Astronomers led by Roger Griffith of the Pennsylvania State University say they have found no evidence of so-called Type III Kardashev super-civilizations in almost 100,000 galaxies from NASA’s Wide-field Infrared Survey Explorer mission.
This image, from Hubble’s Advanced Camera for Surveys, shows the ultraluminous infrared galaxy Arp 220. Image credit: NASA / ESA / C. Wilson, McMaster University.
In 1964, Soviet astronomer Nikolai S. Kardashev proposed a method of measuring the technological advancement of a civilization, based on the amount of energy this civilization is able to utilize.
He identified three types of civilizations called Type I, II, and III. A Type I civilization can manage the entire energy and material resources of a planet. A Type II civilization is capable of harnessing the energy and material resources of a star and its planetary system. A Type III civilization is able to marshal the energy and material resources of an entire galaxy.
It was further postulated by the British-American physicist Freeman Dyson that such super-civilizations could be detected by the presence of thermal infrared emissions from massive objects in space that had dimensions of 1-2 AU in diameter.
Griffith and his colleagues from Carnegie Science Center and California State Polytechnic University, Pomona, have used the Wide-field Infrared Survey Explorer (WISE) to survey nearly 100 million galaxies for objects consistent with a Type III super-civilization – around 1,000 times more galaxies than the only previous such search.
They then examined and categorized around 100,000 of the most promising galaxy images.
“Our results mean that, out of the 100,000 galaxies that WISE could see in sufficient detail, none of them is widely populated by an alien civilization using most of the starlight in its galaxy for its own purposes,” said Dr Jason Wright of the Pennsylvania State University, a co-author of the paper accepted for publication in the Astrophysical Journal Supplement Series (arXiv.org preprint).
“That’s interesting because these galaxies are billions of years old, which should have been plenty of time for them to have been filled with alien civilizations, if they exist. Either they don’t exist, or they don’t yet use enough energy for us to recognize them.”
The scientists found about 50 galaxies (including the previously well-studied Arp 220, the closest ultraluminous infrared galaxy to us) that have unusually high levels of mid-infrared radiation.
“Our follow-up studies of those galaxies may reveal if the origin of their radiation results from natural astronomical processes, or if it could indicate the presence of a highly advanced civilization,” Dr Wright said.
According to the team, five spiral galaxies with unusually high mid-infrared luminosities (labeled WISE J085428.94+084444.4, J113325.93+141618.9, J142619.17+473357.8, J142859.55+605000.5, and J230616.43+135856.4) are really interesting looking.
Also among the team’s discoveries are some mysterious new phenomena in our own Milky Way galaxy: a bright nebula around the nearby star 48 Librae, and IRAS 04287+6444 – a cluster of objects easily detected by WISE in a patch of sky that appears totally black when viewed with telescopes that detect only visible light.
“IRAS 04287+6444 is probably a group of very young stars forming inside a previously undiscovered molecular cloud, and the 48 Librae nebula apparently is due to a huge cloud of dust around the star, but both deserve much more careful study,” explained co-author Dr Matthew Povich of California State Polytechnic University.
Dr Wright added: “as we look more carefully at the light from these galaxies, we should be able to push our sensitivity to alien technology down to much lower levels, and to better distinguish heat resulting from natural astronomical sources from heat produced by advanced technologies. This pilot study is just the beginning.”
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Roger L. Griffith et al. The Ĝ Infrared Search for Extraterrestrial Civilizations with Large Energy Supplies. III. The Reddest Extended Sources in WISE. ApJS, accepted for publication; arXiv: 1504.03418
