Scientists confirm that parts of earliest genetic material may have come from the stars

Jun 13, 2008
Stars

Scientists have confirmed for the first time that an important component of early genetic material which has been found in meteorite fragments is extraterrestrial in origin, in a paper published on 15 June 2008.

The finding suggests that parts of the raw materials to make the first molecules of DNA and RNA may have come from the stars.

The scientists, from Europe and the USA, say that their research, published in the journal Earth and Planetary Science Letters, provides evidence that life's raw materials came from sources beyond the Earth.

The materials they have found include the molecules uracil and xanthine, which are precursors to the molecules that make up DNA and RNA, and are known as nucleobases.

The team discovered the molecules in rock fragments of the Murchison meteorite, which crashed in Australia in 1969.

They tested the meteorite material to determine whether the molecules came from the solar system or were a result of contamination when the meteorite landed on Earth.

The analysis shows that the nucleobases contain a heavy form of carbon which could only have been formed in space. Materials formed on Earth consist of a lighter variety of carbon.

Lead author Dr Zita Martins, of the Department of Earth Science and Engineering at Imperial College London, says that the research may provide another piece of evidence explaining the evolution of early life. She says:

"We believe early life may have adopted nucleobases from meteoritic fragments for use in genetic coding which enabled them to pass on their successful features to subsequent generations."

Between 3.8 to 4.5 billion years ago large numbers of rocks similar to the Murchison meteorite rained down on Earth at the time when primitive life was forming. The heavy bombardment would have dropped large amounts of meteorite material to the surface on planets like Earth and Mars.

Co-author Professor Mark Sephton, also of Imperial's Department of Earth Science and Engineering, believes this research is an important step in understanding how early life might have evolved. He added:

"Because meteorites represent left over materials from the formation of the solar system, the key components for life -- including nucleobases -- could be widespread in the cosmos. As more and more of life's raw materials are discovered in objects from space, the possibility of life springing forth wherever the right chemistry is present becomes more likely."

Paper: “Extraterrestrial nucleobases in the Murchison meteorite”, Earth and Planetary Science Letters, Sunday 15 June 2008 (Print publication) A full copy of the research can be downloaded at: dx.doi.org/10.1016/j.epsl.2008.03.026

Source: Imperial College London

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Quantum_Conundrum
1.6 / 5 (24) Jun 13, 2008
The team discovered the molecules in rock fragments of the Murchison meteorite, which crashed in Australia in 1969.

They tested the meteorite material to determine whether the molecules came from the solar system or were a result of contamination when the meteorite landed on Earth.

The analysis shows that the nucleobases contain a heavy form of carbon which could only have been formed in space. Materials formed on Earth consist of a lighter variety of carbon.

----

Most be joking right? So these brainiacs don't suppose any of this "heavy carbon" fell into earth's atmosphere, was included into some organic molecules through metabolism of earth life forms, and then contaminated the meteorite later?


LOL?

This sort of "science" is simply laughable.
Bonkers
3.8 / 5 (15) Jun 13, 2008
What are you on about?
they are saying the molecules have a high proportion of C14, even if space-made C14 did fall to earth, it would be diluted by all the normal C12.
Mungaman
3.5 / 5 (17) Jun 13, 2008
No kidding Bonkers.... Quantum_Conundrum your 'logic' is laughable. Why don't you stick to stocking the shelves of Kroger.
ontheinternets
2.5 / 5 (15) Jun 13, 2008
From what is said in the article, I think Quantum Conundrum's concern is valid (I was thinking the same thing as I read it) -- It says *contain* the heavy form. It doesn't say these molecules were solely composed of the heavy form. There's nothing wrong with them having analyzed the carbon content though. If they continue their analysis, they could more carefully rule out earthly origin -- and perhaps there was already more to the analysis than reported here (a summary is generally not as good or thorough as an original paper).
Mercury_01
2.8 / 5 (14) Jun 13, 2008
No doubt Mung! Whats the matter QC? Afraid of a little alien DNA? and anyways, what are you suggesting, that an animal must have somehow eaten some of the meteorite and was able to take a shit inside the rock for researchers to find later upon cutting it open for a sample? Get real. If you think you know what "science" is, then why dont you have an open and objective stance, like a real scientist.
googleplex
3.2 / 5 (13) Jun 13, 2008
I would assume that they took a sample from the core of the meteorite under sterile conditions.
Clearly anything on the surface of the meteorite could be contaminated. This would also preclude later contamination by C14. Of course the next question is where did these nucleobases come from? I do find it odd that we have not detected any alien radio signal. I expect one day someone will discover a new communcation medium and find alien data. Perhaps using radio waves is too primitive. Light speed is way too slow anyway.
nano999
3.2 / 5 (15) Jun 13, 2008
Christian_Conundrum consistently makes bizarre attempts to discredit any science that would marginalize his precious god or religion.
Mercury_01
3.4 / 5 (13) Jun 13, 2008
This is hard evidence indeed of panspermia. the article states:
"The analysis shows that the nucleobases contain a heavy form of carbon which could only have been formed in space."

That would indicate that the nucleobases share a chemical bond with the C14. theres not a lot of disputability here.
ontheinternets
3.1 / 5 (12) Jun 13, 2008
I do recall Quantum Conundrum making some kind of apparently creationist and/or religious assertion in the past. If he weren't biased, he probably wouldn't have gone so far as to laugh in the face of these scientists. It would have just been a question. It is however a valid concern which I would hope the scientists would be doing their best to deal with. These guys tend to be intelligent, so I think they probably have.. but there's always the possibility that they were content to finish what they started and wanted to make a publication. Where questions remain, you've got to keep pushing a little (ideally, with a bit more respect).
Mercury_01
1.9 / 5 (10) Jun 13, 2008
Eh, respect is no fun. We like to get in internet fights, dont we guys! Anyways, its interesting to observe everyones opinions and reactions.

By the way, nano, I agree with you, but I also know God. I hope you dont think were all retarded.
nano999
2.9 / 5 (9) Jun 13, 2008
Mercury_01 - Never fear, I have respect for those who don't follow blindly. If there is a God it surely gave us brains to be able to explore our Universe. That's the most fun part!
ontheinternets
4.1 / 5 (8) Jun 13, 2008
To be clear, if I were to eat some C14, then my body would digest it and some of the carbon atoms in my body would be C14. Chemical (not nuclear) reactions in my body aren't going to cause it to spontaneously break down, and the heavier mass of the carbon doesn't particularly matter. The evidence shows that the carbon atoms formed in space (read carefully - "The analysis shows that the nucleobases contain a heavy form of carbon which could only have been formed in space"). Does it say that the molecules formed in space? No (though their hypothesis is that some did). Does it say that the molecules did not form in space? No. But it is an intriguing avenue to follow. Do most scientists believe that some life has existed outside of the earth? Yes. But I'm not going to claim evidence simply because I think it's true and would like it to be true. To best make scientific progress, you need to be honest even in the face of unreasonable criticism.
ontheinternets
3 / 5 (6) Jun 13, 2008
What I'd most like to know is a) what proportion of the carbon atoms in the nucleobases were of the heavier form, and b) where exactly in or around the meteorite did they take their samples. If it's close to 100% heavy carbon, then hot damn. (my last post here - don't want to post too much)
YankInOz
3.3 / 5 (11) Jun 13, 2008
Yo - Quaintum Condom - If you bothered to EVEN read the Abstract (this is assuming that you can read beyond chapter and verse of something) you may learn how extensive the research was performed and how specific the analysis was that warranted these conclusions. OR you may even want to pay (if your Mummy has given you enough allowance to do so) for the paper - it is referenced in the article) and discover what the Pope's Science Guy said a few weeks ago - God created life throughout the Universe.... Oops... guess you didn't get that MFG -message from God, G_d, Allah, Jack In The Box, whatever! -

Here is the abstract:

Abstract

Carbon-rich meteorites, carbonaceous chondrites, contain many biologically relevant organic molecules and delivered prebiotic material to the young Earth. We present compound-specific carbon isotope data indicating that measured purine and pyrimidine compounds are indigenous components of the Murchison meteorite. Carbon isotope ratios for uracil and xanthine of %u03B413C = 44.5%u2030 and 37.7%u2030, respectively, indicate a non-terrestrial origin for these compounds. 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.

Nuff said...

I know that wasn't a formal science related response but they don't work when people thingk with their Okolee (Hawaiian for back end of your alimentary canal)...

Cheers, Mates...
ranfea
1.3 / 5 (3) Jun 13, 2008
DNA kicks ass.
defunctdiety
1.3 / 5 (4) Jun 13, 2008
I love physorg. All warm fuzzies and appy polly loggies.
Mombo_Dogface
3.2 / 5 (6) Jun 13, 2008
What the naysayers are missing is even if (as QC says above) it was contaminated by C14 falling from space and contaminated the meteorite, IT STILL CAME FROM SPACE and still could lead to the same conclusion of the article. Being found in a meteorite just gives us a clearer picture of where the C14 on Earth came from.
RealScience
4 / 5 (8) Jun 13, 2008
Anyone who thinks C14 hasn't had their morning coffee yet; C14 decays far too fast (~6K years) to last billions of years (the age of meteorites).

It is C13, which is stable, that is the "heavy carbon" the article is talking about.

"Ontheinternets" asks the right question, and "YankInOz" has the right answer.

The normal ratio here on earth is around 1%, so 44.5 and 37.7 percent are WAY off the chart for
terrestrial contamination.

But although this leans slightly in the panspermia direction, individual nucleotides are far from complete DNA or RNA.
Mercury_01
1 / 5 (3) Jun 13, 2008
How does a nucleotide form in outer space anyway? People have postulated that it would take millions of years for any such complex molecule to form in a warm shallow pool here on earth.
Quantum_Conundrum
1.1 / 5 (7) Jun 13, 2008
How does a nucleotide form in outer space anyway? People have postulated that it would take millions of years for any such complex molecule to form in a warm shallow pool here on earth.



It shouldn't be possible because most of what is in space is either pure hydrogen in nebulas, or atomic nucleus (ions) created during fusion or super novas. Normal atoms cannot form under those conditions, and neither can chemistry.


Most of the chemistry on earth is either combustion involving oxygen, or a reaction that requires liquid water, which includes the production of DNA and its respective nucleotides in the cell.
RealScience
4.2 / 5 (5) Jun 13, 2008
Nucleotides form in hours under the right conditions (energy being added to the primative molecular ingredient, with electrical, sound, and optical energy all having been shown to be suitable).

While this would take much longer in a
diffuse cloud without dust, if the materials are adsorbed onto dust grains it would go relatively quickly. Most interstellar clouds are rich in dust, and dust is what agglomerates
into what becomes meteorites.
photojack
4 / 5 (6) Jun 14, 2008
This confirms Dr. Carl Sagan's famous quote, "We are the stuff of stars." I'm sure he would have been pleased to learn of this. It seems to be corroboration of the panspermia theory. Maybe it will gain the respect and certainty that evolutionary theory holds today, much to the chagrin of the "holy rollers"!
Mungaman
4 / 5 (3) Jun 14, 2008
Acutally the term nucleotide refers to a a nucleoside (a purine or pyrimidine base with an attached sugar) with either one two or three phosphate groups attached, making nucleotide mono, di or tri phosphate. They found the precursors to these more complex molecules...
tigger
4.2 / 5 (5) Jun 14, 2008
Oh don't worry... the religious nuts will retreat and claim that the universe seems primed for life from the outset and hence there MUST be a God. And then we can argue about the Anthropic principal... and blah blah, once a nutter always a nutter.

Oh, good article btw.
superhuman
2.2 / 5 (6) Jun 14, 2008
On one hand its pretty obvious life comes from the stars, all the elements that now make up Earth were made in stars so theres no doubt whatsoever that "we are the stuff of stars"

But thats a different point that authors of the above article are making - that life was seeded from space. While its not impossible its MUCH less probable then the case of life being created here on Earth and no amount of molecules found on meteorites can change! The conclusion that life arrived from outerspace would only be viable if they managed to compare meteorites composition with the composition of the young Earth's surface, but thats of course a pretty hopeless task. Without showing that at a certain point in time in the history of Solar System there were many more organic molecules on meteoroids and asteroids then there were anywhere on Earth such conclusions are completely baseless!

Its the same thing as claiming that all gold comes from South Africa cause scientists found gold in South African rocks, therefore goldsmiths from all around the world must have obtained their supplies from South Africa.

The fact that there are organic molecules on meteoroids doesn't mean that there were no such molecules on Earth, on the contrary - it means that there were even more of them here on Earth where conditions were much more favorable for their synthesis due to high temperature and pressure and lack of ionizing radiation among other things. In fact it probably took at least a small sea of organic compounds and favorable temperature and pressure before that incredibly improbable event happened and two inert molecules combined creating a new one which was capable of replicating itself!

All in all scientists who published that paper are either stupid or purportedly lie about significance of their results to get more publicity.
Captain_Sakonna
2.3 / 5 (3) Jun 14, 2008
I agree with superhuman. Okay, so these molecules are present in meteors. This isn't confirmation or "hard evidence" for the panspermia hypothesis, it just potentially gives it a little more credibility. The fact that these molecules are present in meteorites, doesn't mean they were responsible for the formation of the first nucleobases on earth.

Besides, I thought panspermia was the idea that, "Life on earth arose from primitive life forms which came from space or were placed here by aliens," not, "Life on earth arose from certain precursor compounds that came from space." Someone correct me if I'm wrong on this point.
HenisDov
not rated yet Jun 15, 2008
"How" Life, Not "Where", Is Most Important

http://www.eureka...1308.php
http://www.physor...096.html

Whether nucleobases evolved on planet Earth or landed here from elsewhere, it is "how" their oligomers became replicating genes that is most important. The "how" would have probably been likewise wherever it evolved and the evolved life, that copiously produced more nucleobases, would have probably been life of similar essentiality, defined as follows:

Proposed Definitions Of Earth Life, Organism And Gene.

http://www.physfo...ic=14988&st=225&#entry346136

Earth Life: 1. a format of temporarily constrained energy, retained in temporary constrained genetic energy packages in forms of genes, genomes and organisms 2. a real virtual affair that pops in and out of existence in its matrix, which is the energy constrained in Earth's biosphere.

Earth organism: a temporary self-replicable constrained-energy genetic system that supports and maintains Earth's biosphere by maintenance of genes.

Gene: a primal Earth's organism.


Suggesting,

Dov Henis

http://blog.360.y...Q--?cq=1
Danthrax
2.8 / 5 (4) Jun 15, 2008
Uracil is just C4H4N202...it's a reasonably simple chemical. Simple organic chemicals do form in space--so what? The idea this somehow helps you get a living cell is ludicrous.

Why do the authors think the Uracil was formed away from Earth? Well, we know the ratios of C-12 to C-13 on Earth, and the measured (asteroidal) ones are about 40 percent different from our terrestial ones. As RealScience points out, it is Carbon 13 enrichment they looked at. Their measurements show a 44.5 and 37.7 (depending on which organic they measured) enrichment in C-13 compared to normal levels. Notice that those are not percent signs! Rather, their findings were that instead of 1 percent C-13, there was about 1.4 percent C-13. That's a significant enough enrichment to make extra-terrestial origin quite likely: it convinces me, anyway.

YankInOz. In order to get a minimal set of proteins needed for the simplest imaginable living cell, uracil and xanthine are practically irrelevant. You need 23 different amino acids, all of them left-handed. Then you need to assemble them to form about 200 different, highly specific proteins. I'm leaving out most of the hard parts, like the fact that you need a system to specify (code for) those proteins, else it can't replicate.

The famous just-deceased Astronomer Fred Hoyle, did the math, and found that to get the proteins needed for a simple cell, you'd need to pack the Universe edge-to-edge with amino acids...and that wouldn't be enough.

IF you think random chemical processes did it.
ontheinternets
3 / 5 (2) Jun 15, 2008
As respected as he was, I think Hoyle was misleading everyone (including himself) when he spoke of 'chance'. By his standard, all happenings could be called 'chance', as our best models would show that even our brains follow the laws of physics. But is it appropriate to call physics 'chance'? For the most part, no. Aside from outcomes at the micro scale in our quantum mechanical models, none of it is up to chance and macro results are largely deterministic, occurring in a complex chain reaction as time progresses. His argument was only reasonable if you aren't critical of his mischaracterization of the situation, and that is why his view was a minority opinion.
Mercury_01
1 / 5 (2) Jun 15, 2008
"Without showing that at a certain point in time in the history of Solar System there were many more organic molecules on meteoroids and asteroids then there were anywhere on Earth such conclusions are completely baseless!"

I think Superhuman is very wrong here. If we admit that there are precursors to life flying through our solar system, then the only next logical step is to assume that these molecules were the first of their kind on earth. Earth was bombarded for at least a billion years by this organic laden debris before it was even cool enough to support this kind of chemistry. I think its obvious that "at a certain point in time in the history of Solar System there were many more organic molecules on meteoroids and asteroids then there were anywhere on Earth"
Earth was a crucible of fire and brimstone, constantly recycling the surface rock through plate tectonics. most of our rock has probably been through the mantle at least a dozen times,while the meteors were at least stable enough to hold these molecules unscathed for us to find later. I am of the opinion that the universe is teeming with life, but I guess well find out.
jeffsaunders
not rated yet Jun 16, 2008
photojack - Carl Sagan was referring to all life on earth being made of stars because stars decay into all the other elements.

We are made of decomposed stars - doesn't sound as romantic.

Danthrax - Sir Fred Hoyle is a favourite scientist of mine - but people are often doing improbable maths to come to improbable conclusions that fits their preconceived ideas.

He did write a a very good book about diseases raining from space - having formed in meteorites - (at least I think it was him - good story and interesting concept)

And to you others that immediately start talking about communicating with aliens. Please! Life in space does not mean someone else we can talk to.

However many of billions of other planets with life on them (out there) even those few that might develop intelligent life forms (like fish or smarter) or even brilliant life forms like monkeys, dogs, horses, pigs and dolphins - and perhaps even people - it does not mean that there is any one out there smart enough or advanced enough that they can or would want to communicate with us.
adam81
5 / 5 (1) Jun 16, 2008
I thought this would be useful here, it's from an article I read earlier (sorry can't remember the site and don't have a link)

Flash back three or four billion years %u2014 Earth is a hot, dry and lifeless place. All is still. Without warning, a meteor slams into the desert plains at over ten thousand miles per hour. With it, this violent collision may have planted the chemical seeds of life on Earth.


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 dominance of %u201Cleft-handed%u201D amino acids, the building blocks of life on this planet.

In a report at the 235th national meeting of the American Chemical Society, Ronald Breslow, Ph.D., University Professor, Columbia University, and former ACS President, described how our amino acid signature came from outer space.

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. This is known as %u201Cchirality.%u201D In order for life to arise, proteins must contain only one chiral form of amino acids, left or right, Breslow noted.

%u201CIf you mix up chirality, a protein%u2019s properties change enormously. Life couldn%u2019t operate with just random mixtures of stuff,%u201D he said.

With the exception of a few right-handed amino acid-based bacteria, left-handed %u201CL-amino acids%u201D dominate on earth. The Columbia University chemistry professor said that amino acids delivered to Earth by meteorite bombardments left us with those left-handed protein units.

These amino acids %u201Cseeds%u201D 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. The stars emit circularly polarized light%u2014in one direction, its rays are polarized to the right. 180 degrees in the other direction, the star emits left-polarized light.

All earthbound meteors catch an excess of one of the two polarized rays. Breslow said that previous experiments confirmed that circularly polarized light selectively destroys one chiral form of amino acids over the other. The end result is a five to ten percent excess of one form, in this case, L-amino acids. Evidence of this left-handed excess was found on the surfaces of these meteorites, which have crashed into Earth even within the last hundred years, landing in Australia and Tennessee.

Breslow simulated what occurred after the dust settled following a meteor bombardment, when the amino acids on the meteor mixed with the primordial soup. Under %u201Ccredible prebiotic conditions%u201D%u2014 desert-like temperatures and a little bit of water %u2014 he exposed amino acid chemical precursors to those amino acids found on meteorites.

Breslow and Columbia chemistry grad student Mindy Levine found that these cosmic amino acids could directly transfer their chirality to simple amino acids found in living things. Thus far, Breslow%u2019s team is the first to demonstrate that this kind of handedness transfer is possible under these conditions.

On the prebiotic Earth, this transfer left a slight excess of left-handed amino acids, Breslow said. His next experiment replicated the chemistry that led to the amplification and eventual dominance of left-handed amino acids. He started with a five percent excess of one form of amino acid in water and dissolved it.

Breslow found that the left and right-handed amino acids would bind together as they crystallized from water. The left-right bound amino acids left the solution as water evaporated, leaving behind increasing amounts of the left-amino acid in solution. Eventually, the amino acid in excess became ubiquitous as it was used selectively by living organisms.

Other theories have been put forth to explain the dominance of L-amino acids. One, for instance, suggests polarized light from neutron stars traveled all the way to earth to %u201Czap%u201D right-handed amino acids directly. %u201CBut the evidence that these materials are being formed out there and brought to us on meteorites is overwhelming,%u201D said Breslow.

superhuman
3 / 5 (2) Jun 16, 2008
Science is not about speculation it is about FACTS, all the authors can claim is that there are now nucleobases in Solar System!

When and where said meteoroid was created is not known!

All that is known is that it has slightly different carbon isotopic composition then current Earh! It could have been created on some hydrocarbon heavy moon like Titan or Hyperion just a million years ago, or it could come from Earth prior to cataclysm which created our Moon!

Scientists have no bloody clue where or when this meteoroid comes from! Thats why drawing conclusion about life origins from it is either stupidity or a despicable exploitation of public ignorance for personal gain.

@Mercury_01: When Earth was ALL molten nucleobases couldn't exists so what does that has to do with it? When the conditions settled and nucleobases could exists there were probably countless places here on earth where they formed. Nucleobases are very simple molecules. Mix alot of carbon, some nitrogen and a bit of oxygen (all abundant on early Earth), pressurise and you will end up with all the nucleobases you want and countless other combinations of hydrocarbons! Hydrocarbons are all over Solar System.

adam81
not rated yet Jun 16, 2008
the point i was making is that, in the case of amino acids, they tend to bind and destroy one another, unless you have an imbalance of one paricular kind, amino acids forming on meteors and crashing to earth provides this imbalance
superhuman
1 / 5 (1) Jun 16, 2008
Amino acids don't destroy one another.
Besides RNA or a similar polymer was most likely the base of all life before proteins and aminoacids played any role and it was probably a chiral RNA molecule which was selective towards one kind of amino acids that is the source of preference.
adam81
not rated yet Jun 16, 2008
ok bad choice of words, but when you have left and right handed amino acids toghether in water they bind with each other and become useless for the formation of life, all experiments to create life from scratch have produced equal amounts of both kinds which have then been renderend useless simply by coming into contact with one another, even if what you say about RNA is true, there would be no useful amino acids to create 'modern' life unless right handed amino acids could be taken out of the equation, thus, life from meteorites is still a valid and very probable answer.
Mercury_01
1 / 5 (2) Jun 16, 2008
Superhuman, You are right about the unknown origins of the meteor. It could have formed anywhere at any time, but isnt it more probable, given the average age of meteors in our vicinity, that it is at least as old as earth?I know this topic is touchy for some people, although I dont understand why. We make scientific assumptions all the time, and sometimes we dont get to confirm them for decades. I may be totally wrong here, But I think its safe to assume that certain chemistry necessary for life first arrived from space, at a heavy rate, even before it was capable of being replicated on earths surface. Life chemistry probably occured a billion times in different locations and was destroyed by volcanism each time before self sustaining chemistry was finally realized, and as soon as it was possible, there were the meteors, ready to cst their dirty chemistry all ofer the bare, sterile rock. Im not saying it couldnt happen here without any help from the meteors and comets, or even that it would happen much slower without them. Im just saying that it is more probable that we are a result of alien germs, or at least the scraps of alien organic chemistry.
Bonkers
1 / 5 (1) Jun 16, 2008
I have alway thought the panspermia hypothesis was most likely, if you add up all the surface area and exposure time of all the meteorites (well actually the "space dust") that fell to earth, its colossal. More importantly, intermediate half-built compounds are stable when pinned to the surface, in water they would react away as fast as they were made. this allows much more complex molecules a chance of assembly, and delivery. This is the "made in space" argument. there is a "carried through space" argument as well, where a bit of life-bearing planet is blasted to here, we have meteorites made from mars, for instance. It doesn't explain the start though.
superhuman
5 / 5 (1) Jun 16, 2008
Theres nothing wrong with scientific assumptions as long as they are not passed around as facts.
thales
1 / 5 (1) Jun 17, 2008
Science is not about speculation it is about FACTS


Except for hypotheses and theories.

Scientists have no bloody clue where or when this meteoroid comes from!


They do have a bloody clue. Approximately 86% of meteorites originate from the asteroid belt. They can also try to match up the meteorite's composition with another planet or moon. Do I need to bring up radiometric dating?


Nucleobases are very simple molecules. Mix alot of carbon, some nitrogen and a bit of oxygen (all abundant on early Earth), pressurise and you will end up with all the nucleobases you want and countless other combinations of hydrocarbons! Hydrocarbons are all over Solar System.


Odd that you would mention these points, but I can't really disagree with them. They don't seem relevant to the article though.
ragazzo
not rated yet Jul 03, 2008
Para

Umby_chan.

Eu só queria te conhecer melhor, e manter algum contato de amizade, mas você não parece ser muito sociável... Você me despertou muito interesse desde o primeiro momento em eu que pus os meus olhos em uma foto sua, estranho mais lindo do mundo... Sinceramente, você me faz sonhar mais e mais a cada dia...

=\