Couldn't you get the dinosaurs to bugger off on big spaceships in SimEarth after you'd achieved nanotech?
Beer, as the Vogons are coming...
Rather than dying out in the dimly lit aftermath of a ginormous asteroid impact, dinosaurs on Earth may have instead spread to other planets and built a terrifying space-conquering empire. Organic chemistry expert Prof Ronald Breslow has suggested from new research into DNA that the Jurassic Park monsters may in fact be living …
Why are some parts of science always looking for ET source for original Organic compounds? They had to start somewhere, so surely the most likely explanation is that the ones we have arose (by whatever mechanism) here. They seem to be anxious to have a "creation myth".
Also creatures don't "spring forth" from DNA. Unless you are one of those tiny creatures in the ocean or a Bacteria then Sex between Adults is required. Resulting in eggs or live birthed young.
So both papers seem as likely as Scientology.
If you think life "evolved" rather than "special creation", why not evolved here from scratch. Also if "life" can do it here, then probably "life" arises EVERYWHERE the conditions are suitable, which is likely not limited to our Terran environment. Or if they claim it came on an Meteor where did it start, or was it always somewhere since the Big Bang (Turtles all the way down).
Lets have some logic.
You must be reading a different article. At no point did I read anything about a creator, creation myth, intelligent design or anything else of a similar vein.
The Earth is about 4.5 billion years old and the Universe is nearly 14 billion years old. This means that there was up to 9 billion years for life to evolve elsewhere before the Earth even existed. That is plenty of time for meteor strikes on other worlds to transport genetic materials throughout the Universe. Whether these materials would be enough to seed other worlds is a different matter altogether. The answer as to whether the Earth was seeded with life via meteorites or if it came about independently will depend upon how easily life evolves from the basic building blocks. If it is easy then the odds are that it evolved here independently, If it is difficult then the odds are it was seeded through meteorites bearing the necessary complex amino acids.
But if it came from somewhere else, how did *that* get started...? Either it's possible to evolve life from building blocks, or it isn't. If it is, then all the building blocks existed on Earth so there's no particular obstacle. If it isn't, then someone outside the Universe set it up.
TBH, chirality is just one of the "why on earth is it like that?" evolutionary oddities, like the blind spot in the human retina. I've no argument with people looking for better reasons, but it's a mistake to think that "it just happened that way" is not an equally valid answer.
> Either it's possible to evolve life from building blocks, or it isn't. If it is, then all the building blocks existed on Earth so there's no particular obstacle.
If the chances of it evolving on any particular planet are 1 in ten billion in any given year then the chances are it would not have evolved here. Since there are probably billions of planets out there the chances are it has evolved on at least some of them and then spread from those planets.
If the chances of it evolving on any particular planet are 1 in a million in any given year then the chances are it will have evolved here.
"The Earth is about 4.5 billion years old and the Universe is nearly 14 billion years old. This means that there was up to 9 billion years for life to evolve elsewhere before the Earth even existed."
sorry, your maths is wrong because in this case 9 is not the answer, it took billions of years for the elements upon which "life as we know it (Jim)" to be created in early generation stars, and then spread around the universe and then conglomerated to form planets.
So probably much closer to 3 or 4 billion at most.
And at fairly low speeds, that material then needs to get to another planet, and then fluke into some situation where the DNA could actually do something - odds for example of a bit of chicken aka dinosaur DNA doing anything are roughly zero. Maybe a bacteria but then, you have to give it another 3 billion years to evolve to dinosaur alien overlord type of life (it took several billion years for life here to spew enough waste product (oxygen) for large life forms to be able to exist.)
So all in all, not much time at all and certainly not 9 billion years.
But you don't have a problem with multicellular organisms springing forth from single celled ones? And asexual reproduction happens in many many complex organisms, up to and including some species of shark. And dropping the right sort of genetic material into just the right soup of acids will cause proteins to form. So I don't quite understand your hostility towards this paper.
The lizards bit is unlikely I think. But the non-random distribution of chirality in species on Earth is a problem that a extra-terrestrial source of amino acids would explain neatly.
"the non-random distribution of chirality in species on Earth is a problem that a extra-terrestrial source of amino acids would explain neatly."
I don't understand why "it happened somewhere else and then got delivered here by meteorite" is neater than "it happened here".
" I don't understand why "it happened somewhere else and then got delivered here by meteorite" is neater than "it happened here". "
Because no-one has yet worked out any mechanism or reason why one handedness should be preferred over another, so currently the only solution to the handedness problem is that all (left-handed) life evolved from an extremely tiny set of amino acids / proteins, all of which were left-handed.
If we are taking this option of equal chances of handedness, if life evolved locally we would expect some life-forms (even past extinct ones) to have right-handed DNA. So either the chances of independent formation are so vanishingly small that all life started locally from a single set of amino acids / proteins that happened to be left-handed, or else life developed equally in left and right-handed versions somewhere else, but Earth got seeded with meteorites containing only left-handed amino acids / proteins.
Either way we are talking about ridiculously tiny probabilities of a single event from which ALL subsequent life on earth evolved (ie life on Earth is a stupendously rare coincidence)
On the other hand, maybe the basic assumption baked into the whole argument is wrong, maybe there is a physical / biochemical reason why left-handed amino acids / proteins evolve to life as we know it, and right-handed ones don't, but we don't know of any such mechanism yet. I'd be interested to hear if anyone had any knowledge of any experiment with synthesising right-handed amino acids / proteins and see whether they behave in 'life-like' fashion
It's been done. A number of proteins and peptides have been made with the "unnatural" D-amino acids and shown to behave in an enantiomeric way i.e. only act on mirror image substances. The most spectacular example is probably the HIV protease (original paper in Science only accessible to subscribers).
The Reg article is rather a misrepresentation of Breslow's paper - the dino bit is a throwaway comment at the very end of the article. The rest actually implies the amino acids are made chiral in space under the influence of circularly polarised light (that theory has been about some while). The only significant flaw I can see is that he proposes transfer of chirality on Earth in a transamination reaction involving copper(II) ions, but as the early Earth atmosphere is supposed to have been reducing, I'm not sure of the availability of copper(II).
Hara's paper is a careful calculation of the probability of material moving from one solar system to another, but they acknowledge that it is difficult to estimate the likelihood of anything remaining viable during the trip.
My bet is that life will be almost equally divided between the 2 enantiomeric regimes, but there will be a nagging and unexplained slight excess of one over the other...
"Because no-one has yet worked out any mechanism or reason why one handedness should be preferred over another...."
Because the first complex organism used right handed RNA (DNA not yet being developed), and patented using right handed nucleic acids in life processes, so everybody else used left handed to avoid the patent.
Doubtful - a half competent patent attorney would advise claims covering both left and right handed chiralities. To do otherwise would be to deny the patentee a fair scope of protection for their invention. Not much point in holding a patent that can easily be designed around.
We are still struggling to explain why the universe we live in is mainly made up of matter since equal amounts of matter and anti-matter were created in the big bang (if you believe in that, which I'm sceptical of). Nature, it would seem, prefers to pick a method and stick to it. I also recall seeing an article about how the affects of photons from particular stars can cause amino acids to form in one handedness over another. There will be an explanation, we just haven't found it yet.
I think, though, that this is yet another BS article from El Reg that takes a reasonable hypothesis and shits all over it with sensational National Enquirer like hyperbole. The man said that it's possible the amino acids on Earth originated elsewhere and it's also possible that DNA from our planet has headed out into the cosmos. He did not suggest in the slightest that dinosaurs built space ships and flew away.
"I don't understand why "it happened somewhere else and then got delivered here by meteorite" is neater than "it happened here"."
I think he was talking about if life forms were found on other planets were "left handed" so to speak genetically like Earth. Far more likely that these building blocks are all over the galaxy than the basic building blocks started here and spread all over the galaxy.
Obviously its just a thought exercise at this point, if we discover microbes on Mars or something it may shed a bit more light, but right now the evidence we have supports either option.
Good question. It's because "sinister" and "dexter" refer specifically to the left hand and right hand sides of an object, whereas "laevo" and "dextro" refer to the absolute directions. It's the difference between saying "take the road to your left" and "turn left", if you see what I mean.
Even humans have arses too big too comfortably lift up and accelerate to appreciable speed. I do not think Trannysaurus will drop down in a vehicular device soon. And then again, why not meet them? Because lizard races are hollywoodian ungood?
Anyway, I remember some paper about how the chirality comes about due to [the magic of] galactic magnetic fields working on amino acids buried in comets. So there.
And on a far planet, we read:
"Death Star ape aliens could rule galaxy!!- Rather than dying out in the dimly lit aftermath of a ginormous asteroid impact, apes on Earth may have instead spread to other planets and built a terrifying space-conquering empire...."
The odds of generating a meteor with specific chirality are assumed to be better than if it is happening in billions of places across the surface of the planet. If the meteor lands and those bits become the basis of the proteins and sugars for the planets, it is reasonable for the planet to have a homogenous environment.
All that being said, this is way out on the speculative edge - way way outside science and much more in mythology, except the boffins with all the letters strung behind their names don't like to admit it.
According to this article a meteor could transport only left microbes if, like with the asteroid impact on earth, it came from a planet that had already evolved "left based" life.
But as a starting point on its own, it could of course carry either.
As side note, How long before Spielberg has T Rex's roaming across Pandora for Jurassic Park 4? In 3D of course...
Actually! everyone who says "Voyager episode : Distant Origin 1997" did it first your FAIL ^_~
It was the main "reveal" of the final episode of "Space : Above and Beyond" 1995-1996
Turned out the "Chigs" (aliens bad-guys) were actually descended from either Bacteria and/or Dino's DNA f early earth. It was spread across the galaxy when the Asteroid that killed the Dion's hit earth...
<Quote> the trillion-ton meteorite impact that killed the dinosaurs 65 million years ago may have blasted off small bits of dinosaur DNA out into space. And quite a lot of those bits of dino-carrying rock will have landed on amenable planets, say the paper's authors</Quote>
Does this mean that someone bleeds, puts some cells in a jar, takes a dump or whatever, sends it out into space and waits for it to crash onto a planet it will spontanaeously bring forth life?
To bring this into the realms of being expirementation, what if we drop some road kill on mars. will it :
a. sit there and be cold forever.
b. spring forth life?
Honestly, im curious. it seems a tad oversimplified.
@Fintan: "Does this mean that someone bleeds, puts some cells in a jar, takes a dump or whatever, sends it out into space and waits for it to crash onto a planet it will spontanaeously bring forth life?"
It's almost a certainty that life has at least visited the other planets in our own solar system - it may have even survived. Some forms of lichen, for example, can survive perfectly well in space (exposed to the vacuum and radiation). Aside from meteors blasting stuff into space, it's possible we've even transmitted something in the equipment we've sent to Mars etc.
"... Some forms of lichen, for example, can survive perfectly well in space (exposed to the vacuum and radiation). Aside from meteors blasting stuff into space, it's possible we've even transmitted something in the equipment we've sent to Mars etc. ..."
Yeah but what kind of super touch lichen would survive entering another planets atmosphere on the back of some flamming space rock... surely it would burn up on re-entry?
@RISC OS: "what kind of super touch lichen would survive entering another planets atmosphere on the back of some flamming space rock"
If something is ejected from the surface of the earth by a huge impact, there's no reason to suppose it is necessarily fixed to a rock. And because there is no friction to slow an object in space, it will travel freely until it's drawn into the gravitational field of a larger body. The relatively low density of something like lichen should allow it to decelerate without igniting and slowly drift to the surface. Huge quantities of dust settle on the earth in this manner. You might also recollect that a rock from Mars was found on Earth, and was initially thought to contain the remains of a living organism. The same process could easily happen in reverse, i.e. from Earth to Mars. But it could always have drifted right out of our solar system too.
The real danger is that the dino-DNA depositing debris reaches an inhabited planet before the terrestrial broadcast of Jurassic Park is successfully decoded and some foolish scientists attempt to clone the DNA. Of course, the back-to-front amino acids that the scientists will no doubt be composed of is likely to give T Rex a bad case of heartburn, but that'll only serve to make him even crankier....
...they come back in their UFOs to farm us.
See also David Icke, etc.
Actually any space-faring culture would have to be industrial , and any industrial culture is going to leave traces that should still be visible - even after 65 million years.
So probably not then.
But it's still a good story. :)
 Unless they use magic, obviously.
After 65 million years even the slow tectonic plates are going to have moved a couple of thousand kilometres, and the quick ones double that. That means most of the evidence of an industrial civilisation is going to have been subducted back under the crust.
Sort of a clean up and start again system - a complete renewal every 100 million years or so.
"After 65 million years even the slow tectonic plates are going to have moved a couple of thousand kilometres, and the quick ones double that. That means most of the evidence of an industrial civilisation is going to have been subducted back under the crust."
Aha, the same process by which all evidence of the existence of dinosaurs was destroyed, meaning that we now have no physical evidence they ever existed. No fossilised bones, no fossilised footprints, no tar-pit or amber specimens. In fact, with so little evidence, we never even postulated their existence or invented the word dinosaur!
Is it deterministic that dinosaurs must evolve first before mammals? Disperse some amino acids to 100 suitable planets, and dinosaurs spring forth in all of them. Kill all dinosaurs, and mammals will take their place?
What if the planets are suitable for life, but provide different stimuli for evolution? One might favours flying creatures, another could be 95% covered by water. Can't the same amino acids seed totally different kinds of life forms with different appearances, organs and reproductive systems?
OK, so if the dinosaurs hadn't been wiped out they might still rule the Earth. But mass extinctions happened quite regularly, so surely the dinosaurs themselves only got a look in because the previous apex species (amphibians?) got eliminated. Perhaps the galaxy is really run by newts and axolotls...
In an equilibrium situation, both forms would be equally stable. The process called racemisation would turn an all-D or all-L starting point into a mixture of 50% each.
But the living cell is not an equilibrium situation: it is what my physics lecturers called a dissipative system. This may be in a steady state, but relies on a more or less steady flow of energy.
Within a dissipative system it is possible to imagine that an imbalance, which started at random, could be magnified until it was totally one-sided.
Biochemistry textbooks explain how the complex molecules of life have to be consistently D or L so that they end up in consistent shapes. As examples, this is needed by enzymes; and is needed to get a backbone for DNA.
There are some questions which arise from this comment.
1. Could a steady state dissipative system be set up in a laboratory to synthesise lactic acid or some similar biochemical as one stereoisomer?
2. If so, would its output be random, or is there some subtle effect which would produce always one stereoisomer?
3. Could a whole living cell work with the opposite stereochemistry to what we find in nature?
So old school.
The "we're all left-handed" because of a single seeding event from a source that contains an even distribution requires something much like a limited gene pool to work. In order to have an ecosystem develop an almost exclusive distribution of one type from a starting source that has an even distribution requires a VERY small sample, as with a 50% distribution, every additional lichen/bacteria has a chance of being the wrong type. I have never been able to have more than a few coins turn up the same way in successive coin tosses. That's the nature of 50/50 odds.
In other words, the only way this theory would work is if one meteorite with less than a dozen bacterium/whatever started the whole thing. With a starting sample that small, it is about indistinguishable from having originated on its own from one happy left-handed start via lightning strike in a bowl of primordial soup.
If external seeding is a factor, and seeding would actually work so easily (one thing to plant, and entirely another to harvest...), and life in the universe has an equal chance of originating in either handedness, then seeded planets most likely would have a distribution of both types, a billion years being a short time for the living species we're able to comprehend, the universe being that big, and time in a geological/astronomic sense being an entirely different thing and all.
I'd think that a greater rarity of life-origination events and some functional benefit from leftedness makes a far more likely explanation. Seeding events where right-handed seeds are destroyed in transit/atmospheric entry would also fit the model, and I should wonder if seeding, handedness, and origination are not three different things -- seeding may be simple 'cross pollination' that drives a more rapid evolutionary cycle using compatible seeds, and the mechanism preferring handedness being as yet unexplained.
Its God's sinister plot to populate the universe, I tell ya!
Yeah, I know. IGMC.
Did someone recently discover and watched V or something ?
Now, while his theory seems plausible to me (if DNA has landed here then in theory a big meteor strike could have left our planet also) he assumes that the dna strands actually survived in space as well as found a planet which met all the right characteristics to develop.
However, during that incident we were already well on our way in the evolution process. These "earth-founded lizard aliens" would have to start all over from scratch. Thus even the idea that these strands may - at this time - have evolved into a space traveling society seems a bit far fetched to me.
If life can burst forth from DNA on a suitable planet, then why didn't the dinosaurs re-generate from all their DNA that was splattered around on Earth instead of just, err, ... well dying out, really. Similarly, I haven't noticed even the slightest tendency for dodos or mammoths to spring back into existence.
As for the chirality of life's chemicals, I've always seen it as just a case of spontaneous symmetry breaking. It's advantageous for all life to use the same system - so you can eat things easily (food chains being a pretty fundamental feature of Earth-based life). Therefore edible living stuff has to be all left, or all right. The choice is down to chance.
The success of humans is dependent on the ability to cooperate. Sophisticated technology requires many hands and minds to work together with a reduced tendency to exploit, threaten, kill and/or eat their neighbors. Of course, it's an ongoing battle between exploiting your fellows as resources or partnering up to get the big stuff done because the many biological payoffs are with the exploit and cheat strategy.
In the end, it's the dinosaurs/newts/whatever that have evolved the cooperation genes along with brains that will be able to build spaceships. I doubt they'll think we are just a new type of breakfast.
I've noticed a lot people throwing around probability as reason why life would have ET origins, speaking from the perspective of a true layman surely the probability of:
Life starts on Melmac (Which is a billion in 1 event as someone else has already used as an arguement against earth origin)
Melmac has massive catastophic event
Small chunks fly into space and with a few bits of Alf strapped on
Tiny bits of Alf manage to survive the millions of years flying through space
Tiny Alf rock manages to manages to find its way to earth (space is really big. You may think its a long way to the shops, but thats just peanuts to space (DA))
Alf manages to survive the intense heat of entering the earths atmosphere
Each one of those steps has a massive probability of failure, surely probability actually favours life starting here?
That depends on the nature of the first self-replicating molecular assembly that gets chemistry started towards life. It certainly wasn't DNA or RNA or life as we know it. It almost certainly doesn't exist any more on this planet, because life as we do know it would eat it or disrupt it.
Some speculate it was a clay-like mineral. If so, it might be remarkably tolerant of interstellar radiation and re-entry. Panspermia is a perfectly respectable theory. However, it's all complete speculation. We have no data to prove or disprove it with.
It hasn't actually been shown to be all that useful. Our dinosaurs never bothered with it and their time on the planet eclipses ours into insignificance. I can buy that life may be inevitable given the right mix of elements and conditions, but I don't buy that intelligence is an inevitable byproduct. There's just so little intelligence around as it is.
You're generalizing from one datum (and the experiment hasn't been running long enough to give any confidence in predicting the long-term outcome). Maybe intelligence always self-destructs (one solution to the Fermi paradox), and maybe it doesn't. Unknown at present.
If you take a wider definition of intelligence, one can observe that the invertebrates have evolved intelligence up to at least the level of a cat, completely independantly of our branch of the tree of life. (Octopuses, if you were wondering). They've also been observed using tools.
There's no mystery at the chemical level. L-amino acids form polymers (proteins) with other L-amino acids, and D-amino acids with other D-amino acids. These chains then fold up into spirals and sheets. Spontaneous bonding between L- and D- amino-acids is chemically unfavorable, because the molecules don't fit together properly.
So, if the first self-replicator was L-based, that would have fixed life (or pre-life) on the L-form, and soon the D-acids in the environment were reprocessed by it/them into small non-chiral molecules (i.e. used as food). Once the L-basis of life was established, it could never change. L-based life can't assemble things out of D-bases, but it can and does use them as fuel when they arise spontaneously.
The deep question is why was the first self-replicator to use amino-acid polymers based on the L-form? The answer may be that symmetry was broken at random. The pencil balanced on its point had to fall one way or the other. If so, and if we can ever find any other life to study, there's a 50% chance it'll be based on D-amino acids.
However, there's a much deeper broken symmetry that is itself chiral. The weak nuclear force. Because of this, the binding energy of L-amino acids is very slightly greater than that of D-amino acids. In a mixture formed by inorganic chemistry from achiral precursor molecules, there will be about 100 more L-molecules per mole than D (i.e. 1 part in 6.10^21). Was this enough to tip the balance? Is L-based life universal, thanks to a physical symmetry that broke almost immediately after the big bang itself? Can we ever know?
Back to trivia. In a few cases some living organisms manufacture an L- molecule and others the same molecule in D-form. What's the difference between lemon flavour and lime flavour? One is L-, the other is D-limonene! Why is 7-up "Limon" flavoured? Because in a chemistry lab, it's far easier to cook up a racemic (50/50) mixture, and that's what your fizzy water is flavoured with.
Was, I think, quite well highlighted in this response
It makes me wonder whether next month's issue will include a fairy cake recipe for those who want to build a Total Perspective Vortex in their backyard.
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