Two mind-boggling conjectures about the existence of advanced alien civilizations have been made by Harvard’s chief astronomer and the director of Columbia University’s Astrobiology Center.

Astrophysicist Caleb Scharf at Columbia University proposes that alien life could be so advanced it becomes indistinguishable from physics. While Harvard’s Avi Loeb suggests that the first-known interstellar visitor to our Solar System, Oumuamua, could be a probe sent by an alien space-faring civilization, and that the scientific community should be more willing to acknowledge and embrace uncertainty.

Physicists have found that for the last 7 billion years or so something is pushing the galaxies, adding energy to them. Something they are calling “dark energy,” a force that is real, but so far eludes detection.

One of the most speculative ideas for the mechanism of an accelerating cosmic expansion is called “quintessence”, a relative of the Higgs field that permeates the cosmos. Perhaps some clever life 5 billion years ago figured out how to activate that field, speculates Scharf. How? “Beats me,” he says, “but it’s a thought-provoking idea, and it echoes some of the thinking of cosmologist Freeman Dyson’s famous 1979 paper “Time Without End,” where he looked at life’s ability in the far, far future to act on an astrophysical scale in an open universe that need not evolve into a state of permanent quiescence. Where life and communication can continue for ever.

Once we start proposing that life could be part of the solution to cosmic mysteries, Scharf concludes, “there’s no end to the fun possibilities. Although dark-matter life is a pretty exotic idea, it’s still conceivable that we might recognize what it is, even capturing it in our labs one day (or being captured by it). We can take a tumble down a different rabbit hole by considering that we don’t recognize advanced life because it forms an integral and unsuspicious part of what we’ve considered to be the natural world.”

Scharf points out that Arthur C. Clarke suggested that any sufficiently advanced technology is going to be indistinguishable from magic. “If you dropped in on a bunch of Paleolithic farmers with your iPhone and a pair of sneakers,” Scharf says, “you’d undoubtedly seem pretty magical. But the contrast is only middling: The farmers would still recognize you as basically like them, and before long they’d be taking selfies. But what if life has moved so far on that it doesn’t just appear magical, but appears like physics?”

If the universe harbors other life, and if some of that life has evolved beyond our own waypoints of complexity and technology, Scharf proposes that we should be considering some very extreme possibilities.

Enter Harvard’s Avi Loeb: “I don’t see extraterrestrials as more speculative than dark matter or extra dimensions. I think it’s the other way around.”

When Oumuamua entered our Solar System, Loeb observed in an interview with Endless Thread, “it spun around over a period of eight hours its brightness changed by a factor of 10. And that’s much more than any object born in the solar system, such as asteroids or comets, that change by at most a factor of three or so.

Another weird anomaly, he said, was the mere fact that it was discovered, [which] implies that the population of such objects is much more abundant than we anticipated. Unless of course it’s on a very specialized orbit such that it’s not a member of a population of random objects.

Mirroring Scarf’s argument, Loeb concluded, “the entire discussion about ‘Oumuamua is very similar to an imaginary scene where you see a cave person being shown an iPhone. And this cave person would look at it and think that it might be a rock. And then would show it to other members of his or her tribe and the people there would still say, No, it’s probably a rock and how dare you say something else, how dare you talk about something that is different than a rock because rocks are everything that we are familiar with.

“And so, to me,” Loeb concludes, “not even putting aliens on the table for discussion is a crime! Because if you look at the history of science, you know, Galileo Galilei argued that the Earth moves around the sun and he was put under house arrest for that. Now, this of course didn’t change the facts. It doesn’t matter what is being said on Twitter, what is being said in other social media or among scientists. This thing is what it is, right? And, you know, the Earth still moves around the sun irrespective of what the church said a while ago. And the fact that Galileo suffered for it has no relevance to nature.”

The Daily Galaxy via WBUR and Nautil.us