Back in October of 2017, astronomers at the University of Hawaii spotted something bizarre passing through our solar system and they named it ‘Oumuamua, Hawaiian for scout or messenger. ‘Oumuamua was the first interstellar object to ever be detected in our solar system.
One year later, in October of 2018, the chair of Harvard’s astronomy department co-wrote a paper examining the object’s acceleration, which they described as “peculiar.” The two, Harvard professor Avi Loeb and Harvard postdoctoral fellow Shmuel Bialy, suggested that the object “may be a fully operational probe sent intentionally to Earth’s vicinity by an alien civilization.” That’s quite the claim and the pair instantly received significant backlash for their controversial theory.
Loeb said of the potential for making contact with alien civilization:
“As soon as we leave the solar system, I believe we will see a great deal of traffic out there. Possibly we’ll get a message that says, ‘Welcome to the interstellar club.’ Or we’ll discover multiple dead civilizations — that is, we’ll find their remains.”
In a recent interview in The New Yorker, Loeb attempts to shed on some light on the object, the paper he co-authored and the controversial theory that his paper presented.
So what’s so unusual about ‘Oumuamua anyway? Loeb explains that astronomers can calculate the rate at which rocks are ejected in space and how that calculation leads one of many peculiar facts about ‘Oumuamua:
“When you look at all the stars in the vicinity of the sun, they move relative to the sun, the sun moves relative to them, but only one in five hundred stars in that frame is moving as slow as ‘Oumuamua. You would expect that most rocks would move roughly at the speed of the star they came from. If this object came from another star, that star would have to be very special.”
The object was observed spinning every eight hours while it’s brightness changed significantly, leaving the astronomers puzzled.
“When it was discovered, we realized it spins every eight hours, and its brightness changed by at least a factor of ten. The fact that its brightness varies by a factor of ten as it spins means that it is at least ten times longer than it is wide. We don’t have a photo, but, in all the artists’ illustrations that you have seen on the Web, it looks like a cigar. That’s one possibility. But it’s also possible that it’s a pancake-like geometry, and, in fact, that is favored.“
‘Oumuamua is shaped like a pancake, another bizarre and significant observation. Why a pancake and why is that abnormal? Objects that orbit the sun have a shape influenced by the gravitational force of the sun, the same force that results in their orbit. Deviation from that rule happens in objects like comets. Evaporation of ice from the surface of a comet creates gasses that push it, sort of like a rocket, and also cause the tail of evaporated gas that most stargazers are familiar with. ‘Oumuamua doesn’t have one of those.
“We don’t see a cometary tail here, but, nevertheless, we see a deviation from the expected orbit. And that is the thing that triggered the paper. Once I realized that the object is moving differently than expected, then the question is what gives it the extra push.“
‘Oumuamua is unlike any comet we have ever seen in our solar system, so it probably isn’t one. Could it be an asteroid?
“Its brightness varies by a factor of ten, and the maximum you typically observe is a factor of three. It has a much more extreme geometry, and there is some other force pushing it.”
So the question remains, what is making ‘Oumuamua move?
“The only thing that came to my mind is that maybe the light from the sun, as it bounces off its surface, gives it an extra push. It’s just like a wind bouncing off a sail on a sailboat. So we checked that and found that you need the thickness of the object to be less than a millimeter in order for that to work. If it is indeed less than a millimeter thick, if it is pushed by the sunlight, then it is maybe a light sail, and I could not think of any natural process that would make a light sail. It is much more likely that it is being made by artificial means, by a technological civilization.”
Loeb, who has “long been interested in the search for extraterrestrial life,” according to The New Yorker, took the opportunity to elaborate on just that:
“I should say, just as background, I do not view the possibility of a technological civilization as speculative, for two reasons. The first is that we exist. And the second is that at least a quarter of the stars in the Milky Way galaxy have a planet like Earth, with surface conditions that are very similar to Earth, and the chemistry of life as we know it could develop. If you roll the dice so many times, and there are tens of billions of stars in the Milky Way, it is quite likely we are not alone.“
If ‘Oumuamua did originate from an alien civilization, it didn’t come from our solar system. According to Loeb, it would have originated from somewhere in our galaxy instead, but there’s a chance “that the civilization is not alive anymore.”
“Imagine another history, in which the Nazis have a nuclear weapon and the Second World War ends differently. You can imagine a civilization that develops technology like that, which would lead to its own destruction.”
Loeb insists the point is simple:
“[T]his is the very first object we found from outside the solar system. It is very similar to when I walk on the beach with my daughter and look at the seashells that are swept ashore. Every now and then we find an object of artificial origin. And this could be a message in a bottle, and we should be open-minded. So we put this sentence in the paper.”
In response to those criticizing his paper and in summary of why ‘Oumuamua is worth paying attention to, Loeb had this to say:
“The point is that we follow the evidence, and the evidence in this particular case is that there are six peculiar facts. And one of these facts is that it deviated from an orbit shaped by gravity while not showing any of the telltale signs of cometary outgassing activity. So we don’t see the gas around it, we don’t see the cometary tail. It has an extreme shape that we have never seen before in either asteroids or comets. We know that we couldn’t detect any heat from it and that it’s much more shiny, by a factor of ten, than a typical asteroid or comet. All of these are facts. I am following the facts.”
Speaking of the facts, Loeb drew a grand distinction between his curiosity of and the facts surrounding ‘Oumuamua and popular ideas such as the multiverse and extra dimensions:
“The multiverse is a mainstream idea—that anything that can happen will happen an infinite number of times. And I think that is not scientific, because it cannot be tested. Whereas the next time we see an object like this one, we can contemplate taking a photograph. My motivation, in part, is to motivate the scientific community to collect more data on the next object rather than argue a priori that they know the answer. In the multiverse case, we have no way of testing it, and everyone is happy to say, “Ya!”
Another mainstream idea is the extra dimension. You see that in string theory, which gets a lot of good press, and awards are given to members of that community. Not only has it not been tested empirically for almost forty years now but there is no hope it will be tested in the next forty years.“
In the end, Loeb’s questioning is simply a part of science:
“We have seen an object from outside the solar system, and we are trying to figure what it is made of and where it came from. We don’t have as much data as I would like. Given the data that we have, I am putting this on the table, and it bothers people to even think about that, just like it bothered the Church in the days of Galileo to even think about the possibility that the Earth moves around the sun. Prejudice is based on experience in the past. The problem is that it prevents you from making discoveries. If you put the probability at zero per cent of an object coming into the solar system, you would never find it!”
In conclusion: “If these beings are peaceful, we could learn a lot from them.”