When it comes to searching for life on other planets, researchers have quite the task before them. After all, we only know of one planet that bears life: our own big blue marble in space.
When an exobiolgist is looking for evidence of life, what, exactly, should they be looking for? Of course, a planet that has oxygen and water is a likely candidate for study. This planet should also be within a habitable distance of its star, similar to our own orbit around the sun.
However, some scientists theorize that one of the most surefire ways to detect the existence of alien life in the cosmos would be the presence of megastructures. What are those, and how can we find them? Let’s take a closer look.
What Are Megastructures?
A megastructure is a hypothetical non-natural structure made by an intelligent species for some large-scale purpose. The classic example that comes to mind is the Dyson Sphere, a massive series of panels that would envelope a star and harvest its energy for use in space travel.
Freeman Dyson, the man for whom the thought experiment is named, pointed to the relatively small amount of light radiation any given planet receives. If a species wanted to use more of a star’s energy, it would make sense to simply build a solar panel array in a sphere to encircle it.
Why should exobiologists be looking for such megastructures? We discussed the Fermi Paradox on the site last week, which holds that the Milky Way is big enough and old enough that we could expect to see at least some evidence of prior intelligent life. If such life had come before us, shouldn’t we see evidence of their civilization?
Spacefaring Civilizations Demand More Power
A species’ power demands are likely to be exponential. Dyson thought as much when he conceived of the spherical megastructure that bears his name. After all, as a population continues to increase and the civilization expands to encompass more planets, the amount of power required for each individual would increase dramatically.
This means we could reasonably expect to see such structures dotting the cosmos if intelligent life is at all common. After all, humanity can’t have just gotten lucky and been the only intelligent life in the galaxy, right?
The Problem of Observation
A complication for observers on Earth looking for megastructures like a Dyson Sphere is that they would likely be hard to detect, even if they were causing a dimming effect of distant stars.
However, one such star has been observed: in 2015, researchers detected abnormalities in the luminosity of star KIC 8462852.
Such abnormalities could not be easily explained by natural phenomenon, and to this day, star KIC 8462852 has captured the imagination of astronomers and exobiolgists. Further research is needed, but an explanation for the strange changes in luminosity could be the result of an alien megastructure.
This could mean that there really could be other life in the universe. Or it could mean that there are natural phenomena we have not yet discovered. Either way, star KIC 8462852 proves we still have much to learn about our galaxy.