Spying Anthropocene...

In Star Trek, the starship Enterprise encounters an alien Dyson Sphere. On Earth, NASA could detect one with its next-gen telescopes, astrobiologists suggest.
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Topics: Astrobiology, Astrophysics, Dyson Sphere, Exoplanets, NASA, SETI

Astrobiologists are calling on NASA to use what geologists are learning about a new era sometimes called the “Anthropocene” to help develop space missions for the search for extraterrestrial intelligence.

Not that astronomers can peer into the rock strata of alien worlds in the hope of finding traces of existing (or vanished) civilizations. What they can do is look for changes in planetary atmospheres — changes that Haqq-Misra and colleagues refer to as “techno-signatures” in a policy paper submitted to the US National Academy of Sciences.

Abstract

Human influence on the biosphere has been evident at least since the development of widespread agriculture, and some stratigraphers have suggested that the activities of modern civilization indicate a geological epoch transition. The study of the anthropocene as a geological epoch, and its implication for the future of energy-intensive civilizations, is an emerging transdisciplinary field in which astrobiology can play a leading role. Habitability research of Earth, Mars, and exoplanets examines extreme cases relevant for understanding climate change as a planetary process. Energy-intensive civilizations will also face thermodynamic limits to growth, which provides an important constraint for estimating the longevity of human civilization and guiding the search for extraterrestrial intelligence. We recommend that missions concepts such as LUVOIR, HabEx, and OST be pursued in order to make significant progress toward understanding the future evolution of life on our planet and the possible evolution of technological, energy-intensive life elsewhere in the universe.

“If you saw a planet like Earth, around a yellow star and you saw methane and ozone and carbon dioxide, that’s a classic bio-signature,” Haqq-Misra says. “But if you see a planet like Mars, just a little outside the traditional habitable zone, where you’d expect it to be cold, but you observe CFCs (chlorofluorocarbons) and PFCs (perfluorocarbons) and exotic greenhouse gases that seem to be raising the [planet’s temperature], that would be pretty good evidence for terraforming — like us terraforming Mars.”

Techno-signatures might also take the form of infrared light that might represent heat loss from large-scale engineering projects, such as orbiting solar collectors or planetary sun shades designed to offset global warming.

Such things, Haqq-Misra says, might lie in the future of any technologically advanced civilization faced with the dual problems of population growth and increasing energy needs.

Use new telescopes to scout for ET tech, astrobiologists tell NASA
Richard A. Lovett, COSMOS Magazine