I thought this looked interesting so I'm passing it on . . .

http://news.bbc.co.uk/1/hi/sci/tech/7893414.stm

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I thought this looked interesting so I'm passing it on . . .

> Alien life 'may exist among us'

Thanks Bill - Great Post Sir . . .

"All our microscopes are customised for life as we know it - so it's no surprise that we haven't found microbes with different biochemistry," said Professor Davies.

"We don't quite know how weird life would look. It's as wide as the imagination and that's why it's really hard to look for."

If it exists, weird life could be based on DNA and RNA - but with a slightly different genetic code or different amino acids.

At the other end of the spectrum, we could find creatures which have more drastic differences.

"Maybe one of the elements life uses - carbon, hydrogen, oxygen, nitrogen, phosphorus - could be replaced by something else," said Professor Davies.

"When I say that, everyone immediately thinks of silicon life - because of Star Trek. But I'm not talking about anything that drastic.

"For example, most of the jobs that can be done by phosphorus can be done by arsenic."

Arsenic may be poisonous to humans, but it has chemical properties which might make it ideal in a microbe's machinery, he said.

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BOINC Wiki . . .

Science Status Page . . .

Except that arsenic is about 15,000 times rarer than phosphorus. Michael

Except that arsenic is about 15,000 times rarer than phosphorus. Michael

On this Planet and one assumes this solar system who is to say that it not more abundant else where.

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Old enough to know better(but)still young enough not to care

One can't prove that arsenic isn't more common elsewhere, of course. But by using what we know of our own solar system, plus the principle of mediocrity, which states that our immediate environment, on a variety of scales is a typical, rather than an exceptional situation, we can make a reasonable inference. That inference is that arsenic is likely to be very rare, relative to phosphorus, in general. Beyond that, we have ample evidence that phosphorus can and has assumed a position in the chemistry of life (our own). We have no evidence that arsenic has ever done so. These considerations do not rule out the possibility of arsenic assuming the place of phosphorous in life chemistry, they merely make it seem much less likely. Michael

I may be mistaken, but I seem to remember reading (or hearing) that life made several attempts on Earth to 'catch on'. Each failed attempt was completely wiped out and has no lineage to anything today. Since the Earth would have been vastly different during these early failed attempts, wouldn't that life been 'alien'?