Can We Use Pollution to Find Aliens?

Can We Use Pollution to Find Aliens?

Published May 23, 2018

Onscreen: What’s the best way to track down an alien civilization?

Avi Loeb: The sign of intelligence is that it produces a signal or a structure that nature at random could not produce.

Onscreen: Avi Loeb wonders whether we can use industrial pollution to identify intelligent life on other planets.

Loeb: If another civilization had billions of years to develop its science and technology, the sky’s the limit.

Onscreen: Imagine an advanced civilization that consumed its planet’s resources to power life, and produced gases as by-products. Just like us.

Loeb: Artificially-produced molecules like CFCs could potentially last for 50,000 years, and they are very resilient.

Onscreen: CFCs are man-made molecules that don’t break apart easily. They’re produced by chemicals found in air conditioners, refrigerators and aerosol cans. These and other pollutants could be red flags for alien industrialization.

The James Webb Space Telescope, scheduled for launch in 2020, might be able to detect those molecules in the atmospheres of distant exoplanets. But if we find them, does that mean we’ve found new neighbors?

Loeb: The environmental impact of a civilization can in principle outlast the civilization itself. We might find evidence for graveyards of preexisting civilizations that either created conditions on their planet that are not habitable or they decided to move on to another place, another location.

Onscreen: In other words, pollution could be detectable in a planet’s atmosphere for millennia, long after intelligent life has gone extinct. This could be true on distant planets, and potentially, for any aliens out there looking for company on this one.

PRODUCTION CREDITS

Digital Producer

Michael Rivera

NOVA WONDERS ARE WE ALONE?

Produced and Directed by

Jane Teeling and Phil Bertelsen

© WGBH Educational Foundation 2018