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The Dyson sphere - hijacked by science fiction


Detecting aliens through artificial sources of infra-red
Freeman Dyson Scientist
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But it occurred to me in 1960, I think, a year after Cocconi and Morrison, that there might be aliens who were not communicating, that they might not want to communicate or they might have other means of communicating, so what about... what about detecting them, how could we detect uncommunicative aliens? And there is another way, which I got interested in. At that time they had satellite pictures of the earth, I think, already - I'm not sure, no, that may have been later - but in any case, if you look at the earth in the infrared band at night, nothing that you see is natural. The whole earth is in fact emitting in the infrared band only through human activities. So if you look down from a couple of thousand miles up at night with infrared telescope, what you see are flares from oil fields primarily, that is, the brightest patches on the earth are in Kuwait; and then after that you see of course big cities where humans are congregated. Everywhere where there is large scale human activities you see infrared radiation, and that's just the result of the second law of thermodynamics, that wherever humans are doing big engineering projects they have to radiate away the waste heat, just because of the laws of thermodynamics. Waste heat... waste heat has to be got rid of and it gets radiated away in the infrared band which is the natural frequency band for activities at a temperature of a few hundred degrees. So why not apply that to the universe at large? If there are extraterrestrials who are expansionist or have not controlled their populations, who are doing enormously big engineering projects, they also will have to radiate away their waste heat, and so they should be detectable over huge distances. So I proposed looking for these artificial sources of infrared, and so I published a little one page letter in Science called Search for Artificial Infrared Sources, and that was fine, and in recent years there have been some activities in that direction. We haven't discovered anything artificial. We now have very good infrared telescopes and so large numbers of sources have been found - nothing that is suspected of being artificial, but it's another channel which should be exploited.

Freeman Dyson (1923-2020), who was born in England, moved to Cornell University after graduating from Cambridge University with a BA in Mathematics. He subsequently became a professor and worked on nuclear reactors, solid state physics, ferromagnetism, astrophysics and biology. He published several books and, among other honours, was awarded the Heineman Prize and the Royal Society's Hughes Medal.

Listeners: Sam Schweber

Silvan Sam Schweber is the Koret Professor of the History of Ideas and Professor of Physics at Brandeis University, and a Faculty Associate in the Department of the History of Science at Harvard University. He is the author of a history of the development of quantum electro mechanics, "QED and the men who made it", and has recently completed a biography of Hans Bethe and the history of nuclear weapons development, "In the Shadow of the Bomb: Oppenheimer, Bethe, and the Moral Responsibility of the Scientist" (Princeton University Press, 2000).

Tags: 1960, Search for Artificial Stellar Sources of Infrared Radiation, Kuwait, Science, Giuseppe Cocconi, Philip Morrison

Duration: 2 minutes, 46 seconds

Date story recorded: June 1998

Date story went live: 24 January 2008