Alien Life May Arise Quickly

Scientists have found that oxygen and the life that generates it
might have enriched the Earth far earlier than currently supposed.
The discovery, sure to be controversial, suggests life could arise
earlier than now thought on alien planets, too.

Currently, scientists widely believe photosynthetic microbes helped
oxygenate the planet roughly 2.4 billion years ago, and that oxygen
was scant in the atmosphere before then.
They base this idea on isotopes of sulfur in ancient rocks.
Isotopes of sulfur all behave virtually the same chemically but have
slightly different masses.

Rocks older than 2.4 billion years contain abnormal ratios of sulfur
isotopes compared with younger rocks. The only way known to
generate these abnormal ratios are reactions between sunlight and
sulfurous volcanic gas in the absence of an ozone shield that would
normally help screen out ultraviolet rays.
Ozone is a form of oxygen, and if the atmosphere has no ozone,
it is assumed it has no oxygen.

Geochemist Hiroshi Ohmoto, director of the Penn State Astrobiology
Research Center and his colleagues examined rocks from western
Australia laid down as sediments on a lakebed and the ocean floor
between about 2.76 and 2.92 billion years ago. These displayed sulfur
isotope ratios like those of more modern rocks from higher oxygen eras.

An implication of the new findings is that "an oxygen-rich atmosphere,
generated by oxygen-producing organisms, may be found in young,
as well as old, planets of other stars," he said.

The new findings could mean oxygen levels on Earth were uniformly high
since 3.8 billion years ago, Ohmoto said. They could also mean oxygen
levels went through yo-yo fluctuations between highs and lows.
Alternatively, ultraviolet radiation from the sun might not be the only
way that can generate the abnormal ratios of sulfur isotopes seen in
older rocks.


LiveScience.com

Ok, I know I've quoted a sizeable amount of information,
but I had to to get the relavent information all in there.

I think this is a very interesting finding.
I hope they are right.


Comments, Opinions?

I don't believe this is the key factor in life. Undoubtedly the Moon is far more influential than A) we give credit and B) than timing of chemical developement or evolution.

The Moon's scared face shows us just how vital a role it played in the stability that allowed life to take a final root.

I suppose to me this is merely interesting as in a note rather than evidence of say...aliens.

Originally posted by Stratrf_Rus
I don't believe this is the key factor in life. Undoubtedly the Moon is far more influential than A) we give credit and B) than timing of chemical developement or evolution.

The Moon's scared face shows us just how vital a role it played in the stability that allowed life to take a final root.

I suppose to me this is merely interesting as in a note rather than evidence of say...aliens.

The moon is as scarred as it is because it does'nt have active
geologic processes.
The reason you don't see all the craters on Earth from the
asteroids and meteorites that have hit us, is because the Earth
does have an active geological process.
Earthquakes, landslides, volcanoes, rain and the environment
have pretty much eroded the craters away.

I honjestly don't believe the Moon is a factor in life,
but it did play a role in how life evolved on Earth.

Wow Iori way to quote a Geol 101 book.

The point is (not to be rude but I am blunt) that the Moon has absorbed that many more impacts than the Earth, and thus has made it that much more stable.

Originally posted by Stratrf_Rus
Wow Iori way to quote a Geol 101 book.

The point is (not to be rude but I am blunt) that the Moon has absorbed that many more impacts than the Earth, and thus has made it that much more stable.

*Thinks*
You know, I've never even seen a geology book of any kind.


Sometimes being blunjt gets your point across when it otherwise
would'nt be, so I don't mind.

As to the amount of impacts the Moon and The Earth have had,
I can't argue against it, or accept it, since I don't know if the moons
had more, considering we'll likely never know how many we've had,
unless there the big global killer ones.

I'd think that The Earth would have had atleast just as many impacts
as the Moon, considering the Earth takes up more space than the Moon.

I'd think that The Earth would have had atleast just as many impacts

But compared to Mars, if we assume the same amount of meteors, Earth would have been hit only by about a half of meteors than Mars since the Moon was in its vecinity and got the other half.

edit for some spelling

[edit on 26-8-2006 by Apass]

That's the basic assumption Apass, which I was getting to, for sake of science who knows exactly what the ratio is, but certainly the Earth has had fewer impacts.

I think the variables would be...the Moon makes the ratio of impacts on Earth to Mars smaller...

The closer proximity to the Sun makes the ratio of Earth to Mars increase.

And the size of the Earth versus Mars makes that ratio increase slightly.

So figuring where the numbers lie, I still think the Moon is a larger scaling than the other factors.

Originally posted by Stratrf_Rus
The closer proximity to the Sun makes the ratio of Earth to Mars increase.

Not necessarily since Mars is closer to the asteroid belt

I don't think proximity to that belt would have the effect since there is a wider or larger area Mars covers in a given time and so greater possibility for misses, such as the Sun theoretically gobbles up all asteroids that are astray ... with time.

I don't think proximity to that belt would have the effect since there is a wider or larger area Mars covers in a given time and so greater possibility for misses, such as the Sun theoretically gobbles up all asteroids that are astray ... with time.

We could argue about that but since we're not actually qualified in the field I guess I'll let the experts decide that.
But I think it's fair to say that the Earth suffered fewer impacts because it has a moon than if there was no moon at all to get in the way of all those cosmic debries.

Originally posted by iori_komei
The moon is as scarred as it is because it does'nt have active
geologic processes.

The Moon is as scarred as it is because it doesn't have a strong atmosphere.

The Earth's atmosphere is responsible for the burning of the smaller meteors and the winds are responsible for covering some of the craters.

Vegetation covers some other craters, and many craters are just under water, or, because the meteor hit the water, the crater never existed.

The "meteor shielding" role of the Moon (as the Earth's role of shielding the Moon) can be seen in the difference on the number of craters that are on the "dark" side of the Moon when compared with "our" side of the Moon.

In this page you can see how the far side looks more worn than the near side.