An advanced alien civilization could evolve in globular clusters
We might be living in the wrong part of the galaxy.
Elsewhere in the Milky Way, vast groups of ancient star populations are packed into dense ellipsoid regions, called globular clusters. Within these tight-knit patches of stellar bodies, there are no new stars and no collapsing supernovae. But evidence indicates these regions may be abundant in planets.
And, if this is the case, any advanced alien civilizations that evolve inside globular clusters would have a definitive advantage when it comes time to form an interstellar society, since the distances between stars in these regions would be far smaller than the vast stretches of space seen in our galactic neighborhood.
And this could make interstellar communication and travel much easier, potentially moving a budding "alien federation" far ahead of rival civilizations "land-locked" on galactic disks (like ours), according to a recent study shared to a preprint server.
But don't pack your bags just yet. The very proximity of nearby solar systems could also spell doom for any thriving alien civilization inhabiting a planet inside a globular cluster.
Advanced aliens in globular clusters would have several distinct advantages
Globular clusters possess some of the most ancient solar systems found in the known universe. They can hold between 100,000 and 1 million stars inside of incredibly dense sphere-shaped regions, and the roughly 150 globular clusters in our Milky Way can be at least 10 billion years old, according to the study. In the study, the researchers considered the possibility that such ancient systems host planets capable of supporting not only intelligent life, but advanced civilizations. "Such civilizations would be immersed in stellar environments so dense that distances between stars could be as small as hundreds or thousands of au: thousands to hundreds of times smaller than typical interstellar distances in the Milky Way's disk, which is home to the sun," wrote the authors in their study.
The unit, "AU", literally means "astronomical unit," which refers to the distance from the Earth to the sun. It takes roughly eight minutes for light from our sun to reach us. Our nearest stellar neighbor, the Alpha Centauri system, is about four light-years away, meaning it takes roughly four years for its light to reach the Earth. Recent studies have suggested that there may be habitable planets there, and while these exoplanets probably don't host intelligent alien life, the prospect of settling any planets even in this closest neighboring solar system faces the seemingly insurmountable issue of interstellar communication, since anything we send to hypothetical settlers there wouldn't get a response for at least eight years (and vice-versa for settlers of the Alpha Centauri system).
Sacrificing one alien civilization to save the collective
But in a globular cluster, a similar situation between two neighboring stars would be far easier to overcome. At only hundreds of times the distance between the Earth and the sun, communications sent between neighboring stars in a globular cluster could have an incredibly short wait-time of 1,600 minutes for a response.
At roughly 27 hours, that's barely more than one Earth day.
This is an extremely ideal case of speculation, since most cases would call for weeks or months of transit time for interstellar communications, according to the study. But the mutual proximity of nearby stars in globular clusters could also lend a distinct advantage to alien civilizations' capacity to survive a catastrophic extinction event — the kind Elon Musk likes to talk about — since they would have a smaller distance to traverse to settle other worlds. But don't get too excited. The statistical probability of the entire "alien federation" going extinct might drop to near-zero numbers, but every individual solar system would be far more likely to undergo chaotic and destructive periods, as gravitational anomalies from nearby solar systems could send apocalyptic asteroids on a collision course with inhabited worlds, or even fling an Earth-like world directly into its host star, or completely out of its solar system. This is a highly fascinating study, one that opens up far too many possibilities for things like the evolution of a species and advanced alien civilizations to discuss here. But our exoplanet-hunting telescopes may one day find something unspeakably awe-inspiring happening in these ancient globular clusters. Assuming anyone's home.