If we’re not alone in the universe and there’s intelligent life out there on another planet, we need to boldly go looking for it.
But for anyone who’s seen Independence Day or any number of disaster-filled alien invasion flicks, and for the scientists theorizing about these existential crises, it may not be in our best interest to be the first to say hello—or second to be noticed.
The search for alien life is a daunting one, with infinite worlds to discover and examine. We have all the time in the universe, but that’s not to say that we don’t need to find them sooner than later—in the scheme of things, the universe is constantly expanding, pushing other worlds farther and farther away from us.
So there’s an immediate need. How do we find others out there, then? The solution may be looking for life that shares things in common with life here on Earth.
There are several things that an Earth-like world would need to support similar life forms. The right sun, the right distance from it—and most crucial of all, a similar magnetic field to the one around our planet.
A recent article pointed out that Earth’s magnetic field was instrumental in protecting life here from being scorched by the sun. NASA is studying the Earth’s field with four satellites launched last year. Information gained from that could lead to a portrait of how Earth’s field protected us, and how to find similar fields in the universe.
The other path is a bit on the traditional side: looking for aliens looking for us. Think of it like an intergalactic game of Marco Polo. And this particular strategy gets a lot of attention, because the more “ears” are turned toward the skies, the better the chance is to “hear” something from another world. It’s a wide-net approach to fishing, rather than casting a single line.
SETI, the official collection of search arrays, has been in the headlines for the last year ever since Russian Internet billionaire Yuri Milner dropped a cool $100 million in funding for the previously underfunded initiative, and has been a force in recruiting the best minds and spurring public interest, as only eccentric billionaires can in such an abstract field of study.
But a recent paper suggested that while wide-open arrays are a good catchall, a focused search would be more effective. Essentially, looking at planets that could actually be looking back is doable and dedicates resources where they have the most potential.
It would also keep us from having to be the ones shouting “Marco” into the cosmos—a strategy that could potentially result in Earth being heard by the wrong people.
That’s a scary consideration, but not one the scientific community isn’t paying attention to. Stephen Hawking famously has reminded all of the less brilliant members of the human race that not every alien species would be as happy to find other life—and some may wish to exterminate it.
But there’s a potentially simple solution to that, too. A recent piece at Space.com outlined one of the theories for “hiding” Earth from potential predators. It involves bending light around the Earth, effectively cloaking the planet’s existence from even the most powerful observation methods from other galaxies.
It wouldn’t even be terribly powerful: “To alter Earth’s signature,” the story explains, “a laser system would have to emit 30 megawatts of power for about 10 hours per year… that equates to significantly less than the energy the International Space Station gathers in a year with its solar panels.”
Of course building one would effectively end our opportunity to be discovered by peaceful or friendly alien species too. But it wouldn’t prevent us from continuing to look for them.
For the moment, however, we’re not protected. And while the threat of real danger from the cosmos comes mostly from rogue asteroids, it’s always a consideration that someone more advanced is out there, studying humans, and trying to figure out whether we’re worth saying “hello” to.
Hopefully they’re not watching reality TV.