New hunt for aliens who “move stars”

Aliens so advanced they use enormous machines to move stars out of their orbits are to be the target of a new hi-tech search for alien life.

A NASA concept image of an exoplanet

Aliens so advanced they use enormous machines to move stars out of their orbits are to be the target of a new hi-tech search for alien life.

So far, the Search for Extraterrestrial Intelligence (SETI) has focused on “listening” for ET using networks of radio telescopes.

But as Britain launches its own hunt for aliens - the UK SETI Research Network - one Scottish scientist believes that we may find signs of alien life not in radio signals, but in the form of enormous machines built in space by alien civilisations.

Dr Duncan Forgan, from Edinburgh’s Royal Observatory, suggests that we should look for “megastructures” - enormous “mirrors” in space, millions of miles wide, used to propel stars out of their orbits.

The mirrors would be a sign of “advanced” civilisations - with the power to destroy planets, and with armies of robots on hand to reshape solar systems, Dr Forgan says, in an interview with Yahoo! News. 

The huge objects could be detected using the same telescope techniques NASA now uses to spot planets outside our solar systems.

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If they exist, these “megastructures” would show up in telescope data we already have, Dr Forgan says.

The “machines” - looking something like sails millions of miles across - would be used to save civilisations from disaster, and would be built from the rubble of destroyed planets, or from asteroids.

“The structures I'm looking at would be used to move the star if it was approaching something dangerous,” Dr Forgan said. “For example, if the Sun passed through a dense cloud of molecular gas, then the Sun's magnetic field could collapse, and the implications for life in the Solar System could be dire.  If we had the ability to build these structures, then we could nudge the Sun out of harm's way.”

"The mirror reflects the star’s own radiation and produces thrust, much like a sail produces thrust from wind. This thrust could be used to move a civilization’s host star from its “natural” orbit if it posed some harm to the civilization."

Dr Forgan says that megastructures would be the sign of civilisations far, far more advanced than ours - known as Kardashev Type II cvilisations among the SETI alien-hunting community.

“These structures are advanced technology,” says Dr Forgan. “To build these, you need a large amount of raw material, which would probably involve destroying a small planet or scooping up lots of asteroids. 

“Civilisations that can construct this sort of stuff would need to be able to manipulate a very large amount of matter and energy, and in hazardous environments,” Dr Forgan says. “To me, this would suggest a civilisation with an impressive spacefaring capability (i.e. several planets fully colonised in their star system), a large amount of automated or robotic assistance to do the grunt work, and a good deal of political will to boot.”

Forgan’s study showed that a giant mirror would leave a characteristic trace in “exoplanet transit data” - the telltale dips in a star’s light which NASA uses to detect planets outside our solar system.

The SETI project has searched for alien life for 50 years - but has been met by silence. But NASA’s Kepler mission has provided SETI’s alien-hunters with known planets to aim at.

Kepler “looks” at a field of 150,000 stars, looking for the telltale dips in brightness caused by planets passing in front of the stars.

“Megastructures” will be visible in the data from future telescopes, Forgan says.

“While the odds of seeing megastructures are probably very low, we will soon have a huge archive of exoplanet data to search for these objects -- at no extra cost to SETI scientists. We may detect the presence, or remains, of an alien civilization that felt the need to move their star!” Forgan said.