Alien Invaders Watching? Scientists Devise Laser ‘Cloak’ To Hide Earth From Hostile Extraterrestrial Civilizations [Video]
Scientists have devised a method to “cloak,” or hide, the Earth from potentially hostile advanced alien civilizations. According to scientists, we could cloak or hide the Earth from hostile alien planet hunters seeking potentially habitable planets by firing laser beams into outer space to disrupt efforts by extraterrestrial astronomers to detect signals that betray our planet’s presence as it orbits the Sun in the habitable zone.
The proposal by Professor David Kipping and and his graduate student Alex Teachey, two astronomers at Columbia University in New York, comes in response to fears that just as astronomers on Earth are scanning the skies in search of potentially habitable exoplanets, technologically advanced alien civilizations located near distant stars may also be searching our solar system for potentially habitable planets.
Prominent scientists, such as the astrophysicist Stephen Hawking, have voiced concern about the potential dangers of our world being discovered by more advanced alien civilizations. A hostile, advanced extraterrestrial civilization that discovers us could decide to invade and take over our world. Even if an alien civilization that discovers our world “comes in peace,” first contact could be very risky because they could introduce deadly diseases that humans on Earth have no defenses against and thus expose humanity to the risk of extinction.
According to Kipping and Teachey, we could make our world invisible and effectively prevent it from being detected by advanced and possibly hostile alien races searching for potentially habitable planets by beaming a laser into space during the periods that Earth is transiting or passing in front of the Sun.
The laser would hide our planet from alien astronomers by disguising the dimming of the Sun’s light — as seen from the perspective of the observing civilization — each time Earth passes in front of the Sun. Beaming a laser with a sufficient amount of power into space could thus render Earth invisible to potential alien invaders.
The “cloaking” concept being proposed by scientists is based on the principle underlying the transit method that human astronomers have used successfully to detect exoplanets orbiting distant stars. The method involves detecting dips in the brightness of the parent star as the orbiting planet passes in front of it.
Analysis of the patterns of dips or dimming of a distant star could give astronomers information about characteristics, such as size and density, of the celestial body passing in front of the star.
“To make it look like the planet is not there at all, you’ve got to get rid of that dip. You’ve got to fill in the missing starlight.”
NASA’s Kepler Space Telescope has used the transit method to detect hundreds of planets orbiting other distant stars in our galaxy. The scientists reasoned that alien astronomers observing our solar system from a distant star in our galaxy would likely use the same method to search for potentially habitable exoplanets.
According to Kipping and Teachey, blasting laser beams into space at the time Earth is passing in front of the Sun compensates for dips in the brightness of the Sun when the Earth passes in front of it. Thus, an alien planet hunter measuring changes in solar brightness would not notice any dips.
The researchers also noted that the concept is implementable because not much energy is needed to “cloak” our planet. Dips or dimming of the Sun’s light could be masked by emitting 30 MW laser continuously for 10 hours once a year at the time the Earth is passing in front of the Sun.
The reports inspired Kipping to consider how an advanced civilization could deliberately alter transit signals it sends out to space to deceive alien astronomers attempting to observe the planet from a distant star.
“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,” Kipping said. “Our work offers humanity a choice, at least for transit events, and we should think about what we want to do.”
The researchers noted there are other ways that an intelligent civilization could hide its world from alien observers. Instead of wiping out the transit signals of its planet entirely, a civilization could distort it. The options include deliberately erasing the signals of life that the planet sends out to space.
For instance, we could emit a laser with a power of only 160 KW into space to cloak atmospheric signatures — such as oxygen — that alien astrobiologists could interpret as signalling presence of biological life on Earth.
Kipping and Teachey emphasized that their proposed “cloaking” technique is so simple that “we could build it this next week if we wanted to.”
[Image via Shutterstock]
