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rfmcdonaldIt remains in the realm of science fiction for now but the discovery of a new planet just four light years away will reignite a race to find a twin of planet Earth that may host extraterrestrial life.
The step change comes as the most powerful telescopes ever built are about to enter into service and as ideas about where life could exist are being turned on their head. At the same time, scientific discussion about the possible existence of alien life is becoming more mainstream.
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Researchers from the Geneva Observatory said the newest planet to be found was too close to its own sun to support life. But previous studies have suggested that when one planet is discovered orbiting a sun there are usually others in the same system.
Rival astronomers are now likely to start scouring Alpha Centauri for more planets, possibly in the habitable zone around its stars.
The technological eyes and ears that scientists have at their disposal are about to take a leap forward too, broadening and deepening their search.
Barring a surprise discovery of microbes on Mars, we will see alien life long before we are ever able to touch it.
“I think it is realistic to expect to be able to infer within a few decades whether a planet like Earth has oxygen/ozone in its atmosphere, and if it is covered with vegetation,” Martin Rees, Britain’s Astronomer Royal, told Reuters.
The next decade will see two record-breaking telescopes come on line; the Square Kilometre Array (SKA), a huge radio telescope sited in South Africa and Australia, and Europe’s Extremely Large Telescope (E-ELT) that will sit on a mountain top in Chile’s Atacama desert and be the largest optical telescope ever built.
Their main task will be to probe the origins and nature of galaxies, but they will also look for signs of life on planets that can now only be seen in the roughest detail.
“I think the capabilities of new telescopes means that the detection of an ETI (extraterrestrial intelligence) is more likely in the next few decades, than it was in the last,” said Mike Garrett, general director of Astron, the Netherlands Institute for Radio Astronomy.
"I have often imagined the day when scientists directly image an Earth-like extra-solar planet," Icarus Deputy Project Leader Robert Freeland told Discovery News. "We would be able to determine the planet's atmosphere and surface temperature from its spectrum, and we would thus know whether it might be able to sustain life as we know it. I suspect that once such a discovery hits the news, people worldwide are going to demand that we send a probe to determine whether the planet has life (of any type) and/or could be suitable for human habitation. If the latter proves true, then a manned mission would eventually follow."
Freeland added that in the case of this most recent discovery, we're not looking at a viable exploration target. This world's orbit is ten-times closer to its star as Mercury is to the sun -- it would be a hellish, (likely) rocky, molten world. Alpha Centauri Bb orbits well inside the nearest edge of the star's 'habitable zone' -- the region where liquid water can exist on the surface -- so this exoplanet is the very antithesis of 'habitable.'
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By Freeland's reckoning, when we do discover a bona fide Earth-like world encircling one of the stars in the Alpha Centauri system (i.e. a world of the approximate mass of Earth orbiting inside the habitable zone), the world's space agencies (particularly NASA) would need to be prepared, lest be caught "flat-footed" when a wave of public pressure to mount a mission to that planet demands why a plan isn't in place.
"Icarus Interstellar and its partner organizations -- the British Interplanetary Society and the Tau Zero Foundation -- have been working on interstellar mission designs for years, and we're eager to help NASA/ESA jump-start a serious, fully-funded interstellar program.
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Although there's reason for some guarded excitement about the discovery of Alpha Centauri Bb, Crawford cautions that detecting small exoplanets at larger orbital distances from the star cannot be done using the "radial velocity" detection technique. Earth-mass worlds orbiting further away will have less of a gravitational impact on the host star, thereby causing it to wobble less.
"Even these very sensitive radial velocity measurements are incapable of detecting Earth-mass planets in the alpha Cen B habitable zone -- with the lowest mass detectable at (habitable zone) orbital distances being 4 Earth-mass super-Earths," he said. "Therefore, despite the very real cause for excitement about this detection, it may still be a long wait before we know whether or not this star also has Earth-mass planets in its habitable zone."
