In Arthur C Clarke’s Rendezvous with Rama, a gigantic, cylindrical, alien vessel whips through the solar system on an unexplained mission. During the roughly one month that the strange object takes to pass near Earth, a crew of scientists explores the massive object.
Not many answers are forthcoming. Rendezvous is a masterpiece of hard-SF that succeeds more by what is never explained than by what is.
Most enigmatically, the novel ends with the line: The Ramans do everything in threes.
As it happens, for the third time in less than a decade, a mysterious, apparently interstellar, object has just been spotted passing through the solar system. Could it be a Rama-style alien spaceship?
Probably not. But that doesn’t make it not intensely interesting.
This interstellar object, with a temporary, cumbersome designation of A11pI3Z, is still pretty far from the sun, located between the orbits of the asteroid belt and Jupiter.
If you think “A11pI3Z” is cumbersome, try saying Oumuamua three times in a row. (For some reason, I have an overwhelming compulsion to listen to the old Rivingtons song.)
As featured in a classic McHale’s Navy gag reel. The Good Oil.
Oumuamua was, of course, the first-known interstellar object. It raced through the solar system in 2017. Followed two years later by the slightly easier-on-the-tongue Borisov, an interstellar comet.
Remember: the Ramans do everything in threes.
On Tuesday, a telescope in Chile spotted what initially looked like an unknown asteroid on a highly eccentric path that might come close to Earth’s orbit […]
“Follow-up observations on July 1 and 2 began to reveal that its orbit might be unusual, possibly interstellar,” said Larry Denneau, a co-principal investigator for [Asteroid Terrestrial-impact Last Alert System (ATLAS)].
Follow-up observations, including by amateur astronomers, allowed more precise calculations of the object’s trajectory.
“Now we’ve got dozens and dozens of observations from loads of different people,” said Matthew Payne, director of the Minor Planet Centre. “And so it’s like becoming almost 100 per cent certain that it’s interstellar.”
Its likely interstellar origin is just one fascinating fact about the object. The other is that it is surprisingly bright. If it, like most rocky asteroids, it has a dark surface, its brightness would have to be a consequence of its size.
The object would have to be big, about 19 kilometres wide, to reflect the amount of light observed. That would be larger than the asteroid that slammed into Earth 66 million years ago, which unleashed the mass extinction that killed off the dinosaurs.
Finding an interstellar object that big would be a surprise, [Avi Loeb, an astrophysicist at Harvard] said. It would possess about 10 million times the mass of Oumuamua, he said.
Because small bodies are much more bountiful than large ones, the existence of a 19-kilometre-wide interstellar object would imply that astronomers should have also seen millions of Oumuamua-sized ones.
On the other hand, like Borisov, it could be a comet. In which case, its brightness is simply because of its glowing cloud of gas and dust.
Loeb offered one other possibility. “The final possibility, and I’m getting more speculative here, is that it makes its own light,” he said. “Probably unlikely, but this is what comes to my mind.”
Because his mind just seems to go there.
When Oumuamua was discovered in 2017, Loeb speculated that it could be an alien artifact because of its unusual shape, like a cigar or a disc, and because it seemed to be pushed by a force other than gravity. He has since proposed a possible alien origin for odd material found on the seafloor of the Pacific.
If it is a comet, astronomers will see a tail.
Astronomers will also have months to study it. Analysis of specific colours emitted could identify elements and molecules on its surface. Loeb said infrared measurements by the James Webb Space Telescope could measure how much heat was coming off the surface.
“If the object is tumbling, we would see the surface area changing over time,” Loeb said, “and by that, infer, in three dimensions, the shape of the object. That’d be very exciting.”
Oh, and even though A11pI3Z was spotted by the asteroid alert system, there’s no chance of it hitting Earth. At its closest path, it will still be outside the orbit of Mars – and Earth will be on the other side of the solar system.
