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Will Exo Planet "Lights" Signal a Technological Civilization? (Today's Most Viewed)


      Iberian penninsula aglow

If an alien civilization builds brightly-lit cities like those shown above of the Iberian Peninsula, future generations of telescopes might allow us to detect them. This would offer a new method of searching for extraterrestrial intelligence elsewhere in our Galaxy.

In the search for extraterrestrial intelligence, astronomers have hunted for radio signals and ultra-short laser pulses, but Avi Loeb (Harvard-Smithsonian Center for Astrophysics) and Edwin Turner (Princeton University) suggest that we look for their urban lights.  "Looking for alien cities would be a long shot, but wouldn't require extra resources. And if we succeed, it would change our perception of our place in the universe," said Loeb.

As with other SETI methods, they rely on the assumption that aliens would use Earth-like technologies. This is reasonable because any intelligent life that evolved in the light from its nearest star is likely to have artificial illumination that switches on during the hours of darkness.

How easy would it be to spot a city on a distant planet? Clearly, this light will have to be distinguished from the glare from the parent star. Loeb and Turner suggest looking at the change in light from an exoplanet as it moves around its star.

As the planet orbits, it goes through phases similar to those of the Moon. When it's in a dark phase, more artificial light from the night side would be visible from Earth than reflected light from the day side. So the total flux from a planet with city lighting will vary in a way that is measurably different from a planet that has no artificial lights.

Spotting this tiny signal would require future generations of telescopes. However, the technique could be tested closer to home, using objects at the edge of our solar system.

Loeb and Turner calculate that today's best telescopes ought to be able to see the light generated by a Tokyo-sized metropolis at the distance of the Kuiper Belt - the region occupied by Pluto, Eris, and thousands of smaller icy bodies. So if there are any cities out there, we ought to be able to see them now. By looking, astronomers can hone the technique and be ready to apply it when the first Earth-sized worlds are found around distant stars in our galaxy.

"It's very unlikely that there are alien cities on the edge of our solar system, but the principle of science is to find a method to check," Turner said. "Before Galileo, it was conventional wisdom that heavier objects fall faster than light objects, but he tested the belief and found they actually fall at the same rate."

As our technology has moved from radio and TV broadcasts to cable and fiber optics, we have become less detectable to aliens. If the same is true of extraterrestrial civilizations, then artificial lights might be the best way to spot them from afar.

The Daily Galaxy via Harvard-Smithsonian Center for Astrophysics



sir, as per my research and observation , it may possible that Aliens are using different life process as we, and also they may using thing different as us for example they using acids, heat,any gases rather than oxygen , as there r some animals on earth living in dark so it may possible they r living in dark, sir i don't want to have a credit of my research, bt i know they will attack us any time by such wapons we cant believe and we can't defance awoke human7 awoke

sir i have hundreds of ideas bt very less equipments plz if u may have any information regarding planets in outer space plz inform me with images,

Well maybe their World has a giant Fireflies? :D

Even if they could see 'light', who is to say it not volcanism or some other natural phenomenon ? What would have someone seen while the Siberian Traps were going strong ?

no worries, it`s impossible to see our street bulbs unless they`re already in our Solar system or very close, and if they`ve got that close, than it`s too late, they know we`re here.

The number of broadcast transmitters has not changed appreciably. Just because more people get the signal from cable/viber does not mean the broadcaster has stopped transmitting their signal over the air.

correct me if I'm wrong, but wouldn't a planet's puny city lights simply be drowned out by the light of the star it's orbiting?

@ not carl
Our telescopes we have right now cant even make out the planets in orbit because the stars brightness overpowers very much the reflection a planet gives. This is why the first sentence says "future generations of telescopes might".

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