"I don't care what people say," claims Avi Loeb, chairman of Harvard University's astronomical department and author of one of the most controversial articles in science's kingdom last year (and also one of The most popular in general media). "It doesn't matter to me," he continues. "I say what I think, and if the general public is interested in what I say, it is a welcome result for me, but an indirect result. Science is not like politics: it is not based on popularity studies."
Prof. Abraham Loeb, 56, was born in Beit Hanan, a mosque in central Israel, and studied physics at the Hebrew University of Jerusalem as part of Israel's defense force's Talpiot recruiting program, demonstrating outstanding academic ability. Freeman Dyson, the theoretical physicist, and late astrophysicist John Bahcall admitted Loeb to the Princeton Advanced Study Institute, whose former faculty members included Albert Einstein and J. Robert Oppenheimer. In 201
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This spacecraft is called Oumuamua. For those who do not stop with space news, Oumuamua is the first thing in history to pass through the solar system and be identified as clearly outside it. The first interstellar guest came to us from Vega, the brightest star in the Lyra constellation, which is 26 light years from us. In the 1997 film "Contact" it is the star from which the radio signal is sent to Jodie Foster.
In fact, Oumuamua was discovered by a Canadian astronomer, Robert Weryk, using the Pan-STARRS telescope at the Haleakala Observatory in Hawaii. "Oumuamua" is Hawaiian for "first distant messenger" – in a word, "scout". It was discovered on October 19, 2017, suspiciously close to Earth (relatively of course: Oumuamua was 33 million miles away from us as it was seen – 85 times longer than the moon is from the earth).
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Where all planets, asteroids and meteors derived from the solar system are more or less circular, what is called the Ecliptic planet, for our sun, when formed from the same disk of gas and dust rotating about itself, Oumuamua entered the solar system north of the aircraft in an extremely hyperbolic circuit and at a speed of 26.3 kilometers per second. second faster in relation to the sun's movement.
A reconstruction of its orbit shows that Oumuamua traversed the ecliptic plane on September 6, 2017, when the sun's gravity accelerated the object to a speed of 87.8 kilometers per second. Second. On September 9, the object passed closer to the sun than the Mercury circuit. And on October 14, five days before it was discovered in Hawaii, the object passed 24.18 million miles away from the ground or 62 times the distance from it to the moon.
What does it think to sit next to colleagues in a university lunch room one day after publishing an article claiming that Oumuamua can actually be a reconnaissance spaceship?
Loeb: "The article I published was partly written by conversations I had with colleagues I respect scientifically. Senior status researchers said that this object was peculiar but worried about making their thoughts Publicly, I don't understand, after all, the academic field is supposed to give researchers the freedom to take risks without having to worry about their jobs. Unfortunately, most researchers gain real estate – and continue to think of their image. We ask ourselves about the world, we allow ourselves to pursue. The Ego does not play a role. We learn about the world of innocence and honesty. As a scientist, you must enjoy the privilege of continuing your childhood. Not to worry about the ego, but to Uncover the truth, especially after you get a job. "
Without real estate would you not have published the article?
"I don't suppose. It's not just the time limit. I'm the head of the astronomy department and founder of the Black Hole Initiative [an interdisciplinary center at Harvard dedicated to the study of black holes]. In addition, I am director of the National Academies Board of Physics and Astronomy. So it may be that I commit suicide if it turns out to be wrong, on the other hand, if it turns out to be correct, it is one of the greatest discoveries in human history. We are trustworthy, and the only way to be trustworthy is to follow what you see, not yourself, and what is the worst thing that can happen to me? that I get more time for science. "
Gravitational pushes & # 39;
The first friend from another solar system touched great excitement among scientists, but form and behavior also raised several issues.
"It was subject to observation, but not enough," Loeb said with disappointment as I met him in Tel Aviv at the end of December. "It was only under consistent observation for six days, from the 25th to the 31st of October – one week after its discovery. At first they said: Okay, it's a comet – but no comet tail was visible. Comets are made of ice, which evaporates when the comet approaches the sun, but we did not see a trace of gas or dust in Oumuamua, so the idea was that it should be an asteroid – simply a clump of stones, but the object rotated on its axis in eight hours, and during that time, the brightness changed by a factor of 10, while the brightness of all the asteroids we are familiar with changes at most by a factor of 3. Assuming that the light reflection is constant, it means that the length is at least 10 times greater than its thickness.
"There are two options for this extreme geometry," Loeb continues. "One is that it is in the form of a cigar, the other than it has the shape of a pancake. The truth is that the same observers who examined Oumuamu's light variation came to the conclusion that if it received a lot of gravity suppression underneath the journey – which is reasonable because it spent a lot of time in interstellar space – its shape is pancake-flat, then further qualities were discovered, such as its origin. "
I wrote above that Oumuamua originates from Vega, but it is not entirely correct: The universe is a great place, and even at Oumuamua's speed – a speed that no human spaceship has achieved – a journey from Vega to the solar system would take 600,000 years. But in the meantime, Vega is circulating in the middle of the Winter Street, just like the sun and all the other stars, and it was not in the sky region 600,000 years ago.
"If you average the speeds of all the stars in the region," Loeb says, "you get a system called" local resting state. "Oumuamua was at rest in relation to that system. It didn't come to us. It waited in place as a buoy on the ocean surface until the solar system's" ship "ran into it. To make it clear, only one of The 500 stars in the system just as much in peace as Oumuamua. The probability of it being very low. After all, if it was a stone that was simply beaten by another solar system, we would expect to have the speed of Its star system, not the average speed of all thousands of stars nearby. "
However, the biggest surprise came in June when new data from the Hubble Space Telescope showed that the mysterious object had accelerated during its visit to the inner solar system in 2017 – an acceleration not explained by the sun's gravity.
Acceleration of this kind can be explained by the comet's rocket effect: The comet approaches the sun, the sun heats the comet's ice and the ice escapes in the space in the form of gas, an emission that makes the comet faster than a rocket. But the observations did not reveal a comet tail behind Oumuamua. In addition, the gas emission would have led to a rapid change in the object's speed, a change that was not observed in practice, and it could also have torn the object apart.
If it were not exhausted, what power did Oumuamua accelerate? This is exactly where Loeb goes into the picture. According to his calculations, Oumuamua's acceleration was caused by a pressure.
"The only hypothesis I could think of," he says, "is a pressure from the solar radiation pressure. To work, the object must be very thin, less than a millimeter thick, in other words a type of pancake. In addition, Spitzer found the Space Telescope No sign of heat emission from the object, which means that it is at least 10 times more reflective than a typical comet or asteroid, so what we have is a thin, flat and shiny object, so I arrived at the idea of a solar capture: A sun seal is a spacecraft that uses the sun for propulsion. Instead of using fuel, it is propelled forward by reflecting light. In fact, it is a technology our civilization is developing at present. "
Bottles in the room
Avi Loeb certainly knows one or two things about sun shades. In 2016, physicist and venture capitalist Yuri Milner, together with Stephen Hawking, Mark Zuckerberg and others, established Breakthrough Starshot, an initiative to accelerate sun shades to a fifth of the speed of light to explore the nearby solar system, Alpha Centauri, which is four light-years away from us. . Loeb was appointed the project's scientific director.
"The first question we asked is whether a sail like Oumuamua could survive billions of years in the Winter Road – and we discovered it could. Being hit by interstellar dust or gas will not carry it down. Then we tried To calculate the acceleration a solar collector would cause in an object [such as a ship or probe] and we found that the acceleration is in accordance with Oumuamua.
"We have no way of knowing whether it is active technology or a spacecraft that no longer works and continues to float in space. But if Oumuamua was created along with a whole population of similar objects that were randomly launched , the fact that we discovered that its creators launched a quadrillion probes like that of any star in the Milky Way, obviously, if we assume that Oumuamua was a reconnaissance mission deliberately sent to the inner solar system, of course, is significantly reduced. namely, to the residential area where life would be possible, but we must remember that mankind did not send out tens of thousands of years ago when the object was still in interstellar space, they did not know there was intelligent life here, so I think it is just a fishing expedition. "
Fishing for what?
"I don't know. I love to walk along the coast when I'm on vacation, like here in Tel Aviv, and look at the shells with my daughters. Occasionally, we find a glass bottle among the shells. Until now, we were looking for signatures of foreign cultures in radio broadcasts because we developed this technology in the last century. But another way is to search for a message in a bottle. Humanity launched Voyager 1 and 2, already are in interstellar spaces, they are bottles in bottles, and in this century there will be many systems that many bottles will be sent to and much faster speeds. "
Like Breakthrough Starshot?
"Exactly. Our goal is to accelerate sun canopies to a fifth of the speed of light so that they reach Alpha Centauri within 20 years. And the reason is clear: I am 56 years old, and Yuri Milner is 57. With that speed we can see the pictures in our lifetime. Of course, the sails will continue long after Milner and I am no longer around, maybe after none of us will still be here. It is possible that the room is filled with sails like these, and we do not see them. We only saw Oumuamua, because this is the first time we've got technology that is sensitive enough to identify objects of a few dozen to a hundred meters in size from the sun's lighting. In three years, the building of the LSST telescope will be completed. It will be far more sensitive than Pan-STARRS, and we will probably see many more objects coming from the solar system. Then we find out if Oumuamua is an anomaly or not.
"The importance of my article lies in attracting the attention of astronomers so that they will use the best telescopes and look for the next object, and will even schedule a meeting with it in space. The current propulsion technology does not allow us to hunt for Oumuamua. The visitor comes to dinner, goes out into the street and disappears in the dark. It is possible we will never know what it was looking for. "
But the Breakthrough List project used a radio telescope and listened to Oumuamua with great sensitivity, to the point of being able to receive a call from a regular cell phone, from within the object. But we didn't hear anything.
"When I suggested Milner that we listen to Oumuamua, back in November 2017, we knew that the chance of picking up something was poor to non-existent. Because even though a signal had been sent, it would not necessarily be sent in our direction – it would be in the form of a ray, in other words, even though this explorer is broadcast to the operators, we would not necessarily have seen it, nor would we know what frequency it was to broadcast, and that is also possible that it did not broadcast all the time, but only at certain times, and maybe there is no longer anybody to send to. "
Okay, this object was silent, but if they're out there, why haven't we heard any radio signals directed at us? We have listened to room extensions for decades and only heard the blood in our ears.
"If we are to judge by our own behavior, it seems to me that the probable explanation is that civilizations are developing the technologies that destroy them. There is a time when a culture is still cautious – for example, not coming But consider that if the Nazis had developed nuclear weapons, human history could have led to mass destruction, and of course there are asteroids and there is global warming and lots of other hazards. these are launched, but they no longer have anyone to send back to. "
We are primitive & # 39;
In other words, to Enrico Fermi's paradox – "Where's everyone? – you answer:" Death. "
"Absolutely. Most of them. Our approach should be one archaeological. Similarly, we dig into the earth to find cultures that no longer exist, we must dig into space to discover civilizations that existed outside the planet Earth. "
Is it not easier and therefore more scientific to assume that we are alone until it is proven otherwise?
"No. Anyone who claims to be unique and special is guilty of arrogance. My premise is cosmic modesty. Thanks to the Kepler Space Telescope, we know today that there are more planets like Earth than there are grains of sand on all the shores of the sea. Imagine a king who manages to take control of a piece of another country in a terrible battle, and who then thinks of himself as a great omnipotent ruler. And then imagine that he manages to take control of the whole country or the whole world: It would be like an ants who have packed his sensors around a grain of sand at a large port. It's meaningless. I suppose we are not the only ants on the coast that we are not alone. "
That's speculation. You don't know for sure.
"The search for extraterrestrial life is not speculation. It is much less speculative than the assumption that there is dark material – invisible material that accounts for 85 percent of the material in the universe. The dark material hypothesis is part of the mainstream of astrophysics – and that is speculation: Life [elsewhere] in the universe is not speculation for two reasons: (a) We exist on Earth, and (b) there are many more places that have physical conditions similar to the earth, science contains many examples of hypotheses which has not yet been borne by observations, because science is progressing on the basis of irregularities based on phenomena that cannot be used for conventional explanations. "
But there is a big difference between the search for dark matter and the search for extraterrestrial life. You would not have been interviewed on "Good Morning America" about an article on dark matter.
"Because there is extensive science-fiction literature on contact with advanced civilizations, and not on dark matter. And what? Most researchers talk about a search for primitive life, but there is a taboo about the quest for intelligent life. Perhaps I do not understand that, the only place where primitive life exists, namely the earth, is after all the intelligent life – if we are actually intelligent, our science is not healthy, I asked a scientist examining objects in the Kuiper belt, high-level astronomer who discovered a large number of objects there if he had discovered changes in their brightness originating in artificial light, he replied: "Why search? There is nothing to look for, it is clear that their brightness will change as light that is naturally reflected back from the sun. & # 39;
"If you are not ready to find extraordinary things, you will not discover them. Of course, any argument must be based on evidence, but if the evidence points to an anomaly, then we must talk about an anomaly. Who cares about this Irregularity appeared or was not shown in science-fiction books? I don't even like science fiction.
Come on now. You don't like science fiction?
"No. When I read a book that is contrary to the laws of nature, it is bothersome to me. I like literature and I like science, but the combination bothers me. "
So as a boy did you not read "Rendezvous with Rama" by Arthur C. Clarke? Because it really resembles the encounter with Oumuamua.
"No. What was me was the basic problems of life. "
The origin of life? Its distribution in the universe?
"Life itself, our lives as human beings. I read books of philosophy, mainly existentialism. I was born in a moshav, and every afternoon I picked up eggs and on the weekend I would drive the tractor into the hills to read there. I loved being alone, I do not have a footprint on social networks, I think of ideas when I am alone in the shower, and I never thought of being famous, I wrote a scientific article that was published in a scientific journal, I did not even issue a press release. Two bloggers found the article in an archive and it went viral. "
And how did you think about being a virus researcher? The report on your piece was, of course, the most popular space article in the past year.
"I took advantage of the media exposure to explain the uncertainty in the scientific process. The populist movements in the United States and Europe are partly due to the public losing faith in the scientific process. For example, people are denying global warming. One of my interviewers in Germany said: "There are researchers who maintain that it is a mistake to go public when you are not yet sure." These scientists believe that if we reveal uncertainties, we will not be believed When we talk about climate change, however, the lack of credibility is precisely due to the fact that we only show the public the final product. If a group of scientists creates themselves in a room and then appears to deliver a lecture on the outcome as if the students, people will Do not believe them – because they have not seen the doubts, they will not have seen it There were not enough data in the earlier phases.
"The right way is to persuade the public that the scientific process is a normal human activity, that it does not differ from what a policeman does or a plumber who comes to make a drain pipe. Scientists are considered an elite, because they artificially create this ivory tower, they say: "The public does not understand, so there is no need to share with them. We decide for ourselves what is right, and then we tell the politicians what needs to be done. "But then the populist politician says:" Only the elite say that they save other things from us. "Because there is a leap to the stage of conclusions and politics. The differences of opinion in the scientific community are what lends humanity to the scientific process, and humanity gives credibility."
If we actually find that we are not alone in the universe, what effect would that discovery have on our lives, do you think?
"A great impact. They will be more advanced than we are when our technology was first developed. We will be able to learn a lot from them about technologies developed over millions and billions of years And it could be that this is why we have not yet identified the extraterrestrial intelligent life: because we are still primitive lives that do not know how to read the characters. As soon as we leave the solar system, I think we will See a lot of traffic out there. Perhaps we get a message that says, "Welcome to the interstellar club." Or we discover more dead civilizations – that is, we find their remains. "
And that will be the good news? Because if there are many civilizations that are more developed than ours being liquidated or liquidating themselves, this is not a good sign of the future.
"It will be an excellent sign. It will give us other thoughts on what we are doing here and now, so that we will not share the same fate. We have to compromise much more decently and less militarily with each other, that cooperation, to prevent climate change and to settle in space. It should lead to a good place. The basic question is whether people are good on the foundation. "
And what is the answer, in your opinion?
"I think they are. As soon as it becomes clear that there have been many civilizations that have been wiped out, I believe that people will learn the right lesson. And if we discover remnants of advanced technologies, they will prove to us that we are only at the beginning of the road, and that if we do not continue down that path, we will miss a great deal of what is to see and experience in the universe. If the cavemen had shown the smartphone you use to record me, what would they have thought of this particular rock? Imagine now that Oumuamua is the iPhone and we are the cavemen. Imagine scientists considered the visionaries of reason among The cavemen, who look at the device and say, "No, it's just a stone. A special stone, but a stone. Where do you come to claim that it is not a stone? & # 39; "