Having said that, there are a few things that simply don’t add up. We seem to have deduced the shape of this object by its variation in magnitude as it tumbles through space–its “light curve”. But I simply can’t imagine any natural geological, accretive or collisional process that would create a piece of space rock (or ice) with an aspect ratio of 1:10. And of course, we have no reason to believe an interstellar spacecraft must necessarily be long and skinny, either, like one of our chemical rockets. And if it is an artifact of some sort, why is it moving so slowly relative to our sun, about the same speed you’d expect of any object moving in the general galactic drift? Its moving right along, relative to us, but its motion relative to the Local Standard of Rest (the average orbital velocity in this part of the galaxy) is not too extreme. It also is approaching from the direction our solar system is traveling due to our natural revolution around the galactic nucleus. Just what you’d expect for natural space junk. Why would a spacecraft not have some excess velocity, which is exactly what you’d see if a high-tech somebody launched it with the express purpose of going somewhere in particular?

I propose the fluctuations in the light curve are due to something other than its shape; perhaps it simply is a potato-like rock that has a high-albedo spot somewhere on its surface, say a patch of ice on a rocky or sooty background. Maybe the object is tumbling around its axis, only periodically revealing a dark or bright feature. There is also a possibility that we are seeing two objects, here. A dark and bright one, in orbit about one another. Many asteroids in our own system have proven to be binary, and perhaps an occasional fortuitous eclipse or transit explains this light curve.

I imagine the investigators who have studied this object have examined and ruled out these possibilities, but the published accounts don’t bother to explain their logic.

Rama, Rama, Omuamua , banana fanna, bo Rama–Obama yo mama

Now, new data reveal the interstellar interloper to be a rocky, cigar-shaped object with a somewhat reddish hue. The asteroid, named ‘Oumuamua by its discoverers, is up to one-quarter mile (400 meters) long and highly-elongated—perhaps 10 times as long as it is wide. That aspect ratio is greater than that of any asteroid or comet observed in our solar system to date. While its elongated shape is quite surprising, and unlike asteroids seen in our solar system, it may provide new clues into how other solar systems formed.

The observations and analyses were funded in part by NASA and appear in the Nov. 20 issue of the journal Nature. They suggest this unusual object had been wandering through the Milky Way, unattached to any star system, for hundreds of millions of years before its chance encounter with our star system.

“For decades we’ve theorized that such interstellar objects are out there, and now – for the first time – we have direct evidence they exist,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate in Washington. “This history-making discovery is opening a new window to study formation of solar systems beyond our own.”

Immediately after its discovery, telescopes around the world, including ESO’s Very Large Telescope in Chile and other observatories around the world were called into action to measure the object’s orbit, brightness and color. Urgency for viewing from ground-based telescopes was vital to get the best data.

Combining the images from the FORS instrument on the ESO telescope using four different filters with those of other large telescopes, a team of astronomers led by Karen Meech of the Institute for Astronomy in Hawaii found that ‘Oumuamua varies in brightness by a factor of ten as it spins on its axis every 7.3 hours. No known asteroid or comet from our solar system varies so widely in brightness, with such a large ratio between length and width. The most elongated objects we have seen to date are no more than three times longer than they are wide.

“This unusually big variation in brightness means that the object is highly elongated: about ten times as long as it is wide, with a complex, convoluted shape,” said Meech. We also found that it had a reddish color, similar to objects in the outer solar system, and confirmed that it is completely inert, without the faintest hint of dust around it.”

Some posters make the case that even though the object is probably interstellar, it is by no means established without doubt. For example, it might have been an Oort Cloud Object perturbed out of its orbit by a passing star millions of years ago. Likewise, it could be a Kuiper Belt object which gained additional kinetic energy from an encounter with Planet X. (The latter is a hypothetical dark object orbiting past Pluto which has been proposed to explain some dynamical anomalies in other objects at the edge of the solar system.

I too, would prefer this object to be a visitor from the Great Black Yonder, but the Solar System still has not lost its ability to occasionally surprise us.