June 15th, 2008 at 12:39 pm
Life did originate in Space…Earth is a part of Space, therefore whether it started here or “out there”, either way it’s “SPACE”. That may sound obvious, but I think the common mistake is to separate Earth/Space. We are just as much a part of Space, as any other point where life originated.
The point is, is that Earth is not the “only” place where ingredients for life exists. So, to me this proves that Life is now even “more” possible to exist in other parts of the Universe. So much so, that given the size of it, absolutely HAS TO!!
June 15th, 2008 at 12:41 pm
Life “DID” originate in Space…Earth is a part of Space, therefore whether it started here or “out there”, either way it’s “SPACE”. That may sound obvious, but I think the common mistake is to separate Earth/Space. We are just as much a part of Space, as any other point where life originated.
The point is, is that Earth is not the “only” place where ingredients for life exists. So, to me this proves that Life is now even “more” possible to exist in other parts of the Universe. So much so, that given the size of it, absolutely HAS TO!!
June 15th, 2008 at 1:13 pm
Does any of this make any difference?
June 15th, 2008 at 1:29 pm
Don’t forget that the hypothesis of panspermia was strongly supported by Fred Hoyle which considered the Universe infinite in time and space. With infinite time anything is possible; life germs were / are everywhere and “rain” on life-friendly planets – so I am wondering why Hoyle needed a “higher intelligence” to create life. However, the Big-Bang should make the panspermia hypothesis much less attractive.
Iant
June 15th, 2008 at 1:44 pm
It is good to see more sources of basic biomolecules.
But purines and pyrimidines doesn’t strike me as the kind of molecules that would be used at the basis of an abiogenesis. IIRC they are easily degraded in water in contrast to amino acids. (Though the discussed sources of incorporation into the meteorites says otherwise, since water contamination, at least under frigid conditions, was a concern.)
OTOH when life could make the non-natural sugars, it is perhaps plausible that a certain concentration of supplied pyrimidine could have bootstrapped an ATP metabolism and from there RNA. The smallest discoveries can help.
I’m sorry, but this doesn’t make sense to me. AFAIU asexual spores are formed by some Bacteria and some Eukarya (famously, Fungi) to survive just hardships here on Earth.
Further, Eukarya is certainly derived, and there are several papers that makes Bacteria younger than Archaea. (Though that is contested as it is difficult to root life.) Here is one looking at protein architecture evolution. They identify six phases in an evolutionary timeline, where Archaea was the first superkingdom to diversify from the common basis, if not the first to become more specified.
Here is what they speculate on the ecological mechanisms behind this diversification, based on the evolutionary order of structural architectures:
It doesn’t seem that the presumably earlier Archaea had spore capability:
So, is it likely that spore formation was an early invention that was subsequently lost in some species, or that it was independently developed by convergent evolution? That I don’t know; perhaps the biologists know the phylogeny for some of that.
But the Bacteria lifestyle, which is to be a streamlined and simplified sports car compared to the clunkier but tougher excavator of Archaea or flexible tractor of Eukarya, involves risk taking while waiting for those stretches of fair weather and straight roads. This is presumably a good reason to develop spores, as well as Eukarya did it for among other reasons sex.
June 15th, 2008 at 2:00 pm
Please, a reference for the eye evolution. Its unfair to state such things without a footnote. If it were so easy to footnote it, and common knowledge, we should all be sending it to Ben Stein to include in a video follow up to his film.
June 15th, 2008 at 2:30 pm
…my sons, you blaspheme tremendously and invoke the ire of the lord.
…now bend over now so I may spank each and every delicious one of you…
June 15th, 2008 at 2:46 pm
This whole alien talk is getting tiresome; What (may or may not) have come from space were chemicals. These chemicals are parts of the very tiny building blocks of _all_ life. In that context it is useless to talk about alien versus earth-based life.
That humans are capable of evil where most animals are not is probably more based in our frontal-lobe capabilities, that we are capable of (bound to?) imagining things different than they are, not us being aliens. Please read books every now and then.
June 15th, 2008 at 3:12 pm
@GH
I was under the impression that the evolution of the eye was more or less “common knowledge,” since I was taught it in school. (that is, of course, common to those who would care)
The eye would have began as simple light-sensitive cells, which could be useful for various purposes.
I’d suggest googling evolution of the eye, also there’s a wikipedia entry: http://en.wikipedia.org/wiki/Evolution_of_the_eye
Also, having seen parts of Ben Stein’s film, I doubt he has any interest in where actual evidence leads, he’s a little too busy preying on ignorance for $.
June 15th, 2008 at 6:01 pm
Well, it took you creatures long enough to figure out that we seeded you here billions of years ago.
No, really don’t thank us, whatever you do.
Sincerely,
The Grand Aturian High Council of Threkasia VII
June 15th, 2008 at 6:17 pm
[...] Researchers have found that some molecules which are the basis for life on Earth can have an extraterrestrial origin. These alien molecules can survive an impact with Earth and may have been crucial to the development of life on Earth. Intact life from space — bacteria, viruses, and such — is still just an idea, with no credible supporting evidence. [link] [...]
June 15th, 2008 at 6:19 pm
News flash: everything on this planet came from space. How do you think the planet was formed?
June 15th, 2008 at 6:54 pm
This may have been covered already, but I’ll say it anyway…I’m pretty sure we are all aware that the Earth is in space, so when you say “of course we are aliens; Earth is in space”, you’re dodging the question. Did life originate on Earth, or not on Earth? That is the question. And yes, if not on Earth, that just pushes back the question of where, but it is still interesting.
June 15th, 2008 at 11:35 pm
We really have no idea of where this object originated from. It could be a piece of Earth that got blasted in the space. It could be from a planet that existed earlier in the solar system and was obliterated somehow.
June 16th, 2008 at 2:19 am
[...] source Share and Enjoy: These icons link to social bookmarking sites where readers can share and discover new web pages. [...]
June 16th, 2008 at 3:00 am
And I thought all our aliens came from Mexico. On the other hand, can an organic molecule on a meteorite mow your lawn?
June 16th, 2008 at 5:14 am
Pick sides ? haha .. sides are for fools.
June 16th, 2008 at 8:39 am
I think that the most important item this points to is that the biological makeup of life on earth is not unique or special, relative to the rest of the universe. We have proven by our own existence that life can be constructed out of these chemicals. Since these chemicals exist elsewhere, it bolsters the support that life may be ubiquitous in the universe.
June 16th, 2008 at 8:52 am
Ken S. beat me to it. The biggest and best rational conclusion to draw from this news is that organic compounds are not all that rare nor are they that fragile. So it stands that life is not unique to Earth, and could very well be throughout the universe. Jury’s still out if we’ll every find some of those pockets of life, but they’re no longer whispers in the wind. There is finally some hard evidence that we are not alone–maybe.
June 16th, 2008 at 8:58 am
I’ve got a question regarding the isotope tests. You say this testing can differentiate terrestrial from extra-terrestrial compounds. If the compounds on these meteorites don’t match the terrestrial compounds, that tells us they’re from space. But if they don’t match the terrestrial compounds and the isotopes in our bodies DO match the terrestrial compounds, then doesn’t that tell us we didn’t develop from the purines and pyrimidines found on these rocks? Most of this is just slightly beyond my understanding, so I’m just curious.
June 16th, 2008 at 9:01 am
everybody is talking about those Aliens,
what if WE are the aliens, but we came here so long time ago
that we simply forgot all about it ?
June 16th, 2008 at 9:24 am
It seems very likely that our basic chemical makeup came from space. We ARE afterall….”star stuff” (See Cosmos). We are products of the universe and the universe is a product of us…we are one. (insert ohm chant here)
June 16th, 2008 at 9:29 am
Jameson,
I know this is BA’s expertise, but let me take a stab at it.
Life chemistry fundamentally works by making molecular copies of itself in order to reproduce. It copies itself by taking hydrogen, carbon, oxygen, plus a few trace element atoms from the surrounding environment to make the new copies. But isotopes are at a sub-chemical level. They are at a nuclear level. They, for the most part, do not affect how the chemistry behaves. So, we have these life chemicals that fell from space that are “tagged” with an isotope marker. If they started copying themselves, thew would do so with the “untagged” local atoms. The newly created molecules would be the same chemically, but would not have the extraterrestrial isotope tag. These in turn would copy themselves over and over as life progressed. So, life created on earth would not carry over the isotope tags from the space seed material. I’m not saying this DID happen, but if it did, this would be the result.
June 16th, 2008 at 3:19 pm
GH said:
> Please, a reference for the eye evolution.
Try The Origin of Species, by Charles Darwin. No, seriously, Darwin used it as his specific example to refute the question of assumed complexity. Of course, others have done more with it, but that shows the ridiculousness of Creationists that they still cite the eye as too complex to have evolved.
June 17th, 2008 at 12:31 am
Ken, a million thanks. Fantastic explanation, clears up my puzzlement perfectly.
June 17th, 2008 at 12:56 pm
Which leads to the question: Why did you think you’d come across as an ass?
So am I, but I just don’t see all that much importance in this particular question.
We know the organic molecule can form just about anywhere. Some were on Earth, some came from space after the Earth was at a stage where they could survive.
*shrug* It’s all the same thing, and the answer is probably impossible to find. How do trace the specific molecules in the first primitive life-like entities to their origin without a time machine? Even then you might trace them back to the primordial goo which has both native and extrterrestrial organic molecules. Then what?
June 17th, 2008 at 2:36 pm
[...] “Somos Aliens?”: O Discreto Blog da Burguesia novamente se aventura na tradução direta de um trecho, dessa vez de [...]
June 17th, 2008 at 3:17 pm
http://en.wikipedia.org/wiki/Isotopes_of_carbon
The natural abundance of carbon isotopes on earth is 98.93% carbon-12 and 1.07% carbon-13. This apparently represents the isotopic composition of the solar nebula which formed the sun and the planets.
Now the important point about Earth biology is that it favors the carbon-12 isotope. Thus, in sedimentary rock containing the remains of living organisms the percentage of carbon-13 is smaller than 1.07%. This is thus a signature of life. A group of scientists have used this signature to date the beginnings of earthly life back to 3.85 billion years and perhaps beyond that.
http://www.pbs.org/wgbh/evolution/library/03/3/text_pop/l_033_28.html
So far, all of the carbon tested in meteorites contains the usual percentage of carbon-13 (1.07%) and is therefore a pretty good indication that panspermia is bunk.
June 17th, 2008 at 9:31 pm
[...] – Are we aliens? “So this means that the some of the basic building blocks of life formed out in space, and [...]
June 18th, 2008 at 5:03 am
So when you thought you came from “europe” let’s say, they discovered you really came from Africa, so whe’re africans? Whe are humans, whe’re from the world. Now researchers have found that some kind of molecules that form part in basis of life can have an extraterrestrial origin, so, whe’re aliens? It all started in a “small bang”, life, matter… even the computer in front of you. Whe’re all from the Universe
June 18th, 2008 at 7:38 am
I agree with this writeup.But i think still lots need to be researched to finally reach the conclusion.
June 18th, 2008 at 2:31 pm
Things are all ways fallen from space unto earth some things we see and some things we cant ,there are so many wonderful thing that could be happen all around us and not even know it!It goes all the way back to christ days or even befor that what about his dad GOD, how did he get there. eygeptions seem to be live there where aliens and im quite sure there are there are tomany planets that s out some we”ve never seen. But yes we are aliens and they are the predators…just kiding by the way is there any more quicksand any were in the world??
June 18th, 2008 at 2:36 pm
Remeber if you look you shall find or is it you shall see its one of them but what I forgot to say is that its right in front of our eyes!
June 19th, 2008 at 6:19 pm
[...] making it possible for life as we know it to evolve. Especially if the building blocks of life are floating around in space. Comments (0) [...]
June 25th, 2008 at 9:28 pm
Chinese–LIUGONG wheel loader, HC forklift, Feeler Forklift, Carter Excavator, XCMG wheel loader, motor grader, Paver, Road Roller.
July 7th, 2008 at 7:46 am
http://Www.yahoo.com Horoscopes
) Some individuals or companies have abused the TrackBack feature to insert spam links on some blogs (see sping).It has since been
July 7th, 2008 at 11:23 am
Cool Free Daily Horoscopes
July 7th, 2008 at 3:56 pm
Horoscopes Daily Physics
July 10th, 2008 at 12:00 pm
[...] Alleen betekent dit niet meteen dat het leven ook echt buitenaards is. Een aantal elementen komen vanuit de ruimte, maar anderen zijn ongetwijfeld hier aanwezig geweest en samen hebben ze… wel, ons geschapen. [...]
July 11th, 2008 at 9:03 am
Use Occam’s Razor FTW!
November 1st, 2008 at 10:11 pm
I suggest ALL of you READ/RESEARCH Zacharia Sitchin. Look him up on youtube; there is a lot of information there. It appears that yes in fact we are all part alien… I’ve heard one researcher say that we are supposedly made up of 22 different species of humanoid aliens mixed with the neanderthal i guess…
November 28th, 2008 at 4:35 pm
I believe this to be the truth of our origins. Although evolution has changed our appearance, it has not changed our drive to use resources until they are gone. We have gone from planet to planet using its resources until the planet can no longer sustain us. My theory is we come from planets in our solar system that can no longer sustain life or itself. The latest planet we destroyed is what we now call our moon. We all know there is no gravity on the moon and we all know when we die we turn to dust. Imagine a meteor striking the moon and sending the dust into space. If there are corpses included in that dust dna could be present.
February 20th, 2009 at 6:32 am
[...] Are we aliens? | Bad Astronomy | Discover Magazine [...]
September 22nd, 2009 at 8:39 am
The Torchwood comment was a tad silly. I’m from Cardiff and never knew of this group before. I’ve always thought about this subject and decided today to see if there was any kind of material regarding this, I have found a site that MAY prove me right
It’s such a simple idea that non scientists (like me) can come to this conclusion, it just depends on how much you are willing to think and use your brain. (I feel sorry for the MTV retards that beleive everything they read in the tabloids) It’s nice to see some scientific evidence to support some of these claims.
September 27th, 2009 at 8:09 am
[...] e a Chuva Vermelha de Kerala. Podem ler sobre isto, aqui, e neste nosso post. O Phil Plait tem este artigo, no blog Bad Astronomy, onde critica a forma como a panspermia tem sido divulgada pelos cientistas [...]
October 6th, 2009 at 8:54 am
We are the aliens! I am pretty sure. Otherwise why would we look up at the stars and feel something that we can’t grasp. We are looking at home. We see a home when we look up there. It’s intrinsic. We don’t need science to prove anything. We made science. Science did not make us. God damn!
October 11th, 2009 at 9:49 pm
[...] e a Chuva Vermelha de Kerala. Podem ler sobre isto, aqui, e neste nosso post. O Phil Plait tem este artigo, no blog Bad Astronomy, onde critica a forma como a panspermia tem sido divulgada pelos cientistas [...]
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Phil Plait, the creator of Bad Astronomy, is an astronomer, lecturer, and author. After ten years working on Hubble Space Telescope and six more working on astronomy education, he struck out on his own as a writer. He has written two books, dozens of magazine articles, and 12 bazillion blog articles. He is a skeptic, and fights misuses of science as well as praising the wonder of real science.
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