Listen to the tape then answer the question below.
Which life forms are most likely to develope on a distant planet?
Recent developments in astronomy have made it possible to detect planets in our
own Millky Way and in other galaxies.This is a major achievement because, in
relative terms, planets are very small and do not emit light. Finding planets is
proving hard enough, but finding life on them will prove infinitely more difficult.The
first question to answer is whether a planet can actually support life.In our own
solar system,for example,Venus is far too hot and Mars is far too cold to support life
Only the Earth provides ideal conditions,and even here it has more than four billion
years for plant and animal life to evolve.
Whether a planet can support life depends on the size and brightness of its star,
that is its 'sun'. Imagine a star up to twenty times larger,brighter and hotter than
our own sun.A planet would have to be a very long way from it to be capable of
supporting life.Alternatively,if the star were small, the life-supporting planet would
have to have a close orbit round it and also provide the perfect conditions for life
forms to develop.But how would we find such a planet? At present, there is no
telescope in existence that is capable of detecting the presence of life. The development of such a telescope will be one of the great astronomical projects of the