There are "hundreds of billions" of planets in our galaxy just
waiting to be discovered, a team of Scottish scientists has found.
Astronomers from the University of St Andrews said that wherever we
look in the sky, there are planets, even though we can't see
them.
The team spent six years studying data from telescopes based all
around the southern hemisphere, from Australia to Chile. They only
looked at a tiny portion of the Milky Way and found just a few
planets.
But they say that they can use what they found to estimate how
many other planets there are in the rest of the galaxy. Around 700
planets beyond our solar system have been discovered since
1995.
Dr Martin Dominik, who led the team, said:
"So far, we have detected only a tiny fraction of planets out
there. We expect hundreds of billions exist in the Milky Way
alone."
But he can't say if there could be life on any of them. There
are several ways that scientists can use to find exoplanets. The St
Andrews scientists looked for an increase in light from a star,
which is caused by gravity when a planet or another star passes
between the Earth and the star.
NASA's Kepler telescope looks for fluctuations in light from a
star as a planet orbiting crosses in front of it. When its orbiting
planet passes in front of a star, it blocks out some of the star's
light.
This video shows you how NASA's Kepler telescope finds
exoplanets:
Remember that the next time you are looking at the sky on a
clear night!
Dr Martin Dominik, the scientist in charge of the study, told
the Daily What News why he was so excited
about the findings:
Dr Martin Dominik (c) St Andrews
University
Can you explain to us how the planets were
detected?
An apple falls from a tree because it is attracted by the Earth.
Similarly, planets and stars can attract light. As a result, a star
appears brighter if another star passes in front, and if the star
in front comes with a planet, the planet can create a further small
blip or dip, which we can observe.
Do you know how big the planets are?
Of most of the planets, we do not know how big or small they
are, how dense or fluffy, whether they teem with life or not. We
may not see them, but wherever we look in the sky, they are
there.
Why has no one found these planets before?
While we now think that there are 100 billion planets in the
Milky Way alone, only about 700 have been identified. Apparently,
we only know very little so far, and there is much left to
explore.
Do you think there could be life on any of the
planets?
One of the big mysteries still is the origin of life. We do not
know how likely it is for life to evolve, and we do not know the
conditions that make this happen. What we do know is that there is
no lack of planets. So, there could be life elsewhere, or we could
be alone. Only by finding life beyond Earth we will get the
answer.
How long would it take to travel to the closest of these
planets?
Even light would need 20 years to the closest planet that is
considered to be a good candidate to support life. A spacecraft
would take at least ten times as long, in other words 200 years,
and would have to become its own sustainable ecosystem.
Adapted from an article in the Daily
What News