Everyone has imagined how excited people would be if alien life were finally discovered. You’ve all seen those movies where one day a huge spaceship breaks through the clouds and imposes its presence on the world. I, for one, sometimes think what it would be like if I’m driving down the interstate and suddenly this enormous mothership slowly looms over the horizon. I’d hunch over my steering wheel and look up at the sky in shock, but then I’d immediately get mad at the other drivers because they would all pull over, or stop right there on the road, just so they can get out and look at it. “Come on, people. I’ve got places to be. Yeah, there’s a spaceship; let’s move on. I have to be at work in, like, five minutes.” Well, that’s if the aliens came knocking on our door. In reality, there are a few ways that scientists search for extraterrestrial life, e.g., searching for radio signals, laser signals, or evidence of neutrinos. And now we can add one more new way to search for alien life: analyzing for something called “dimers.”
Earth’s atmosphere not only helps hold in heat, it is also heavy enough to prevent water from flying out into space. With this in mind, scientists have now found a way to search for planets that have atmospheres similar to Earth.
According to a new report in Astrobiology, scientists have now found a way to gauge a distant planet’s atmosphere for molecules that couple together to form what are called “dimers.” In the case we’re talking about, they’re looking for a union of two oxygen molecules.
So here’s how it works:
Scientists watch as an exoplanet passes in front of its star and how the light from that star passes through the planet’s atmosphere. Dimers in that atmosphere will absorb the passing light like a camera’s color filter, creating anomalies. This effect is detectable if the atmospheric pressure is less than .25 bars – high enough to hold down liquid water.
Come 2018, Scientists will be able to gauge the strength of the atmospheric pressure of prospective exoplanets by using the James Webb Space Telescope. Once operational it can study the signals and determine whether or not these atmospheres contain another key component: oxygenation. You see, these signals are only detectable if the atmosphere is well oxygenated. And, the only way that scientists know you can make an atmosphere oxygenated is with photosynthetic life.
So if scientists find a planet that has oxygen dimers in the atmosphere, they not only have found a place that has water and breathable air, they’ve also found a potentially habitable world.