So I’ll kick off what I hope will be a regular feature here: science sunday, where I’ll blog about a recent scientific result I think is interesting. This week, I’ll blog on something a bit close to me.
(It’s a bit late this week since I’ve been chopping down trees, spreading mulch and dealing with a sick kid. But it’s still Sunday somewhere.)
One of the biggest questions in science — indeed in human history — is whether we are alone in the universe. I am convinced that we will soon find evidence of very simple life within our solar system — archaea or some other simple organism in martian fossils or in the seas of Europa, Ganymede or Titan. We have now detected thousands of planets beyond our solar system, including a number in the “goldilocks zone” where liquid water can exist. But detecting intelligent life is way beyond our current capabilities.
It might actually be possible to detect a sufficiently advanced civilization. SETI has looked in the radio for a long time with no results. But radio communication may be a short-lived phase for alien civilizations. What may be more plausible is looking for heat signatures:
One of the largest-ever searches for distant alien empires has scoured 100,000 galaxies for signs of suspicious infrared activity and found… nothing.
The study by Penn State used data from Nasa’s Wise (“Wide-field Infrared Survey Explorer”) orbiting observatory to scour far-off galaxies for radiation which, astronomers theorise, would likely be produced if a civilisation were powerful enough to colonise thousands of stars.
The theory that aliens might be visible on a galactic scale is based on the ideas of physicist Freeman Dyson, who suggested in the 1960s that galactic civilisations would almost by definition use most of the starlight in their galaxy for their own ends. This should be detectable using mid-infrared telescopes. That wasn’t possible when Dyson’s theory emerged, but Nasa’s Wise telescope does have the ability to make close measurements for thousands of galaxies, and so allow scientists to study the data for telltale signs of life.
No, they didn’t find it. But scientists have found 50 galaxies with unusual radiation signatures, indicating something strange is happening inside many distant collections of stars — even if it’s nothing to do with aliens at all.
There have been a few other studies looking for the radiation signatures of nearby Dyson Spheres but there haven’t been any hints of anything yet.
An alien species would have had to have been around for millions of years for us to see the effects of their capturing vast amounts of starlight. So this is the extreme end of the hunt for extraterrestrial intelligence. But with millions of galaxies out there, there’s at least a chance we could find one. It’s a million to one shot but if it ever paid off it would be an incredible discovery. And even it doesn’t, we’ll still learn a lot about galaxies.