[Neil]

Neil asked the Naked Scientists:

Hi,

I was looking in your forums and saw a discussion on UFOs, over life in the universe etc.

It got me thinking. Why do you often hear 'experts' saying that a planet is unable to sustain life? What are they basing that on?

Are they saying that all life forms must be carbon based and assuming that, for instance, gaseous life forms simply couldn't exist somewhere?

Thanks

Neil

What do you think?

[LeeE]

I think it can only be assumed on the basis of "not as we know it (Jim) and there has been a lot of speculation about lifeforms based upon other elemants.  Gaseous lifeforms have been hypothesed quite plausibly in a couple of Sci-fi novels, one of the best being in Iain M. Banks 'The Algebraist'

[RD]

The presence liquid water seems essential for life,
so areas of the universe too hot or too cold for liquid water to exist are considered uninhabitable.

[syhprum]

So why are they wasting time and money searching on Mars?.

[RD]

So why are they wasting time and money searching on Mars?.

http://mars.jpl.nasa.gov/msp98/why.html

[Alan McDougall]

Silica based life is a far off possibilty. Maybe plasma based life living on the Sun?

[Alan McDougall]

 Lack of Water the stuff of life