Years ago a strange object named ‘Oumuamua was distantly observed. It rather seemed to have entered the solar system from outside the solar system. Being only between 100 and 1000 meters long and passing many millions of miles away, 85 times farther away than the moon, the object was never photographed as anything more than a speck. We can see some astronomical photos of ‘Oumuamua at the link here, where ‘Oumuamua appears as a mere featureless dot, using up only a few pixels in the images.
Many articles on ‘Oumuamua have been published showing a cigar-shaped rocky object, but such a visual is merely a speculative artist's visualization, not a photograph. We do not have any reliable data on the shape of ‘Oumuamua. Its shape is sometimes described as cigar-shaped, and sometimes called pancake-shaped. That merely proves that no one knows what its shape was. In a Scientific American article, Harvard astronomer Abraham Loeb stated that ‘Oumuamua "has an extreme elongated shape with its length at least five to 10 times larger than its projected width." But that is a confession that the object may be merely pickle-shaped, not cigar-shaped.
Loeb is out with a new book trying to sell us on the idea that the poorly observed space object named ‘Oumuamua was some kind of extraterrestrial spacecraft. In two previous posts (here and here) I explained some reasons for rejecting this claim. One reason is that the object was reported as having a tumbling motion. It seems unlikely that anyone would ever design a spacecraft that had a tumbling motion. Humans have never sent a spacecraft with a tumbling motion to the moon or to another planet. Instead of a tumbling motion, a sensibly designed spacecraft will move constantly in one direction, in the direction opposite of where its rocket is pointing. Giving a spacecraft a tumbling motion would be a perfect recipe for making its path of motion unpredictable and erratic.
Another reason for rejecting the claim that ‘Oumuamua was some kind of extraterrestrial spacecraft is that the object showed no sign of moving towards our planet. Presumably a probe from another solar system would have moved closer to any Earth-like planet, to observe it better, if such a planet was discovered in some solar system that the probe visited.
Loeb has a recent interview in Scientific American on his new book. In that interview, he fails to present any compelling reason for regarding ‘Oumuamua as a spacecraft from another planet. He spends quite a bit of time complaining about the doctrinal shortcomings of today's scientists, suggesting that many of them spend lots of time confidently pushing dubious speculations with little basis in fact. That's true, but it doesn't make us any more likely to believe Loeb's theory of an artificial origin of ‘Oumuamua.
He states the following, which makes it sound like he's crossing his fingers about some evidence that may arrive:
"If ‘Oumuamua is a member of a population of objects moving on random trajectories, then based on its discovery with the Pan-STARRS telescope, you can estimate that we should very soon begin finding, on average, one of these objects per month after the Vera C. Rubin Observatory comes online. We can also establish a system of instruments—satellites, maybe—that would not only monitor the sky but also be able to react to the approach of such objects so we can get photographs of them as they come in rather than chasing them as they go out, because they move very fast."
That isn't a current reason for thinking ‘Oumuamua is an extraterrestrial spacecraft, but merely a possible weak reason that might materialize in the future: the possibility that there might not be other objects like ‘Oumuamua observed in the near future. And if there was a discrepancy between theoretical predictions of how many objects like ‘Oumuamua should be observed, and how many such objects have been observed, that would not show ‘Oumuamua was probably artificial, but merely suggest some problem with the theoretical predictions.
Very strangely, Loeb makes this statement:
"People ask why I get this media attention. The only reason is because my colleagues are not using common sense."
No, I think the reason Loeb is getting media attention is because he is making the very sensational claim that an object very faintly observed in telescopes was some kind of artificial extraterrestrial spacecraft, and because his publisher has arranged for lots of press coverage and publicity and interviews to help sell Loeb's book. (Loeb brags he's "got about 100 podcast interviews to do in the next few weeks.")
Loeb then repeats a line of reasoning that his astronomer colleagues have made countless times, even though it is fallacious:
"So if you roll the dice on life billions of times in the Milky Way, what is the chance that we are alone? Minuscule, most likely!"
It is erroneous to reason that something is likely to happen merely because there are billions of chances for it to occur. If the chance of the thing occurring is some low probability such as less than 1 in 1,000,000,000,000,000,000, then it will be very unlikely to happen even if there are billions of chances for it occur. If everyone in the world were to spend an hour throwing a deck of cards into the air, we should not expect that even one of these billions of throws would result in a house of cards forming from a throw. There are strong reasons for thinking that the accidental origin of life would be as unlikely as a house of cards forming when someone threw a deck of cards into the air.
Loeb then goes on and on about a variety of topics such as the search for signatures of technological civilizations on other planets, and other forms of SETI. But at no point in his long interview does he give us any solid reason for thinking that ‘Oumuamua was some kind of extraterrestrial spacecraft. So why should we suspect that his book discusses any such evidence?
We can imagine how a layman would be treated if he presented observational evidence comparable to the observations of ‘Oumuamua. The layman might show some little speck in a photo of an earthly sky, and he might say, "This looks strange." People would just laugh it off, and say something like, "Come back to me when you have a decent photo of something strange, not just a few blurry pixels."
Nature can produce unusual shapes such as arch shapes and pillar shapes and cigar shapes. You are not on solid ground if you try to argue that something was designed because you think its shape was very unusual. You are on much better ground if you argue that something was designed because it has very many parts arranged in such an organized and functional way that no natural process would have produced so functional and organized an arrangement of parts. But no such argument is being used about ‘Oumuamua, for we don't even know whether it has more than one part.
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