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Life may really be out there.
Astronomers have found the first evidence of habitable planets outside
our own solar system.
The discovery of the shattered remains of an asteroid which once
contained huge amounts of water - crucial for life - has left scientists
‘incredibly excited’.
It suggests that hundreds of millions of years ago, the distant system
may have harboured Earth-like planets.
But any potential inhabitants would be long since left the region -
either extinct or mastering space travel - as their sun blew up and then
collapsed into a ‘white dwarf’.
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Now all that remains are rocky bodies orbiting the dead star.
Scientists believe it is a glimpse into the distant future of our own
corner of the universe, after the Sun finally burns out. But there is no
need for alarm - the end is still several billion years away.
Professor Boris Gänsicke of the Department of Physics at the University
of Warwick said: ‘It is the first time we have found a rocky body that
also contains water outside our solar system.
‘Those two ingredients - a rocky surface and water - are key in the hunt
for habitable planets outside our solar system, so it’s very exciting to
find them together outside our solar system.
‘What this means is that we have the building blocks of what makes
planets like Earth.’ He said it was too early to speculate if the region
supported alien life, and that if it had existed, it would be long
departed following the collapse of the sun.
‘At this stage in its existence, all that remains of this rocky body is
simply dust and debris that has been pulled into the orbit of its dying
parent star,’ he said.
‘However this planetary graveyard swirling around the embers of its
parent star is a rich source of information about its former life. In
these remnants lie chemical clues which point towards a previous
existence as a water-rich terrestrial body.’
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The research, which appears in the journal Science and was made using
Nasa’s Hubble telescope, looked at the light emitted by GD 61. The
region located 150 light years away from the Earth.
Astronomers detected an abundance of ‘rocky’ elements such as magnesium,
silicon and iron, and also found oxygen in quantities that indicated a
large amounts of water.
Only a water-rich massive asteroid, or minor planet, can explain the
observations, they claimed.
Earth is essentially a ‘dry’ planet, with only 0.02 per cent of its mass
made up of surface water. Our oceans only formed after the planet was
formed, likely a result of water-rich asteroids or comets crashed into
us.
The latest findings suggest something similar could have happened in
this distant solar system.
Lead author Jay Farihi, from Cambridge’s Institute of Astronomy, said:
‘The finding of water in a large asteroid means the building blocks of
habitable planets existed - and maybe still exist - in the GD 61 system,
and likely also around substantial number of similar parent stars.
‘These water-rich building blocks, and the terrestrial planets they
build, may in fact be common - a system cannot create things as big as
asteroids and avoid building planets, and GD 61 had the ingredients to
deliver lots of water to their surfaces.
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‘Our results demonstrate that there was definitely potential for
habitable planets in this exoplanetary system.’
Scientists believe that the universe could be teeming with planets that
are able to support life.
Latest NASA estimates suggest that there could be as many as 60 million
habitable planets.
Data taken from the Kepler telescope, which has spent several years
exploring exoplanets outside of the solar system, had suggested that
there could be at least one planet that is capable of supporting life
close to each red dwarf.
But that theory has since been revised as NASA scientists now also
believe that cloud cover could potentially help a planet support life.
In order for life to occur on a planet, it needs to be within the
habitable zone of a star - that is close enough for water on its surface
to stay in its liquid form.
If a planet is too close to its star, the water vapourises as it is too
hot. But if it is too far away, the water freezes.
Thanks to exploration from telescopes such as Kepler and the Spitzer
telescope, scientists' knowledge of planets outside our solar system is
becoming increasingly sophisticated.
Last week NASA released the first ever map of cloud cover on an
exoplanet - Kepler-7b.
The image offered a first look at clouds on hot Jupiter-like planet
Kepler-7b which is some 1,000 light-years away from the Earth.
The Kepler telescope has discovered more than 150 confirmed planets
outside the solar system.
The telescope's problematic reaction wheels prevent it from hunting
planets any more, but astronomers continue to pore over almost four
years' worth of collected data from the planets already discovered.
It is hoped that the same cloud-mapping techniques can be used to
observe smaller Earth-like worlds. |