Laser Cloaking Can Hide Earth From Aliens: Study

With a laser cloaking device, the earth could be camouflaged and hidden from advanced extra-terrestrial civilizations, says a new paper written by a couple of Columbia University astronomers. A number of prominent scientists, such as Stephen Hawking, have cautioned that revealing the earth to alien life could be destructive.

In the search for alien life, there is usually a seeking of a friend, or the dip in light that happens when a planet moves just before the star that it is orbiting. While this method has been employed in the Kepler mission and other projects, the new study shows that alien scientists may use this method to locate even our planet in the sun's "habitable zone".

With extra-terrestrials finding our planet, they may want to harness its resources, which made the scientists speculate that the visit could repeat whatever happened with the "discovery" of America.

Hence, scientists suggest that transits can be hidden through laser cloaking if a laser beam is targeted at a star in which aliens are probably residing. During transits, the laser would be switched on to make up for the dip in light, which prevents the aiens from using it to find our planet.

This can be achieved with a continuous 30-megawatt laser used for around 10 hours every year. It would help to destroy the "transit signal in visible light." But the energy required for this procedure would be equal to the annual collection of the International Space Station (ISS).

To use a chromatic cloak that can be effective at every wavelength, apart from visible light, scientists require a number of "tunable lasers" that has a high power of 250 megawatts, which would work to about eight times the energy gathered by the ISS every year.

"Alternatively, we could cloak only the atmospheric signatures associated with biological activity, such as oxygen, which is achievable with a peak laser power of just 160 kilowatts per transit," said  Alex Teachey, co-author of the study. "To another civilization, this should make the Earth appear as if life never took hold on our world."

It is possible to use the lasers in order to modify the nature of light from the sun so that it could look artificial. This would open up the way to use it in order to communicate through information along the laser beams.

"There is an ongoing debate as to whether we should advertise ourselves or hide from advanced civilizations potentially living on planets elsewhere in the Galaxy," said David Kipping, co-author of the study along with Teachey. "Our work offers humanity a choice, at least for transit events, and we should think about what we want to do."

The findings can be used by the Search for Extraterrestrial Intelligence (SETI).

The findings were published in the March 30, 2016 issue of the Monthly Notices of the Royal Astronomical Society.