back to article New evidence: Comets seeded life on Earth

Ever since its formation, the Earth has been bombarded by comets, and scientists think they now have evidence that these cosmic missiles could have carried the building blocks for life along with them when they impacted. In 2009, NASA's Stardust mission rendezvoused with the comet Wild-2 and returned to Earth with a sample of an …

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Anonymous Coward

WTF : who says men's nipples are a useless organ ??

Sad, sad, sad !

http://www.cosmopolitan.com/sex-love/advice/men-nipples-sensitive

I'd choose the Paris icon here, she'd know what to do with a man's nipples !

(clue: it's evolution, fellas - the more you like to do it, the more kids you sire - and guess what they'll like to do more of ??)

Facepalm icon is another possibility I'm cheerfully foregoing here .....

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Silver badge

Re: WTF : who says men's nipples are a useless organ ??

Exactly, male nipples are far from useless, Iain just hasn't found the right lady yet!

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Anonymous Coward

God arrived by comet!

Comets brought the building blocks for life...

The building blocks created life as we know it...

Man created God...

Ergo: God arrived by comet!

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Silver badge

Re: God arrived by comet!

Blitzen was having a day off?

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Childcatcher

Re: God arrived by comet!

He may well have done, but what sort of shielding did He use to prevent incineration on entry to the atmosphere and the thermal event of impact?

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Joke

Re: God arrived by comet!

he's god - he doesn't need shielding.

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Re: God arrived by comet!

"he's god - he doesn't need shielding."

No no - you're thinking of Chuck Norris.

God needs shielding of course, poor little poppet. That's why we have the Holy Inquisition and blasphemy laws.

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Yag
Joke

Re: God arrived by comet!

> he's god - he doesn't need shielding.

Neither other kind of protection, just ask Mary...

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Anonymous Coward

Re: God arrived by comet!

I knew there would be a "god" element to it.

So planet earth was like a big egg and god cracked one off and it hit the earth, bringing it to life?

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Boffin

Miller-Urey experiment is ongoing

Miller-Urey will probably remain ongoing for at least another century. It is currently under the care of their protege Jeffrey Bada.

Just now we have an interstellar comet called Siding Spring headed toward Mars on a hyperbolic course. The hyperbolic shape of its course and its speed tells us that it cannot be from our solar system and won't be staying unless it hits something. It already has solar system escape velocity, as any mass entering Sol's influence naturally would - an object in motion remains in motion... The coma, or "head" of this comet is almost certain to scatter debris on Mars from its interstellar journey and its distant home. The coma is expected to have a larger radius than the average Mars miss distance. There is no telling how far it has flown but that it is not from here is certain. That coma is a considerable threat to our Mars system assets as to be hit by a flyspeck of something moving 55km/s is outside of worst-case design spec.

As it tracks through about two light-years of sol system's Hill Sphere Siding Spring will naturally pick up material from here - dust and gas from the solar system's creation, bits of asteroid, some microscopic interstellar particles, and debris from asteroid and comet collisions with Earth and Mars. As asteroids have struck Earth since life arose with sufficient force to knock bits of life-bearing matter off, it is likely the comet will scoop up some of that, and it's notable later in this story. It might land on Mars with its full payload, but that outcome is unlikely. If that does happen it will be quite dramatic, blasting up to a 500km crater 4km deep in the surface - roughly 7% of Mars' diameter. That blast has been calculated as up to as much energy as 20 billion megatons of TNT equivalent - on par with a dinosaur killer. You would be able to see it as an increased brightness of Mars unaided by a telescope. Mars would be warm for a while, and all our orbiting and landed science would likely be destroyed - but hopefully they might send back great science and dramatic pictures first.

If it misses Mars and the Martian moons it will not make the grand tour of the major planets. It's coming from off the main plane of the solar system and departs the same way without interacting with any other planet's sphere of influence. Away it will go into the dark carrying with it the mysteries it brought, and a few it picked up here. At some future time it will dispense this bounty throughout another solar system - as comets do, mostly as dust that will fall on all bodies there.

If it misses back into the dark it will go, disappointing thousands of planetary scientists and carrying with it proof that at least the dinosaurs - but not we - were here. There is little chance that it will not fall into another sun's sway some day, collide with an object large enough to break it up, or otherwise end its journey. Space is vast but it's not that vast, and time is long. Over eons Siding Spring's Earthly Life discoveries - barring a Mars hit - will be spread throughout our local group of stars, and over the next billion years spread throughout the Milky Way. Life is unbelievably toxic and persistent, so some fragments of it are certain to fall on fertile ground just from this one comet that we see, let alone the billions that we didn't.

It's likely that these wandering comets pass through our solar system every year and this is just the first one we've seen come so close to the sun that we can see it. The prospect is exciting - it has a lot to teach us about the mixing of masses in the galaxy. If a hyperbolic comet can carry samples of Earth life away to a different star, then a hyperbolic comet can bring the life from another star here. For all we know Earth gets hit by one of these every 30 million years and passes through its coma quite more often. In terms of the age of the galaxy Earth is quite young, this cometary composition has been quite common for more than three times the age of our solar system, there is considerable mass exchange between stars.

If this one picks up life from here and carries it to another star who are we to say that life as we know it didn't arrive here this same way? We have actual, factual evidence of interstellar comets and the rest we know for fact too. Life began on Earth suspiciously soon for biogenesis to happen here. The Milky Way had an 8 billion years head start on us, and a vaster field for biogenesis to occur by about 20 billion times.

Intelligent life is a different question. Given our own experience it seems unlikely even here, and likely to be brief as well given our lack of interest in off-planet backups and the narrow window in which such a thing is possible. Soon the Holocene interglacial epoch will end and then it's back into the cold and dark for us as well - and with it our ability to save Man from what seems an inevitable collision with physics. If we fail to achieve interplanetary persistence it's likely Man will die out or at least lose his science culture sometime in the next 5,000 years - and that figure is extremely generous.

Panspermia theory just got a big bump. Fermi is still equal weight. If we navigate this danger then Fermi looms: why didn't others?

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Mushroom

Re: Miller-Urey experiment is ongoing

Nice analysis, but where did you get the idea that this comet has come from outside the solar system? According to NASA it's from our own Oort cloud (http://www.nasa.gov/mission_pages/asteroids/news/comet20130305.html).

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Re: Miller-Urey experiment is ongoing

It's all about the speed. It's moving too fast to be from our solar system. The reportage will be corrected later.

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non-Keplerian orbits

Nice comment, however, not arguing with you about the panspermia idea in the whole, have to say about this comet's orbit though.

It is hard to claim that this comet is coming from outside of the solar system, since although the eccentricity is greater than 1 right now, however it is not "much greater" than 1, hence it's not stable (according to NASA). Of course, it's not the classical 2-body Keplerian dynamics Sun-body we should use, but a non-Keplerian one where you have to incorporate gravitational perturbations of other (large) bodies, such as giant planets. The eccentricity oscillates around 1, (I guess.) Hence, the you cannot posit with high certainty that the initial conditions for this comet (as well as other higher than 1 ecc. ones) .

Very few comets seem to have significantly higher ecc. to rule out 3d bodies perturbations, hence Oort came up with his namesake hypothesis.

Remember that the ratio between the two velocities, v_c,the one to stay on the circular orbit and v_e, the to escape the solar system for the given distance to Sun is 1/sqrt(2). Since

(v_c/R)^2=(a/R), where a is the centrifugal acceleration equaling the negative of centripetal acc. due to gravity. While for the escape velocity you need to "cancel" the gravitational potential M_S*G/R by the kinetic energy mv_e^2/2 .

So for the Earth it's about

v_c=sqrt(MG/R)=27,700 m/s and

v_e=sqrt(2MG/R)=42,127m/s

where M is the mass of the Sun, R is the mid-distance from the Earth to the Sun, G- the grav. constant For Mars it would be divided by appr. sqrt(1.5) (since R for Mars is about 1.5 AU), so the escape vel there is 34,397m/s How does this comet pass it to be about 55,000 m/s relative to Mars, I don't know. Of course, if you get a comet getting out of the hypothetical Oort's cloud which could go as far as 50,00AU you get

v_e=188 m/s, v_c=133m/s , respectively, not too far apart as you can see.

--

**PS calculations are done in the GNU Emacs' calc

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Stop

Appendix not useless

Just for the record: the appendix function has been found. Its use is to harbor intestinal flora and to reseed the colon with beneficial bacteria after a diarrhoea. As such, it's either a nice piece of evolutionary work, or another proof of intelligent design, depending upon your axioms.

Given the prevalence of diarrhoea-giving diseases, the appendix probably improves mankind's survival rate. From which you can deduct that death from the aftermath of a cholera-type disease was historically a bigger risk than appendicitis.

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Neither are man boobs.

Wasn't there a story about a chinese guy who started lactating and breast feeding his daughter after the death of is wife a few years ago?

then doctors did confirm that men CAN in certain circumstances lactate?

Not so useless now eh?

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Bronze badge

Re: Neither are man boobs.

And when you vomit out all of your internal flora after reading about that chinese guy, you appendix will kindly reseed your guts with replacement flora.

Hmmm, interlinky.

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Trollface

Re:Re: Neither are man boobs.

Read up on fetal development.

in the early stages, there is no difference between men and women (physically, that is).

Since women need to be able to nurse the babies, then the men have at least the rudimentary equipment. It just doesn't develop without the hormones.

A great many 'sex differences' arise because in some fashion, men are 'immature women' and women are 'immature men'.

It doesn't prove ANYTHING about whether humans arose accidentally, or by a guided design. both are theories without any real proof.

In spite of what some preachers say, the bible says "something was done", but says nothing about "how" it was done.

Similarly, in spite of what some atheists who study or more properly philosophize about development of living systems and creatures say, evolution says that something had to have happened, but says nothing about what that may have been. All evidence we have can be interpreted either way. You see what you want to see.

Don't let either side get away with the false premise that they have 'won'. They haven't, and probably never will 'win'. The religionists err by proposing that they know more than God (or at least more than God has chosen to say). The philosophers (scientists answering questions outside of their demonstrable area of expertise, or proposing solutions that they cannot demonstrate) err by proposing that they know the 'final' answer, without having any testable reproducible way to verify the hypothesis they put forward.

Mr. Dawkins is constantly reduced to mere name calling for evidence. He and his ilk are really no better than the blind sort who insist that we have to abandon science and just 'have faith', without ever knowing what faith is.

(Faith is a very old word. It means that you keep your promises. Faith in your wife is EXACTLY the same as faith in God. You promised (men) not to get intimate with any other woman when you got married. If you don't 'betray' her, then you are faithful. if not, then you are not. So it is with God. If you keep your promises, then you are faithful. If not, then you are not. If you have made no promises with God, then you cannot ever be faithful. Just saying 'I believe will do nothing. And, Yes, I realize that means that 95% or more of all Christians are not among the 'faithful'. The same holds true for Jews and Muslims, too.)

Both sides are wrong to even have this 'debate'.

The correct answer is we don't know yet. Keep looking. Much more research is needed. We not only don't know the answers, we don't even know all the questions yet!

I wouldn't expect that to change in the foreseeable future.

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Anonymous Coward

Couldn't leave it alone, could he ...

Pretty generic Q-land theory of life-on-earth. Electrozap damn near anything and out comes a peptide. WooHoo kinda like how random sets of non-linear differential equations regularly produce quasi-periodic solutions. But at the end he couldn't leave it alone; inane TOEboi spew.

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The most interesting question is...

...whether the comet that seeded life on Earth - if one did - contained life to begin with, from some other body. The sooner we can get decent comet samples back down to Earth for detailed forensics the better!

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Happy

Re: The most interesting question is...

The sooner we can get decent comet samples back down to Earth for detailed forensics the better!

Given the most reliable way of getting a decent comet sample to Earth involves a collision between the two, forgive me if I don't share your enthusiasm...

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Boffin

Re: The most interesting question is...

Given that the comets who visit Earth have probably spent the last couple of million millenia in the Oort cloud, in an environment where even hydrogen freezes, it'll be a plucky lifeform that came from there. Maybe a Scot?

Anyway, the soonest clue should come from ESA's Rosetta mission, which, though it doesn't take a comet sample to a lab, will take the lab to the comet around this time next year, and hopefully will give us a better understanding of the sorts of stuff we find there - always assuming the hypothetical Scottish comet-dwellers don't eat it first.

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Mushroom

Re: The most interesting question is...

Bacteria form cysts. These cysts freeze well, and can be revived any time they warm up enough to sit in liquid water. In a well frozen environment, as long as they are safe from too much radiation (some bacteria can withstand several thousand times as much radiation as we humans can) they could last for a Billion Years as deep frozen crystals.

Many bacteria and mold spores can even survive naked in space for a while, and some even survive 're-entry'. Remember, it was mold that doomed MIR. The Russians are reported to have even tried evacuating all the air for an hour or so. No effect.

Scum is tough!!!

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One small step

So a new twist on the famous Miller experiment has produced an amino acid.

This is still a long way from producing the large-scale regularity and precision of cellulose, protein, or DNA. That last is not just the codons A, C, G, T, but a precise backbone of sugar and phosphate.

In the 1970s, A. G. Cairns-Smith, then a senior lecturer in chemistry at Glasgow University, wrote his famous book Genetic Takeover. As a chemist rather than a biologist, he emphasised the sheer difficulty of organic chemistry: "the outcome of a loosely controlled organic synthesis is usually a very complicated mixture of metastable molecules - a tar of some sort".

We seem to be as far as ever from bridging the gap between amino acids and proteins/DNA. Cairns-Smith suggested an intermediate stage catalysed by clay. Current thinking seems to favour sea water percolating volcanic rocks under the ocean.

We shall understand living cells much better once we have created them. I am 68 but still hope to see that in my lifetime.

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Stop

Men can lactate. Men can breastfeed. Male nipples are not useless, they're just rarely used.

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Anonymous Coward

Re men's nipples, shouldn't he fanboi icon be the most appropriate?

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Alien

Your nipples don't work?

How do you pick up Jazz FM?

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Paris Hilton

Spookily - this has been predicted in the past with working methods of comets as "bringers of stuff" to human (and others?) cell activities.

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Pint

Yeah right...

... 'cause 13.77 billion years is ~so~ much better than 4.5 billion years. [sarcasm off]

Point being, this 'Panspermia' hypothesis is perfectly possible, but perfectly unnecessary.

Life not only evolved on Earth directly (and almost immediately at that), it almost certainly happened multiple times and places in parallel. The first life strain to invent teeth won.

Chemical reactions double in speed for every +10°C. The cold dark vacuum of space is no match for a warm puddle on Earth.

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Alien

Re: Yeah right... SORRY

Sorry to rain on your parade, but, per reputable biologists, in terms of number of species, habitat range, and even in terms of total mass, we aren't living in the Age of Mammals, it is the Age of Bacteria, and it always was. As far back as we can measure.

Bacteria are there in the oldest rocks we have ever found. They are in the deepest wells we have ever drilled, and we find them in the highest balloons we have ever sent up to the edge of space. The bacteria and the virus strains that prey on them are the oldest and most widespread forms of life. they evidently appeared as soon as rock solidified. Yet, we have never managed to create one from scratch. Most of the pieces, yes, but a complete organism? No. that's why the Panspermia hypothesis keeps coming back. There just wasn't time. If it could have happened that fast, then it would have happened in a lab by now. It hasn't. given the number of variables that have to be right, it won't.

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FAIL

Poor experimental design?

The article says the experimenters used high-energy electrons to simulate cosmic rays, but wiki says 99% of cosmic rays are in fact electron-free positively charged atomic nuclei (mostly naked protons). This naive reader would think the discrepancy would invalidate the experiment due to poor design, had he been one of its peer reviewers.

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