How Will Aliens Find Us?

Trying to keep a low profile, to prevent the aliens from invading? Bad news. Life has actually been broadcasting our existence to the Universe for hundreds of millions of years.

Have you heard these crazy plans to send signals out into deep space? What if evil aliens receive them, come steal our water, enslave, eat, and use us as guinea pigs for their exotic probulators. How we could stop these madmen from announcing our presence to the galaxy? A petition on whitehouse.gov? An all caps Facebook group? An all pusheen protest? Somebody call Reddit, they’ll know what to do.

If this is a worry for you and your friends, I’ve got bad news, or possibly good news depending on which side you come down on. We’ve already been broadcasting our existence for hundreds of millions of years. If aliens wanted to know we were here, all they needed to do was look through their telescopes.

We’re in a golden age of extrasolar planet discovery, recently crossing the thousand-planets-mark thanks to Kepler and other space telescopes. With all these amazing planetary candidates, our next challenge will be to study the atmospheres of these planets, searching for evidence of life. There are chemicals which are naturally occurring, like water and carbon dioxide, and there are substances that can only be present if some source is replenishing them. Methane, for example, would only last only few hundred years in the atmosphere if it wasn’t for farting cows and colonies of bacteria eating dead things.

If we see methane or oxygen in the atmosphere of an extrasolar planet, we’ll have a good idea there’s life there. And if we see the byproducts of an industrial civilization, like air pollution, we can pinpoint exactly where they are in their technical development. It will work for us, and that means it would work for aliens.

For the first few billion years, oxygen was toxic. But then cyanobacteria evolved photosynthesis and figured out how to work with oxygen more than 2.4 billion years ago. This is known as the Great Oxidation Event.

For the first billion years, all this biologically generated oxygen was absorbed by the oceans and the rocks. Once those oxygen sinks filled up, oxygen began accumulating in the atmosphere. By 500 million years ago, there was enough oxygen in the atmosphere to support the kind of breathing we do today. And this much oxygen would have been obvious to the aliens. They would have known that life had evolved here on Earth, and they could have sent out their berserker spaceships to steal our water and made us watch while they ate all our small rodents.

If the aliens waited, we would have given them more signs. The Industrial Revolution began in the mid 1700’s. And this time, it was humans that filled the atmosphere with the pollution of our industrial processes. Again, aliens watching the planet with their space telescopes would know the moment we became a technological civilization.

The innermost antennae along the north arm of the Very Large Array, superimposed upon a false-color representation of a radio (red) and optical (blue) image of the radio galaxy 3C31. Image courtesy of NRAO/AUI
The innermost antennae along the north arm of the Very Large Array, superimposed upon a false-color representation of a radio (red) and optical (blue) image of the radio galaxy 3C31. Image courtesy of NRAO/AUI

In the 20th century, we harnessed the power of radio transmissions, and began sending our messages out into space. For about a hundred years now, our transmissions have been expanding into a bubble of space. And so, any aliens listening within this expanding sphere of space might have a chance of hearing us. They know we’re here, and they know some of us really like Ke$ha.

And finally, for the last few decades, a few groups have tried broadcasting messages using our powerful radio telescopes directly at other stars. These messages haven’t gotten very far, but I honestly wouldn’t worry. Life itself gave away our position hundreds of millions of years ago. And life will help us find other civilizations, if they’re out there.

What do you think? Should we turn out the lights and pretend like we’re not home or keep on actively broadcasting our presence to the Universe? Tell us what you think we should do in the comments below.

Europa’s Hidden Great Lakes May Harbor Life

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New research on Jupiter’s ice-covered moon Europa indicates the presence of a subsurface lake buried beneath frozen mounds of huge jumbled chunks of ice. While it has long been believed that Europa’s ice lies atop a deep underground ocean, these new findings support the possibility of large pockets of liquid water being much closer to the moon’s surface — as well as energy from the Sun — and ultimately boosting the possibility it could contain life.

During a press conference today, November 16 at 1 p.m. EST, researchers Britney Schmidt, Tori Hoeler, Louise Prockter and Tom Wagner presented new theories concerning the creation of “chaos terrain” on Europa.

Chaos terrain is exactly what it sounds like: irregularly-shaped landforms and surface textures on a world. In the case of Europa, the terrain is made of water ice that evidence shows has been loosened by the motion of liquid water beneath, expanded, and then has refrozen into hills and jagged mounds.

Topographic data shows the chaos terrain elevations above the surrounding surface. Reds and purples are the highest elevations. Credit: NASA

These mounds are visible in topographic data acquired by the Galileo spacecraft in 1998.

During the presentation a good analogy for the processes at work on Europa was made by Britney Schmidt, a postdoctoral fellow at the Institute for Geophysics, University of Texas at Austin and lead author of the paper. She demonstrated the formation of Europa’s “mosh pit of icebergs” using a drinking glass partially filled with ice cubes. When water was added to the glass, the ice cubes naturally rose up and shifted orientation. Should the water beneath them refreeze, as it would in the frigid environments found in the Jovian system, the ice cubes would be held fast in their new expanded, “chaotic” positions.

“Now we see evidence that it’s a thick ice shell that can mix vigorously, and new evidence for giant shallow lakes. That could make Europa and its ocean more habitable.”

– Britney Schmidt, lead author

Similar processes have also been seen occurring on Earth, both in Antarctica along the edges of ice shelves and in Greenland, where glaciers continually break apart and flow into the sea – often rolling over themselves and each other in the process.

Europa's "Great Lake." Scientists speculate many more exist throughout the shallow regions of the moon's icy shell. Image Credit: Britney Schmidt/Dead Pixel FX/Univ. of Texas at Austin.

The importance of these findings is that scientists finally have a model that demonstrates how Europa’s deep liquid ocean interacts with the ice near its surface in such a way as to allow for the transportation of energy and nutrients.

“This is the first time that anyone has come up with an end-to-end model that explains what we see on the surface,” said APL senior planetary scientist Louise Prockter.

With such strong evidence for this process, the likelihood that Europa could harbor environments friendly to life goes up dramatically.

“The potential for exchange of material between the surface and subsurface is a big key for astrobiology,” said Wes Patterson, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., and a co-author of the study. “Europa’s subsurface harbors much of what we believe is necessary for life but chemical nutrients found at the surface are likely vital for driving biology.”

Although the research favors the existence of these lakes, however, confirmation of such has not yet been found. That will require a future mission to Europa and the direct investigation of its icy surface – and what lies beneath.

Luckily a Europa mission was recently rated as one of the highest priority flagship missions by the National Research Council’s Planetary Science Decadal Survey and is currently being studied by NASA.

“If we’re ever to send a landed mission to Europa, these areas would be great places to study,” Prockter said.

Read more about this discovery in the Johns Hopkins University Applied Physics Laboratory press release, or in the NASA news release here. Also, watch the full conference recorded on Ustream below: