Comet Impacts May Have Led to Life on Earth

Well, this is an old theory but it now it seems we have more proof on the subject;

Comet impact on Earth are synonymous with great extinctions, but now research presented at the Goldschmidt geochemistry conference in Prague shows that early comet impact would have become a driving force to cause substantial synthesis of peptides - the first building blocks of life. This may have implications for the genesis of life on other worlds.

Dr. Haruna Sugahara, from the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) in Yokahama, and Dr. Koichi Mimura, from Nagoya University performed a series of experiments to mimic the conditions of comet impacts on the Early Earth at the time when life first appeared, around 4 billion years ago.

They took frozen mixtures of amino acid, water ice and silicate (forsterite) at cryogenic condition (77 K), and used a propellant gun to simulate the shock of a comet impact. After analyzing the post-impact mixture with gas chromatography, they found that some of the amino acids had joined into short peptides of up to 3 units long (tripeptides).

Based on the experimental data, the researchers were able to estimate that the amount of peptides produced would be around the same as had been thought to be produced by normal terrestrial processes (such as lighting storms or hydration and dehydration cycles).

For me is entirely possible that life could came from elsewhere. But i also believe life has more than one way to show up from nowhere. Either way, comets brought enourmous quanties of water to our world.

According to Haruna Sugahara, "Our experiment showed that the cold conditions of comets at the time of the impacts were key to this synthesis, as the type of peptide formed this way are more likely to evolve to longer peptides.

"This finding indicates that comet impacts almost certainly played an important role in delivering the seeds of life to the early Earth. It also opens the likelihood that we will have seen "similar chemical evolution in other extraterrestrial bodies, starting with cometary-derived peptides.

"Within our own solar system the icy satellites of Jupiter and Saturn, such as Europa and Enceladus are likely to have undergone a similar comet bombardment. Indeed, the NASA stardust mission has shown the presence of the amino acid glycine in comets.

Sauce

Always found this theory impressive because we look at comets as bringers of death and destruction , while on the long run these rocks might just be where life is originated from.

This is why I find the rosseta mission and stardust very interesting because they might give the answers to the question where does life come from or the building blocks for life that is.

I also heard that comets are responsible for bringing the majority of water to the earth.

a reply to: Frocharocha

And the very important implication of this discovery is that life elsewhere could actually be quite similar to ours. Simply put: if comets all carry the same approximate chemical makeup, and if planetary life is seeded by these comets, then most life (at least in our sector of the galaxy) will share the same approximate chemical makeup.

S&F for the thought-provoking OP

a reply to: swanne

Sort of depends on what you mean by approximate. They may all be composed of amino acids, but could have different coding mechanisms, or even decoding. Here's a theory of the origin of life that's backwards of what's usual. It has a simplified DNA being solely self-replicative at first, and only after a long, long time does coding start.
stanericksonsblog.blogspot.com...

Great science. Comets MIGHT have led to life on Earth.

Or it might NOT have.

Glad we got that nailed down.

So was it like Noah's ark?

Or just one tiny hitchhiker who luckily survived and has grown into all life we know on this planet?

a reply to: swanne

Where do these comets come from? It must have had contact with some sort of life, an exploded planet that ones had living organisms?

a reply to: intergalactic fire

The theory is not that there was existing life on comet which was deposited on Earth but that comets containing amino acids (which do not require life to form) impacted with Earth. It is theorized that the pressures, temperatures and energies involved during the impact can cause the already existing amino acid molecules to bond together to form peptides, important for the formation of proteins.

To me this is sort of a double edged sword. The thought of discovering hints of life elsewhere in our solar system and beyond is very exciting. But now if/when scientists announce that peptides have been detected on say Mars or Europa the news won't be nearly as exciting as we now have a working theory for peptide formation that does not require biology.

originally posted by: intergalactic fire
a reply to: swanne

Where do these comets come from? It must have had contact with some sort of life, an exploded planet that ones had living organisms?

The idea is that comets can carry complex hydrocarbons (organic molecules) and thus "seed" a planet with them, allowing for life to develop. It's not like comets carry the actual microbes.

Comet come from primordial material that forms a system around a star (such as the Solar System around the Sun). Water, carbon, and even hydrocarbon molecules, form from elements created within stars and expelled in supernovae.

a reply to: Blue Shift

It's somebody adding an option they thought of. Organics can form on earth in several ways, and some can arrive on an impacting comet. Which source led to the formation of the first life? Nobody can tell, as there is no evidence that remains.

a reply to: intergalactic fire

This is probably a more interesting question that you thought. Comets reside and are likely formed out in the far reaches of the solar system, but just why there is a preponderance of lighter elements out there and the heavier ones migrated in to form the inner planets is not quite clear. Don't know if the solar wind could be responsible.

a reply to: Syphon

So in other words, In order to have 'life' you need the right ingredients and one of those is carried by comets?

originally posted by: intergalactic fire
a reply to: Syphon

So in other words, In order to have 'life' you need the right ingredients and one of those is carried by comets?

Not just one. Several.

Water is the big one but other volatiles are thought to be delivered by comets early in a solar system's life.

See also: The Composition of Cometary Volatiles - D. Bockelée-Morvan and J. Crovisier - Observatoire de Paris, M. J. Mumma - NASA Goddard Space Flight Center, H. A. Weaver - The Johns Hopkins University Applied Physics Laboratory

originally posted by: wildespace

originally posted by: intergalactic fire
a reply to: swanne

Where do these comets come from? It must have had contact with some sort of life, an exploded planet that ones had living organisms?

The idea is that comets can carry complex hydrocarbons (organic molecules) and thus "seed" a planet with them, allowing for life to develop. It's not like comets carry the actual microbes.

Comet come from primordial material that forms a system around a star (such as the Solar System around the Sun). Water, carbon, and even hydrocarbon molecules, form from elements created within stars and expelled in supernovae.

^^^ THIS.

originally posted by: StanFL
a reply to: intergalactic fire

This is probably a more interesting question that you thought. Comets reside and are likely formed out in the far reaches of the solar system, but just why there is a preponderance of lighter elements out there and the heavier ones migrated in to form the inner planets is not quite clear. Don't know if the solar wind could be responsible.

Here is your answer: Frost line (astrophysics).

In astronomy or planetary science, the frost line, also known as the snow line or ice line, is the particular distance in the solar nebula from the central protostar where it is cold enough for volatile compounds such as water, ammonia, methane, carbon dioxide, carbon monoxide to condense into solid ice grains. This condensation temperature depends on the volatile substance and the partial pressure of vapor in the protostar nebula.

In other words its a function of temperature during a planetary system's formation and that temperature depends on the protostar as well as pressure in the nebular and the type of volatile you're talking about.

a reply to: swanne

if comets all carry the same approximate chemical makeup, and if planetary life is seeded by these comets, then most life (at least in our sector of the galaxy) will share the same approximate chemical makeup.

Do you think they'd all be based on DNA and RNA replication? Same bases?

That would be interesting. Interstellar interbreeding.

originally posted by: StanFL
It's somebody adding an option they thought of. Organics can form on earth in several ways, and some can arrive on an impacting comet. Which source led to the formation of the first life? Nobody can tell, as there is no evidence that remains.

This notion has been floated around for decades. It was the origin story of The Blob. This particular study adds essentially nothing to the mix, other than possibly, maybe, a little bit increasing the odds, but not really, because as you say, if space rocks are full of organic molecules, then the Earth probably had a crapload of them already. Is that science?