Slashdot Mirror
Advanced Civilizations Probably Don't Exist In Our Galactic Neighborhood
schwit1 writes: New observations of the best candidate galaxies now suggest that advanced civilizations are very rare or don't exist in the local universe. Researchers looked at several hundred nearby galaxies that emitted a high amount of mid-infrared radiation (abstract), which could possibly be produced as the waste heat from civilizations using energy on galactic scales.
They found: "The presence of radio emission at the levels expected from the correlation, suggests that the mid-IR emission is not heat from alien factories but more likely emission from dust — for example, dust generated and heated by regions of massive star formation. As Professor Garrett explains: 'the original research at Penn State has already told us that such systems are very rare but the new analysis suggests that this is probably an understatement, and that advanced Kardashev Type III civilizations basically don't exist in the local Universe.'"
Obviously, the uncertainty of these results is quite high. Nonetheless, the results indicate that either humanity really is the only intelligent species in this part of the universe, or advanced civilizations are far more efficient in their use of energy than is reasonable to assume.
They found: "The presence of radio emission at the levels expected from the correlation, suggests that the mid-IR emission is not heat from alien factories but more likely emission from dust — for example, dust generated and heated by regions of massive star formation. As Professor Garrett explains: 'the original research at Penn State has already told us that such systems are very rare but the new analysis suggests that this is probably an understatement, and that advanced Kardashev Type III civilizations basically don't exist in the local Universe.'"
Obviously, the uncertainty of these results is quite high. Nonetheless, the results indicate that either humanity really is the only intelligent species in this part of the universe, or advanced civilizations are far more efficient in their use of energy than is reasonable to assume.
Planets are common. Planets within the habitable zone look like they are common. So, is this evidence of the Great Filter - https://en.wikipedia.org/wiki/... ?
The firmament is peppered with huge concentrations of high-density plasma, supporting computation and communication far beyond the capacity of low-temperature, low-energy, solid-state matter. The byproducts of all that computation and communication look to us like thermal and optical noise because, being advanced, the minds running on them do so efficiently. Why leak information out into the vast, cold universe before you've taken full advantage of your substrate's Shannon capacity?
But, no, you're probably right. If there are other civilizations out there, why aren't we seeing the smoke from their cook-fires?
I'm no expert, but I remember reading that digital communication is virtually undetectable at galactic distances, because it fades way more quickly and becomes indistinguishable from background noise.
About the heat emissions... dunno what to say. An advanced civilization might be so thinned out, galactic-wise that it would emit an insignificant amount of heat. Or it could be a race which doesn't reproduce easily and lives for a long time, e.g. a couple million sentient beings per planet, who need very little in terms of energy. The possibilities are limitless.
Just wondering... how much heat does mankind generate? Can someone 1000 LY away detect our heat emissions?
...gis sdrawkcab (usually not responding to ACs; don't bother posting as AC)