6 Weird Ways To Hunt For Aliens

These E.T. search strategies are a little ... out there.

At a meeting in July, NASA scientists predicted that humans will detect extraterrestrial life within the next 20 years.

The Kepler telescope has churned up thousands of new exoplanet candidates over the past few years, and now scientists estimate that there could be upwards of 100 billion planets in the Milky Way. At the same time, here on Earth, we've found life thriving even in the strangest places. That's got some scientists thinking that the odds are stacked in favor of life being pervasive throughout the universe—and now it's just a matter of finding it.

NASA’s prediction is based on two telescopes expected to debut in 2017 and 2018. The first is the Transiting Exoplanet Survey Satellite, which will look for Earth-sized exoplanets. The second is the James Webb Space Telescope, which should (hopefully) be able to spot water and the chemical signatures of life in the atmospheres of other worlds.

But there are other ways to look for aliens. Here are some of science’s most interesting proposals. They may sound a little nutty, but–who knows?– they might just work.

Where There's Smoke, There's Fire

Sure, big telescopes can scan for oxygen and methane in the atmospheres of other worlds, to hunt for tiny microorganisms. But to find more intelligent aliens, maybe we could look for their smog. Scientists at Harvard have suggested that if advanced civilizations are out there, their planets are probably also wrapped in a cloud of air pollution. The scientists recommend looking for chlorofluorocarbons (CFCs) like the ones emitted by aerosol sprays and refrigerants here on Earth. Ozone-depleting CFCs can exist in a planet's atmosphere for up to 50,000 years.NASA

Beacons In The Night

While SETI is listening for alien radio transmissions, other scientists think we can also use our eyes in the sky to look for the light and heat that might radiate from alien cities. Space.com reports that modern telescopes could spot a city the size of Tokyo if it were located in the outer brinks of our solar system. Of course, other star systems are much, much farther away, but the next generation of space telescopes may be able to peer across the interstellar abyss.NASA

Black Hole Sun

An advanced civilization eats up a lot of energy to maintain itself. Cosmologist Clement Vidal from the Free University of Brussels has proposed that the REALLY advanced alien species—like, the ones that could maybe tinker with elementary particles and the space-time continuum—could potentially build artificial black holes to harvest more energy than they would get from a star like the Sun. But how can humans tell if a black hole is artificial? Discovery News explains: "Tell-tale evidence would come from measurements that showed the black hole weighed less than 3.5 solar masses. That's the minimum mass for crushing matter into a black hole via a supernova core-collapse."Ute Kraus via Wikipedia Commons

Solar Panels On Crack

Another way for an alien society to fuel its advanced technology is by using solar energy—just like us! Only, in the scenario envisioned by physicist Freeman Dyson in 1960, the aliens' solar panels would completely surround a star. We could theoretically detect these hulking megastructures by looking for their heat signatures–some or all of the star's light would be obscured, while its infrared output would likely increase as it got re-radiated from the solar panels.Anders Sandberg via Flickr CC By 2.0

Aliens Among Us

Here on Earth, there may be creatures that are based on biology so different from our own that we don't even recognize them as living organisms. For example, NASA astrobiologist Carol Cleland (who helped to coin the term "shadow biosphere" in 2005) has suggested that desert varnish (the red rusty stuff that grows on rocks) may be one such alien. Desert varnish looks like a microbial mat, and even appears to produce organic molecules, but scientists can't tell whether it's alive or not. So aliens could be living right under our noses—or even inside them, for all we know.Jeff Turner via Flickr CC By 2.0

The Wait-And-See Strategy

When it comes to understanding the origins of life, a group that calls itself WETI says it's taking a novel approach: "Instead of actively searching for extraterrestrial intelligence, the idea is to simply WAIT - until the others find us." Short for "Wait for Extraterrestrial Intelligence", WETI's strategy (if you can call it that) is certainly the cheapest option. The group jokes that it has secured funding until the year 2620.The WETI Institute