Latest / Daniel and Kelly’s Extraordinary Universe / Was the interstellar visitor oumuamua natural or artificial?

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Was the interstellar visitor oumuamua natural or artificial? · Daniel and Kelly’s Extraordinary Universe

• 0:08
  Speaker 1: Hey, Daniel, you like having visitors.
• 0:10
  Speaker 2: I like having visitors at my university and visitors at home. Sure,
• 0:14
  Speaker 2: I like people.
• 0:16
  Speaker 1: You like people. How about aliens?
• 0:19
  Speaker 2: I would love if aliens send us a message or
• 0:23
  Speaker 2: an object or came to visit. They're welcome to have
• 0:25
  Speaker 2: dinner at my house.
• 0:26
  Speaker 1: What about the university?
• 0:27
  Speaker 2: If aliens came, I would be a superstar at the university.
• 0:30
  Speaker 1: Wait, you would be the star or the aliens would
• 0:32
  Speaker 1: be the star. I think the aliens would probably grab
• 0:34
  Speaker 1: the headlines more than than the receiving professor.
• 0:40
  Speaker 2: Yeah, probably, and we'd have lots of great questions for them.
• 0:43
  Speaker 1: But then, what would you feed them for dinner if
• 0:45
  Speaker 1: they came to your house?
• 0:46
  Speaker 2: Probably some engineers.
• 0:47
  Speaker 1: Ouch. Wait, you would do the cooking. That's pretty dark, man.
• 0:50
  Speaker 2: I would do a lot for alien answers.
• 0:52
  Speaker 1: Yeah, boy, remind me never to go visit your house.
• 0:58
  Speaker 2: You never know if you're coming for dinner or if
• 1:00
  Speaker 2: you are dinner.
• 1:01
  Speaker 1: Definitely not staying for dinner. Hi am Rhem, a cartoonist
• 1:19
  Speaker 1: and the author of Oliver's Great Big Universe.
• 1:22
  Speaker 2: Oh I'm Daniel. I'm a particle physicist and a professor
• 1:25
  Speaker 2: at UC Irvine, and I would love to get my
• 1:27
  Speaker 2: hands on anything alien, ideas, objects.
• 1:31
  Speaker 1: Visitors, anything alien that sounds little and not safe for work,
• 1:35
  Speaker 1: Like you would put your hands on any part of alien.
• 1:38
  Speaker 2: I think any part of alien would be safe for work.
• 1:40
  Speaker 2: You know, it's all in the interest of science.
• 1:42
  Speaker 1: I guess. I guess it depends on what kind of
• 1:44
  Speaker 1: work or you are.
• 1:47
  Speaker 2: If you are looking into unravel the mysteries of the cosmos,
• 1:50
  Speaker 2: then yeah, it's all up for grabs.
• 1:52
  Speaker 1: I see, you might not do like pat some bags
• 1:54
  Speaker 1: or something, shake some hands or tentacles perhaps.
• 1:57
  Speaker 2: You know, there's a lot of people on campus here
• 1:59
  Speaker 2: who literally get their hands a lot dirtier than I
• 2:01
  Speaker 2: ever do.
• 2:02
  Speaker 1: I'm pretty sure everybody in the world gets their hands
• 2:05
  Speaker 1: dirty than a physicist. I mean, I guess you do
• 2:09
  Speaker 1: get chalk dust on your hands kind of, or dry
• 2:12
  Speaker 1: eras or dust on your fingers.
• 2:14
  Speaker 2: We once had to unbox one thousand computers that all
• 2:17
  Speaker 2: arrived from Dell the same day and set them all up.
• 2:20
  Speaker 2: But I'm not sure what kind of dirt we got
• 2:21
  Speaker 2: on our hands that day.
• 2:23
  Speaker 1: Yeah, yeah, it doesn't sound like a working class dust there.
• 2:26
  Speaker 1: But anyways, welcome to our podcast. Daniel and Jorge explain
• 2:29
  Speaker 1: the Universe, a production of iHeartRadio, in which we.
• 2:32
  Speaker 2: Treat the entire universe as safe for work. We think
• 2:35
  Speaker 2: everything about the universe is beautiful and wonderful, nothing should
• 2:39
  Speaker 2: be censored, and all of its secrets should be revealed
• 2:42
  Speaker 2: to us. We would love to unravel them for ourselves,
• 2:45
  Speaker 2: but we'd also love to get some tips from aliens
• 2:48
  Speaker 2: about what's going on out there in deep space.
• 2:51
  Speaker 1: That's right. It is a beautiful universe, and we are
• 2:53
  Speaker 1: all visitors in it, at least for the time that
• 2:55
  Speaker 1: we are in this universe. So we like to give
• 2:58
  Speaker 1: you a little bit of a tour of what we
• 3:00
  Speaker 1: know and what we found out about all the cool
• 3:02
  Speaker 1: spots and all of the great places to see in
• 3:05
  Speaker 1: this great cosmos.
• 3:06
  Speaker 2: And most of the things we know about the cosmos
• 3:08
  Speaker 2: come from seeing, come from receiving photons from outer edges
• 3:13
  Speaker 2: of the galaxy or from other galaxies, from using that
• 3:16
  Speaker 2: to build a mental model in our minds of how
• 3:19
  Speaker 2: the universe is built. But sometimes we also get stuff
• 3:22
  Speaker 2: from other parts of the universe. We get tiny little
• 3:25
  Speaker 2: protons that might have flowed from other parts of the galaxy.
• 3:27
  Speaker 2: We get dust from all over. Sometimes we might even
• 3:31
  Speaker 2: get rocks and other stuff.
• 3:33
  Speaker 1: Yeah. Well, although small rocks are okay to get here
• 3:36
  Speaker 1: on Earth right from the deaths of space, big rocks
• 3:38
  Speaker 1: are a problem.
• 3:39
  Speaker 2: It depends a little bit on how they arrive. If
• 3:41
  Speaker 2: they fly by and let us study them, then that's
• 3:43
  Speaker 2: all right. But yeah, if they impact in the Pacific
• 3:46
  Speaker 2: and cause a mile high tsunami, then yes, that's a problem.
• 3:49
  Speaker 3: Mmmm.
• 3:50
  Speaker 1: You like like day visitors, not like overnight visitors.
• 3:55
  Speaker 2: I mean, hey, come into orbit, right, then we can
• 3:57
  Speaker 2: study you for years. That'd be awesome.
• 4:00
  Speaker 1: Is that possible? It could like a rock come and
• 4:02
  Speaker 1: suddenly we get a new moon.
• 4:03
  Speaker 2: Absolutely. As we talked about on our episode about how
• 4:06
  Speaker 2: moons are formed, some moons in the Solar System were
• 4:08
  Speaker 2: captured as they flew by. So it's certainly possible for
• 4:12
  Speaker 2: us to catch some weird object from another Solar system
• 4:15
  Speaker 2: and have it become pout of ours, an adopted planet
• 4:18
  Speaker 2: or moon.
• 4:19
  Speaker 1: Well, it's like a visitor that never leaves.
• 4:21
  Speaker 2: It becomes part of our family.
• 4:23
  Speaker 1: Man, We don't discriminate, But could it crash it into
• 4:25
  Speaker 1: our moon? Like, if we catch it, could it maybe
• 4:27
  Speaker 1: run into our current moon? That would be a problem, right.
• 4:30
  Speaker 2: That would be a problem. If it like disintegrated the
• 4:32
  Speaker 2: Moon and that to breathe and rain down on the
• 4:34
  Speaker 2: surface of the Earth. Yeah, you seemed to be in
• 4:37
  Speaker 2: kind of a cataclysmic mood today. I mean, mostly we're
• 4:39
  Speaker 2: just looking at this stuff and learning about the universe.
• 4:42
  Speaker 1: Well, you know, apparently if I go visit you, I
• 4:45
  Speaker 1: might end up as dinner. So I gotta, you know,
• 4:47
  Speaker 1: think of the worst case scenario. Apparently in this podcast,
• 4:50
  Speaker 1: I gotta watch out.
• 4:51
  Speaker 2: You do got to pay attention. That's true.
• 4:53
  Speaker 1: But it is a wonderful universe to visit and to
• 4:55
  Speaker 1: live in, and to study and to explore. And as
• 5:00
  Speaker 1: Daniel said, sometimes we get visitors from the far reaches
• 5:03
  Speaker 1: of space, and recently we got an extra special, an
• 5:06
  Speaker 1: extra rare kind of visitor.
• 5:08
  Speaker 2: That's right. In twenty seventeen, a strange rock came through
• 5:12
  Speaker 2: the Solar system. We called it oh Muama. It was
• 5:14
  Speaker 2: a big surprise to everyone and an exceptional opportunity to
• 5:18
  Speaker 2: learn something about the rest of the galaxy, to actually
• 5:22
  Speaker 2: look at a chunk from another solar system.
• 5:25
  Speaker 1: Wait, I feel like you're maybe prebiasing this a little bit.
• 5:28
  Speaker 1: How do we know it was a rock? Do we
• 5:30
  Speaker 1: know it was a rock?
• 5:31
  Speaker 2: I guess I'm not speaking technically When I say a rock,
• 5:34
  Speaker 2: I just mean a chunk of something, a chunk of stuff. Yes,
• 5:37
  Speaker 2: it was a thing, how about that?
• 5:39
  Speaker 1: And it has maybe one of the coolest names in astronomy,
• 5:42
  Speaker 1: oh Muhama. What's the origin of that name?
• 5:45
  Speaker 2: Daniel? That's right. It was discovered by a telescope in Hawaii,
• 5:48
  Speaker 2: and so they called it oh Muama, which means messenger
• 5:52
  Speaker 2: from Afar in one of the Hawaiian languages.
• 5:55
  Speaker 1: WHOA. It's like email, space email, or like space ups driver.
• 6:01
  Speaker 2: Does your email come in at twenty seven kilometers per second?
• 6:04
  Speaker 1: I think it comes a little faster than that, doesn't it? Helene?
• 6:06
  Speaker 1: Takes me to read it though, that's a different question.
• 6:09
  Speaker 2: That's right. And we talked about this object shortly after
• 6:12
  Speaker 2: it arrived, and all the controversy had stirred up because
• 6:14
  Speaker 2: there were some weird things about this object. It was
• 6:17
  Speaker 2: weirdly shaped, it was sort of glittering in a strange way.
• 6:20
  Speaker 2: It was a surprise that we even saw it. And
• 6:22
  Speaker 2: since then even more controversy has been stirred up.
• 6:25
  Speaker 1: Yeah, there's a big controversy about its origins and whether
• 6:28
  Speaker 1: or not it's natural.
• 6:30
  Speaker 2: Is it to.
• 6:30
  Speaker 1: On the podcast, we'll be tackling the question, was the
• 6:38
  Speaker 1: interstellar visitor oh muamua natural or artificial?
• 6:42
  Speaker 4: Band And by artificial we mean alien. Oh I thought
• 6:47
  Speaker 4: you just meant like not organic, like not good to eat. Yeah,
• 6:53
  Speaker 4: like it has esper tame or something.
• 6:54
  Speaker 2: Yeah, you got to cut down on your artificial space
• 6:57
  Speaker 2: junk man. It's not good for your diet.
• 6:59
  Speaker 5: Yeah.
• 6:59
  Speaker 2: Yeah, come to my house. We serve you purely organic engineers.
• 7:03
  Speaker 1: Oh my goodness, your house again. You seem to be
• 7:09
  Speaker 1: making that joke a little too much.
• 7:11
  Speaker 2: But this is a really fun question because getting a
• 7:14
  Speaker 2: chunk of stuff from another Solar system is a way
• 7:17
  Speaker 2: to see what's out there. Right, It's like a core
• 7:19
  Speaker 2: sample of the rest of the universe, something we very
• 7:21
  Speaker 2: rarely get to see because we're on this little island
• 7:24
  Speaker 2: of the Solar System, this little patch of land that
• 7:26
  Speaker 2: we've been able to explore with our probes.
• 7:28
  Speaker 1: Well, it might be a core sample of perhaps alien
• 7:31
  Speaker 1: technology or something.
• 7:32
  Speaker 3: Right.
• 7:32
  Speaker 1: That is the big question about OHM. Was it natural?
• 7:35
  Speaker 1: Is it like just a rock that's naturally floating out
• 7:37
  Speaker 1: there in space, or could it be some sort of
• 7:40
  Speaker 1: device or spaceship or something made by an alien civilization.
• 7:45
  Speaker 2: That's the big question. And when this thing came to
• 7:47
  Speaker 2: the Solar system, a bunch of astronomers looked at it
• 7:50
  Speaker 2: and studied it and debated it, of course, and one
• 7:52
  Speaker 2: astronomer in particular has made a lot of hay about it,
• 7:55
  Speaker 2: Avi Lob But professor at Harvard wrote a book called
• 7:58
  Speaker 2: Extraterrestrial The First Sign of Intelligent Life whoa This of
• 8:03
  Speaker 2: course made a big splash and was a best seller
• 8:06
  Speaker 2: and got a lot of people talking. The sort of
• 8:08
  Speaker 2: mainstream community in astronomer didn't take it very seriously, and
• 8:12
  Speaker 2: Professor Loepe has complained somewhat that his arguments have not
• 8:15
  Speaker 2: been addressed by sort of mainstream astronomy.
• 8:17
  Speaker 1: You mean, he claimed that the omuma was a sign
• 8:20
  Speaker 1: that there are aliens out there, and now he's saying
• 8:24
  Speaker 1: that the people aren't taking him seriously.
• 8:25
  Speaker 2: Yeah, that's exactly right.
• 8:27
  Speaker 1: Well, as usual, we were wondering how many of our
• 8:28
  Speaker 1: listeners out there had heard of Omuama and had thought
• 8:31
  Speaker 1: about whether it was natural or artificial.
• 8:34
  Speaker 2: So I'm actually visiting UC Riverside this week, so I
• 8:36
  Speaker 2: took the opportunity to walk around campus here at Usey
• 8:39
  Speaker 2: Riverside and ask people if they had heard of omuamua
• 8:42
  Speaker 2: and if they thought it was natural or artificial.
• 8:45
  Speaker 1: So think about it for a second. Have you heard
• 8:46
  Speaker 1: of omuama before? And do you think it could be
• 8:50
  Speaker 1: a sign of aliens? Here's what people had to say.
• 8:53
  Speaker 2: All right, So do you think omuamua was natural or artificial?
• 8:57
  Speaker 3: Natural?
• 8:58
  Speaker 2: Why is that? Have you heard of the object, oh,
• 9:02
  Speaker 2: Mua mua, the interstellar commet They came through the solar
• 9:05
  Speaker 2: system five years ago?
• 9:07
  Speaker 3: No?
• 9:07
  Speaker 2: No, okay? Great? Do you have an opinion about whether
• 9:09
  Speaker 2: it was a natural object like a comment from another
• 9:12
  Speaker 2: solar system or an artificial object like an alien craft?
• 9:16
  Speaker 1: Maybe natural?
• 9:17
  Speaker 2: Maybe?
• 9:18
  Speaker 3: Natural?
• 9:18
  Speaker 2: Okay, great? I never heard about it, this object that
• 9:23
  Speaker 2: came through Russell Solar System. All right, great? Do you
• 9:26
  Speaker 2: think it's more likely to be a natural object or
• 9:29
  Speaker 2: alien space junk?
• 9:33
  Speaker 5: More like a natural object?
• 9:35
  Speaker 2: Natural object? Because there's no evidence now.
• 9:37
  Speaker 1: We found an alien right right, so.
• 9:41
  Speaker 5: It's more like a natural object.
• 9:43
  Speaker 2: How did you do an opinion?
• 9:45
  Speaker 5: Yeah?
• 9:45
  Speaker 1: More or less the same natural objects.
• 9:47
  Speaker 3: It was more likely absolutely natural objects.
• 9:51
  Speaker 1: All right. First of all, I'm not a lot of
• 9:52
  Speaker 1: name recognition, it seems, at least not in Riverside.
• 9:55
  Speaker 2: I was even walking around the physics department at the
• 9:58
  Speaker 2: Riverside hoping to get people who thought about this stuff.
• 10:01
  Speaker 1: Maybe you weren't pronouncing it right, Probably not.
• 10:04
  Speaker 2: Yeah, you were.
• 10:05
  Speaker 1: Attaching it to a dinner invitation, which is a problem
• 10:08
  Speaker 1: now that you have a reputation.
• 10:10
  Speaker 2: I'm standing away from the engineering buildings on every campus
• 10:12
  Speaker 2: from now on.
• 10:13
  Speaker 1: Yeah, it sounds like the engeneers just stay away from you.
• 10:16
  Speaker 1: But yeah, a not a lot of recognition. Although some
• 10:18
  Speaker 1: people had heard of it and they seem to think
• 10:21
  Speaker 1: it's natural.
• 10:21
  Speaker 2: They do seem to think it's natural. I mean, it's
• 10:23
  Speaker 2: a fascinating object and there are some things about it
• 10:26
  Speaker 2: that are weird that can teach us about what's out
• 10:29
  Speaker 2: there in the universe. I think the evidence for it
• 10:31
  Speaker 2: being actually alien is quite a reach. That kind of
• 10:34
  Speaker 2: thing you might put in a best selling book that
• 10:36
  Speaker 2: you want to sell a lot of copies of, but
• 10:38
  Speaker 2: not something that would really stand up to peer review.
• 10:40
  Speaker 2: I see.
• 10:41
  Speaker 1: I mean, if a physics professor writes a book about aliens,
• 10:44
  Speaker 1: that's obviously just a big money grab, right.
• 10:49
  Speaker 2: I think it depends on the claims you put in
• 10:50
  Speaker 2: that book. And so on the episode today, we wanted
• 10:53
  Speaker 2: to dig deep into what's going on with Omua Mua.
• 10:57
  Speaker 2: Is it natural? Is it artificial? What do we know
• 10:59
  Speaker 2: about it? What can we say?
• 11:01
  Speaker 1: Well, let's dig into it, then, Daniel, what is this
• 11:03
  Speaker 1: object and when was it first spotted?
• 11:05
  Speaker 2: So it's definitely from another solar system. We spotted it
• 11:08
  Speaker 2: first on October eighteenth, twenty seventeen by the pan Star's telescope.
• 11:14
  Speaker 2: This is a really awesome telescope. It's in Hawaii. It's
• 11:16
  Speaker 2: actually two of them. Each of them are almost two
• 11:19
  Speaker 2: meters in diameter, and they're on the summit of Haleyakela
• 11:22
  Speaker 2: on the island of Maui, and their job is basically
• 11:25
  Speaker 2: to look for stuff that might hit the Earth. They're
• 11:28
  Speaker 2: taking pictures of the night sky all the time and
• 11:30
  Speaker 2: they're looking for changes, looking for stuff that's moving. It's
• 11:33
  Speaker 2: part of this search for Near Earth objects to see
• 11:36
  Speaker 2: whether there are things out there that are moving that
• 11:38
  Speaker 2: might of course hit the Earth.
• 11:39
  Speaker 1: Well, it's pretty cool. It's like a WatchGuard almost for
• 11:42
  Speaker 1: the entire planet. It's a full time it's doing that
• 11:44
  Speaker 1: full time.
• 11:45
  Speaker 2: It's doing that full time. It's pretty awesome. This is
• 11:48
  Speaker 2: sort of a newer effort by NASK. It really was
• 11:50
  Speaker 2: kicked off after comet shoemaker Levy in the nineties when
• 11:53
  Speaker 2: we saw, wow, things in the Solar system really can
• 11:55
  Speaker 2: impact comments and cause huge fireballs. We got to put
• 11:59
  Speaker 2: some more money on this. So in the last twenty
• 12:01
  Speaker 2: or thirty years, NASA and some international partners have really
• 12:03
  Speaker 2: dedicated some resources to looking for near Earth objects. And
• 12:07
  Speaker 2: they see a lot of them, and they've cataloged all
• 12:09
  Speaker 2: the big ones, and we know mostly what's out there,
• 12:12
  Speaker 2: but sometimes they see something strange. And in twenty seventeen
• 12:15
  Speaker 2: they saw this object moving in a way that they
• 12:17
  Speaker 2: could tell it was not coming from inside of our
• 12:20
  Speaker 2: Solar system.
• 12:21
  Speaker 1: Interesting, so just out there looking at this night sky
• 12:24
  Speaker 1: all the time and it records if something changes. Now,
• 12:27
  Speaker 1: how did they know that it was coming from outside
• 12:30
  Speaker 1: the Solar.
• 12:31
  Speaker 2: System because of where he was coming from. It entered
• 12:33
  Speaker 2: from above the plane of the Solar system. The whole
• 12:35
  Speaker 2: Solar system is basically flat. Everything's orbiting in a plane
• 12:38
  Speaker 2: that's determined by the north south pole of the Sun.
• 12:41
  Speaker 2: But this thing was sort of coming in from above
• 12:43
  Speaker 2: the plane from the direction of the constellation Lira, and
• 12:46
  Speaker 2: passed really close to the Sun, actually within the orbit
• 12:49
  Speaker 2: of Mercury, and then out the other side.
• 12:51
  Speaker 1: I guess the question is, you know, if you look
• 12:53
  Speaker 1: at the night sky and you see a streak, it's
• 12:55
  Speaker 1: kind of hard to tell in three D where it
• 12:57
  Speaker 1: is or where it's going, or you know exactly what direction,
• 13:01
  Speaker 1: just because you're getting just to the view of it.
• 13:03
  Speaker 1: How did they figure out where in the Solar system
• 13:05
  Speaker 1: it was going?
• 13:06
  Speaker 2: You can reconstruct its three D trajectory. First of all,
• 13:08
  Speaker 2: we have two of these cameras who have a slightly
• 13:10
  Speaker 2: binocular view. But then also as it gets brighter and dimmer,
• 13:13
  Speaker 2: you can figure out sort of its radial velocity, and
• 13:15
  Speaker 2: they can measure its velocity across our view just by
• 13:17
  Speaker 2: seeing how the points of light are moving, So they
• 13:19
  Speaker 2: can end up with a three D trajectory and then
• 13:21
  Speaker 2: backtrack and say where could this thing have come from
• 13:24
  Speaker 2: in order to give us this path?
• 13:26
  Speaker 1: Now, I think you said that they saw a streak,
• 13:28
  Speaker 1: not just a little point flying through space.
• 13:30
  Speaker 2: Yeah, most of the stuff in the Solar system is moving,
• 13:33
  Speaker 2: and it's moving fast, but it's not moving that fast.
• 13:35
  Speaker 2: So on this camera it usually just registers as a
• 13:38
  Speaker 2: pixel like light from the Sun hits it bounces off
• 13:40
  Speaker 2: and it comes into the telescope in Hawaii and it
• 13:43
  Speaker 2: makes a bright pixel and we say, okay, there's something there.
• 13:46
  Speaker 2: But this was moving so fast twenty six kilometers per
• 13:49
  Speaker 2: second relative to our solar system that actually made a streak.
• 13:52
  Speaker 2: It was like multiple pixels across whoa.
• 13:55
  Speaker 1: And so, and I guess they didn't just see it once.
• 13:57
  Speaker 1: They could track this thing, right.
• 13:59
  Speaker 2: They could track this thing exactly, But by the time
• 14:01
  Speaker 2: they saw it, it was already on its way out
• 14:03
  Speaker 2: of the Solar system. Like it made its closest approach
• 14:05
  Speaker 2: to the Sun and then came closer and closer to
• 14:07
  Speaker 2: the Earth, And by the time we saw it on
• 14:09
  Speaker 2: the Earth, it was already sort of like on its
• 14:11
  Speaker 2: way out of the Solar system. So then we could
• 14:13
  Speaker 2: just sort of like watch it from behind as it left,
• 14:16
  Speaker 2: and then it got dimmer and dimmer and dimmer. So
• 14:18
  Speaker 2: we only had a few weeks to gather data about
• 14:20
  Speaker 2: this thing. Whoa wa, wait, wait, why didn't we see
• 14:22
  Speaker 2: it before we saw it when it came close to
• 14:24
  Speaker 2: the Earth, And that's the easiest time to see it.
• 14:27
  Speaker 2: Before that, it was either like coming from the Sun,
• 14:29
  Speaker 2: which makes it impossible to see it, or it was
• 14:31
  Speaker 2: too dark.
• 14:32
  Speaker 1: The object itself was too dark because I guess it
• 14:34
  Speaker 1: wasn't glowing by itself. It was just reflecting light exactly.
• 14:38
  Speaker 2: You need to be sort of lucky with the arrangement
• 14:40
  Speaker 2: of the Sun and the object and the Earth to
• 14:41
  Speaker 2: even see these things, right, because you need light from
• 14:44
  Speaker 2: the Sun to hit it and then bounce off and
• 14:46
  Speaker 2: hit the Earth. As you say, it's not glowing. It
• 14:48
  Speaker 2: doesn't have fusion. It's just a big chunk of stuff.
• 14:50
  Speaker 2: It has to reflect light to us from the Sun
• 14:53
  Speaker 2: and lots of spots on its trajectory to be basically invisible.
• 14:56
  Speaker 1: Well, scientists noticed some weird things about it that make
• 14:58
  Speaker 1: them think that, hmm, if this thing is natural or
• 15:02
  Speaker 1: of alien origin. So let's stick into what those odd
• 15:04
  Speaker 1: things about it were and talk about whether it is
• 15:07
  Speaker 1: a message from aliens. But first let's take a quick break,
• 15:22
  Speaker 1: all right, we're talking about visitors to our solar system.
• 15:26
  Speaker 1: In twenty seventeen, we got one that we seemed a
• 15:30
  Speaker 1: little fishy.
• 15:31
  Speaker 2: Called it definitely was a lot of fun to look
• 15:34
  Speaker 2: at and to think about, all right.
• 15:35
  Speaker 1: So we saw this in our telescopes looking for asteroids
• 15:39
  Speaker 1: out there in space, and there was something a little
• 15:41
  Speaker 1: bit different about its trajectory seemed to be coming definitely
• 15:44
  Speaker 1: from outside the Solar system, and scientists think at least
• 15:47
  Speaker 1: the time they thought or are they considered the possibility
• 15:51
  Speaker 1: that it might be from an alien civilization or something.
• 15:54
  Speaker 1: What were some of the things that made people think, hmm,
• 15:56
  Speaker 1: this isn't maybe just an asteroid.
• 15:58
  Speaker 2: So first of all, it seemed to have a weird shape,
• 16:01
  Speaker 2: like a lot of the asteroids in our solar system
• 16:03
  Speaker 2: are mostly spherical, like they're round ish. This thing either
• 16:07
  Speaker 2: was really really long and thin. A lot of the
• 16:09
  Speaker 2: artistic depictions of it draw it sort of like a cigar,
• 16:12
  Speaker 2: or it was sort of flat, like a pancake. So
• 16:14
  Speaker 2: that's thing number one that makes it kind of weird.
• 16:16
  Speaker 1: But could we actually see its shape or isn't it
• 16:19
  Speaker 1: so far away? Could you basically just see a dot?
• 16:21
  Speaker 2: Yeah, we can't see its shape directly, you're right, but
• 16:24
  Speaker 2: we could deduce its shape by how it's spinning and
• 16:26
  Speaker 2: how its brightness changes. So it's not a sphere. Then
• 16:29
  Speaker 2: as it spins, you might reflect more or less light
• 16:32
  Speaker 2: off the larger or smaller surfaces that it's presenting, So
• 16:35
  Speaker 2: they have to deduce its shape from how it's spinning,
• 16:38
  Speaker 2: which is why we're not sure if it's a cigar
• 16:40
  Speaker 2: or a pancake. We just know it's not very spherical.
• 16:43
  Speaker 1: Wait, so if it was spherical, then we just looked
• 16:46
  Speaker 1: like a constant dot of light in the sky, right.
• 16:49
  Speaker 1: But this wasn't a constant dot of light.
• 16:51
  Speaker 2: It was not a constant dot of light. Exactly what
• 16:53
  Speaker 2: was it? The light varied really dramatically, like by factors
• 16:56
  Speaker 2: of ten, so which made them think that maybe it
• 16:59
  Speaker 2: was really long and thin, and sometimes you were seeing
• 17:01
  Speaker 2: the long side of it, and sometimes it was really
• 17:03
  Speaker 2: narrow and you were just reflecting light off the tip.
• 17:05
  Speaker 2: But definitely was not a sphere because otherwise, as you say,
• 17:09
  Speaker 2: it would give you a constant signal.
• 17:10
  Speaker 1: So it was like blinking or just kind of fading
• 17:13
  Speaker 1: in and out.
• 17:13
  Speaker 2: It was more fading in and out, never totally disappear.
• 17:16
  Speaker 2: If you look at the light curve, you see it
• 17:17
  Speaker 2: varies over a very wide range.
• 17:19
  Speaker 1: In what timescale, like every hour, every second.
• 17:22
  Speaker 2: More like hours exactly. We only have a few weeks
• 17:25
  Speaker 2: of data of this thing. But it was spinning pretty fast.
• 17:27
  Speaker 2: I think it was also tumbling, like it wasn't only
• 17:30
  Speaker 2: spinning along one axis, it was like spinning in two
• 17:33
  Speaker 2: different ways at the same time.
• 17:34
  Speaker 1: But at least we think it was spinning, right, We
• 17:36
  Speaker 1: don't actually know because you just see a pixel of light, right.
• 17:39
  Speaker 2: Yeah, exactly, this is all reconstruction. But there was a
• 17:42
  Speaker 2: bunch of stuff about it which seemed kind of weird.
• 17:44
  Speaker 2: There was the shape that was how it moved. It
• 17:47
  Speaker 2: seemed to move in a way that wasn't just gravity.
• 17:50
  Speaker 2: Seemed like it got a little boost as it was
• 17:52
  Speaker 2: leaving the Solar System, which made people think like, ooh,
• 17:54
  Speaker 2: maybe it's an alien spaceship, or maybe it's a light
• 17:57
  Speaker 2: sale or these things that like gathers folk tons from
• 18:00
  Speaker 2: stars to pick up acceleration. So that was Avi Lobe's
• 18:03
  Speaker 2: suggestion that this might be a discarded alien light sale
• 18:07
  Speaker 2: that fell through our Solar system.
• 18:10
  Speaker 1: And it's also kind of rare to get stuff from
• 18:13
  Speaker 1: that direction, right, like we don't get a lot of
• 18:15
  Speaker 1: comments or asteroids from our asteroid build.
• 18:18
  Speaker 2: Well, we don't know how rare it is, right. We
• 18:20
  Speaker 2: sort of turned on this eyeball to the universe fairly recently,
• 18:23
  Speaker 2: and seeing one sort of new either means that we're very,
• 18:27
  Speaker 2: very lucky, or it means that there may be more
• 18:29
  Speaker 2: common than initial calculations suggest it could be that space
• 18:33
  Speaker 2: is filled with chunks little bits from other solar systems,
• 18:37
  Speaker 2: and it's not that unusual to see one.
• 18:38
  Speaker 1: All right. There were some weird things about it that
• 18:40
  Speaker 1: made people wonder about this, but one professor in particular
• 18:44
  Speaker 1: sort of seemed to have gone all in on it.
• 18:46
  Speaker 2: That's right. Jason Wright, a professor at Penn State, wrote
• 18:49
  Speaker 2: a detailed blog post responding point by point to all
• 18:53
  Speaker 2: the claims made in Avi Lobe's book. And I thought
• 18:56
  Speaker 2: it would be a good idea to chat with him
• 18:58
  Speaker 2: about all these ideas and what he thought Omama might
• 19:01
  Speaker 2: actually have been.
• 19:02
  Speaker 1: Okay, So then, just to be clear, you spoke to
• 19:04
  Speaker 1: Jason Wright, who's arguing against the book written by Lobe,
• 19:08
  Speaker 1: who argued that om Oma was of not just extra
• 19:12
  Speaker 1: terrestrial origin, which it is because it's not from Earth,
• 19:15
  Speaker 1: but that it's a sign of intelligent life.
• 19:17
  Speaker 2: Yeah, that's right. Loeb is making some pretty outlandish claims
• 19:21
  Speaker 2: in his book, and he's also complaining that nobody's taking
• 19:23
  Speaker 2: him seriously. So Jason Wright decided to take it seriously
• 19:26
  Speaker 2: and address all the claims and say what we know
• 19:29
  Speaker 2: and what we don't know. And of course nobody knows
• 19:31
  Speaker 2: for sure what this thing was, but we should be
• 19:32
  Speaker 2: careful about the claims we make.
• 19:34
  Speaker 1: All right, Well, here's Daniel's interview with Professor Jason Wright.
• 19:39
  Speaker 2: Great so that it's my pleasure to introduce to the
• 19:41
  Speaker 2: podcast Professor Jason Wright. He's professor of astronomy and astrophysics
• 19:46
  Speaker 2: at Penn State. He's a member of the Center for
• 19:49
  Speaker 2: Exo Planet's and Habitable Worlds, and amazingly, he's the director
• 19:53
  Speaker 2: of the Penn State Extraterrestrial Intelligence Center, which sounds like
• 19:58
  Speaker 2: a lot of fun. Jason, Welcome to the podcast.
• 20:00
  Speaker 5: Thanks good to be here.
• 20:01
  Speaker 2: As director of the Extraterrestrial Intelligence Center, do you get
• 20:04
  Speaker 2: first access to the alien bodies to interrogate them and
• 20:07
  Speaker 2: ask them questions?
• 20:08
  Speaker 3: No, no, thank goodness. That's that's definitely outside the purview
• 20:12
  Speaker 3: of what we do here at the Pace SETI Center.
• 20:14
  Speaker 3: So yeah, I can't have no information on that.
• 20:17
  Speaker 5: Score for you.
• 20:18
  Speaker 2: All right, Well, I do want to ask you questions
• 20:20
  Speaker 2: about things you're actually an expert in, and I was
• 20:22
  Speaker 2: very excited to talk to you because this blog post
• 20:24
  Speaker 2: you wrote where you did a point by point analysis
• 20:27
  Speaker 2: of the claims made in Avulobe's book about the possible
• 20:31
  Speaker 2: extraterrestrial or alien nature of O Muamua. So I'd love
• 20:35
  Speaker 2: to ask you first to briefly run down what are
• 20:37
  Speaker 2: the evidence for the anomalies what a sort of five
• 20:40
  Speaker 2: categories he lays out, and then dig into them with you.
• 20:43
  Speaker 3: Yeah, so, Omuma, you know, it was definitely interstellar, We
• 20:47
  Speaker 3: know that for sure, and it was definitely very strange.
• 20:51
  Speaker 3: But when we say it's strange, what we mean is
• 20:53
  Speaker 3: we kind of had a sense for roughly what comments
• 20:56
  Speaker 3: look like in general, and we thought when we saw
• 20:58
  Speaker 3: one come from interstellar space, it would more or less
• 21:01
  Speaker 3: look like the comets that orbit the Sun. And the
• 21:04
  Speaker 3: main reason is that the comets that orbit the Sun,
• 21:06
  Speaker 3: that come from the Ork Cloud very far out, they're
• 21:09
  Speaker 3: basically in interstellar space. There's not a big difference between
• 21:12
  Speaker 3: the space and the Ork Cloud and between the stars,
• 21:14
  Speaker 3: and so we didn't expect it to be so different
• 21:17
  Speaker 3: from typical comets.
• 21:19
  Speaker 5: There's a big.
• 21:19
  Speaker 3: Caveat with that, though, which is that O Muhamuha was
• 21:22
  Speaker 3: extremely small, and we don't generally detect comets that's small
• 21:28
  Speaker 3: in the Solar System just because being so small, they
• 21:31
  Speaker 3: reflect hardly any light and they're very hard to see.
• 21:34
  Speaker 3: We have very few examples of any objects in the
• 21:36
  Speaker 3: Solar System that small orbiting the Sun, which means we
• 21:39
  Speaker 3: don't actually have a basis to compare to. So when
• 21:43
  Speaker 3: we say it's strange, it's really strange compared to expectations,
• 21:46
  Speaker 3: not necessarily strange with respect to ordinary comets in the
• 21:50
  Speaker 3: Solar System of that size. So the first thing that
• 21:54
  Speaker 3: was really strange about it is that its brightness varied
• 21:58
  Speaker 3: a lot, and that has been interpreted to mean that
• 22:02
  Speaker 3: it must not be round, which is perfectly reasonable for
• 22:06
  Speaker 3: something of that size. You have to be quite large,
• 22:08
  Speaker 3: like a large asteroid, to be round. But it was
• 22:10
  Speaker 3: really extreme. I mean, the brightness variations indicated that the
• 22:15
  Speaker 3: axis ratios had to be something like five to one,
• 22:18
  Speaker 3: or maybe even as high as ten to one, and
• 22:20
  Speaker 3: the shape was kind of unclear. We say this because
• 22:24
  Speaker 3: if it were just that part of the surface was
• 22:26
  Speaker 3: dark and part of it was highly reflective, that can
• 22:29
  Speaker 3: only change the brightness so much as it rotates, and
• 22:32
  Speaker 3: the brightness variations are highly irregular, so that suggests it's
• 22:36
  Speaker 3: either like flat like a pancake, or long like a cigar,
• 22:39
  Speaker 3: and that it's tumbling doing this kind of uncontrolled rotation,
• 22:43
  Speaker 3: and sometimes we see the thin end of a muamua
• 22:47
  Speaker 3: and that's what it's hardly reflecting, and the light towards us,
• 22:49
  Speaker 3: and that's when it gets very dark.
• 22:51
  Speaker 2: So when you say brightness, you're not talking about this
• 22:53
  Speaker 2: thing glowing obviously, right, it's reflecting light from the sun.
• 22:56
  Speaker 5: That's right. All objects are going to reflect light from
• 22:58
  Speaker 5: the sun.
• 22:59
  Speaker 3: And if it's shaped like a pancake and as it's tumbling,
• 23:02
  Speaker 3: then when we see the whole pancake sort of face on,
• 23:05
  Speaker 3: then it's reflecting a lot more sunlight and it'll appear bright.
• 23:09
  Speaker 3: But then if we see it edge on, we'll hardly
• 23:11
  Speaker 3: see any sunlight reflective. We can try to infer the shape,
• 23:15
  Speaker 3: but it's a really inexact science. It's an unconstrained problem,
• 23:19
  Speaker 3: and so it's possible it's something like a ten to
• 23:22
  Speaker 3: one long cigar, like in a lot of the imagery
• 23:24
  Speaker 3: you might have seen online. There was an artist's picture
• 23:27
  Speaker 3: of it being almost needlelike, but I think most planetary
• 23:31
  Speaker 3: scientists think it's probably more like a flat pancake, maybe
• 23:34
  Speaker 3: six times wider than it is thick. If it were
• 23:36
  Speaker 3: shaped like a round rock than a sphere, then as
• 23:40
  Speaker 3: the sphere spins, we always see the same size. So
• 23:42
  Speaker 3: the only way that the brightness would vary is if
• 23:45
  Speaker 3: part of it was reflective and part of it was not.
• 23:47
  Speaker 3: Now that's normal. Things have dark areas and bright areas
• 23:50
  Speaker 3: on them, But we would see it change in exactly
• 23:54
  Speaker 3: the same pattern every rotation. And there's only so much
• 23:57
  Speaker 3: variation that you can get from from that sort of
• 24:01
  Speaker 3: a surface brightness changing. When you see this kind of
• 24:05
  Speaker 3: very irregular, very strong brightness variations, that's most naturally explained by.
• 24:10
  Speaker 5: A strain shape.
• 24:11
  Speaker 2: So imagine you had like a piece of charcoal and
• 24:14
  Speaker 2: half of it was dipped in white paint, so you know,
• 24:17
  Speaker 2: if you illuminated it, it looked like black and white, but
• 24:19
  Speaker 2: it's perfectly spherical and it's spinning. You're saying that we
• 24:22
  Speaker 2: would see a regular variation in the brightness. We would
• 24:25
  Speaker 2: see it bright and dark and bright and dark.
• 24:27
  Speaker 3: Right, you see almost a sinus soidal variation. And only
• 24:30
  Speaker 3: if you happen to be at that special orientation that
• 24:33
  Speaker 3: you got it completely white or completely black once a
• 24:37
  Speaker 3: rotation would those brightness variations be.
• 24:40
  Speaker 5: You know, ten to one or something extremely strong.
• 24:43
  Speaker 2: And so you're saying that what we saw were huge
• 24:45
  Speaker 2: variations in the brightness, and the pattern was kind of irregular,
• 24:49
  Speaker 2: meaning that we're not like seeing the same side of
• 24:50
  Speaker 2: it over and over. Is that what you mean by tumbling?
• 24:53
  Speaker 2: That is what I mean by tumbling.
• 24:54
  Speaker 3: So when something just spins, then every single rotation it
• 24:58
  Speaker 3: comes back to the same area, like the earth spinning
• 25:01
  Speaker 3: or something like that. But if you take an a
• 25:03
  Speaker 3: regularly shaped object, and the classic example here is something
• 25:07
  Speaker 3: like a chalk border eraser or a white border eraser,
• 25:11
  Speaker 3: if you try to spin it lengthwise, you'll find it
• 25:14
  Speaker 3: won't uniformly spin.
• 25:16
  Speaker 5: It'll start doing this very strange.
• 25:17
  Speaker 3: Irregular, almost kind of random flipping in the air in
• 25:21
  Speaker 3: all these different directions, and that's called tumbling. And when
• 25:24
  Speaker 3: that happens, you do not see this regular brightness variation.
• 25:27
  Speaker 3: And so Omuamua is definitely tumbling. And what that means
• 25:31
  Speaker 3: is it's very hard to model because it's almost a
• 25:33
  Speaker 3: random variation, and that's why it's so frustratingly difficult to
• 25:37
  Speaker 3: figure out what its actual shape is.
• 25:38
  Speaker 2: So does tumbling just means spinning on more than one
• 25:41
  Speaker 2: axis at the same time.
• 25:43
  Speaker 5: That's right, that's a good way of thinking about it.
• 25:45
  Speaker 3: Basically, the axis of rotation sort of changes with respect
• 25:49
  Speaker 3: to the shape of the object, and it's not regular.
• 25:54
  Speaker 3: This object is so small and so far away that
• 25:56
  Speaker 3: it's just a point of light, and so everything.
• 25:58
  Speaker 5: About it we have to infer. From that light.
• 26:00
  Speaker 3: We can watch it change its brightness and so try
• 26:03
  Speaker 3: and figure out what shapes would do that. We can
• 26:05
  Speaker 3: also look at how bright it is at different wavelengths,
• 26:09
  Speaker 3: and that helps us infer what the surface might be
• 26:11
  Speaker 3: made of based on what light gets reflective and what
• 26:14
  Speaker 3: light gets absorbed.
• 26:15
  Speaker 2: So we're looking at a single pixel in a telescope
• 26:18
  Speaker 2: and just watching it get darker and brighter, and from
• 26:20
  Speaker 2: that we have this crazy artist impression with all these
• 26:23
  Speaker 2: like crags and knooks and all these vinkles on it.
• 26:25
  Speaker 5: That's exactly right.
• 26:28
  Speaker 2: Crazy.
• 26:30
  Speaker 5: It really helps to imagine yourself there.
• 26:32
  Speaker 3: It really helps give you physical intuition for what's going on,
• 26:35
  Speaker 3: and so I think it's a really valuable exercise for
• 26:37
  Speaker 3: us to imagine what these things might look like. But
• 26:40
  Speaker 3: we always have to bring with that the caveat that
• 26:42
  Speaker 3: we have filled in way more details than we actually know,
• 26:45
  Speaker 3: and sometimes that can be frustrating when communicating to the public.
• 26:48
  Speaker 3: Trying to convey we are sure about this, but these
• 26:51
  Speaker 3: other details I'm showing you are just complete fiction and
• 26:54
  Speaker 3: could easily be wrong, like the crags right, the little
• 26:56
  Speaker 3: shapes on that long black cigar shape.
• 26:59
  Speaker 2: Especially in exo planet science, I feel like they're often
• 27:01
  Speaker 2: showing us essentially fantasy data. You know, this is what
• 27:05
  Speaker 2: an artist thinks this planet looks like, when really the
• 27:07
  Speaker 2: image we have is a single pixel.
• 27:10
  Speaker 3: Every planet around another star we've ever detected, We've only gotten,
• 27:13
  Speaker 3: you know, information from just just a point. Sometimes that
• 27:16
  Speaker 3: point is just the star and we can infer it's there,
• 27:20
  Speaker 3: and in a few cases we can actually image the planet,
• 27:22
  Speaker 3: but by that we just mean we see the star
• 27:24
  Speaker 3: in one part of the image and this little dot
• 27:26
  Speaker 3: that's the planet in another part of the image. Exoplanets
• 27:29
  Speaker 3: have a really special place in the imagination of, you know,
• 27:33
  Speaker 3: of the world, because unlike you know, a nebula or
• 27:36
  Speaker 3: a supernova or a gamma ray burst, a planet feels
• 27:39
  Speaker 3: like a place you know, that we could in principle visit,
• 27:42
  Speaker 3: and in science fiction where you know, we do go
• 27:45
  Speaker 3: and visit. And so the reason people are interested is
• 27:49
  Speaker 3: it's like, what would it be like if you were there.
• 27:50
  Speaker 3: You want to imagine what it's like if you were there.
• 27:53
  Speaker 3: It's one of the things that made planetary exploration so
• 27:56
  Speaker 3: compelling when we started to visit Venus and Mars and
• 27:59
  Speaker 3: Jupiter and Saturn, is that we actually send robots there
• 28:02
  Speaker 3: and we will even say we've been to Jupiter. Right, Okay,
• 28:05
  Speaker 3: we have not been to Jupiter, but we've got great
• 28:07
  Speaker 3: pictures that make us feel like we've been to Jupiter.
• 28:10
  Speaker 3: And so that's why you get these like NASA Exoplanet
• 28:14
  Speaker 3: Travel Bureau posters right where they're like advertising come to
• 28:17
  Speaker 3: this planet and they you know, all the cool stuff
• 28:19
  Speaker 3: and these very retro style those are really popular and
• 28:22
  Speaker 3: those are really fun for that reason, and it makes
• 28:24
  Speaker 3: exoplanets a lot of fun to study.
• 28:26
  Speaker 2: All right, but we're not selling Omuamua as a tourist destination.
• 28:29
  Speaker 2: We wanted to understand the shape of it because we
• 28:32
  Speaker 2: had sort of a deeper question, right, which was like,
• 28:34
  Speaker 2: is this thing weird or unusual? And so you were
• 28:37
  Speaker 2: saying that the initial idea was that it was long
• 28:40
  Speaker 2: and thin, sort of like ten times longer than it
• 28:43
  Speaker 2: is thin. But now we have another idea that maybe
• 28:45
  Speaker 2: it's flat, like a pancake. How can both of those
• 28:48
  Speaker 2: be consistent with the light variation?
• 28:49
  Speaker 5: Right?
• 28:50
  Speaker 3: And I think that's because it's tumbling, and so we
• 28:53
  Speaker 3: don't actually know what its orientation was because it's kind
• 28:56
  Speaker 3: of this random orientation and the data are really sparse,
• 29:00
  Speaker 3: you know. We don't get to point the Hubble Space
• 29:02
  Speaker 3: telescope at it constantly and follow its brightness all the time.
• 29:05
  Speaker 5: Only the largest telescopes.
• 29:07
  Speaker 3: Because it was so small it could make accurate brightness
• 29:10
  Speaker 3: measurements on the ground, you can only do it during
• 29:12
  Speaker 3: the day, and you know when you're allowed to use
• 29:14
  Speaker 3: the telescope. So you end up with this very sparse
• 29:17
  Speaker 3: data set where you only know it's brightness, you know,
• 29:20
  Speaker 3: for a few times. Maybe you get a bunch of
• 29:22
  Speaker 3: measurements over the course of a couple of days, and
• 29:23
  Speaker 3: then nothing for a month, And so you're trying to
• 29:26
  Speaker 3: infer the shape from very limited information, and it just
• 29:30
  Speaker 3: turns out there are multiple different shapes that plausibly could
• 29:33
  Speaker 3: do that depending on exactly how it's tumbling, which is random.
• 29:36
  Speaker 5: It can't be.
• 29:36
  Speaker 2: Predicted, And so then the shape is important to this
• 29:39
  Speaker 2: larger question of like what is it? Because the argument
• 29:43
  Speaker 2: is made that like long thin things are weird and
• 29:46
  Speaker 2: unusual and therefore might be alien. Is that the idea.
• 29:49
  Speaker 3: So Abby's point was that if you look at the
• 29:53
  Speaker 3: the most extreme models that fit the data, some of
• 29:56
  Speaker 3: them said the access ratio is ten to one to one,
• 30:00
  Speaker 3: and you know, we could also fit it with something
• 30:02
  Speaker 3: only five to one to one, and.
• 30:03
  Speaker 5: We could also fit it with pancakes.
• 30:04
  Speaker 3: But that was like the strangest and most extreme value
• 30:08
  Speaker 3: that people published as a possibility, and he really grabbed
• 30:11
  Speaker 3: onto that, and he argued that that's far beyond the
• 30:14
  Speaker 3: access ratio that we see in any object in the
• 30:17
  Speaker 3: Solar system, and so that automatically puts it in this
• 30:21
  Speaker 3: you know, that looks unnatural, that looks weird, that's something
• 30:24
  Speaker 3: else kind of category. And so that's when all these
• 30:26
  Speaker 3: caveats come in. This is a very small object. We
• 30:29
  Speaker 3: have very few examples of such small objects. But interestingly,
• 30:33
  Speaker 3: the objects in the Solar system that do have extreme
• 30:36
  Speaker 3: access ratio it's like five to five to one or something,
• 30:38
  Speaker 3: are also among the very smallest things in the solar system.
• 30:42
  Speaker 3: So it's very possible that very small objects often have
• 30:46
  Speaker 3: these kinds of access ratio. And you know, it's not
• 30:48
  Speaker 3: like we can't you know, come up with reasons why
• 30:51
  Speaker 3: that might be. If you take a bar of soap,
• 30:54
  Speaker 3: and you know, a bar of soap sitting there in
• 30:56
  Speaker 3: your shower, every time you take a shower, the soap
• 30:59
  Speaker 3: loses so and it kind of loses soap from all sides.
• 31:02
  Speaker 3: It doesn't just become a smaller, you know, rectangular prism
• 31:05
  Speaker 3: with every shower. It becomes flatter and flatter and thinner
• 31:09
  Speaker 3: and thinner until it's just like, you know, this little wafer.
• 31:12
  Speaker 3: And so whenever you erode something evenly on all sides,
• 31:16
  Speaker 3: that's sort of naturally what happens. If you start kind of,
• 31:19
  Speaker 3: you know, pancake shaped, you'll end up extremely pancake shaped.
• 31:24
  Speaker 3: So if this object is made of ices of some sort,
• 31:28
  Speaker 3: some very you know, cold stuff like like water ice
• 31:32
  Speaker 3: or carbon dioxide ice or nitogen ice or something like that,
• 31:35
  Speaker 3: then as that ice sublimates away, it would be very
• 31:38
  Speaker 3: natural for it to end.
• 31:39
  Speaker 5: Up having an access ratio like that. That makes sense.
• 31:43
  Speaker 3: That could be what's going on, But we have access
• 31:46
  Speaker 3: to so few objects of this size that it's just
• 31:48
  Speaker 3: a story.
• 31:49
  Speaker 5: But it's plausible, it makes sense.
• 31:51
  Speaker 3: The strangest thing about it is probably its orbit so
• 31:55
  Speaker 3: we caught it pretty late in the game. It had
• 31:57
  Speaker 3: already come in from interstellar space. It whipped around the Sun.
• 32:00
  Speaker 3: It was on its way out when it was discovered.
• 32:03
  Speaker 3: It happened to come very close to Earth then, and
• 32:05
  Speaker 3: then as it left the Solar System, because it was
• 32:08
  Speaker 3: the first time we'd seen such an object, it was
• 32:10
  Speaker 3: tracked pretty carefully by the Hubble Space telescope and other
• 32:13
  Speaker 3: telescopes on Earth.
• 32:14
  Speaker 5: And as we tracked its orbit, it did not.
• 32:17
  Speaker 3: Follow the orbit you would expect from just Newtonian gravity,
• 32:21
  Speaker 3: the orbits that the planets follow around the Sun. It
• 32:24
  Speaker 3: seemed to be getting some sort of a push away
• 32:27
  Speaker 3: from the Sun that made it slow down less than
• 32:30
  Speaker 3: you would think on its way out. So that's called
• 32:34
  Speaker 3: a non gravitational acceleration. It's not usually seen in large
• 32:38
  Speaker 3: objects like planets, because what could push a planet around
• 32:40
  Speaker 3: other than gravity.
• 32:42
  Speaker 5: Comets, on the other.
• 32:43
  Speaker 3: Hand, tend to have this a lot, and that's because
• 32:46
  Speaker 3: as they get close to the Sun, the ices on
• 32:49
  Speaker 3: their surfaces melt. They come off in these big jets,
• 32:52
  Speaker 3: and then from the rocket effect of that gas escaping
• 32:55
  Speaker 3: the surface of the comet, the comet will react and
• 32:58
  Speaker 3: move the other way. And so comets sort of propel
• 33:00
  Speaker 3: themselves by all of that gas coming off of their surface.
• 33:03
  Speaker 2: So, just so that I understand, you're saying, if you
• 33:05
  Speaker 2: dropped like an innert rock, rock that didn't have any rockets,
• 33:09
  Speaker 2: wasn't the spaceship had no way to apply a force.
• 33:11
  Speaker 2: We could predict very precisely how it would move in
• 33:14
  Speaker 2: the sun the gravitational field.
• 33:15
  Speaker 3: If it's a big enough rock that other things can't
• 33:17
  Speaker 3: push it around, that's right, it's going to follow a
• 33:20
  Speaker 3: very well defined curve. If you take an astronomy class,
• 33:23
  Speaker 3: you know it's got to be a circle and ellipse
• 33:25
  Speaker 3: or a problem or hyperbole.
• 33:27
  Speaker 5: These are the conic sections.
• 33:28
  Speaker 3: They are the solutions to Newton's equations for two objects
• 33:32
  Speaker 3: that are gravitationally attracted to each other.
• 33:34
  Speaker 2: And so one way to find out if something is
• 33:37
  Speaker 2: an alien ship, for example, is to see is it
• 33:39
  Speaker 2: moving under thrust? Basically, is it firing. Some engines like
• 33:43
  Speaker 2: the Space Shuttle or our ships don't obviously move just
• 33:46
  Speaker 2: in gravitational orbits.
• 33:47
  Speaker 5: Right, right, there's.
• 33:48
  Speaker 3: Actually two reasons you would expect an artificial object to
• 33:52
  Speaker 3: do this. Interestingly, one of the first claims of an
• 33:55
  Speaker 3: alien spaceship in the Solar System was under very very
• 34:00
  Speaker 3: similar reasoning. It was by Joseph Schklovsky, who was a
• 34:04
  Speaker 3: Soviet astronomer who co wrote a book with Carl Sagan
• 34:09
  Speaker 3: on Life in the Universe, and in that book he
• 34:12
  Speaker 3: described the difficulties in getting the orbit of Phobos, the
• 34:16
  Speaker 3: moon of Mars, which people were trying to predict where
• 34:19
  Speaker 3: the moon would be and it just wouldn't be where
• 34:21
  Speaker 3: it was supposed to be, and trying to figure out
• 34:23
  Speaker 3: what the problem was. Now, the problem was probably just
• 34:26
  Speaker 3: bad data at the time. It was a very faint
• 34:28
  Speaker 3: object to see back then. But one possibility Shklovsky pointed
• 34:32
  Speaker 3: out was that it was hollow. Now, why would being
• 34:35
  Speaker 3: hollow mean it doesn't follow a normal lunar orbit. The
• 34:38
  Speaker 3: reason is that the Sun's radiation actually carries with it
• 34:41
  Speaker 3: a little bit of momentum. When the solar photons hit you,
• 34:44
  Speaker 3: they're kind of gently nudging you away from the Sun. Now,
• 34:47
  Speaker 3: this is an incredibly weak effect, you'll never notice just
• 34:50
  Speaker 3: standing there. But if you have a light enough object
• 34:53
  Speaker 3: like a pebble orbiting the Sun, this actually matters, and
• 34:57
  Speaker 3: it will make that pebble's orbit around the Sun a
• 35:00
  Speaker 3: little different than you'd otherwise expect, and so Schklovsky's suggestion
• 35:04
  Speaker 3: was that despite being very large, many kilometers across that
• 35:08
  Speaker 3: Phobos was actually hollow, and so that photon pressure from
• 35:12
  Speaker 3: the Sun was enough because it hardly weighed anything because
• 35:14
  Speaker 3: it wasn't solid rock to alter its orbit. This didn't
• 35:18
  Speaker 3: really go anywhere. I think in the end they figured
• 35:20
  Speaker 3: out it really is just a rock. But it was
• 35:22
  Speaker 3: an early example of this, and so the same thing
• 35:25
  Speaker 3: could be happening.
• 35:26
  Speaker 5: AVI argues to omu.
• 35:27
  Speaker 3: Wa Mua that if it's actually not a big lump
• 35:32
  Speaker 3: of rock, but it's very thin, or it's hollow or
• 35:34
  Speaker 3: something like that, then the pressure from the solar photons
• 35:38
  Speaker 3: will push it away from the Sun much the way
• 35:40
  Speaker 3: that we saw it getting pushed away from the Sun.
• 35:43
  Speaker 3: So the argument was, you know, it could be a
• 35:46
  Speaker 3: comment and that's what we're seeing, or AVI says it
• 35:49
  Speaker 3: could be highly reflective and hardly weigh anything, and that would.
• 35:52
  Speaker 2: Do it too, basically if it's an alien light sale right.
• 35:56
  Speaker 3: So AVI works on a project called Breakthrough Starshot, and
• 35:59
  Speaker 3: the idea idea is to build spacecraft that can travel
• 36:03
  Speaker 3: interstellar distances to actually go and visit a nearby star system.
• 36:06
  Speaker 3: And the method that breakthrough Starshot proposes is to build
• 36:11
  Speaker 3: a light sail. So you have a very small spacecraft
• 36:14
  Speaker 3: and you attach it to a highly reflective sail, and
• 36:17
  Speaker 3: then you shoot a powerful laser at the sale, and
• 36:20
  Speaker 3: that powerful laser will then, through radiation pressure, accelerate it
• 36:24
  Speaker 3: to extremely high speeds if it's low enough mass. So
• 36:28
  Speaker 3: his suggestion was that this might be the method that
• 36:31
  Speaker 3: aliens around the galaxy use to propel their spacecraft. And
• 36:35
  Speaker 3: then once you get going, you know, those sales, perhaps
• 36:38
  Speaker 3: they get discarded or perhaps something hits them and they
• 36:41
  Speaker 3: fall off. But his argument is that the galaxy could
• 36:44
  Speaker 3: be littered with the detritus.
• 36:45
  Speaker 5: Of all of these launches.
• 36:48
  Speaker 3: And if that's the case, then we might expect now
• 36:50
  Speaker 3: and then one of these sales to come, you know,
• 36:52
  Speaker 3: through the solar system, and you'll be able to tell
• 36:54
  Speaker 3: it to sale because when light hits it, it pushes it
• 36:57
  Speaker 3: very easily. It has a very large surface area or
• 37:00
  Speaker 3: its mass, and you know it was designed so that
• 37:03
  Speaker 3: photons could push it around.
• 37:05
  Speaker 2: And then wouldn't you be able to predict very specifically
• 37:08
  Speaker 2: how that would move through our solar system? Like it
• 37:10
  Speaker 2: should get a bigger push when it's closer to the Sun,
• 37:12
  Speaker 2: a smaller push when it is further away. Did OMMA
• 37:15
  Speaker 2: follow that kind of trajectory?
• 37:17
  Speaker 3: Again, we only caught it on the way out, not
• 37:19
  Speaker 3: on the way in, so we don't have the complete
• 37:21
  Speaker 3: orbit for OMU, But from what we could tell, the
• 37:25
  Speaker 3: acceleration it felt, the non gravitational acceleration was entirely away
• 37:29
  Speaker 3: from the Sun. So that is consistent with solar photons
• 37:33
  Speaker 3: pushing on it. It's also consistent with a comment. Now,
• 37:37
  Speaker 3: there was just a little while ago a study that
• 37:40
  Speaker 3: looked at what if you had a sale, what, you know,
• 37:44
  Speaker 3: would it really all be just pushing away from the sun.
• 37:46
  Speaker 3: So we don't know, you know, how a sale would fold,
• 37:50
  Speaker 3: what it would be made of, you know what degrees
• 37:52
  Speaker 3: of freedom it has, what its shape would be, you know,
• 37:55
  Speaker 3: alien solar sales.
• 37:56
  Speaker 5: Who knows. So they just started with.
• 37:58
  Speaker 3: A simple toy model to see, you know, roughly what
• 38:00
  Speaker 3: we might expect. So they just said, okay, it's a
• 38:02
  Speaker 3: rigid sheet. Let's just take a rigid sheet, let it
• 38:06
  Speaker 3: get pushed by sunlight, throw it to the sun and
• 38:08
  Speaker 3: see what happens to it. Oh, and they made it tumble.
• 38:11
  Speaker 3: They didn't have it always present the same face to
• 38:13
  Speaker 3: the sun because we know Oua was tumbling. And what
• 38:17
  Speaker 3: they found was that most of the time the sheet
• 38:21
  Speaker 3: is not directly pointed at the Sun, which means when
• 38:24
  Speaker 3: the light reflects off of it, the push is not
• 38:26
  Speaker 3: directly away from the Sun, but off to the side
• 38:29
  Speaker 3: at some angle depending on how it's oriented. And so
• 38:32
  Speaker 3: as it flutters, as it tumbles, the push it receives
• 38:35
  Speaker 3: from the Sun will keep changing directions, but it will
• 38:37
  Speaker 3: often be lateral. It's not entirely away. And they found
• 38:42
  Speaker 3: that for their model anyway, that was inconsistent with the
• 38:45
  Speaker 3: orbit of omu Wa Mua. And so you can't rule
• 38:47
  Speaker 3: out any possible solar sail or whatnot. But they said,
• 38:50
  Speaker 3: if it's really thin and tumbling and it's radiation pressure,
• 38:53
  Speaker 3: you probably would have seen lateral acceleration. So it's probably
• 38:56
  Speaker 3: not a light sale.
• 38:57
  Speaker 2: So what have zigzagged more if it was a light.
• 38:59
  Speaker 5: Sail something like that.
• 39:01
  Speaker 3: I don't know the details about whether it would have
• 39:03
  Speaker 3: a preferential direction to the side. It probably depends on
• 39:06
  Speaker 3: exactly how it's being pushed. Now, Avi's big argument for
• 39:10
  Speaker 3: why it needed to be radiation pressure, and not commentary outgassing.
• 39:15
  Speaker 3: Is that a Muhamua never showed a coma. Most comments
• 39:19
  Speaker 3: when they get close to the sun, they start evaporating
• 39:21
  Speaker 3: their ices and that forms a cloud that reflects a
• 39:24
  Speaker 3: lot of sunlight and they get bright and then some
• 39:26
  Speaker 3: of that cloud goes off the back and that's their tail.
• 39:29
  Speaker 3: Muhamoua never showed evidence of a coma. In addition, we
• 39:33
  Speaker 3: looked carefully to see if we could detect any gases
• 39:36
  Speaker 3: around it, and the Spitzer space telescope couldn't find any,
• 39:40
  Speaker 3: and so to AVI, this is pretty conclusive that it's
• 39:43
  Speaker 3: not a comet, that it was not outgassing, and it
• 39:45
  Speaker 3: must have been reflection. And if it's reflection, it must
• 39:47
  Speaker 3: have been low mass, which means it must be artificial. Now,
• 39:50
  Speaker 3: a lot of planetary scientists subjected to this. It could
• 39:53
  Speaker 3: be made of a strange kind of ice. After all,
• 39:56
  Speaker 3: this is an interstellar comet. It's the first one we've seen.
• 39:59
  Speaker 3: Who knows, you know, what common out there. So my
• 40:01
  Speaker 3: colleague Steve Dash has proposed that it is made of
• 40:04
  Speaker 3: nitrogen ice.
• 40:05
  Speaker 5: We know nitrogen ice exists. The surface of Pluto has
• 40:08
  Speaker 5: big regions. That's just nitrogen ice.
• 40:11
  Speaker 3: And here I mean if you get you know, the
• 40:13
  Speaker 3: area breathing cold enough, you know, first you'll get the
• 40:16
  Speaker 3: liquid nitrogen. And then if you get that liquid nitrogen
• 40:19
  Speaker 3: much much colder, it'll turn solid. And that's what I'm
• 40:22
  Speaker 3: talking about. This is so cold that it's solid nitrogen ice.
• 40:26
  Speaker 3: And that actually fits the data very well.
• 40:28
  Speaker 5: If it's a chunk of nitrogen ice.
• 40:30
  Speaker 2: So we're talking about a chunk of nitrogen ice coming
• 40:32
  Speaker 2: through the Solar system, and then the Sun is heating
• 40:34
  Speaker 2: it up and the nitrogen boils off, and that's effectively
• 40:38
  Speaker 2: like a little rocket. So the comet is getting non
• 40:41
  Speaker 2: gravitational acceleration because it's pushing out all those nitrogen atoms,
• 40:45
  Speaker 2: and that's effectively how a rocket works. So it's like
• 40:47
  Speaker 2: a natural rocket on the back of a comet. That's
• 40:50
  Speaker 2: what you're saying.
• 40:50
  Speaker 3: That's exactly right, and that's how all commets work. The
• 40:53
  Speaker 3: question was, with this apparent comet, why didn't we see
• 40:57
  Speaker 3: all of this dust and gas around it? And so
• 41:00
  Speaker 3: the answer needs to be it's a very clean commet.
• 41:03
  Speaker 3: It doesn't have a lot of dust to blow off,
• 41:05
  Speaker 3: and the gas must be something we didn't look for,
• 41:08
  Speaker 3: like nitrogen there's another suggestion that it might be hydrogenized,
• 41:11
  Speaker 3: which would.
• 41:12
  Speaker 5: Be pretty exotic. We don't know that hydrogen ized can
• 41:15
  Speaker 5: even exist in space, but it's.
• 41:16
  Speaker 3: A possibility, and that might also fit the data pretty well.
• 41:20
  Speaker 3: So these are kind of out there explanations. We haven't
• 41:22
  Speaker 3: seen something like that in the Solar System, or at
• 41:24
  Speaker 3: least we haven't obviously seen something like that in the
• 41:27
  Speaker 3: Solar system.
• 41:28
  Speaker 5: There are so called dark comets.
• 41:30
  Speaker 3: These are clearly commets that're clearly outgassing, because we see
• 41:34
  Speaker 3: these non gravitational accelerations, but they don't have comi, they
• 41:39
  Speaker 3: don't have tails, and it's hard to find the gas
• 41:41
  Speaker 3: around them, and so it could just be that these
• 41:44
  Speaker 3: dark comets weren't really recognized as being important and interesting
• 41:47
  Speaker 3: and characteristic of the first thing we'd have.
• 41:50
  Speaker 5: Come through the Solar system.
• 41:52
  Speaker 2: So you're saying that there are other examples in our
• 41:54
  Speaker 2: Solar system of non gravitational acceleration without obvious outgassing with
• 41:59
  Speaker 2: no tail kind of thing. We've seen it before.
• 42:01
  Speaker 3: Yes, yes, we've discovered many more of them recently. I
• 42:05
  Speaker 3: think Omumua has spurred a lot of interest in them.
• 42:08
  Speaker 3: But yes, there are examples like that.
• 42:23
  Speaker 2: That's sort of. My other question is one line of
• 42:26
  Speaker 2: argument you're making is this thing is small and weird,
• 42:30
  Speaker 2: and it might just seem weird because we haven't seen
• 42:32
  Speaker 2: the small stuff in our solar system, and so when
• 42:35
  Speaker 2: we compare it to the big stuff, it seems weird.
• 42:37
  Speaker 2: But then why did we see omuumu If the small
• 42:40
  Speaker 2: stuff in our solar system is hard for us to see,
• 42:42
  Speaker 2: why did we even see Omuamua.
• 42:44
  Speaker 3: Well, one thing, it's very hard to see very small objects,
• 42:47
  Speaker 3: so it's not surprising it took a long time to
• 42:49
  Speaker 3: find something that small. Secondly, it's got to get very
• 42:52
  Speaker 3: close to Earth. Things orbiting the Sun sort of have
• 42:55
  Speaker 3: preferential orbits. There are certain places we find them, and
• 42:58
  Speaker 3: they tend not to come very close to Earth because
• 43:01
  Speaker 3: anything that comes close to Earth will feel Earth's gravity
• 43:03
  Speaker 3: and get perturbed, and then it won't be in that
• 43:06
  Speaker 3: orbit anymore. And after five billion years, you know, all
• 43:09
  Speaker 3: those things will have been cleared out. So you need
• 43:12
  Speaker 3: something on a strange, temporary orbit. It's not gonna last long.
• 43:15
  Speaker 3: That comes by, gets deflected by the Earth and it's gone.
• 43:18
  Speaker 3: So interstellar objects don't care about that. They just go
• 43:21
  Speaker 3: where they go. If they get perturbed. They get perturbed
• 43:23
  Speaker 3: because you know they're not going to be around for
• 43:25
  Speaker 3: long anyway, it doesn't matter. So it's not that surprising
• 43:29
  Speaker 3: that we don't see these very small objects super close
• 43:32
  Speaker 3: to Earth if they're orbiting the Sun. But I think
• 43:34
  Speaker 3: the real answer is just they're hard to find. You've
• 43:36
  Speaker 3: got to get incredibly lucky, and for the reason I
• 43:38
  Speaker 3: just said, you're more likely to get lucky apparently with
• 43:40
  Speaker 3: these interstellar.
• 43:42
  Speaker 2: Ones and for a Mumu. There's a detail that I
• 43:44
  Speaker 2: never understood which released specifically to that, which is that
• 43:47
  Speaker 2: we only saw it after it was moving away from us.
• 43:49
  Speaker 2: Why didn't we see it when it was closer to us?
• 43:51
  Speaker 2: Isn't that when it would have been easiest.
• 43:53
  Speaker 5: No, No, we did see it when it was closest
• 43:55
  Speaker 5: to the Earth, or not long after. It was closest
• 43:58
  Speaker 5: to the Earth in and out of the Soul system
• 44:00
  Speaker 5: has to do with where it was with respect to
• 44:02
  Speaker 5: the Sun. So as it approached the Sun, it was
• 44:04
  Speaker 5: pretty far away from Earth. I don't remember the exact orbit.
• 44:07
  Speaker 5: It may have even been in the same direction as
• 44:09
  Speaker 5: the Sun from Earth's perspective, in which case you.
• 44:12
  Speaker 3: Have no hope to see it during the day, and
• 44:14
  Speaker 3: it was only on its way out that it was
• 44:16
  Speaker 3: both close to the Earth and visible at night. And
• 44:20
  Speaker 3: then we got very lucky with its discovery in the
• 44:23
  Speaker 3: pan Star's survey.
• 44:24
  Speaker 2: So its closest approach to the Sun was before it
• 44:27
  Speaker 2: came by the Earth, which is when we spotted it.
• 44:30
  Speaker 2: So one lesson from Omulamua might be, hey, there's a
• 44:33
  Speaker 2: bunch of interesting tiny stuff in our solar system. We
• 44:36
  Speaker 2: should understand it better so that when tiny stuff from
• 44:38
  Speaker 2: other solar systems comes through we have more context. Is
• 44:41
  Speaker 2: that the message?
• 44:42
  Speaker 5: I think that's very important. I think all of this discussion.
• 44:45
  Speaker 3: On Amula Mua has really made these objects perhaps seem
• 44:49
  Speaker 3: more interesting and spurred a lot of interest in them,
• 44:52
  Speaker 3: because it doesn't seem right that the very first interstellar
• 44:55
  Speaker 3: object we see would be something that has no analogs
• 44:59
  Speaker 3: in our own soul system. And we're very interested in
• 45:02
  Speaker 3: these interstellar objects because we have very few examples of
• 45:06
  Speaker 3: material that's not from our own solar system, and principle,
• 45:09
  Speaker 3: these things probably formed when the planets in other stellar
• 45:13
  Speaker 3: systems were forming, and those are hard to study because
• 45:16
  Speaker 3: they're very far away. But if little, you know, bits
• 45:19
  Speaker 3: of stuff gets flung out of those and comes here
• 45:23
  Speaker 3: to Earth and just you know, sort of lands in
• 45:24
  Speaker 3: our lap.
• 45:25
  Speaker 5: That's a great way to study these other systems.
• 45:27
  Speaker 3: Not that we can tell exactly which system it came from,
• 45:30
  Speaker 3: but you know, in principle, just in general, to see
• 45:32
  Speaker 3: what other fragments of planets from other sellar systems might
• 45:36
  Speaker 3: be like is super interesting.
• 45:38
  Speaker 2: So another topic that people mentioned a lot when Omumua
• 45:41
  Speaker 2: was discovered was that it seems surprising that we found
• 45:44
  Speaker 2: one so quickly. As soon as we turned on this telescope,
• 45:47
  Speaker 2: very shortly afterwards, we found this weird object objects which
• 45:51
  Speaker 2: people expected to be very very rare. I remember reading
• 45:54
  Speaker 2: this argument that for us to see one so quickly,
• 45:56
  Speaker 2: basically every star in the Milky Way would have to
• 45:58
  Speaker 2: have and eject like ten to the fifteen objects during
• 46:02
  Speaker 2: its lifetime for us to so quickly see one. What's
• 46:05
  Speaker 2: the understanding now is now do we understand that while
• 46:07
  Speaker 2: really stars are creating lots of these stellar debris and
• 46:10
  Speaker 2: flinging around the Solar System.
• 46:12
  Speaker 3: So first of all, we didn't detect a Mua MUAs
• 46:15
  Speaker 3: as soon as possible. The Pan star survey has been
• 46:17
  Speaker 3: going on for over ten years. It's just very hard
• 46:20
  Speaker 3: to detect something this small. You have to really get
• 46:22
  Speaker 3: lucky that you just happen to catch it when.
• 46:24
  Speaker 5: It's close to Earth.
• 46:25
  Speaker 3: So it's not that we found when as soon as
• 46:27
  Speaker 3: we started looking. Rather, when people calculated how many of
• 46:30
  Speaker 3: these things they expected there to be in the galaxy,
• 46:34
  Speaker 3: it was thought that these surveys wouldn't get lucky enough
• 46:37
  Speaker 3: to see one.
• 46:38
  Speaker 5: But remember these guesses are based on our.
• 46:42
  Speaker 3: Understanding of planet formation, for which we've never had a
• 46:45
  Speaker 3: physical sample. A lot of these models are, you know,
• 46:48
  Speaker 3: just trying to understand what's going on inside of these
• 46:51
  Speaker 3: proto planetsary nebula where you can't really see what's going.
• 46:53
  Speaker 5: On, especially objects of this size.
• 46:56
  Speaker 3: Those estimates really strongly depend on how many things there
• 47:01
  Speaker 3: are at different sizes. So generally you know there's gonna
• 47:04
  Speaker 3: be a lot of big rocks orbiting a star, and
• 47:07
  Speaker 3: then more medium rocks, and then lots and lots of
• 47:09
  Speaker 3: little tiny ones, And the total number of rocks strongly
• 47:13
  Speaker 3: depends on how sort of steep that relationship is. So
• 47:16
  Speaker 3: for every one rock that's a kilometer across, how many
• 47:19
  Speaker 3: are one hundred meters across? Is it is ten times
• 47:22
  Speaker 3: as many? Is it twenty times as many, is it
• 47:24
  Speaker 3: two hundred times as many? And so on all the
• 47:27
  Speaker 3: way down to the size of omumamua, And that's really unknown.
• 47:30
  Speaker 3: We just don't know how many little objects there should be.
• 47:34
  Speaker 3: So the you know, the number that get ejected for
• 47:37
  Speaker 3: star required for us to have seen one is a
• 47:39
  Speaker 3: little on the high end of what we expected, but
• 47:43
  Speaker 3: it's not completely outrageous. And that number also depends on
• 47:48
  Speaker 3: how reflective and shiny they are. This object seems to
• 47:51
  Speaker 3: be extremely reflective, like it's pure ice. That makes the
• 47:55
  Speaker 3: smaller ones much easier to detect than those previous estimates
• 47:59
  Speaker 3: would have guessed.
• 48:00
  Speaker 2: So even just by getting one or two objects, we
• 48:02
  Speaker 2: can infer something about the broader population of zillions and
• 48:06
  Speaker 2: zillions of objects.
• 48:07
  Speaker 3: That's really fascinating, right, Yeah, in order for us to
• 48:09
  Speaker 3: have seen one by now, there must have been a lot,
• 48:11
  Speaker 3: and I.
• 48:11
  Speaker 5: Should point out we now have two.
• 48:13
  Speaker 3: There's also common borisofv So shortly after a muhama, a
• 48:17
  Speaker 3: second comment, interstellar comment was discovered, and it actually looks
• 48:20
  Speaker 3: a lot like we.
• 48:21
  Speaker 5: Expected Intersteller comments to look.
• 48:23
  Speaker 3: So I don't know whether that makes a muamoa weirder
• 48:26
  Speaker 3: or more ordinary. It kind of goes both ways. It
• 48:28
  Speaker 3: means that, yes, it's not weird that we found a muhama.
• 48:31
  Speaker 3: We found Borisov too. On the other hand, Borisoft doesn't
• 48:34
  Speaker 3: look like a muhama. So there's at least two different
• 48:36
  Speaker 3: kinds of these comments.
• 48:37
  Speaker 2: Apparently, and in the context of the question of like
• 48:40
  Speaker 2: is this a natural object or an alien object? It's
• 48:43
  Speaker 2: not implausible. You're saying that there could be enormous numbers
• 48:47
  Speaker 2: of these bits and pieces of other Solar systems floating around,
• 48:51
  Speaker 2: rainy down on us occasionally.
• 48:52
  Speaker 5: It's in fact quite expected.
• 48:54
  Speaker 3: Like we know that the planet formation process kicks out
• 48:59
  Speaker 3: the building blocks, planets, little asteroids, little commets. We know
• 49:02
  Speaker 3: that that happens, and we still see that in the
• 49:04
  Speaker 3: Solar System because Jupiter knocked a lot of these things
• 49:07
  Speaker 3: during planet formation out of the Solar System. We know
• 49:10
  Speaker 3: that because some small fraction of those things that kicked
• 49:14
  Speaker 3: out of the Solar System didn't quite make it. They
• 49:16
  Speaker 3: got far from the Sun, they slowed down, slow down
• 49:18
  Speaker 3: from the Sun's gravity, and the Sun just barely held
• 49:20
  Speaker 3: on to them. And now they orbit the Sun in
• 49:22
  Speaker 3: the Orc cloud and occasionally come and visit us as
• 49:25
  Speaker 3: long period commets, and so you know, you can tell
• 49:28
  Speaker 3: from the number of comets that come in how many
• 49:31
  Speaker 3: didn't get fully ejected, and from that try to extrapolate
• 49:34
  Speaker 3: to how many must have successfully been ejected.
• 49:36
  Speaker 5: And it's a lot.
• 49:37
  Speaker 2: But in comparison for us to see, for example, a
• 49:40
  Speaker 2: piece of alien junk, it would mean that the galaxy
• 49:42
  Speaker 2: has to be like overflowing with alien junk, right, Like
• 49:45
  Speaker 2: if we're seeing a light sale, that would suggest that
• 49:47
  Speaker 2: there are like ten to the fifteen alien junk light
• 49:51
  Speaker 2: sales out there as well.
• 49:52
  Speaker 3: So Audi's hypothesis is that it is very common to
• 49:55
  Speaker 3: launch large numbers of spacecraft with light sails, and that
• 50:00
  Speaker 3: the galaxy is just filled with the litter from all
• 50:04
  Speaker 3: of these space launches all the time. So yeah, you
• 50:06
  Speaker 3: have to imagine sort of a pangalactic technology that's sending
• 50:11
  Speaker 3: ships from star to star.
• 50:13
  Speaker 5: All the time.
• 50:13
  Speaker 2: Wow, well, that is a large hypothesis to consider. Let's
• 50:17
  Speaker 2: also talk about the velocity of this object. I understand
• 50:21
  Speaker 2: that it had a sort of unusual or unexpected speed
• 50:23
  Speaker 2: as it entered the Solar System, right.
• 50:25
  Speaker 3: So there's a big caveat which is that we don't
• 50:28
  Speaker 3: know how it entered the Solar System, because that depends
• 50:31
  Speaker 3: on the amount of non gravitational acceleration that it experienced,
• 50:36
  Speaker 3: and it depends on how much mass it lost. So
• 50:39
  Speaker 3: under the ice models, I think we favor most it
• 50:43
  Speaker 3: lost something like ninety percent of its mass as it
• 50:48
  Speaker 3: warmed up and got near the Sun, which means it
• 50:50
  Speaker 3: experienced a lot of non gravitational acceleration before we even
• 50:54
  Speaker 3: saw it. But we don't really know how much that.
• 50:57
  Speaker 2: Big error bars on there, So it could have been
• 50:59
  Speaker 2: a huge bar of soap as it approached the Solar
• 51:01
  Speaker 2: system and then we just saw a little sliver after
• 51:04
  Speaker 2: it got melted by the Sun.
• 51:05
  Speaker 5: That's exactly right. That could very easily be what happened.
• 51:08
  Speaker 3: And with big uncertainties like that, it's hard to extrapolate
• 51:12
  Speaker 3: backwards and get.
• 51:14
  Speaker 5: An accurate reading on how it came in.
• 51:16
  Speaker 3: Now, if we do our best and say, you know,
• 51:18
  Speaker 3: where did it probably come from, then the direction it
• 51:21
  Speaker 3: came from is kind of interesting. It's basically exactly the
• 51:25
  Speaker 3: direction the Sun is headed through the galaxy, and the
• 51:29
  Speaker 3: speed it came in at is basically exactly the speed
• 51:33
  Speaker 3: of the Sun through the galaxy, which means it was
• 51:37
  Speaker 3: basically from the galaxy's perspective.
• 51:39
  Speaker 5: Sitting still, it wasn't moving at all. We ran into it,
• 51:44
  Speaker 5: and that's very.
• 51:45
  Speaker 3: Interesting, and so some people have tried to hypothesize what
• 51:48
  Speaker 3: that could mean. We suspect that this thing was kicked
• 51:51
  Speaker 3: out of a young stellar system when its planets were forming,
• 51:55
  Speaker 3: So a new star that had been born, say millions
• 51:58
  Speaker 3: of years ago or something like that, and stars form
• 52:03
  Speaker 3: out of clouds of gas, and clouds of gas typically
• 52:07
  Speaker 3: are kind of stationary in the galaxy. So everything orbits
• 52:10
  Speaker 3: the galaxy. And if you just sort of look at
• 52:13
  Speaker 3: the velocity on average of all this stuff orbiting, that's
• 52:15
  Speaker 3: what I mean by standing still. That's what we call
• 52:17
  Speaker 3: the local standard of rest, and that's the orbit you
• 52:20
  Speaker 3: would just expect stuff to take.
• 52:22
  Speaker 5: If it hadn't been pushed around gravitationally by things. So
• 52:26
  Speaker 5: gas tends to be in that kind of an orbit.
• 52:28
  Speaker 3: The stars it forms tend to be in that kind
• 52:30
  Speaker 3: of orbit, and this stuff that gets ejected from those
• 52:33
  Speaker 3: young stars tend to be in that kind of an orbit.
• 52:36
  Speaker 3: The Sun is over four.
• 52:37
  Speaker 5: Billion years old.
• 52:38
  Speaker 3: In those four and a half billion years, it's had
• 52:40
  Speaker 3: close encounters with stars, It's gone by giant molecular clouds.
• 52:44
  Speaker 3: It's gotten perturbed and bumped around, and now its orbit
• 52:47
  Speaker 3: is kind of wonky. It kind of bobs up and
• 52:49
  Speaker 3: down and in and out, and it has this velocity,
• 52:52
  Speaker 3: and it's that velocity that we saw reflected back at
• 52:55
  Speaker 3: us from Omuamua. So the story that makes sense, but
• 52:59
  Speaker 3: again big Aerbars, is that a nearby cloud of gas
• 53:03
  Speaker 3: formed a star millions of years ago in this special
• 53:08
  Speaker 3: velocity frame, you know, in this kind of orbit around
• 53:10
  Speaker 3: the galaxy, that star kicked out o'muamua. Omua has very
• 53:14
  Speaker 3: low velocity with respect to that star because it just
• 53:17
  Speaker 3: barely escaped and then whacked the sun came.
• 53:19
  Speaker 5: And plowed right into it. So it all kind of
• 53:21
  Speaker 5: hangs together.
• 53:22
  Speaker 2: And this sort of more sensationalist view is that it's
• 53:25
  Speaker 2: like a buoy. It's some sort of like it's at
• 53:28
  Speaker 2: rest with respects of the galaxy to serve as like
• 53:30
  Speaker 2: a navigational beacon or something.
• 53:33
  Speaker 3: Right, And so Aby sees this special velocity and says,
• 53:37
  Speaker 3: what are the odds that it would have that velocity?
• 53:39
  Speaker 3: And we're like, well, you know, pretty good if it's
• 53:41
  Speaker 3: a young object, because that's the velocity young objects has
• 53:44
  Speaker 3: it's never mind, lots of things going different velocities, why
• 53:46
  Speaker 3: would it be special. So then he dreams up a
• 53:49
  Speaker 3: reason why aliens might want to put an object in
• 53:53
  Speaker 3: that particular reference frame, and so he suggested it was
• 53:56
  Speaker 3: like a booi, that it sits there for some purpose
• 53:58
  Speaker 3: at that velocity. And then I guess the sun came
• 54:01
  Speaker 3: along and knocked it out, and now it's, you know,
• 54:03
  Speaker 3: headed off in some other direction. I mean, I guess
• 54:06
  Speaker 3: I don't know why they would do that. It also
• 54:07
  Speaker 3: doesn't seem consistent with it being a light sale. If
• 54:10
  Speaker 3: it's just a discarded light sale, that's not a booi,
• 54:12
  Speaker 3: that's just a piece of litter. Or maybe the thing
• 54:14
  Speaker 3: that got launched was a booi, and it's I don't
• 54:16
  Speaker 3: really understand anyway. You know, you can always dream up
• 54:19
  Speaker 3: some reason aliens might make something have a particular character,
• 54:24
  Speaker 3: but I'm not sure for Omua Mua. We have one
• 54:26
  Speaker 3: story that explains all of these characters.
• 54:29
  Speaker 2: So then to wrap up, Omumu is definitely an interesting object, right.
• 54:33
  Speaker 2: It had a sort of unusual shape, maybe some unusual reflectivity.
• 54:37
  Speaker 2: Fascinating acceleration tells us something maybe about the population of
• 54:41
  Speaker 2: these things in our Solar System and in other solar systems,
• 54:44
  Speaker 2: the velocity of stuff. But all in all, what is
• 54:47
  Speaker 2: your best hypothesis? Is it that it's some chunk of
• 54:50
  Speaker 2: nitrogen or hydrogen ice that the Sun basically plowed into.
• 54:54
  Speaker 3: Yeah, So with the caveat that I'm not a planetary scientist,
• 54:57
  Speaker 3: like I got into this because people were asking me,
• 55:00
  Speaker 3: as the director of the Penn State Extraterrestrial Intelligence Center,
• 55:04
  Speaker 3: what I thought of claims that it might be a spacecraft.
• 55:06
  Speaker 3: And so in addressing those claims, you know, I had
• 55:09
  Speaker 3: to learn from the planetary science community.
• 55:12
  Speaker 5: What was weird about it, what wasn't weird about it?
• 55:15
  Speaker 3: And so, you know, I worked with two planetary scientists,
• 55:18
  Speaker 3: Sean Raymond and Steve Desh, who taught me a lot
• 55:21
  Speaker 3: about these things and about what we do and don't
• 55:24
  Speaker 3: know about Omuamua, And we thought about all of the.
• 55:26
  Speaker 5: Different suggestions that have been made.
• 55:29
  Speaker 3: So I basically reflect what they, as experts, tell me
• 55:32
  Speaker 3: sounds most reasonable, and that is that it's a chunk
• 55:35
  Speaker 3: of ice, that it's a comet that has some weird
• 55:37
  Speaker 3: kind of ice, and that's really interesting. Steve's preferred hypothesis
• 55:41
  Speaker 3: is that it's nitrogen ice, and he's worked really hard
• 55:43
  Speaker 3: to show that that fits all the data very well
• 55:45
  Speaker 3: and is a plausible substance other people like hydrogen. And
• 55:49
  Speaker 3: you know, there also might be ideas that just we
• 55:51
  Speaker 3: haven't come up with yet. It could be that when
• 55:53
  Speaker 3: we finally get a close look at one of these things,
• 55:55
  Speaker 3: we're surprised. You know.
• 55:56
  Speaker 5: Oh, of course, that's why Omumama looked like that.
• 55:59
  Speaker 2: Tell you talk about the sort of role of these
• 56:01
  Speaker 2: crazy hypotheses in science. You know, Amy makes a lot
• 56:04
  Speaker 2: of noise about being like Galileo. You know that his
• 56:08
  Speaker 2: ideas aren't being taken seriously, et cetera. Tell me, do
• 56:11
  Speaker 2: you think it's useful for us to entertain these crazy ideas?
• 56:14
  Speaker 2: What do you think about is the comments he's made
• 56:16
  Speaker 2: in public about this versus the comments he's made in
• 56:19
  Speaker 2: sort of more academic settings.
• 56:21
  Speaker 3: I think it's really important that we constantly challenge conventional wisdom,
• 56:25
  Speaker 3: especially in areas where we have very little data, like
• 56:27
  Speaker 3: small small objects around the Sun or interstellar comments. And
• 56:32
  Speaker 3: I think it's very easy for us to feel like
• 56:35
  Speaker 3: we've got everything figured out and then be blind when
• 56:39
  Speaker 3: data showing us that we're wrong comes along.
• 56:41
  Speaker 5: And rejecting it.
• 56:42
  Speaker 3: It's like, oh, well, that's that's an extraordinary hypothesis that
• 56:44
  Speaker 3: we could have been wrong.
• 56:46
  Speaker 2: You know.
• 56:46
  Speaker 5: But for the.
• 56:47
  Speaker 3: Most part, I think scientists are really eager to be
• 56:50
  Speaker 3: the one that makes that big surprising discovery. We tend
• 56:53
  Speaker 3: to be very open minded about this stuff. And you know,
• 56:57
  Speaker 3: when this started coming through, science fiction had already primed
• 57:00
  Speaker 3: us to think it might be an alien spacecraft. You know,
• 57:03
  Speaker 3: there's this story by Arthur Clark Rendezvous with Rama, and
• 57:06
  Speaker 3: on Twitter. As soon as it, you know, was announced,
• 57:08
  Speaker 3: we were joking like, oh, we've got to name it Rama.
• 57:10
  Speaker 3: Maybe it's an alien spacecraft. Like, you know, this idea
• 57:13
  Speaker 3: was out there. These kinds of challenges to our conventional
• 57:17
  Speaker 3: thinking are important, and I think in general they are
• 57:20
  Speaker 3: appreciated by most scientists, provided you know, the level of
• 57:25
  Speaker 3: certainty that's being conveyed here is appropriate. You know, have
• 57:29
  Speaker 3: we considered this, have we ruled it out? Could it
• 57:31
  Speaker 3: be this is kind of weird?
• 57:32
  Speaker 5: Wouldn't that be cool? You know, as long as.
• 57:35
  Speaker 3: You're acknowledging the weight of evidence that it's not from
• 57:38
  Speaker 3: prior experience, I think it's fine. Where I think Avi
• 57:42
  Speaker 3: rankles a lot of people is by you know, claiming that,
• 57:46
  Speaker 3: you know, his ideas are being shot down, you know,
• 57:49
  Speaker 3: just because they're radical, and not because of the certainty.
• 57:53
  Speaker 5: He's conveying to the public and how likely it is.
• 57:55
  Speaker 3: I mean, he wrote wrote a whole book that you know,
• 57:58
  Speaker 3: it hedges a little, it's little meally mouthed, but it's
• 58:01
  Speaker 3: basically making the argument that it must.
• 58:03
  Speaker 5: Be an alien spacecraft.
• 58:05
  Speaker 3: And he makes statements in the media that you know,
• 58:08
  Speaker 3: it really needs to be artificial, when that's not true
• 58:11
  Speaker 3: at all. And that's when people really start getting you know,
• 58:15
  Speaker 3: upset with a lot of obvious behavior. And then you know,
• 58:18
  Speaker 3: when he comes back and says, we're just being closed
• 58:20
  Speaker 3: minded and we're just this is just professional jealousy of
• 58:23
  Speaker 3: all the attention he's getting.
• 58:26
  Speaker 2: You know, that gets old really fast, right, You wrote
• 58:29
  Speaker 2: in your essay quote Loeb's work is unambiguously counterproductive, alienating
• 58:34
  Speaker 2: the community working on these problems and misinforming the public
• 58:38
  Speaker 2: about the state of the field. And as somebody who
• 58:40
  Speaker 2: works both in academia trying to understand the sort of
• 58:43
  Speaker 2: the cutting edge knowledge and interfacing with the public, I'm
• 58:47
  Speaker 2: definitely sensitive to this question of like how we present
• 58:50
  Speaker 2: our work to the public with all of its nuances
• 58:52
  Speaker 2: and caveats, and how that reflects the work being done
• 58:54
  Speaker 2: sort of at the cutting edge. It's important to get
• 58:57
  Speaker 2: that balance, right, I agree with.
• 58:58
  Speaker 3: You, Yeah, And you know, to be clear, the problem
• 59:01
  Speaker 3: isn't that he suggested it's an alien spacecraft, right, That's
• 59:03
  Speaker 3: not counterproductive. That's fun, that's interesting. We should be wondering,
• 59:08
  Speaker 3: just like Shrowsky did, if there we might be able
• 59:11
  Speaker 3: to find alien spacecraft in the Solar System, that'd be
• 59:13
  Speaker 3: very cool. So or at least we can show there
• 59:15
  Speaker 3: aren't any. And you know, that's something people have studied
• 59:18
  Speaker 3: and talked about and you know, is very appropriate. It's
• 59:21
  Speaker 3: the you know, my objection is to the level of
• 59:24
  Speaker 3: certainty that he projects on the fact that this is
• 59:27
  Speaker 3: one to the public, but also the way that he
• 59:30
  Speaker 3: dismisses expertise of people who have studied this stuff their
• 59:34
  Speaker 3: whole careers and gets angry at them for contradicting him,
• 59:37
  Speaker 3: and just tells people that they're wrong and closed minded
• 59:39
  Speaker 3: and they don't know what they're talking about, even though they,
• 59:42
  Speaker 3: you know, are the ones that have degrees in the
• 59:44
  Speaker 3: field and have studied it for.
• 59:45
  Speaker 5: Decades, you know, And he's just coming into it for the.
• 59:48
  Speaker 2: First time, right, And of course every scientist would love
• 59:52
  Speaker 2: if he was right, if we did discover aliens or
• 59:54
  Speaker 2: a piece of alien junk, we'd all be jumping for joy.
• 59:58
  Speaker 2: Something else you wrote in your essay quote, there is
• 1:00:00
  Speaker 2: little joy for debunking claims in science. I think resonated
• 1:00:04
  Speaker 2: with me also, because, yeah, we would love to make
• 1:00:06
  Speaker 2: this discovery, but of course we got to be cautious
• 1:00:08
  Speaker 2: and we got to be careful extraordinary claims and extraordinary evidence.
• 1:00:12
  Speaker 2: As we've always said, yeah.
• 1:00:13
  Speaker 3: That's right, and it really is no fun debunking claim
• 1:00:16
  Speaker 3: In the early days of planet discovery, when I was
• 1:00:19
  Speaker 3: a graduate student, there were lots you know, every time
• 1:00:22
  Speaker 3: you found a planet, it was on the front page
• 1:00:23
  Speaker 3: of the New York Times, and so there was a
• 1:00:25
  Speaker 3: lot of incentive to fool yourself into thinking that some
• 1:00:29
  Speaker 3: signal that you detected was a planet around another star.
• 1:00:32
  Speaker 3: And so there were a lot of planes made that
• 1:00:34
  Speaker 3: were clearly right, a lot that you know, a little iffy, and.
• 1:00:37
  Speaker 5: Some that were just wishful thinking, unfortunately on the part
• 1:00:40
  Speaker 5: of the astronomers that made them.
• 1:00:41
  Speaker 3: And we were always torn, like do we stop the
• 1:00:44
  Speaker 3: work we're doing finding these new planets to go and
• 1:00:47
  Speaker 3: debunk this other claim and kind of clean up the
• 1:00:49
  Speaker 3: masks and say no, no, that one turned out not
• 1:00:51
  Speaker 3: to be right, because you know that's no fun. No
• 1:00:54
  Speaker 3: one likes being the party pooper. You know that person
• 1:00:57
  Speaker 3: isn't going to like you very much after you've done
• 1:00:59
  Speaker 3: something like that. But also, we have better things to do, right,
• 1:01:03
  Speaker 3: You have cool new planets to go find, and you
• 1:01:05
  Speaker 3: only have so much time, and so it is frustrating,
• 1:01:07
  Speaker 3: and you know it needs to be done. When claims
• 1:01:10
  Speaker 3: reach a certain level of attention that you know someone
• 1:01:13
  Speaker 3: needs to come in and sort of spell out, actually,
• 1:01:15
  Speaker 3: you know what we really think about it.
• 1:01:17
  Speaker 2: Well, thank you very much for taking the time to
• 1:01:19
  Speaker 2: go through all these points and give us an understanding
• 1:01:21
  Speaker 2: of what sort of the cutting edge science is on
• 1:01:24
  Speaker 2: these questions. And thank you very much for talking to
• 1:01:26
  Speaker 2: us today. Very helpful and a lot of fun to
• 1:01:28
  Speaker 2: learn about this. What do you think the future holds
• 1:01:30
  Speaker 2: for this field? Do you think we'll see more of
• 1:01:32
  Speaker 2: these things come into our solar system and learn more
• 1:01:35
  Speaker 2: about the sort of small dark objects in our own
• 1:01:38
  Speaker 2: solar system and the rest of the galaxy.
• 1:01:40
  Speaker 5: Yeah, I really do.
• 1:01:41
  Speaker 3: The Reuben observatory is coming online in just a few years,
• 1:01:45
  Speaker 3: and it's going to perform this gigantic survey. It's going
• 1:01:48
  Speaker 3: to image the entire southern sky every three days basically,
• 1:01:52
  Speaker 3: and it will have so much light collecting power and
• 1:01:56
  Speaker 3: it will survey so much of the sky at once
• 1:01:58
  Speaker 3: that it will probably find things like oh Muamo almost
• 1:02:03
  Speaker 3: every year. And that means we'll have a lot of
• 1:02:06
  Speaker 3: these to study, and we'll be able to catch some
• 1:02:08
  Speaker 3: of them on the way into the Solar System and
• 1:02:10
  Speaker 3: see how much mass they lose. We'll be able to
• 1:02:12
  Speaker 3: see how many of them look like oh Muhamoa, you know,
• 1:02:15
  Speaker 3: and try and you know, learn about their characteristics more generally.
• 1:02:19
  Speaker 3: They're even plans, which I just find amazing and wonderful,
• 1:02:23
  Speaker 3: to launch spacecraft to go catch one of them. Now
• 1:02:26
  Speaker 3: they're moving too fast to actually just straight up catch,
• 1:02:29
  Speaker 3: but you could launch something that sort of lurks in
• 1:02:31
  Speaker 3: the Solar System and when an opportune one comes on
• 1:02:34
  Speaker 3: that it could intercept, could fly in the way and
• 1:02:37
  Speaker 3: intercept it and get close up pictures and maybe even
• 1:02:39
  Speaker 3: get a sample.
• 1:02:40
  Speaker 2: Wow, that would be awesome. And I do still, of course,
• 1:02:42
  Speaker 2: have some hope that maybe one of them is a
• 1:02:44
  Speaker 2: piece of alien space junk, and that would be an
• 1:02:47
  Speaker 2: incredible discovery.
• 1:02:48
  Speaker 5: That would be pretty cool that I'd be very excited
• 1:02:50
  Speaker 5: about that.
• 1:02:51
  Speaker 2: All right, Well, thanks again very much for coming on
• 1:02:53
  Speaker 2: the program today.
• 1:02:54
  Speaker 5: My pleasure. Thanks for having me.
• 1:02:56
  Speaker 1: All Right, that was a great interview. It's kind of
• 1:02:58
  Speaker 1: interesting that Jason's job it is also to look for
• 1:03:01
  Speaker 1: extraterrestrial life.
• 1:03:02
  Speaker 2: Yeah, he's not only interested in this stuff, and like
• 1:03:04
  Speaker 2: many of us, he wants to discover aliens. Right, Nobody
• 1:03:07
  Speaker 2: is out there debunking obvious claims because we don't want
• 1:03:10
  Speaker 2: to believe in aliens. We all want to believe it.
• 1:03:13
  Speaker 2: It would be the discovery of the millennium of history.
• 1:03:16
  Speaker 2: But we also don't want to mislead the general public
• 1:03:19
  Speaker 2: about something that was most likely just a chunk of ice.
• 1:03:22
  Speaker 1: And so in general, Jason thinks that it could all
• 1:03:25
  Speaker 1: be explained, all of the weird things about Omuama have
• 1:03:29
  Speaker 1: a more non alien explanation.
• 1:03:32
  Speaker 2: Yeah, Jason thinks that this is actually teaching us something
• 1:03:34
  Speaker 2: about solar systems, that Omama may not be that unusual,
• 1:03:39
  Speaker 2: and that there might be these chunks of ice out
• 1:03:41
  Speaker 2: there in other solar systems and in ours. One of
• 1:03:43
  Speaker 2: the big points in the book is that this thing
• 1:03:45
  Speaker 2: looks different from the things in our solar system. But
• 1:03:47
  Speaker 2: Jason points out that we're not great at seeing these
• 1:03:49
  Speaker 2: things even in our solar systems. So it might be
• 1:03:52
  Speaker 2: that there's a whole hidden ocean of these chunks of
• 1:03:55
  Speaker 2: ice out there in our own or cloud we just
• 1:03:57
  Speaker 2: didn't know about them, And so maybe Omumua's not that unusual.
• 1:04:00
  Speaker 2: It's just sort of telling us something about the world
• 1:04:03
  Speaker 2: out there and our own backyard.
• 1:04:05
  Speaker 1: Have we seen anything like it since it's been now
• 1:04:08
  Speaker 1: five years.
• 1:04:09
  Speaker 2: Well, we have seen another interstellar object two Iborisov also
• 1:04:13
  Speaker 2: came through our solar system a couple of years later,
• 1:04:15
  Speaker 2: and people have started looking for Oma like objects in
• 1:04:19
  Speaker 2: our solar system and they've seen a few. They've seen
• 1:04:21
  Speaker 2: some dark comets, these things that have non gravitational acceleration
• 1:04:25
  Speaker 2: without displaying any sort of tail or coma. So I
• 1:04:28
  Speaker 2: think it really has cracked open the door for us
• 1:04:30
  Speaker 2: understanding our own solar system a bit better.
• 1:04:33
  Speaker 1: Or maybe the aliens are just sending us a bunch
• 1:04:34
  Speaker 1: of messages, or maybe we're a popular tourist destination.
• 1:04:38
  Speaker 2: Or maybe we're just a dumping ground for alien junk.
• 1:04:41
  Speaker 1: No, but the junk left, didn't it.
• 1:04:43
  Speaker 2: That's true. Yeah, maybe we're just a byway for alien
• 1:04:46
  Speaker 2: junk towards the galactic dump.
• 1:04:48
  Speaker 1: Well, I guess that would still be a pretty interesting
• 1:04:50
  Speaker 1: discovery Alien junk mail.
• 1:04:52
  Speaker 2: That would be awesome and I look forward to the day. Aliens.
• 1:04:55
  Speaker 2: Please do send us your.
• 1:04:56
  Speaker 1: Junk all right, Well, we hope you enjoyed that. Thanks
• 1:04:59
  Speaker 1: for joining us, see you next time.
• 1:05:09
  Speaker 2: Thanks for listening, and remember that Daniel and Jorge Explain
• 1:05:12
  Speaker 2: the Universe is a production of iHeartRadio. For more podcasts
• 1:05:16
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• 1:05:20
  Speaker 2: you listen to your favorite shows.