When early Greek and Arabic
astrologers studied outer space, some believed beyond Earth was the realms of
the Gods, whereas others (like Ptolemy and Galileo) felt the universe had an
abundance of life. Epicurus was adamant
there was an entire civilisation within our reach.
The current discussion begins
with a look at what is life and where it (may have) began?
When a meteorite from Mars was
found on Antarctica in 1979 which contained trapped gas it gave us a one-to-one
match of the atmosphere of Mars. The martian
rock contained things within it which was deposited from water and that water
contained organic matter. This organic
matter was assessed to be indigenous to the rock which had similarities to the
beginning of life as seen on Earth. Another
rock was found to have contained a fossil although some argued this was
contaminated when it landed on Earth; thus not seen as extraordinary.
Pillinger’s Beagle 2 project was set
up to collect a piece of rock from Mars, conceal it and bring it back to detect
residues that would have the remnants of organisms that once lived there (or
are still living there); unfortunately we all know what happened to Beagle 2.
There probably are other planets
out there teeming with life, some perhaps more advanced than us (or less
depending on how you measure this). If
we do find life on Mars, was it a meteorite from Mars hitting Earth that
spurred life here or was it just a natural evolution of our planet in relation
to the Sun and the wider universe?
Just like Darwin who went to a different
part of the planet and compared and contrasted two life islands, we need to
directly compare and contrast elements from two different planets.
If there was life out there and
they were looking at us, what would they see?
If an alien was out there looking at
us from 50million light years away they would first be drawn to the sun and see
they as an ordinary bright star. The Earth
would be a “pale blue dot” and the aliens would see the pale blue dot as
different shades depending on the angle of the Atlantic or Pacific oceans and
infer a lot by the climate and we will be doing that in twenty years’ time to
other planets.
The Kepler spacecraft will use
techniques that look for transits, the idea here that when a planet moves in
front of a star, the star will dim slightly.
If an Earth-like planet moved in front of a Sun like star, the star
would dim by 1 part in 10,000. We assess
the Kepler spacecraft will find many planets no bigger than our Earth.
Analysing outer space is tricky and
expensive. Some would argue we are at
the end of our great space explorations but astronomer will believe that
because we know very well how our Sun is going to evolve. Our sun is less than half way through
its life (it has been shining for four and a half billion years) and it will
shine for another billion years before it flairs up and engulfs the planets. The universe will go on expanding forever
until it goes cold and empty (ten to hundred million years) – there is a lot
more future ahead of us than the past. Any
creature witnessing the death of the sun or making contact with an alien life
may not be like us. They will be as different
to us as we are to a bug. There is time
for evolution on Earth in the post human era as Darwin realised that there is
time ahead and there will be evolution – this may not be on a natural timescale
but on a technological timescale that we will control.
Darwin has told us how simple
life evolved in into our biosphere but we need to understand how life actually got started. This will give us clues and understandings if
it has happened in other solar systems or a rare fluke, and assist in finding
out whether there is (and where) life is out there.
