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Speaker 1: Now here's a highlight from Coast to Coast am on iHeartRadio.

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Speaker 2: And welcome back to Coast to Coast George Nori with you.

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Speaker 2: Avi Lobe with Us, professor of science at Harvard University

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Speaker 2: as well as an author his books that are called

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Speaker 2: Extraterrestrial the First Sign of Intelligent Life beyond Earth. His

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Speaker 2: latest is Interstellar, The Search for Extraterrestrial Life and Our

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Speaker 2: Future and the Stars. He received a PhD in physics

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Speaker 2: from the Hebrew University of Jerusalem at the age of

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Speaker 2: twenty four. Writes on a wide range of topics including

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Speaker 2: black holes, the first stars, and the search for extraterrestrial

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Speaker 2: life in the future of the universe. Avi, welcome back,

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Speaker 2: Thanks for having me, and by the way, I want

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Speaker 2: to congratulate you and thank you those of us who

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Speaker 2: have been in the search for UFOs and extraterrestrial life

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Speaker 2: for you so many years. Appreciate people who like you

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Speaker 2: truly understand and do good research and work.

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Speaker 3: So thank you.

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Speaker 2: On behalf of everybody who wants to get these answers.

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Speaker 3: Thank you and hopefully will have good clues in the

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Speaker 3: coming years.

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Speaker 2: To twenty seventeen, you came out with the story of

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Speaker 2: an object called the Mura Moura. Tell us about that.

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Speaker 2: That's one of the most unique interstellar objects I've ever

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Speaker 2: heard about.

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Speaker 3: Yeah, that's what attracted me to the subject.

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Speaker 4: It was the first object that astronomers recognized from outside

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Speaker 4: the Solar System. It was moving faster than the escape

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Speaker 4: speed from the Solar System, and therefore it originated outside

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Speaker 4: the Solar System, and all the astronomers thought it must

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Speaker 4: be a comet or an asteroid, the familiar objects rocks

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Speaker 4: that we found in the Solar System.

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Speaker 3: But then it didn't look like a comet. There was

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Speaker 3: no cometary tale, so people said, well, maybe.

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Speaker 4: It's an asteroid, just a rock without any eyes on it,

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Speaker 4: so there is no evaporation. But then it was realized

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Speaker 4: that the object is being pushed away from the Sun

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Speaker 4: by some mysterious force. It wasn't clear what's pushing it

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Speaker 4: because there was no evaporation, so the rocket effect was

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Speaker 4: not effective. So then it was not an asteroid because

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Speaker 4: you don't get such a push without the evaporation usually

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Speaker 4: for a natural rock. And so the question was what

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Speaker 4: was it? And also as it was tumbling every eight hours,

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Speaker 4: the amount of sunlight that was reflected from it changed

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Speaker 4: by a factor of ten, and that meant that it

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Speaker 4: has a very extreme shape. The best fit to the

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Speaker 4: variation of light was that of a pancake shaped object,

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Speaker 4: a flat object, not cigar shaped like some artists illustrated.

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Speaker 3: We couldn't get an image.

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Speaker 4: Of it because it was only the size of a

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Speaker 4: football field. I say only because the distance that it

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Speaker 4: was at was a fraction of the distance to the Sun.

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Speaker 4: So no tell scope that we have can resolve an

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Speaker 4: object that is about one hundred meters across a fraction

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Speaker 4: of the Earth's Sun separation. It's orders of magnitude too

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Speaker 4: small for us to resolve it.

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Speaker 3: Of course, if.

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Speaker 4: We could send a spacecraft that would come close to it,

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Speaker 4: we could take a photograph of it, but that was

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Speaker 4: not possible at the time, and it was very mysterious,

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Speaker 4: anomalous in many different ways. It also was nearly at

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Speaker 4: rest in the frame of the Milky Way galaxy when

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Speaker 4: the Solar System bumped into it, sort of like a

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Speaker 4: buy lying at rest on the surface of the ocean,

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Speaker 4: and the Solar System like a giant ship bumping into it.

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Speaker 4: So you know, it was all very strange, and I

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Speaker 4: suggested that it maybe just pushed by reflecting sunlight. You know,

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Speaker 4: the sun itself, the light from the Sun is pushing it,

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Speaker 4: just like wind pushes a sail on a boat, you know,

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Speaker 4: and it turns out, you know, in retrospect. Now, just

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Speaker 4: this year, you know, I learned about a whole class

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Speaker 4: of objects that are called the empty trash bag objects.

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Speaker 3: These are objects that are seen near the Earth.

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Speaker 4: And they are thought to be broken pieces of satellites

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Speaker 4: that are just pushed by reflecting sunlight and they are

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Speaker 4: moving around in very strange ways. And there is also

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Speaker 4: another object that was found by the same telescope in

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Speaker 4: Hawaii that discovered this first interstellar object. By the way,

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Speaker 4: the object was named which means a scout in the

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Speaker 4: Hawaiian language. And the same telescope in Hawaii discovered another

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Speaker 4: object that was pushed, definitely pushed by reflecting sunlight. And

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Speaker 4: within a month or so the astronomers realized that was

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Speaker 4: in September twenty twenty, they realized that this one is

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Speaker 4: actually a rock boost, an upper stage of a mission

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Speaker 4: to reach the Moon that was launched.

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Speaker 3: By NASA in nineteen sixty six.

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Speaker 4: And you know, there are many objects that are space

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Speaker 4: trash that resulted after Sputnik. You know, all the space

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Speaker 4: missions that the Soviets and the US launched to space,

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Speaker 4: Some of these objects are out there. And there was

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Speaker 4: a claim just six months ago that there are dark comets,

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Speaker 4: that Mua was a dark comet, because those comet experts

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Speaker 4: wrote a paper in a prestigious journal, Proceedings of the

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Speaker 4: National Academy of Sciences, and they said, you know, there

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Speaker 4: is a population of dark comets that we see. By

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Speaker 4: dark comments, they mean that there is no evidence for

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Speaker 4: a comma, There is no cometary tail.

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Speaker 3: What you see is an object.

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Speaker 4: That exhibits a little bit of acceleration in addition to

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Speaker 4: And it turns out now we I'm writing a paper

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Speaker 4: about this with a collaborator that shows that most of

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Speaker 4: these dark comets that the comet experts wrote a paper about,

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Speaker 4: most of them are you know, space treasure relics of

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Speaker 4: missions that were launched by the Soviets and the US

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Speaker 4: over the past fifty years or six years. So that

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Speaker 4: actually they just shut themselves in the foot because by

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Speaker 4: claiming that could have been a dark comet, you know,

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Speaker 4: a comet where the tail is not visible, and us

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Speaker 4: finding that these dark comets that they found afterwards are

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Speaker 4: actually human made. You know that they basically demonstrated that

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Speaker 4: tom might have been also technologically manufactured.

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Speaker 3: And the question is who produced it?

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Speaker 2: Big deal? Absolutely? Now where is there?

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Speaker 1: More? And more?

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Speaker 2: Now?

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Speaker 4: Ab well, it's very far. It's beyond the orbit of Jupiter.

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Speaker 4: And the point is that it's very faint. You know,

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Speaker 4: it's millions of times fainted than it was when it

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Speaker 4: came close to Earth. Because you know, as an object

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Speaker 4: goes away farther from the Sun, it gets dimmer inversely

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Speaker 4: with distance to the fourth so it very quickly it

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Speaker 4: becomes extremely dim. We can't really see it. We cannot

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Speaker 4: launch a spacecraft that would chase it because it's moving

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Speaker 4: fast and we don't know exactly where it is.

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Speaker 3: So our best hope is.

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Speaker 4: Actually to look for another object of the same class,

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Speaker 4: and that would be a sibling from Amu MUA's family.

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Speaker 4: And actually we have a good chance of finding such

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Speaker 4: siblings because we have a new telescope, a new survey

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Speaker 4: telescope that is much better than the one in Hawaii

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Speaker 4: pant Stars, the new one that was just inaugurated a

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Speaker 4: week ago.

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Speaker 3: It's called the Rubin, the Very Sea Rubin.

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Speaker 4: Observatory in Chile, and it's using a camera that has

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Speaker 4: three point two giga pixels, a thousand times more than

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Speaker 4: the number of pixels on your cellphone. And this camera

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Speaker 4: will serve at the southern sky every four nights, and

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Speaker 4: we'll do that for ten years, and we're likely to

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Speaker 4: find you know, tens of objects like with it. And

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Speaker 4: I'm just looking forward to that data, you know, I

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Speaker 4: have together with my post doc, we developed machine learning

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Speaker 4: software that would identify interstellar objects like in the Rubin

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Speaker 4: Observatory data set, and we we will then of course

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Speaker 4: look at any kind of the date object, not only

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Speaker 4: with ground based telescopes that would give us information similar

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Speaker 4: to that that we had on a memoir, but also

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Speaker 4: with the web telescope that we now have, because the

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Speaker 4: web telescope is you know, a million miles away from Earth,

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Speaker 4: and looking at an object from the advantage point of

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Speaker 4: the web telescope and from Earth, you know, it's just

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Speaker 4: like having two eyes. It allows you to assess the

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Speaker 4: distance to the object because you see it from different directions,

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Speaker 4: and that would pinpoint the trajectory of the object very precisely,

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Speaker 4: so we would know if it has any propulsion.

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Speaker 3: A future object.

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Speaker 4: And Moreover, the web telescope can detect the heat from

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Speaker 4: the object, the radiation emitted by the object in the infrared,

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Speaker 4: because it's a telescope that is primarily detecting infrared radiation, and.

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Speaker 3: That itself would allow us to figure.

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Speaker 4: Out the area of the object, the temperature of the object,

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Speaker 4: and as it's stumbling, we can actually map its structure,

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Speaker 4: its shape in three dimensions very accurately. So we will

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Speaker 4: know much more. We will know things that we don't

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Speaker 4: know about MUMO. We'll also know their albito, the reflection

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Speaker 4: coefficient of sunlight, because we will detect the actual radiation

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Speaker 4: that the object emits and figure out its surface area

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Speaker 4: and so altogether, you know, I think we will know

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Speaker 4: much more about the next analog and I very much

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Speaker 4: look forward to that. That could happen in the coming year.

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Speaker 4: Exact that will be Yeah.

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Speaker 2: How are you how do you believe in extraterrestrial life?

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Speaker 2: What are your thoughts?

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Speaker 4: Oh, I think it's very likely to be the case

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Speaker 4: because in the Milky Way galaxy, you know, there are

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Speaker 4: one hundred billion stars like the Sun, okay, and so

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Speaker 4: just think of it as if we are seeing many

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Speaker 4: houses in our cosmic street. Okay, because we know about

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Speaker 4: the Earth Sun system, and we know that, you know,

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Speaker 4: very likely, based on all the data that was collected

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Speaker 4: over the past decade or two, we know that of

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Speaker 4: the order of tens of percent of those stars have

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Speaker 4: a planet like the Earth roughly the same separation, and

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Speaker 4: at the very least a few percent of those stars.

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Speaker 4: And so that means that there are billions of Earth

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Speaker 4: Sun analogs. And so think about the street that you

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Speaker 4: reside on, when there you see billions of houses just

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Speaker 4: like yours. Okay, And then my colleagues, you know, the

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Speaker 4: mainstream in the astronomy community, says, oh, we don't know

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Speaker 4: if any of these houses has any residents, and I say, well,

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Speaker 4: it's you know, it's quite unlikely that they don't, because

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Speaker 4: you know, I don't think that we humans are the

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Speaker 4: pinnacle of creation, you know, I think we just came

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Speaker 4: along as a result of circumstances on this rock, the Earth,

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Speaker 4: that we were born on. And if you have billions

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Speaker 4: of other rocks with similar conditions, it's very likely you know,

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Speaker 4: that you had similar beings out there. Now if you ask,

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Speaker 4: for example, on Earth, you know, where is everybody you

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Speaker 4: know that like that is the question that Enrico Fermi

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Speaker 4: asked about exrateracors. Where is everybody? You know, most of

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Speaker 4: the people that ever lived on Earth over the past

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Speaker 4: few million years.

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Speaker 3: They're dead.

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Speaker 4: By now, there were about one hundred billion people who

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Speaker 4: ever lived on Earth, and right now there.

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Speaker 3: Are eight billion living.

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Speaker 4: Okay, so the rest ninety two billion people they died,

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Speaker 4: they're gone. And so most civilizations that ever existed in

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Speaker 4: the Milky Way galaxy they're probably dead, you know. So say,

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Speaker 4: you know, the number of people that lived on Earth

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Speaker 4: is roughly the number of stars in the Milky Way

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Speaker 4: Galaxy by coincidence, one hundred billion, and most of them

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Speaker 4: are dead.

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Speaker 3: So it's quite likely.

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Speaker 4: That most of the civilizations like ours died by now.

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Speaker 4: We know that most of the stars in the Milky

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Speaker 4: Way Galaxy formed billions of years before the Sun. The

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Speaker 4: Sun is a late comer. It just formed in the

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Speaker 4: last one third of cosmic history. Most of the stars

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Speaker 4: fromed before the Sun by billions of years.

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Speaker 3: And actually, you.

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Speaker 4: Know, the Sun itself will boil off all the oceans

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Speaker 4: on Earth within one billion years. It will become brighter.

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Speaker 4: We will have to move somewhere else. Earth will not

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Speaker 4: be hospitable for life as we know it in one

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Speaker 4: billion years. So you know, there were plenty of other

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Speaker 4: civilizations probably that cried for help, you know, said our

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Speaker 4: star is about to kill us.

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Speaker 3: You know, the sun that is the source of life

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Speaker 3: on Earth.

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Speaker 4: We think very fondly about the Sun, but it will

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Speaker 4: actually kill us. You know, we will have to move

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Speaker 4: somewhere else, irrespective of what we do.

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Speaker 3: You know, people talk about global warming and so it's irrelevant.

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Speaker 4: The Sun will boil off all liquid water on Earth

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Speaker 4: within a billion years.

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Speaker 3: That's it.

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Speaker 4: So we will have to move somewhere else. And that

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Speaker 4: happened to other civilizations. And you know, I can imagine

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Speaker 4: situations where you know, they first of all, all the

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Speaker 4: wealthy people on those planets started building their own spacecraft

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Speaker 4: to escape. But then there were you know, bigger projects.

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Speaker 4: I call them a knock spaceship. You know, it's just

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Speaker 4: like knocks arc in the biblical story, to protect animals

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Speaker 4: from the flood, he built an arc and put animals

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Speaker 4: on it. That's the story. And you can imagine something

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Speaker 4: like that on a planet that is about to get

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Speaker 4: burned up by the star. You know, the whoever lives

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Speaker 4: that would build the giant, giant arc or spacecraft that

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Speaker 4: would take those beings, many of them, out of the

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Speaker 4: planet to space. So you know, things like that could

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Speaker 4: have happened. I have no doubt that we are not

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Speaker 4: the first ones, and we are not the smartest one.

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Speaker 4: You know, just look at world politics, you know, look

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Speaker 4: at what we are doing everywhere around the world. You know,

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Speaker 4: there must be a smarter student in our class. You know,

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Speaker 4: there must be a smarter kid in our block. And

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Speaker 4: I'm looking forward to finding evidence for it.

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Speaker 2: What do you think happened to Mars and why didn't

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Speaker 2: it happen to us?

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Speaker 4: Oh, that's an excellent question. So Mars is quite started

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Speaker 4: quite similar to Earth. It's a smaller body. It's a

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Speaker 4: smaller rock that happened to be very close to the

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Speaker 4: orbit of the Earth around the Sun.

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Speaker 3: So it had liquid water. We have no doubt about it.

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Speaker 3: It had.

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Speaker 4: We can see the evidence for it having you know, oceans, rivers, lakes.

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Speaker 4: We see what's left behind, which is a desert, but

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Speaker 4: we do see evidence for the flowing water that were

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Speaker 4: on it in the first half of its history about

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Speaker 4: two to three billion years.

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Speaker 1: And it could be underneath.

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Speaker 4: Yeah, there could be some underneath, and we do see

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Speaker 4: right now ice water ice, evidence for water ice on

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Speaker 4: the surface of Mars. So what happened, Well, there was

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Speaker 4: an event or a process that led to the fact

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Speaker 4: that Mars lost its atmosphere. So in order to have

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Speaker 4: liquid water, it's not enough to have the right temperature

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Speaker 4: on the surface of a planet, because if you put

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Speaker 4: water ice in vacuum, it sublimates, it goes straight into gas.

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Speaker 4: You can't get liquid water in vacuum. So what you

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Speaker 4: need is external pressure, and on Earth it's provided by

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Speaker 4: the atmosphere of the Earth, and Mars had an atmosphere

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Speaker 4: to start with. It was very similar to Earth, and

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Speaker 4: then it lost its atmosphere halfway through, you know, a

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Speaker 4: couple of billion years ago. It lost its atmosphere, became

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Speaker 4: a desert. All the liquid water evaporated. There was some

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Speaker 4: ice left, water ice, and probably some is buried underneath

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Speaker 4: the surface, some ice. But right now it has a

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Speaker 4: very thin atmosphere, very a little bit of gas left.

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Speaker 4: And in addition, it obviously is because it doesn't have

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Speaker 4: an atmosphere, the temperature on the surface changes by hundreds

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Speaker 4: of degrees between day and night. You know, just think,

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Speaker 4: I mean, we have deserts on Earth, but the temperature,

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Speaker 4: and of course if you live in a desert, like

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Speaker 4: if you live in Las Vegas, you know that the temperature.

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Speaker 4: Now I was there, actually notice the temperature at night

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Speaker 4: is very different the temperature during you know, at the

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Speaker 4: mid day. But on Mars, the variation in temperature is

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Speaker 4: not moderated with an atmosphere like difference. It's huge, It's

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Speaker 4: hundreds of degrees. And you know, so when Elon Musk

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Speaker 4: talks about going back to Mars, I would be really

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Speaker 4: cautious at accepting his invitation to go there because because

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Speaker 4: you know, temperature variations are hundreds of degrees. Also, there

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Speaker 4: is no atmosphere to protect you. You know, the atmosphere

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Speaker 4: protects us from cosmic rays.

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