In this Hub Dialogue, The Hub’s editor-at-large Sean Speer speaks to astronomer Avi Loeb.
This conversation has been revised and edited for length and clarity.
MORE SIGNAL. LESS NOISE. THE HUB NEWSLETTER.
Sean Speer
Today’s Hub Dialogue is with Harvard University astronomer Avi Loeb whose 2021 book, Extraterrestrial: The First Signs of Intelligent Life Beyond Earth, has generated tremendous attention in both the scientific community as well as among a more general audience.
The book, which outlines Loeb’s argument that a 2017 interstellar object known as ‘Oumuamua is proof of previous alien civilizations, could have significant implications for our understanding of the universe and our place within it.
We’re honoured to be joined by Professor Loeb to talk about his book and the reaction to it, as well as his case for significant, new investments in “space archaeology” in search of past and present extra-terrestrial civilizations.
Professor Loeb, you’ve long been at the frontier of astronomy and astrophysics, including black holes, gamma ray bursts and the early universe. About five years ago or so, though, you went into even more contentious territory: You shifted your research to the question of extraterrestrial life. What drove you to pursue this topic?
Professor Loeb
Well, I would not regard this topic as more speculative or more controversial, because we know that we exist. We know that the Earth’s sun system is not particularly unique or special. In fact, half of all sun-like stars have planets the size of the Earth with roughly the same separation in terms of distance. We know that from Kepler satellite data.
If you arrange for similar circumstances, you might as well get similar outcomes. So, it makes sense to search for things like us including possible evidence of previous civilizations elsewhere in the galaxy. The time horizon is important in this regard. If there was a civilization that predated us by a billion years, they had enough time to go across the Milky Way galaxy many times over. In fact, if they had artificial intelligence systems, that could replicate themselves with some form of 3D printers, and those could populate all the habitable planets in the Milky Way.
It’s just a matter of checking what may have happened in the past based on a sense of modesty. The idea here is that we should not argue that we are special and unique, and close the curtains on our windows based on the assumption that we must have no neighbours. That makes very little sense, because even if we claim that, we will not get rid of the neighbours.
At the same time, as part of mainstream astronomy, you’ll find that searches, for example, for dark matter and most of the matter in the universe is of a nature that is not well understood. People have searched for decades for different types of particles. That’s completely appropriate. Hundreds of millions of dollars were spent, and it is considered part of mainstream science. Yet I regard that as more speculative than searching for evidence of intelligent life in the universe.
Take looking for specific type of particles, like weakly interacting massive particles for instance. We haven’t found those particles and yet we still continue to search. I once asked an experimentalist that worked for several decades in the search for weakly interacting massive particles: “How long will you continue? It’s already been several decades, and you might spend your entire career searching and not finding anything.” He said: “As long as I’m funded, I will continue.”
So, here is an example searching for a particular type of particles that may not exist. Why would that be considered a legitimate part of mainstream scientific activity with hundreds of millions of dollars spent, whereas searching for something like us, that left relics as a result of technological advances in space, is considered so highly speculative, so highly treacherous, that you should not even discuss it until we have extraordinary evidence?
I find that very strange, frankly. All I’ve done is applied exactly the same approach to this subject, as I did to other subjects, like the nature of the dark matter and the first stars in the universe. It’s surprising to me that the rest of the community somehow treats it differently.
Sean Speer
I’ll soon ask you to share your thoughts and insights about broader issues within the realm of science. But before we do, your book Extraterrestrial: The First Sign of Intelligent Life Beyond Earth, documents your research and experience with the interstellar object, ʻOumuamua, which was first discovered by a Canadian astronomer in October 2017. Can you please explain to our readers what ʻOumuamua is and why you ultimately concluded that it was “an artifact of extraterrestrial intelligence?”
Professor Loeb
ʻOumuamua was the first object that we discovered from outside the solar system, not bound to the sun because it moves too fast, and that was spotted near Earth. It was discovered by the Pan-STARRS telescope in Hawaii in October 2017.
Its discovery was surprising to me, because a decade earlier I wrote a paper forecasting how many rocks we should expect from other stars that may visit our solar system if they were ejected from other planetary systems. We expected a very small number. In fact, we predicted that Pan-STARRS would not find any. So the discovery of the ʻOumuamua was surprising and intriguing.
As time went on, and astronomers collected more evidence about ʻOumuamua, it looked more and more weird relative to objects we’ve seen before. It didn’t have a cometary tail, there was no dust or gas around it. So, it was definitely not a comet of the type we have seen in the solar system. And it didn’t have the properties of an asteroid, because as it was tumbling every eight hours, the amount of sunlight reflected from it changed by a factor of 10. That meant that it has a very extreme shape: flat pancake-like. Then it was pushed away from the sun, even though it had no rocket effect; there was nothing evaporating from it.
The only way I could explain these unique properties is that it was a result of reflecting sunlight, and for that, the object had to be very thin, sort of like a sail. Nature doesn’t make very thin objects, so I suggested maybe it is artificial in origin.
In September 2020, there was another object that shared similar qualities which was given the name 2020 SO. It was pushed away from the sun by reflecting sunlight and had no cometary tail. But then it was realized shortly after it was discovered that it came from Earth. It was in fact a rocket booster that was launched in 1966. It had very thin walls, and that’s why it had a large area for its mass, and it was pushed by reflecting sunlight. So here you had an artificial object that we produced. It was not necessarily designed as a light sail, but it was thin enough to exhibit a push by reflecting sunlight.
Perhaps ʻOumuamua was similar. It may have not been light sail, it could have instead been, for example, a receiver that was supposed to collect information data. Who knows what its purpose was? My point is there was no obvious natural explanation and it could therefore have been of artificial origin. That’s the suggestion that was made in my book.
But the way to settle it is not by philosophical arguments. The way to settle it is by science: by getting a high-resolution image of an object like ʻOumuamua. We can do that if we find another interstellar object with enough lead time. In a year in advance, we can launch a spacecraft equipped with a camera that will take a close-up photograph. You know, they say a picture’s worth 1,000 words. In my case, a picture’s worth 66,000 words, the number of words in my book.
Sean Speer
As you point out, unlike others who characterized ʻOumuamua as a natural phenomenon, you reached the conclusion that based on these highly unique properties you’ve described, it must be something different. What was the reaction to your extraordinary conclusion?
Professor Loeb
The response was a major push back. I expected my colleagues to say, “Okay, this is one of the possible explanations of the unusual properties of this object, let’s just get more data on the next object that looks as weird as ʻOumuamua so we can reach a more informed conclusion.” But instead, after a seminar at Harvard about the subject, one of my colleagues said, “ʻOumuamua is so weird, I wish it never existed.”
It actually bothered people the fact that it’s unusual. They wanted to continue business as usual, and just ignore it. There were a few scientists that tried to explain its anomalies away. They had to contemplate objects like a hydrogen iceberg, a nitrogen iceberg, or a dust bunny, all objects that we’ve never seen before.
My point is simple: If it’s something that we’ve never seen before, we will learn something new no matter what, by getting more data. So, let’s just get more data and stay open minded. That’s all I was saying.
Nevertheless, there was a huge amount of pushback saying, “We don’t want to even consider that possibility until there is extraordinary evidence.” The problem with that argument is, if you are not willing to engage in actually gathering more evidence, then you will never find that evidence. It’s a self-fulfilling prophecy by which you maintain your ignorance.
The Galileo Project (which has received significant private funding to search for evidence of alien artifacts) that we recently announced is aiming at searching for more evidence to try to figure out the nature of objects like ʻOumuamua or the unidentified aerial phenomena that were described in the report to Congress in June 2021. We simply want to get high resolution images of these unidentified objects, so that we can infer their nature. If they happen to be human made, or some aerial phenomena that we can explain by exotic events in the atmosphere, so be it. But let’s just clear up the fog using the scientific method by deploying telescopes equipped with cameras connected to computer systems, and let’s just follow the standard scientific procedure of a transparent analysis of the data, which is how we can clarify the nature of these objects.
Sean Speer
Professor, your experience that you’ve outlined, both in the book and in today’s conversation, has broader implications for the world of scientific study.
In a way, you’ve just articulated two competing visions: the first is represented by your colleague who said, “ʻOumuamua is so weird, I wish it didn’t exist.” The second is reflected in something that you observe in the book:, “when you’re not ready to find exceptional things, you won’t find them.” How should we think about these two competing views with respect to science? And how can we restore the capacity for curiousness and a sense of wonder?
Professor Loeb
This is not a new occurrence. During the days of Galileo, there were philosophers that refused to look through his telescope. He was arguing that there is evidence that implied the Earth is moving around the sun. Yet philosophers argued, “No, we know that we are at the center of the universe. We don’t need to look through a telescope.” Then they put him in house arrest. If Galileo was alive today, he would most likely have been cancelled on social media.
The point is this type of scientific push back and unwillingness to consider new ideas is itself not new. But we should have learned the lesson of paying attention to evidence because science is a learning experience: we should be humble; we should not assume that we know the answers in advance. We should collect evidence, and based on that, be guided in the right direction. That’s what I’m advocating for. It’s particularly important in this context, because if we are not the smartest kid on the cosmic block, if there are smarter civilizations out there, we can learn from them. It would have a huge impact on our society.
A lot of human activity is guided by trying to feel superior relative to each other. If you look at human history, the worst actions have stemmed from a sense of trying to feel superior. That’s what racism is about. The Second World War was driven by the Nazi regime’s sense of superiority which was a key part of its doctrine.
If there is another civilization out there that is indeed far more advanced than ours, it would look ridiculous for us to try and feel superior when there is this other kid on the block who is far more advanced than we are. So perhaps it will change our relations with each other once we realize that we do not belong to a superior civilization. It will also change our religious or philosophical beliefs about our place in the universe. It will change our aspirations for space, and it will have a huge impact on society.
I call that “ʻOumuamua’s wager” in my book because the implications would be huge. If you consider the magnitude of such a discovery and you realize that not only that the public cares about this question, not only does that same public fund science, not only that if scientists were to engage in this question, there would be many more young people attracted to science and there would be more funds allocated, but the implications could indeed be huge for our society, then the case for pursuing these questions just seems overwhelming to me.
It’s unlike the question of the nature of dark matter or other interesting but not particularly relevant or applicable questions that we currently pursue without any hesitation. I cannot comprehend this state of affairs where this subject is not mainstream in science.
But with the Galileo Project, I’ve basically demonstrated two things: one, that without fundraising, in the course of two weeks, I got $1.75 million from people that I never met before to support this work. That demonstrates my point that there would be more funding dedicated to science if we attended to this question. And second, since the announcement of the project, I’ve received thousands of emails from young people who are very excited to be engaged in the project. This extraordinary level of interest demonstrates my point that science can be exciting, and there is no reason for us to shy away from this subject. In fact the opposite is true: We will attract young talent to science, if we just don’t ridicule this question.
Sean Speer
You talked about the potential insights that we can gain as a civilization by pursuing these questions. One means by which we would carry out such a pursuit is something that you’ve described as space archaeology. Can you just unpack for our readers what space archaeology is? And why you believe that advanced societies, including the United States, Canada, and others, ought to be investing far more in the pursuit of space archaeology?
Professor Loeb
In the past 70 years, we’ve been searching for radio signals from other civilizations; that’s called SETI: the search for extraterrestrial intelligence. It was conducted mainly by searching through either radio waves or perhaps laser signals. But that’s the wrong approach, because it’s just like trying to have a phone conversation: you need the other counterpart to be alive at the time that you’re having the conversation.
A much better approach, which I’m advocating, is searching for relics that were left behind by past civilizations. Even if the sender is dead by now, it’s like sending a letter in the mail. The letter may arrive to the destination long after the sender is not around anymore.
If another civilization predated us, they may have sent a lot of equipment into the universe prior to our existence, and we can find that equipment. I call that space archaeology or extraterrestrial archaeology because it resembles what we do on Earth. By digging into the ground, we find relics of cultures that predated us and are not around anymore.
That’s a better approach because, if you go to the ocean, you might find plastic bottles on its surface, and those plastic bottles accumulated over time, and they never go away. You have a better chance of learning about what happened in the past by looking for relics. So, my proposal is to just “walk on the beach,” and most of the time we would see natural rocks like comets or asteroids, and then every now and then we might see a plastic bottle that implies that the civilization predated us.
Sean Speer
Thank you for your insights, today.
Professor Loeb’s book is Extraterrestrial: The First Signs of Intelligent Life Beyond Earth. It’s a fascinating read that’s been called “seminal”, “tantalizing”, and “powerful” which are also good words to describe today’s conversation. Thank you so much.
Professor Loeb
Thanks for having me.
