Spot ET's Waste Heat For Chance To Find Alien Life

mdsolar passes along this selection from New Scientist describing a (comparatively) low-tech means of scanning the skies for extraterrestrial civilizations: The best-known technique used to search for tech-savvy aliens is eavesdropping on their communications with each other. But this approach assumes ET is chatty in channels we can hear. The new approach, dubbed G-HAT for Glimpsing Heat from Alien Technologies, makes no assumptions about what alien civilisations may be like.

"This approach is very different," says Franck Marchis at the SETI Institute in California, who was not involved in the project. "I like it because it doesn't put any constraints on the origin of the civilisation or their willingness to communicate." Instead, it utilises the laws of thermodynamics. All machines and living things give off heat, and that heat is visible as infrared radiation. The G-HAT team combed through the catalogue of images generated by the Wide-field Infrared Survey Explorer, or WISE, which released an infrared map of the entire sky in 2012. A galaxy should emit about 10 per cent of its light in the mid-infrared range, says team leader Jason Wright at Pennsylvania State University. If it gives off much more, it could be being warmed by vast networks of alien technology – though it could also be a sign of more prosaic processes, such as rapid star formation or an actively feeding black hole at the galaxy's centre.

Comments

False positives are far too easy

[Dr. Spork]

Basically, this method of searching for aliens returns a positive whenever there is something producing heat which we don't see/understand. I have a feeling that the universe is quite full of such things. But maybe explaining these will help us make scientific advances. When astronomers first discovered a pulsar, they labeled the signal LGM for "little green men". But since then, we learned a lot about astronomy. Explaining apparent anomalies is good for science, and if you want to make the process sexier by talking about possible alien civilizations, I don't see much harm.

Re:False positives are far too easy

[mdsolar]

It comes down to fig. 3 in their paper. http://arxiv.org/pdf/1408.1134... Natural source don't have the expected colors for waste heat from a solid surface. But that is the case when perhaps half the starlight in a galaxy is being used for power (their gamma=0.5). So, the civilization has to be pretty much like locusts for it the be easy to discern. There may be some civilization lifetime issues to worry about in that case.

Kardashev scale

[arielCo]

So, they're looking for civili[zs]ations classified as Type 3 in the Kardashev scale:

A civilization in possession of energy on the scale of its own galaxy.

OK, suppose we find their galaxy, conspicuous like a flamingo. How do we hail in order to confirm?