We
know for sure that there is life on one planet because we are part of that life
but Patrick Moore always says he wonders if there is ‘intelligent’ life even on
this planet.
This
is really a two part question, question one is, ‘is there life on any of the
other planets in our Solar System?’ and question two is, ‘is there life on
planets orbiting other stars ?’. Of
course this poses the third question, ‘are there planets orbiting other stars ?’
Recently
there has been much debate and even arguments over the microscopic ‘fossils’
found in a meteorite from Mars. The
jury is still out on that question although it now seems likely that the
microscopic worm like objects were not produced by life forms. There has also been a lot of debate about
photographic evidence from Mars which appears to show gullies where water may
have flowed in the last million or so years and possibly in the much more
recent past. A number of orbiters and
landers are planned to survey the most interesting sites in the next few
years. It is even hoped that samples of
the Martian soil can be brought back to Earth for study.
None
of the other seven solar system planets can be expected to have or had life
because they are either too hot or too cold.
Life as we know it needs liquid water which can only exist at a small
range of temperatures. Life also needs
so sort of energy source like the light and heat from the Sun. However there is the possibility of life on
one of Jupiter’s moons called Europa.
Space probe surveys have indicated that Europa has a deep layer of
liquid salty water under a thick layer of ice.
Europa is heated by the enormous gravitational forces of Jupiter which
stretches and squashes Europa causing powerful tidal forces. We know for deep sea studies on Earth that
life can exist with no Sun light but driven by the heat from volcanic vents
called ‘Black Smokers’. Some people
even think that life on Earth may have begun around Black Smokers. It is possible that Europa may also have
Black Smokers and therefore may also have life in the Great oceans under the
ice. NASA has plans to send a probe to
Europa to drill through the ice and search for life using a miniature
submarine.
But
what about other Solar Systems around other stars and could there be life on
those planets ? Astronomers have only
recently hade telescopes powerful enough to identify planets orbiting other
stars and a few have been found. It is
not yet possible to see these planets directly because the star is millions of
times brighter than any planet and completely drowns out the light from the planet. However large planets have been detected
through the wobbling of the star due to the orbiting planets. Nearly all the planets identified so far are
large gas planets like Jupiter only larger and orbiting very close to the star. One has been found recently orbiting much
further out so there might be smaller rocky Earth like planets further in. Bigger and more sensitive telescopes are
planned to look for smaller planets and even to detect Oxygen which can only be
maintained in a planet’s atmosphere as a by product of life.
One
idea for detecting planets orbiting other stars is to use a number of large
telescopes linked together to create a giant interferometer. This
works by combining the light from the telescopes so that the light waves from
the star are exactly half a wave out of phase.
By doing this each set of waves will cancel out the light from the other
and the light from the star will disappear.
If there is a planet orbiting that star it should now be visible. The Very Large Telescope array in Chile will
be the first telescope to put this idea into practice.
So
the question is now ‘LIFE WHERE ARE YOU ?