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Our future, our universe, and other weighty topics


Saturday, August 23, 2014

Hints of ET Civilizations Found in 50 Galaxies?

There are various possibilities for how mankind might first learn of the existence of extraterrestrial life. We might one day see a huge alien spaceship heading toward our planet. Or we might sniff out the chemical signatures of extraterrestrial life by studying nearby planets. Or we might get a radio message from extraterrestrials. Or, we might discover extraterrestrial intelligence by detecting indirect signs of large-scale astronomical engineering by alien civilizations.

I have always thought the last of these possibilities is quite plausible, and I have argued that perhaps the mysterious hard-to-explain planet Kepler 78b may be an example of extraterrestrial engineering at work. But now astronomers may have discovered evidence of astronomical engineering on a much vaster scale. The finding suggests the possibility of very large-scale astronomical engineering in about 50 different galaxies.

Before discussing the finding, I should discuss why the idea of large-scale engineering projects by extraterrestrials is a very plausible one, rather than some far-fetched idea dreamed up by a wild-eyed fantasist. The universe is about 13 billion years old, and intelligent life could have arisen on other planets at any time during the past several billion years. The universe consists of billions of galaxies which each contain millions or billions of stars. There are therefore a huge number of planets on which intelligent life could have evolved, and many eons during which such intelligent life could have appeared. A civilization much older than ours might be expected to engage in large astronomical engineering projects such as building large space colonies, constructing Dyson spheres, moving planets, or breaking up planets and creating space colonies from some of their parts. Such projects, very difficult for us, might be “child's play” for a civilization thousands or millions more advanced than ours.

Given all these factors, scientists have half-expected to scan the far reaches of space, and find evidence of the large-scale activities of extraterrestrials. It was hoped that such evidence would show up in the form of “heat signatures” that would take the form of infrared radiation. Infrared radiation is given off by all hot bodies. If an extraterrestrial civilization were to be engaging in large-scale engineering projects, this would give off a lot of excess heat which would create infrared radiation that could be read by scientific instruments. But prior to this year, scientists had found no such evidence. Quite a few scientists have said that it is surprising that such evidence has not been found. 

infrared radiation
Map of infrared radiation given off by a human

 So we should not be too surprised to hear about the exciting results from a recent astronomical survey. The survey was done by the Center for Exoplanets and Habitable Worlds at Penn State University, using data from a scientific satellite known as the Wide-Field Infrared Survey Explorer (WISE). According to team leader Jason Wright, a galaxy should emit only about 10 percent of its radiation as mid-infrared radiation. But the survey detected about 50 galaxies that are emitting more than half of their radiation as mid-infrared radiation.

This is exactly what we might expect to see if these galaxies had been “taken over” by one or more extraterrestrial civilizations that engaged in huge engineering projects that caused excess heat to be emitted. Someone speaking in the style of Erich von Daniken (author of Chariots of the Gods?) might call this excess infrared radiation the heat of the gods.

But scientists will need to do more work to rule out natural sources of radiation that might be producing all of this excess heat in these galaxies. Until that is done, we cannot say that proof has been found for extraterrestrial intelligence. But for the time being, we seem to have a tantalizing hint that extraterrestrial intelligence exists, and exists abundantly.