: Tue Mar 10, 2009 11:59 pm
To take this a stage further and given that there are a number of satellite launches in recent weeks, it is perhaps a good time to mention it here.
It is not-so-long-ago that science would have you believe that the Terran System was the only planetary system in our Galaxy, we are unique and basically there's a load of other stars, dust, matter and that's about it.
Current science now shows that planetary formation is common-place and there are around 300 'exoplanets' now in exisitance. Sadly, most of them are so far away and so small, they are actually mesured by the minute 'wobble' the create against the gravitational pull of the star they orbit. Additionally, most of them observed fall outside the 'Goldilocks Zone' (not too hot / not too cold) where water would be in a liquid form and there is the potential for life 'as we know it' to be present.
There have been other advances too .... Around the Deep Sea Vents at the bottom of the oceans, science would have told you not-so-long-ago that nothing could survive the pressure and the chemical soup, not to to mention the heat ... However, when we finally got down there to take a look for ourselves, it was teeming with life and for the first time, we came across creatures where the primary driver on the foodchain was not light from the Sun, but actually the chemicals that surrounded them.
You also need to take in to account the relative short time that life as a whole has been present on this planet ... Some of you will have seen QI not too long ago that put the presence of any forms of life against the scale of a 12 month calendar (actually it was first perfected by Carl Sagan) and in the grand scheme of things, where 1st Jan = The Big Bang, life on Earth of any form did not develop until early October in the same scale.
It is also worth considering that us mere humans are actually here by accident. A quirk of fate / nature .... Remember the inital dominant life form on this planet was not human, but lizard based and save for the mass extinction event 65 million years ago, primate life on Earth might not have got a look in .... Thus, consider those planets where the mass extinction event didn't take place and you could be having a serious re-write of the concept of life 'as we know it' ....
Still, there is a lot more to discover out there. What's to say that they're not already here and maybe influencing popular culture by the number of bug-eyed warty things we see in mass entertainment on the off-chance of preparing the human race for meeting something not disimilar in reality some time in the future ? And we still haven't solved the question of what is generating the large quantities of methane on Mars. The 'dead' planet producing a great deal of a typically organic gas (Ok, Ok, I know it can be produced by geological processes too, but ...). If we did discover life of any sort on Mars, even microbial, it would have a massive effect on how we thought about the universe around us. If it can 'live' there, then where else could it be that we have previously dismissed as inhospitable ?
