Meeting With ‘Oumuamua



Observations from ESO’s Very Large Telescope in Chile and other observatories around the world show that this unique object was traveling through space for millions of years before its chance encounter with our star system. It appears to be a dark, reddish, highly-elongated rocky or high-metal-content object.
European Southern Observatory, Nov. 20, 2017 

Science fiction, at its best, interrogates not just the possible future but also the present. While playing with things like time travel or aliens or teleportation, the genre makes us consider our experience of time and mortality, reckon with our identities and our treatment of others, and contemplate the lasting impacts of our actions. The carefully constructed worlds of science fiction and fantasy can be used as magnifying glasses, or as looking glasses. They amplify and distort our world; in pretending, we can see reality differently, challenging our presumptions or maybe catching something unseen or misunderstood.

Sometimes the refracted reality is obvious. For instance, scholars have long recognized a correlation between waves of alien-invasion fiction and waves of immigration. Sometimes it is less obvious, at least in the moment. You might think you are reading a simple piece of fiction, and chuckle at its outmoded references and anachronisms, until you realize its prescience, and understand you are actually reading something preparatory. Just as children’s imaginative play serves as a form of social practice, science fiction can serve as a test bed for possible realities. Really, what would we do with humans who possess unexplained mutations or abilities? What would we do if aliens showed up?

Sometimes, these practiced realities are just for fun, of course. But it’s especially fun to experience science fiction that gets science fact down pat. An interstellar interloper recently provided the best example of this I’ve seen in quite some time (at least since the Tatooine discovery). Humans just found an interstellar asteroid for the first time: a space rock that originated around a star other than our own, and somehow showed up on our cosmic doorstep. Science fiction nailed this. The object, its parameters, its arrival, its orbit — almost its entire story was first written down more than 40 years ago, in a classic in the sci-fi pantheon, Arthur C. Clarke’s “Rendezvous with Rama.”

Here is Clarke, with very minor tweaks made by me to reflect nothing more than the name of our real object, described in detail for the first time two weeks ago.

The object first catalogued as A/2017 U1, according to its nature and the year of its discovery, was detected after it had sailed past the orbit of Earth. There was nothing unusual about its location; many asteroids follow irregular paths before turning toward their distant master, the sun. But its trajectory was unprecedented. Then its orbit was calculated, and the mystery was resolved — to be replaced by a greater one. A/2017 U1 was not traveling on a normal asteroidal path, along an ellipse it retraced with clockwork precision every few years. It was a lonely wanderer among the stars, making its first and last visit to the solar system — for it was moving so swiftly that the gravitational field of the sun could never capture it. It had already flown inward, past the orbits of Earth, Venus, and Mercury, until it rounded the sun and headed out once again into the unknown.

It was at this point that the computers started flashing their “we have something interesting” signal, and for the first time, A/2107 U1 came to the attention of human beings. There was a brief flurry of excitement, and the interstellar vagabond was quickly dignified by a name instead of a mere number.

For a few days, the news media made a fuss over the visitor*, but we were badly handicapped by the sparsity of information. Only two facts were known about A/2017 U1: its unusual orbit and its approximate size. Even this last was merely an educated guess, based upon the strength of the radar echo.

… And there is more, but I grow afraid of both belaboring the point and ripping off an idol. So I offer thanks and apologies to Clarke, and will summarize some of his other apparently clairvoyant observations.

In the book, asteroids — in 2131 — were being discovered at the rate of a dozen a day. This is accurate as of this month. On Thursday, Nov. 9, the Center for Near Earth Object Studies had catalogued 17,044 known asteroids. By Monday, Nov. 27, the number had risen to 17,246. That is an average rate of 11.2 per day.

In the book, astronomers had long ago stopped naming celestial objects for characters in Western mythology, and had moved on to the Hindu pantheon. Clarke’s object was renamed Rama. In our case, the astronomers turned to Pacific Islander tradition. And so A/2017 U1 was christened ‘Oumuamua. The name is Hawaiian, and reflects the strange object’s nature: ‘ou, with the apostrophe, means to “reach out for,” and mua, with the second mua adding emphasis, means “in advance of.” The name means “scout sent from the distant past to reach out to us,” according to the International Astronomical Union’s Minor Planet Center.

In the book and in real life, Rama and ‘Oumuamua are weird, elongated, and unnatural-looking. ‘Oumuamua varies dramatically in brightness by a factor of 10, which suggests it is much longer than it is wide, with a complex shape. It is also dark red and inert, without any dust around it. In the hours after it first appeared in telescopes, astronomers thought it may have been an interstellar comet, but it lacks any dust whatsoever. It has no water, either, according to Karen Meech, of the Institute for Astronomy in Hawaii, who led the effort to take ‘Oumuamua’s vitals.

Astronomers think it was bombarded by cosmic rays over millions of years, during which it traveled solo and ultra-fast through the Milky Way. ‘Oumuamua rotates every 7.3 hours, and is at least 400 meters long. This means it must be dense and maybe rocky or heavy with metals, otherwise it would fly apart. (Physics favors the spheroidal.) But it’s not spinning fast enough to generate any form of artificial gravity, as physicist Rhett Allain calculated. Phew: It’s (probably) not a vessel containing beings from beyond.

When it was discovered, astronomers pointed out that ‘Oumuamua appeared to emanate from roughly the direction of Vega, in the constellation Lyra. It’s a familiar constellation in the northern hemisphere, and it’s especially familiar to fans of science fiction: Vega is the origin of the interstellar message in “Contact,” the book by Carl Sagan and the movie starring Jodie Foster. But then there was some disappointing news. Vega was not in its present position 300,000 years ago, which is how long it would have taken ‘Oumuamua to get here from there, even traveling at a breakneck speed of 95,000 km/hour. ‘Oumuamua may have been wandering through the Milky Way, unattached to any star system, for hundreds of millions of years. A vagabond indeed.

Many astronomers and writers have pointed out the Rama-‘Oumuamua connection. It’s fun to imagine what else Clarke could have gotten right: Is it, in fact, a probe? I think there is a vanishingly small chance, but a chance all the same. (Don’t @ me.) Will a crew of “biots” spill forth from ‘Oumuamua’s dark edge? If so, would Earth try to nuke it? Would brave, tolerant explorers try to thwart the nuke-happy fearful ones?

“Our observations are entirely consistent with it being a natural object,” Meech said. Phew. Or bummer.

After ‘Oumuamua arrived, I started re-reading “Rama.” Some of the coincidences give me the chills. But one made me laugh:

Even by the 22nd century, no way had yet been discovered of keeping elderly and conservative scientists from occupying crucial administrative positions. Indeed, it was doubted if the problem ever would be solved.

Well. Several of the astronomers studying ‘Oumuamua are amateurs and young women. Good thing not all science fiction gets the future right.

* Guilty.

Photo credit: European Southern Observatory/M. Kornmesser.

Share Button

One thought on “Meeting With ‘Oumuamua

  1. Thank you for this.

    I read LWON because I find out about things I didn’t know about or hadn’t much thought on, and it’s a double pleasure to find out about something I knew nothing about while being reminded about something else that had more or less fallen away from my life. I think I just might pull Arthur C. Clark or Samuel R. Delaney off the downstairs bookshelf this weekend and contemplate what’s next.

Leave a Reply

Your email address will not be published. Required fields are marked *

Categorized in: Astronomy, Rebecca

Tags: , ,