新概念英语听力mp3下载第三册lesson 55

 Radio astronomy has greatly increased
our understanding of the universe. Radio
telescopes have one big advantage over
conventional telescopes in that they can
operate in all weather conditions and can
pick up signals coming from very distant
stars. These signals are produced by
colliding stars or nuclear reactions in
outer space. The most powerful signals
that have been received have been emitted
by what seem to be truly colossal stars
which scientists have named 'quasars'.
A better understanding of these pheno-
mena may completely alter our concep-
tion of the nature of the universe. The
radio telescope at Jodrell Bank in
England was for many years the largest in the world. A new telescope, over
twice the size, was recently built at Sugar Grove in West Virginia.
Astronomers no longer regard as fanciful the idea that they may one day
pick up signals which have been sent by intelligent beings on other worlds.
This possibility gives rise to interesting speculations. Highly advanced civiliza-
tions may have existed on other planets long before intelligent f.mp3s of life
evolved on the earth. Conversely, intelligent being which are just beginning to
develop on remote worlds may be ready to pick up our signals in thousands of
years' time, or when life on earth has become extinct. Such speculations no
longer belong to the realm of science fiction, for astronomers are now exploring
the chances of communicating with living creatures (if they exist) on distant
planets. This undertaking which has been named Project Ozma was begun in
1960, but it may take a great many years before results are obtained.
Aware of the fact that it would be impossible to wait thousands or millions of
years to receive an answer from a distant planet, scientists engaged in Project
Ozma are concentrating their attention on stars which are relatively close. One
of the most likely stars is Tau Ceti which is eleven light years away. If signals
from the earth were received by intelligent creatures on a planet circling this
star, we would have to wait twenty-two years for an answer. The Green Bank
telescope in West Virginia has been specially designed to distinguish between
random signals and signals which might be in code. Even if contact were
eventually established, astronomers would not be able to rely on language to
communicate with other beings. They would use mathematics as this is the
only truly universal language. Numbers have the same value anywhere. For
this reason, intelligent creatures in any part of the universe would be able to
understand a simple arithmetical sequence. They would be able to reply to our
signals using similar methods. The next step would be to try to develop means
for sending television pictures. A single picture would tell us more than thou-
sands of words. In an age when anything seems to be possible, it would be
narrow-minded in the extreme to ridicule these attempts to find out if there is
life in other parts of the universe.