I have been reading with great interest the subject "When did
life start on Earth? In the General Science Forum.
A very interesting subject started by Bill (Oklahoma), and continued by Paul, and Samwick, etc. with a number of excellent url, contributions by New Scientist, and National Geographic Magazine.
I dont wish to intrude upon this particular discussion, but I would like to set down my own ideas as to how life might have started upon Earth, with logical explanations.
I am excluding the Biblical or Religious accounts, and am quite amazed that no one has come up with the idea that PANSPERMIA was responsible for seeding life upon our Earth.
At least three derivative theories of PAMNSPERMIA exist. Lithopanspermia and Ballistic panspermia, for example, contend that when an asteroid or meteor strikes a planetary body on which microbial life exists, that it is possible for the debris from that planet to be ejected into space. The debris would presumably carry microbes across interplanetary, in the case of ballistic panspermia, or even interstellar distances, in the case of lithopanspermia, where it could later land on another body, seeding it with the molecules that are the basis for life.
Given the usual non-provable ideas put out by various scientific publications. Such as....within the warm pools of water, or within the damp muds on land. Or the hot plumes of upwelling waters deep within the Oceans, or within the oceans themselves.
Each has their detractions, but I dont believe one should allow detractions, when we decide how life might have started on earth.
So I will now try to counter some previous ideas with (hopefully) logical claims of my own.
Panspermia depends upon the idea that the Earth was seeded with micro-biological life early in its life.
NASA now agrees with Prof: Hoyle, the originator of this idea.
https://bitcointalk.org/index.php?topic=35972.0http://en.wikipedia.org/wiki/Panspermia I would like to go further with the Panspermia idea, and suggest that our Earth was being seeded with life even as our Earth was being formed and cooling...over 4.4 Billion years ago
Microbes are incapable of living in temperatures greater than 250C, or being bathed in UV light.
But they are perfectly at home living within rocks that fly thru the vacuum of space.
Bathed in radiation but protected from UV light.
Thats the idea of Panspermia.
How long might have these panspermia microbes been around?
Well how about....long before our own Sun centered planetary system was formed?
Just why would I suggest that?
Well...Oxygen hating anerobic microbes are alive and well
within the solid rocks that are three miles deep in the deepest Gold mines in the World. No man can live there as the rock walls are 60C, unless huge amounts of electricity is used to cool the recirculating air. But remember its only 60C for the microbes, thats cool for them.
....Microbes are more than likely to be living down 10, 15 or 20 miles deep, as long as their temp stays below 250C, they are probably there.
If you accept that-- the next logical question I wish to ask is:-
How did they get there, ten miles deep and in what time scale??
Just how long might it take Panspermia oxygen hating microbes,
that were deposited upon the surface of this earth to multiply
to such an amazing extent that they grew down to say 10 miles
deep. And just why would they?
I dont believe they had to, or would, burrow that deep.
I prefer to believe that 4 million years ago while the Earth was heaving and bubbling as it cooled.
Conditions would have allowed panspermia microbes to have been deposited very deep, into Earth sites that did not exceed 250C temp:, early in the Earths history.
What do I think about life starting in our oceans?
Not a lot.
If meteorites brought micro-life, their crashing into a dry (Ocean free) Earth would not make such a difference to a Microbes lifestyle, as it crashing into an ocean.
In any case, if we had an ocean in the distant past....It would only have condensed and stayed a liquid, as long as the earth was cool enough. I dont think that condensed steam/water in a non-oxygen atmosphere, can contain any free oxygen, can it?
Just how would that effect the panspermia microbes hitting this non-oxygenated Sea water?
Bill mentioned in his original "When did life Start " in the
General Science Forum, that Iron deposits became oxidised and rusty due to Oxygen in water.
I read somewhere, that boiled water sealed water, would not rust a metal nail....any one tried this experiment?
I suppose that means the oxygen in Sea water must have arrived very much later? Which would then have allowed normal oxygen loving microbes to develop later, meaning that the anerobic panspermia microbes were still the first life on Earth?
More about life and Diatoms found in Meteorites (youTube)
http://www.youtube.com/watch?v=NF_TOtgZoS0 Science continues to provide evidence that the ideas presented by these theories are possible. A meteorite, positively identified as being from Mars, was recovered in Antarctica in the 1980s and is believed by some scientists to contain fossilized bacteria, lending support to this theory, although these findings and the theory itself are still widely contested by many.