New evidence comets gave prebiotics to Earth:

http://phys.org/news/2013-03-evidence-comets-seeded-life-earth.html#ajTabs

Bye Bye Creationisim, hello abiogenesis🙂

I knew it was aliens all along 🙂

Originally posted by sonhouse
Bye Bye Creationisim,.....

Creationism is a religious belief and was largely dismissed by science over a hundred years ago, but persists today in religions and will continue to so persist despite any evidence to the contrary.

Originally posted by twhitehead
Creationism is a religious belief and was largely dismissed by science over a hundred years ago, but persists today in religions and will continue to so persist despite any evidence to the contrary.

its you who will look silly when the little grey men arrive 🙂

Originally posted by sonhouse
http://phys.org/news/2013-03-evidence-comets-seeded-life-earth.html#ajTabs

Bye Bye Creationisim, hello abiogenesis🙂

I saw and read that link some time ago. I wasn't impressed by it for the same reason why I am never impressed by the all-to-common suggestion that the organic chemicals necessary for life came from outer space -simulations of the early-Earth clearly show that all the necessary organic chemicals for the first protocell to form would have spontaneously formed on the Earth without any of it required to come from outer space.

Also, the amounts of those necessary chemicals spontaneously formed on the Earth would surely dwarf the amounts coming from outer space! That's because these chemicals would have been continually generated all over the globe!
And, in addition, I would guess that much if not very nearly all of the complex organic chemicals from outer space would be just destroyed by the intense heat when the meteor/comet enters the Earth's atmosphere and then either blows up in the atmosphere or blows up on the ground!
And this appears to be confirmed by the link itself which says:

"While scientists have discovered basic organic molecules, such as amino acids, in numerous meteorites that have fallen to Earth, they have been unable to find the more complex molecular structures that are prerequisites for our planet's biology"

-this surely suggests that the amounts of complex organic molecules coming from outer space would have been, at best, tiny!

(I have basically said all the above in the post I have now put on at the bottom of that link)

Originally posted by humy
I saw and read that link some time ago. I wasn't impressed by it for the same reason why I am never impressed by the all-to-common suggestion that the organic chemicals necessary for life came from outer space -simulations of the early-Earth clearly show that all the necessary organic chemicals for the first protocell to form would have spontaneously formed on ...[text shortened]... ave basically said all the above in the post I have now put on at the bottom of that link)

Yes, it could just as well have originated as you say, for one thing there are ocean floor vents providing heat which can drive chemistry and clays have been implicated in creating the first bags for organics to generate, perhaps later the clay was replaced by membranes. I guess it all depends on the energy conditions, how long energy sources lasted and such. Lightning would give millisecond pulses of high energy, sunlight diffuse lower energy but longer lasting, ocean vents high energy for a relatively long time. Ice could be an incubator also. We will see how it plays out in the next couple decades, I think.

Originally posted by sonhouse
I guess it all depends on the energy conditions, how long energy sources lasted and such.

Not its all about quantities. There is simply so much more room for variety and chemistry on earth and nothing particularly unique about meteorite chemistry that there is no good reason whatsoever to think they were involved even remotely. In fact the article you linked gives no justifications whatsoever for even thinking that meteorites were involved.

Originally posted by humy
I saw and read that link some time ago. I wasn't impressed by it for the same reason why I am never impressed by the all-to-common suggestion that the organic chemicals necessary for life came from outer space -simulations of the early-Earth clearly show that all the necessary organic chemicals for the first protocell to form would have spontaneously formed on ave basically said all the above in the post I have now put on at the bottom of that link)

I think you get bucky balls in space (in the vacuum) along with simple organic componds. Wonder if something could grow out of them? it wouldn't be a prebiotic tho... remember 'The Andromeda Strain' ?

Originally posted by sonhouse
Yes, it could just as well have originated as you say, for one thing there are ocean floor vents providing heat which can drive chemistry and clays have been implicated in creating the first bags for organics to generate, perhaps later the clay was replaced by membranes. I guess it all depends on the energy conditions, how long energy sources lasted and suc ...[text shortened]... ce could be an incubator also. We will see how it plays out in the next couple decades, I think.

Sunlight would have provided much more energy pre-life than now. No life would mean no oxygen in the atmosphere and therefore no ozone layer to block high energy UV light. This is one more reason why hydrothermal vents are regarded as likely starting place for life, the energy present is sufficient to drive chemistry without destroying larger molecules.

Originally posted by Kepler
Sunlight would have provided much more energy pre-life than now. No life would mean no oxygen in the atmosphere and therefore no ozone layer to block high energy UV light. This is one more reason why hydrothermal vents are regarded as likely starting place for life, the energy present is sufficient to drive chemistry without destroying larger molecules.

If that is the reasoning behind life starting around or in hydrothermal vents then the reasoning is flawed and because of two reasons:

1, a large amount of UV radiation would not have got in the way of protocells forming within, say, an UV-exposed tidal pool.

2, the first protocell might not have needed any of the very large complex organic molecules that life depends on today but had relatively simple organic molecules only like those found to spontaneously occur in physical simulations of the early-Earth done in the lab and with constant UV exposer. So UV radiation breaking up the very complex organic molecules would not have stopped it.

Personally, given the current evidence, I think that the most likely place for the first protocell to have formed that then evolved into life would by in a UV-exposed tidal pool because regular drying or partial drying when the tide was out would have helped concentrate the organic molecules there and that should help the process I think.

Originally posted by humy
If that is the reasoning behind life starting around or in hydrothermal vents then the reasoning is flawed and because of two reasons:

1, a large amount of UV radiation would not have got in the way of protocells forming within, say, an UV-exposed tidal pool.

2, the first protocell might not have needed any of the very large complex organic molecules that ...[text shortened]... ld have helped concentrate the organic molecules there and that should help the process I think.

The problem with UV is that it breaks up the large molecules required for membranes so the first life might not have been a protocell at all if it was in a small tidal pool. The whole pool could have been a single organism. The problem then becomes "What is life?" rather than where did it start. Ask a collection of n biologists what life is and you will get n+1 answers.

Another possible locality is volcanic mud pools. The mud provides shielding from UV and there is abundant energy from heat and chemistry, much like at hydrothermal vents. There are other possibilities as well. In the end, you just have to decide what you like best and then modify it if and when some evidence for where and what the earliest life was is found.

Originally posted by Kepler
The problem with UV is that it breaks up the large molecules required for membranes so the first life might not have been a protocell at all if it was in a small tidal pool. The whole pool could have been a single organism. The problem then becomes "What is life?" rather than where did it start. Ask a collection of n biologists what life is and you will get n ...[text shortened]... nd then modify it if and when some evidence for where and what the earliest life was is found.

The problem with UV is that it breaks up the large molecules required for membranes

The first membranes of the first protocells may have been and probably were made of nothing more than oily saturated hydrocarbons or, alternatively, saturated fatty acids with none of the delicate complex proteins that exist today (I will give some relevant links on this on request). Neither saturated hydrocarbons or saturated fatty acids are easily damaged from intense UV light (partly because they don't have double carbon-to-carbon bonds) as shown by the physical simulations in the lab.
UV would not have been a problem at all for the start of the first life. UV may have been more of a problem later on as life evolved to have more complex molecules that are not so UV resistant but, by then, that life could have easily moved to the deep-ocean.

Originally posted by humy

The problem with UV is that it breaks up the large molecules required for membranes

The first membranes of the first protocells may have been and probably were made of nothing more than oily saturated hydrocarbons or, alternatively, saturated fatty acids with none of the delicate complex proteins that exist today (I will give some relevan ...[text shortened]... that are not so UV resistant but, by then, that life could have easily moved to the deep-ocean.

I wonder if anyone knows about oceanic vents, if they were present say 1 billion years ago. It seems to me if so, and were there for a few million years, that could have been an ideal environment for abiogenesis. Abundant energy for reactions and the temperature gradients that could have driven early organic prebiotic chemstry. It might be 700 degrees C at the vent, water that would have been steam but for the extreme pressure at the depths of the ocean but just a few feet away the temperature would have gone to way under 100 degrees C so life could have evolved from the beginning right there.

Originally posted by sonhouse
http://phys.org/news/2013-03-evidence-comets-seeded-life-earth.html#ajTabs

Bye Bye Creationisim, hello abiogenesis🙂

RH Hinds has ya in a tizzy.

There is probably some highly advanced silicon life form from outer space living on earth right now, just its always been mistaken for a rock! As for prebotics from space.... i doubt it... but we are putting bacteria and fungi into space as we travel. so maybe someone else has?