In his new book Take Me to Your Leader, astrophysicist Neil deGrasse Tyson contemplates possible powers and limits of extraterrestrials. Noting reports of extreme acceleration by suspected alien spacecraft, he writes: “Happy to grant them propulsion systems we don’t yet know how to make. If the Aliens are composed of biological tissue and not steel or some other rigid substance, and if the pilot or passengers accelerated from zero to one thousand miles per hour in a second, everyone on board will have experienced upward of 50-Gs, squashing them into a pile of goo for each impressive maneuver in our skies.”
Tyson wonders whether extraterrestrials may have resilient physiology, illustrated by the fictional alien Superman expressly endowed with super internal organs. Super digestion would occur via super bacteria generating super levels of waste gases such as hydrogen sulfide and methane. There could be problems, however, as Tyson notes: “Hydrogen sulfide is smelly and actually deadly, even in small concentrations, giving literal meaning to the phrase ‘silent but deadly.’” Furthermore: “Combine the methane in Superman’s farts with his infrared vision, and he could roll down his drawers, aim his butt at a target, let one loose, and direct his infrared vision at the gas stream, creating a veritable flamethrower.”
Whimsical but informative, Take Me to Your Leader offers valuable perspective on alien life at a time when public interest in the subject is resurgent. The Pentagon recently released a batch of images related to unidentified anomalous phenomena, or UAP, also known as UFOs. Though in favor of disclosure of files on such matters, I was nonplussed by an image released with the caption: “Actual site photo with FBI Lab rendered graphic overlay depicting corroborating eyewitness reports from September 2023 of an apparent ellipsoid bronze metallic object materializing out of a bright light in the sky, 130-195 feet in length, and disappearing instantaneously.” This was an illustration, not a corroboration.
In a recent article at The UnPopulist, I argued that seeking extraterrestrial intelligence poses challenges best handled by non-authoritarian political systems, “liberal” in the classical sense of promoting free exchange of ideas and rejecting arbitrary power. If, say, a radio signal of evident intelligent origin arrives from space, there are protocols for scientifically evaluating the information and announcing any conclusions, but these would only have credibility in the context of open societies and international cooperation. Otherwise, humanity’s reactions will likely be panic, paranoia and internecine strife.
Reasoned discourse on this subject requires keeping separate the question of whether intelligent extraterrestrials exist somewhere in our galaxy (or beyond, though in that case prospects of detecting them diminish) from that of whether they’re visiting Earth currently. Tyson upholds the mainstream scientific view that evidence for the latter is unpersuasive. Noting how smartphones and other tech have expanded opportunities for such observation, he writes: “More than a million people are airborne at any moment, yet nobody with a window seat has ever captured a high-resolution image of a Mother Ship or some other Alien craft. When combined with Google Earth, and other satellite-generated imagery of Earth’s surface, we’re poised to crowdsource the observations of any Alien invasion of Earth. Wouldn’t we see them coming before any government agency does?”
How many civilizations capable of interstellar communication may exist in our galaxy at any time depends on factors ranging from how many planets are suitable for life, to how likely intelligence and tech are to develop, to how long such civilizations survive. “Running these numbers with the latest and best available estimates, as I’ve done elsewhere with Princeton colleagues, we get about a hundred extraterrestrial civilizations in the Milky Way Galaxy that are capable of transmitting and receiving radio signals through space,” he writes.
This translates, Tyson points out, to an average distance between civilizations of about 5,000 light-years. “So, without wormhole communications, if we received signals from Aliens today, those signals would have been sent five thousand years ago, back when we were inventing paper. More importantly, for any signal we send today, we should not expect a response before a round-trip travel time of tens of thousands of years.”
Given the eons in which aliens could have arisen and spread through the galaxy, however, the question remains as to why their presence isn’t pervasive and obvious, known as the “Fermi Paradox” as it was raised by physicist Enrico Fermi. It has many possible answers, ranging from impediments in evolution, to interstellar travel’s difficulty, to the “Dark Forest” view that aliens keep quiet to avoid dangers from other aliens. Tyson has an affinity for the “Cosmic Quarantine” hypothesis, that aliens set aside our region of the galaxy as a reserve, so it wouldn’t be overrun by competing extraterrestrial colonizers or real-estate developers.