Latest / Daniel and Kelly’s Extraordinary Universe / Listener Questions 59: Interstellar probes and fractional electrons

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Listener Questions 59: Interstellar probes and fractional electrons · Daniel and Kelly’s Extraordinary Universe

• 0:00
  Speaker 1: Hey, everyone, A quick note to let you know that
• 0:02
  Speaker 1: our preschool science TV show on PBS Kids called Eleanor
• 0:06
  Speaker 1: Wonders Why just launched its second season. It's a show
• 0:10
  Speaker 1: about curiosity and exploration and learning to use science to
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  Speaker 1: find your own answers to questions or Hey and I
• 0:17
  Speaker 1: created the show a few years ago, and the second
• 0:19
  Speaker 1: season has just premiered. We're so excited to share this
• 0:23
  Speaker 1: new batch of stories and adventures. Check it out on
• 0:25
  Speaker 1: PBS Kids. Eleanor Wonders Why.
• 0:37
  Speaker 2: Hey, Daniel, what do you think will happen first? That
• 0:39
  Speaker 2: we discover aen life or that Aian life discovers us?
• 0:44
  Speaker 1: Ooh, I really hope that they find us first.
• 0:47
  Speaker 2: Why?
• 0:48
  Speaker 1: Because in that scenario, they're more likely to be smart
• 0:51
  Speaker 1: and curious critters. If we find them first, it might
• 0:54
  Speaker 1: just be that they're like microbial slime somewhere.
• 0:56
  Speaker 2: Mmmm. How do you know they would be smart and curious?
• 0:59
  Speaker 2: What if they're dumb hungry? Wouldn't we want to find
• 1:02
  Speaker 2: them first and figure that out.
• 1:04
  Speaker 1: If they're dumb and hungry, at least they're smart enough
• 1:07
  Speaker 1: to have found us, right.
• 1:08
  Speaker 2: What if they stumble upon it.
• 1:11
  Speaker 1: In their hunger fueled stupidity?
• 1:14
  Speaker 2: Exactly in indy. Case that we want to avoid them,
• 1:17
  Speaker 2: we'll just feed them some microbial slime. If they're so dumb,
• 1:20
  Speaker 2: they'll be happy with that. But what if we find
• 1:22
  Speaker 2: them and they're smart and microbial slime.
• 1:25
  Speaker 1: I'll put up with some slime if they're happy to
• 1:27
  Speaker 1: share their knowledge.
• 1:28
  Speaker 2: Yeah, But what if all they have are sticky facts,
• 1:31
  Speaker 2: stick it to me or slimy data.
• 1:48
  Speaker 3: Hi?
• 1:49
  Speaker 2: I am Orge, my cartoonist and the author of Oliver's
• 1:51
  Speaker 2: Great Big Universe.
• 1:52
  Speaker 1: Hi. I'm Daniel. I'm a particle physicist, and I'm married
• 1:55
  Speaker 1: to a biologist who tells me quote, microbes run the world.
• 1:58
  Speaker 1: Makes me wonder when aliens come, who they would talk
• 2:01
  Speaker 1: to first, us or the microbes that vastly outnumber us
• 2:05
  Speaker 1: and out mass us.
• 2:06
  Speaker 2: Wait, your spouse thinks that microbes run the world? I mean,
• 2:10
  Speaker 2: is she talking about politicians?
• 2:13
  Speaker 1: I think she's talking about like the metabolic processes of
• 2:16
  Speaker 1: our ecosystem, you know, moving stuff around, processing stuff, transforming stuff.
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  Speaker 2: So are they working for us or are we working
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  Speaker 2: for the microbes?
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  Speaker 1: I think that remains to be determined. Maybe the aliens
• 2:27
  Speaker 1: will help us figure it out.
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  Speaker 2: But what if the aliens are clean freaks? And they
• 2:30
  Speaker 2: don't like microbes.
• 2:31
  Speaker 1: It's hard to imagine even aliens surviving without microbes, you
• 2:34
  Speaker 1: know Howso well, of course, we don't know what life
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  Speaker 1: might look like on those planets, but at least here
• 2:39
  Speaker 1: on Earth, everything evolved from microbes, and microbes remain an
• 2:43
  Speaker 1: essential part of all of our life processes. We couldn't
• 2:47
  Speaker 1: survive without them.
• 2:48
  Speaker 3: Mmmm.
• 2:50
  Speaker 2: Slimy as it it is, we need microes. But anyways,
• 2:53
  Speaker 2: welcome to our podcast, Daniel and Jorge Explain the Universe,
• 2:55
  Speaker 2: a production of iHeartRadio in.
• 2:57
  Speaker 1: Which we try to cut through all that mental slum
• 3:00
  Speaker 1: and give you a clear picture for how the universe works,
• 3:03
  Speaker 1: at least as much of it as we understand. We
• 3:06
  Speaker 1: think that everybody out there who's curious and wonders about
• 3:09
  Speaker 1: this incredible, amazing, but kind of bonkers cosmos deserves to
• 3:13
  Speaker 1: have it explained to them. So on this podcast we
• 3:15
  Speaker 1: did through all of your questions and your curiosity and
• 3:18
  Speaker 1: try to bring you to the latest understanding of our universe.
• 3:21
  Speaker 2: That's right. We try to give you a gut feeling
• 3:23
  Speaker 2: about the universe and how it works, and fill you
• 3:26
  Speaker 2: up with micro doses of knowledge and curiosity as we
• 3:31
  Speaker 2: ponder what the universe is made out of, and how
• 3:34
  Speaker 2: we're going to ever explore all of it?
• 3:36
  Speaker 1: Somehow amazingly, by taking these tiny little micro bites of
• 3:40
  Speaker 1: knowledge out of the universe, we've built up something of
• 3:43
  Speaker 1: an understanding of how the universe works. But of course
• 3:47
  Speaker 1: vast critical foundational questions remain about the way the universe works.
• 3:51
  Speaker 1: What are space and time? How can we have a
• 3:54
  Speaker 1: quantum understanding of it? How did the universe all begin?
• 3:57
  Speaker 1: And of course are we alone in it?
• 3:59
  Speaker 2: Yeah, and seeings that there are too many questions for
• 4:02
  Speaker 2: us to ever answer them all. But asking questions is
• 4:05
  Speaker 2: how science starts and how we start building our knowledge
• 4:08
  Speaker 2: of the universe.
• 4:09
  Speaker 1: And that science is powered by individuals asking questions. There's
• 4:13
  Speaker 1: no monolithic institution out there somewhere churning out science. Is
• 4:17
  Speaker 1: just a bunch of curious people wondering about the universe
• 4:20
  Speaker 1: and being so passionate about their particular question that they
• 4:23
  Speaker 1: devote their lives to figuring it out, even if that
• 4:26
  Speaker 1: means climbing trees in the rainforests of Costa Rica or
• 4:29
  Speaker 1: spending their lives in labs underground with lasers. It takes dedication,
• 4:33
  Speaker 1: it takes curiosity. It takes perseverance to make progress on
• 4:36
  Speaker 1: these questions. But it's not just professional scientists who power
• 4:39
  Speaker 1: this human curiosity. It's everybody. Everybody who lives in this
• 4:43
  Speaker 1: universe and demands answers about how it works.
• 4:46
  Speaker 2: And that's because everybody has questions about deniverse. We all
• 4:49
  Speaker 2: look around us and we all wonder how it all works,
• 4:52
  Speaker 2: and we all learn about what scientists now, and still we.
• 4:55
  Speaker 1: Have questions, and we want to hear your questions. When
• 4:59
  Speaker 1: you read something in science journalism about a new discovery
• 5:02
  Speaker 1: that was made that doesn't quite make sense to you,
• 5:04
  Speaker 1: or when you watch a video that explains thermodynamics to
• 5:07
  Speaker 1: you but it doesn't quite click in your brain, or
• 5:09
  Speaker 1: when you hear us talk about something and you have
• 5:11
  Speaker 1: follow up questions, please write to us to questions at
• 5:14
  Speaker 1: Danielanjorge dot com. We really will answer every question.
• 5:18
  Speaker 2: And sometimes we answer those questions here on the podcast.
• 5:21
  Speaker 1: That's right. Sometimes the questions are really fun or I
• 5:24
  Speaker 1: think everybody might want to hear the answer, and so
• 5:27
  Speaker 1: we ask folks to record themselves asking it so we
• 5:29
  Speaker 1: can joke about it and sometimes even answer it here
• 5:31
  Speaker 1: on the pod.
• 5:32
  Speaker 2: Sometimes answer it. Most often not.
• 5:35
  Speaker 1: I don't know how often those answers are actually satisfactory,
• 5:38
  Speaker 1: because usually the answer is we don't know. It might
• 5:40
  Speaker 1: be this, or it might be that.
• 5:42
  Speaker 2: I think we do a pretty good job of providing
• 5:44
  Speaker 2: an answer, even if the answer is sometimes just a question.
• 5:50
  Speaker 1: It's entertaining as much as it's educational.
• 5:52
  Speaker 2: So today on the podcast, we'll be tagling listener question
• 6:00
  Speaker 2: and number fifty nine. I love how we're still numbering
• 6:03
  Speaker 2: these after all these years. Is there anyone keeping track?
• 6:08
  Speaker 3: Like?
• 6:08
  Speaker 2: What if we skip a number, would anyone notice?
• 6:12
  Speaker 1: I don't know. Maybe I did. How do you know exactly?
• 6:15
  Speaker 1: That's what I mean. I'm gonna start giving these random numbers.
• 6:18
  Speaker 1: Then next time it's going to be listening to questions six,
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  Speaker 1: four hundred and fifty two thousand.
• 6:23
  Speaker 2: We should be like Taylor Swift and put in little
• 6:25
  Speaker 2: codes or secret messages in these numbers.
• 6:28
  Speaker 1: Maybe I have been. How do you know? Yes, everybody
• 6:30
  Speaker 1: dig into it.
• 6:33
  Speaker 2: You're the tte of Science Communication podcast.
• 6:36
  Speaker 1: No, this is the Da Vinci code. Actually, I'm leaving
• 6:38
  Speaker 1: secrets for future civilizations. Oh, I see, I see. You're
• 6:41
  Speaker 1: not Taylor Swift, You're Da Vinci. No, I'm the Pope.
• 6:44
  Speaker 2: Yeah, let's keep going.
• 6:51
  Speaker 1: I don't know where you go from the pope, so hmm.
• 6:54
  Speaker 2: But yeah, we do like to answer questions here on
• 6:56
  Speaker 2: the podcast, and so today we have three pretty awesome questions,
• 7:00
  Speaker 2: most of them about space exploration and space probes, but
• 7:03
  Speaker 2: also an interesting question about splitting the electron and so
• 7:08
  Speaker 2: let's jump right in. Our first question comes from Charles.
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  Speaker 4: Hey, Daniel and Jorge. That was a recent listener question
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  Speaker 4: about traveling to a different star, and it got me thinking,
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  Speaker 4: given the state of technology today or in the near future,
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  Speaker 4: could we build a probe that could survive long enough
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  Speaker 4: to reach another star. A second part of it is
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  Speaker 4: when it does reach another star, could it send back
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  Speaker 4: meaningful data that we could receive. We do live in
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  Speaker 4: a real world, so I think that the answer should
• 7:38
  Speaker 4: be limited to Apollo levels of funding, So about two
• 7:41
  Speaker 4: point five percent of GDP for ten years.
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  Speaker 1: Thanks a lot.
• 7:46
  Speaker 2: All right, great question. It seems that Charles er wants
• 7:49
  Speaker 2: to know could we send a probe to another star
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  Speaker 2: and would it even survive that long?
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  Speaker 1: Yeah, I totally get where this question is coming from.
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  Speaker 1: We feel sort of like isolated in our little solar
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  Speaker 1: system and we can send probes to explore nearby planets,
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  Speaker 1: but we're always wondering, like what do those planets look
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  Speaker 1: like around other stars? And that we have incredible telescopes,
• 8:10
  Speaker 1: the Hubble and James Web, we still can't visualize those
• 8:13
  Speaker 1: planets and those solar systems. So the question basically is like,
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  Speaker 1: why don't we just send some science instruments to those
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  Speaker 1: solar systems, snap some photos, and send them back. Couldn't
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  Speaker 1: that be like revelatory. Couldn't we see incredible things things
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  Speaker 1: we might not even be able to imagine.
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  Speaker 2: Right, Because I guess so far we've only been able
• 8:29
  Speaker 2: to see up close six or seven planets, right, or
• 8:32
  Speaker 2: eight planets? Where are we at in our solar system?
• 8:36
  Speaker 2: Eight planets including eight planets, Yeah, including ours? I guess
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  Speaker 2: those are the only ones we've been able to see
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  Speaker 2: up close with probes, And so I guess Charles's question
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  Speaker 2: is could we send probes to another solar system to
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  Speaker 2: take pictures of other planets, maybe to find one that
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  Speaker 2: is habitable or one that has maybe things we haven't
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  Speaker 2: seen before on a planet.
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  Speaker 1: And Charles is also trying to be reasonable. It's not
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  Speaker 1: like let's pour all of the resources of humanity into this.
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  Speaker 1: Let's limit it to like, you know, two and a
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  Speaker 1: half percent of our GDP, which would be an incredible
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  Speaker 1: amount of science funding. I would love if we would
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  Speaker 1: spend two and a half percent of our GDP on science. Wow.
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  Speaker 2: Yeah, that would be amazing. So I guess his question
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  Speaker 2: is a two parter. First one is could we send
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  Speaker 2: a probe to another star? How long would that take?
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  Speaker 1: Yeah? The challenge here, and the reason that is so
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  Speaker 1: difficult and we haven't done it yet, is these other
• 9:29
  Speaker 1: stars are sort of like mind blowingly far away. Like
• 9:33
  Speaker 1: even our solar system is pretty big, you know, like
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  Speaker 1: Pluto is very very far away. It's like ten thousand
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  Speaker 1: times further away than the Moon. So that's why even
• 9:43
  Speaker 1: sending probes to the outer Solar system is an incredible feat.
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  Speaker 1: But the nearest star is much much further away than Pluto.
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  Speaker 1: It's like ten thousand times further away than Pluto. So
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  Speaker 1: it's not like the next solar system is like the
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  Speaker 1: next town over. It's like we're in a little town
• 9:59
  Speaker 1: and there's another on the other side of the world.
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  Speaker 1: So these solar systems are very very far away. It's
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  Speaker 1: not just like a simple extension of our current technologies
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  Speaker 1: that's going to allow us to send probes there.
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  Speaker 2: But I guess what is the nearest star to us.
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  Speaker 1: The nearest star is Proximus Centauri. It's just under four
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  Speaker 1: light years away.
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  Speaker 2: Okay, four light years away. How many kilometers is that?
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  Speaker 1: That's thirty seven qua tillion kilometers away, three point seven
• 10:26
  Speaker 1: times ten to the thirteen kilometers.
• 10:28
  Speaker 2: Okay, that's a lot of zeros. But in space, I
• 10:31
  Speaker 2: feel like you can go super duper fast.
• 10:33
  Speaker 1: Right, Well, in space, you can go super duper fast
• 10:35
  Speaker 1: if you can get up to high speed. Right. The
• 10:38
  Speaker 1: speed of light, of course, is pretty fast. If you
• 10:40
  Speaker 1: could travel at the speed of light, it would only
• 10:42
  Speaker 1: take four years to get there. But the question is,
• 10:44
  Speaker 1: can you get some piece of mass, some scientific probe
• 10:48
  Speaker 1: up near the speed of light? If you want this
• 10:50
  Speaker 1: thing to get there and to send us a message
• 10:53
  Speaker 1: back in like less than one hundred years or so,
• 10:55
  Speaker 1: then you need to get this thing up to like
• 10:57
  Speaker 1: ten or twenty percent of the speed of light. It
• 11:00
  Speaker 1: takes a few decades to get there, and that turns
• 11:02
  Speaker 1: out to be quite a challenge.
• 11:04
  Speaker 2: Wait, how fast do we need it to.
• 11:05
  Speaker 1: Go something like ten or twenty percent of the speed
• 11:07
  Speaker 1: of light for it to get there within a few.
• 11:09
  Speaker 2: Decades, which is how fast.
• 11:11
  Speaker 1: And the speed of light is three times ten to
• 11:13
  Speaker 1: eight meters per second, so ten percent of that is
• 11:15
  Speaker 1: three times ten to the seven meters per second, but.
• 11:18
  Speaker 2: In like kilometers per hour.
• 11:20
  Speaker 1: So the speed of light is like a billion kilometers
• 11:22
  Speaker 1: per hour. So we need this thing to go like
• 11:25
  Speaker 1: one hundred million kilometers per hour. Whoa.
• 11:28
  Speaker 2: And that's if we wanted to go there and come
• 11:30
  Speaker 2: back within a few decades.
• 11:32
  Speaker 1: Now, that's just if we wanted to reach there in
• 11:34
  Speaker 1: a few decades. And then we're hoping it's going to
• 11:36
  Speaker 1: send us signals. We're not actually going to take samples
• 11:39
  Speaker 1: from that solar system and fly them back. I think
• 11:41
  Speaker 1: the first thing that it would be sent probes and
• 11:43
  Speaker 1: then have them shoot the pictures back using messages rather
• 11:45
  Speaker 1: than like actually returning.
• 11:47
  Speaker 2: Oh I see, So you want it to go there
• 11:49
  Speaker 2: in a few decades and then it sends a signal
• 11:52
  Speaker 2: back which comes back in four years.
• 11:54
  Speaker 1: Yeah, exactly. And so the challenges are getting the thing
• 11:57
  Speaker 1: up to that speed, having it survive the journey, and
• 12:00
  Speaker 1: sending us a message back. Whoa.
• 12:02
  Speaker 2: And so I guess it's hard to get up to
• 12:04
  Speaker 2: that speed and space.
• 12:05
  Speaker 1: It is hard to get up to that speed in
• 12:07
  Speaker 1: space depending on the technology you use, Like if you
• 12:10
  Speaker 1: use the kind of technology we use in like the
• 12:12
  Speaker 1: Space Shuttle and in most of our rockets, then you
• 12:15
  Speaker 1: run into a really difficult problem, which is you not
• 12:18
  Speaker 1: only need to accelerate your payload like your science probe,
• 12:21
  Speaker 1: you need to accelerate in the fuel that you're using
• 12:24
  Speaker 1: to accelerate it. So you need a lot of fuel
• 12:26
  Speaker 1: to get up to high speed. You're not burning all
• 12:28
  Speaker 1: that fuel initially, it's not like one big boost and
• 12:31
  Speaker 1: then boom, you're going ten percent of the speed of light,
• 12:33
  Speaker 1: which means that a lot of the fuel needs to
• 12:35
  Speaker 1: accelerate the rest of the fuel, which means you need
• 12:37
  Speaker 1: more fuel for that, which means you need more fuel
• 12:40
  Speaker 1: for that, And then pretty quickly your ship is almost
• 12:42
  Speaker 1: all fuel.
• 12:43
  Speaker 2: Right, Like to put a rocket or to put even
• 12:46
  Speaker 2: a small satellite into orbit, you need a giant rocket,
• 12:49
  Speaker 2: and those rockets are like mostly filled with fuel.
• 12:52
  Speaker 1: Yeah, exactly, they're mostly filled with fuel. So the practical
• 12:56
  Speaker 1: limit of rocket technology, like rockets we could actually build
• 12:59
  Speaker 1: and send towards other solar system it would take tens
• 13:02
  Speaker 1: of thousands of years for those probes to reach those
• 13:05
  Speaker 1: solar systems because we couldn't get them anywhere near ten
• 13:08
  Speaker 1: percent of the speed of light using like solid or
• 13:10
  Speaker 1: liquid fuel rocket technology.
• 13:12
  Speaker 2: Wait, how do you know what's the fastest we could
• 13:14
  Speaker 2: accelerate today.
• 13:15
  Speaker 1: Well, it's not like exactly a fastest speed, but if
• 13:17
  Speaker 1: you think about like simple extensions of the current rockets,
• 13:20
  Speaker 1: you know, doubling tripling them, this kind of stuff, you
• 13:23
  Speaker 1: don't get anywhere close to ten percent of the speed
• 13:25
  Speaker 1: of light, and so it would take tens of thousands
• 13:27
  Speaker 1: of years.
• 13:28
  Speaker 2: Like maybe, for example, the voyagerer pros that have now
• 13:31
  Speaker 2: left the Solar System, how fast are they going?
• 13:34
  Speaker 1: Yeah, so Voyager is the furthest man made object currently.
• 13:37
  Speaker 1: Was launched in nineteen seventy seven and it's only gone
• 13:40
  Speaker 1: one hundred and sixty three au, like that's the distance
• 13:44
  Speaker 1: between the Earth and the Sun. So it's just out
• 13:47
  Speaker 1: of the edge of the Solar System, and it's been
• 13:49
  Speaker 1: going for almost fifty years. It's traveling at like three
• 13:52
  Speaker 1: point six au per year. But that's not really a
• 13:55
  Speaker 1: powered object in the same way, like we launched it
• 13:58
  Speaker 1: and we sent it off in a space and it's
• 13:59
  Speaker 1: got a little bit of like nozzle and thruster for control,
• 14:02
  Speaker 1: but it's mostly just cruising. It's never really designed to
• 14:05
  Speaker 1: go at very high speed.
• 14:07
  Speaker 2: Well, you mentioned sort of an interesting idea, like what
• 14:09
  Speaker 2: if we gave it a whole bunch of acceleration at
• 14:11
  Speaker 2: the beginning, like if we exploded it out of a
• 14:14
  Speaker 2: gun or something.
• 14:15
  Speaker 1: Yeah, so there are other ideas for how to get
• 14:17
  Speaker 1: something to another solar system other than just like do
• 14:20
  Speaker 1: a dumb rocket. There was a really fun idea in
• 14:23
  Speaker 1: the fifties and sixties called project Orion, which said, like,
• 14:26
  Speaker 1: let's blow up nuclear weapons behind the spaceship, so who
• 14:29
  Speaker 1: can like surf a wave of nuclear weapon explosions. This
• 14:32
  Speaker 1: is called project Orion.
• 14:33
  Speaker 2: This is yeah, I mean, what could go wrong?
• 14:38
  Speaker 1: This is Freeman Dyson's idea. And people kind of took
• 14:41
  Speaker 1: this semi seriously for a while until there was a
• 14:43
  Speaker 1: treaty saying no blowing up nuclear weapons in space, which
• 14:46
  Speaker 1: basically killed this whole plan.
• 14:49
  Speaker 2: But wait, so it's a political problem.
• 14:52
  Speaker 1: That's a political problem. Yes, And he wrote a paper
• 14:54
  Speaker 1: decades and decades ago estimating that this ship would take
• 14:57
  Speaker 1: between two hundred and one thousand years to get to
• 15:01
  Speaker 1: Alpha Centauri if it was powered by nuclear complosions.
• 15:04
  Speaker 2: WHOA, that's a long time. Do you think that's what
• 15:08
  Speaker 2: Charles meant? Do you think that's too long?
• 15:11
  Speaker 1: I think that's too long. I think you want to
• 15:13
  Speaker 1: send this thing and then have it send you back data,
• 15:16
  Speaker 1: like in the lifetime of a scientist. You know, you
• 15:18
  Speaker 1: can imagine somebody building this thing as a young scientist,
• 15:21
  Speaker 1: sending it out there, getting the data back before they
• 15:23
  Speaker 1: retire seems like a reasonable strategy. I'm all for multi
• 15:27
  Speaker 1: generational science projects, but it just seems like too long
• 15:29
  Speaker 1: to wait.
• 15:30
  Speaker 2: Well for you, because you're not the results exactly.
• 15:34
  Speaker 1: I want the answers.
• 15:35
  Speaker 2: Think about your grade grade grand kid scientist and how
• 15:39
  Speaker 2: excited they would be to receive a message from this probe.
• 15:42
  Speaker 1: Yeah, as they're scratching out of living in a cave
• 15:45
  Speaker 1: somewhere when civilization has fallen and that data is beamed
• 15:48
  Speaker 1: back from that other solar system and then just splashes
• 15:50
  Speaker 1: on the ground totally ignored.
• 15:52
  Speaker 2: M I guess that's the other part of it, is
• 15:55
  Speaker 2: what can happen in a few hundred years exactly, Like
• 15:58
  Speaker 2: the United States, it is not even more than three
• 16:00
  Speaker 2: hundred years exactly.
• 16:02
  Speaker 1: So that's why people have been thinking about faster ways
• 16:04
  Speaker 1: to get stuff to other solar systems. There are other
• 16:07
  Speaker 1: ways to power these rockets, like ramjets, which are a
• 16:11
  Speaker 1: technique that scoop up fuel as you go, because you know,
• 16:14
  Speaker 1: space is not empty, it's filled with protons, and protons
• 16:17
  Speaker 1: are hydrogen and you can use that as propellant. So
• 16:20
  Speaker 1: there are techniques for like scooping up hydrogen and using
• 16:23
  Speaker 1: that along the way. But I think the most realistic
• 16:25
  Speaker 1: is actually maybe the most science fiction y, which is
• 16:28
  Speaker 1: a solar sail pushed along by lasers. And the idea
• 16:31
  Speaker 1: is to escape this rocket trap by not bringing your
• 16:34
  Speaker 1: fuel along at all. Just have a huge sail and
• 16:38
  Speaker 1: point a laser beam at it, and that'll push the
• 16:40
  Speaker 1: probe along and the probe doesn't have to carry the
• 16:42
  Speaker 1: fuel with it.
• 16:43
  Speaker 2: Well, you'd have to be really accurate, though, right, to
• 16:46
  Speaker 2: like shoot this tiny little probe in the middle space
• 16:49
  Speaker 2: really far away.
• 16:50
  Speaker 1: Yes, you would have to be accurate because these things
• 16:53
  Speaker 1: are tiny targets from like an angular point of view.
• 16:56
  Speaker 1: But in principle you could also maybe steer these things
• 16:58
  Speaker 1: a little bit. You have a magnetic fin that you
• 17:01
  Speaker 1: could use, you know, to take advantage of interstellar magnetic fields,
• 17:05
  Speaker 1: et cetera.
• 17:06
  Speaker 2: So if you do that, how fast can you get
• 17:08
  Speaker 2: a probe going?
• 17:09
  Speaker 1: So they suspect that if you build these things with
• 17:12
  Speaker 1: huge sales, we're talking kilometer sized sales, and you build
• 17:16
  Speaker 1: a huge beam of lasers, like a square kilometer array
• 17:20
  Speaker 1: of lasers that can pump out like giga WoT hours
• 17:23
  Speaker 1: of energy, then you could get these things realistically up
• 17:26
  Speaker 1: to ten or twenty percent of the speed of light,
• 17:28
  Speaker 1: which means they could reach the neighboring star system in
• 17:30
  Speaker 1: like twenty ish years.
• 17:32
  Speaker 2: WHOA, And with this fit within the budget that Charles
• 17:34
  Speaker 2: laid out.
• 17:35
  Speaker 1: It depends on energy costs. Mostly a few gigawatt hours
• 17:39
  Speaker 1: of energy is a pretty big fraction of our energy output.
• 17:42
  Speaker 1: If we can make energy production more efficient or somehow
• 17:45
  Speaker 1: harness energy from the Sun to power these lasers directly,
• 17:48
  Speaker 1: or something that would be more productive.
• 17:51
  Speaker 2: Could you just build like a giant magnifying glass to
• 17:53
  Speaker 2: fill this of the light from the sun put it
• 17:56
  Speaker 2: out there in space.
• 17:57
  Speaker 1: Yeah, potentially. It's a funny thing to try to play
• 18:00
  Speaker 1: in these projects because you never know if you should
• 18:02
  Speaker 1: start building today or wait five years until the technology
• 18:06
  Speaker 1: has improved so that you could actually get your probe going. Faster,
• 18:09
  Speaker 1: Like which probe would actually arrive first, the one you
• 18:12
  Speaker 1: start building today or the one you start building in
• 18:14
  Speaker 1: ten years that might get up to a higher speed.
• 18:18
  Speaker 2: Yeah, Those giant magnifying glasses just keep getting better and
• 18:21
  Speaker 2: better every year.
• 18:23
  Speaker 1: And then, of course this challenge is in flight. Right
• 18:25
  Speaker 1: while you're flying from here to there, you have to
• 18:28
  Speaker 1: worry about like micrometeorites tearing your sale or destroying your
• 18:31
  Speaker 1: space probe or all sorts of stuff.
• 18:33
  Speaker 2: Yeah, it's kind of what Charles asked as the second
• 18:35
  Speaker 2: part of his question is would the probe even survived
• 18:38
  Speaker 2: that long?
• 18:38
  Speaker 1: It's hard to say. And one of the current plans
• 18:40
  Speaker 1: I read from the Breakthrough Starshuk program is to send
• 18:43
  Speaker 1: a bunch of probes, like not an individual one, but
• 18:46
  Speaker 1: like a whole array of small probes. The idea of
• 18:49
  Speaker 1: being you're spreading your risk. But it is tricky because
• 18:52
  Speaker 1: even a tiny particle like a hundredth of a millimeter
• 18:55
  Speaker 1: in size at very high speed we're talking, you know,
• 18:58
  Speaker 1: twenty percent of the speed of LFE could basically destroy
• 19:01
  Speaker 1: that kind of probe.
• 19:02
  Speaker 2: Hmmm, even if you put it like a shield in front.
• 19:05
  Speaker 1: Yeah, there is possibility to have shields. We talked about
• 19:07
  Speaker 1: on the podcast once to have these whipple shields, like
• 19:09
  Speaker 1: thin layers of graphite that might make it work. I
• 19:12
  Speaker 1: did read an analysis of how likely these probes are
• 19:15
  Speaker 1: to survive, and the famous Avi Lobe says, quote, we
• 19:19
  Speaker 1: did a thorough analysis, taking all relevant physics into consideration.
• 19:22
  Speaker 1: We didn't see any showstoppers. But you know, thorough analysis
• 19:26
  Speaker 1: by Avi Lob. Who knows what that means.
• 19:30
  Speaker 2: I'm not sure who Avi Lob is, but he sounds
• 19:32
  Speaker 2: very sure of himself.
• 19:33
  Speaker 1: Well, remember we talked about him on the podcast before.
• 19:35
  Speaker 1: He's the guy who claimed to have found interstellar material
• 19:39
  Speaker 1: from sperials under the ocean, and then planetary scientists came
• 19:42
  Speaker 1: along and they were like, yeah, you don't really know
• 19:44
  Speaker 1: what you're talking.
• 19:44
  Speaker 2: About, So where are we quoting him on the podcast?
• 19:48
  Speaker 1: Incredible, so we can dunk on him, of course.
• 19:51
  Speaker 2: But I guess maybe even a bigger question is even
• 19:54
  Speaker 2: we could get a probe that far, would it even
• 19:56
  Speaker 2: be able to talk to us? Because you know, sending
• 19:59
  Speaker 2: a signal that bar takes a lot of energy.
• 20:01
  Speaker 1: Yeah, it's tricky, and you're fighting the one over are squared,
• 20:03
  Speaker 1: Like if you just broadcast from Earth, you might think
• 20:06
  Speaker 1: our signals are pretty strong, but the signals get weaker
• 20:09
  Speaker 1: and weaker, and if you're ten times further then the
• 20:12
  Speaker 1: signals one hundred times weaker, and if you're a thousand
• 20:14
  Speaker 1: times further, the signal gets a million times weaker. And
• 20:17
  Speaker 1: so broadcasts of that strength can't actually be picked up
• 20:20
  Speaker 1: by technology that we have further than like a couple
• 20:23
  Speaker 1: of light years. And so in order to get a
• 20:26
  Speaker 1: signal from another solar system two hours, you don't want
• 20:29
  Speaker 1: to broadcast in every direction. You want as tight a
• 20:31
  Speaker 1: beam as possible. And so if you have, for example,
• 20:34
  Speaker 1: a laser on board, it in principle could send you
• 20:37
  Speaker 1: a signal which would outshine that star in particular wavelengths
• 20:41
  Speaker 1: that you could pick up.
• 20:42
  Speaker 2: Interesting. All right, So it sounds like the answer for
• 20:45
  Speaker 2: Charles is that, yeah, it is possible for us to
• 20:48
  Speaker 2: send a probe that goes to another planet, to the
• 20:52
  Speaker 2: nearest star and census back signals within the budget. We
• 20:56
  Speaker 2: just kind of have to do it, right.
• 20:57
  Speaker 1: Yeah, it's an exciting moment because we're like and on
• 21:00
  Speaker 1: the edge of having all these technologies come together where
• 21:02
  Speaker 1: we really could actually do this. It would still be
• 21:05
  Speaker 1: very very expensive, but mostly I think at this point,
• 21:08
  Speaker 1: it's a political and organizational challenge. We're in the place.
• 21:11
  Speaker 1: We are in lots of scientific fields where we could
• 21:13
  Speaker 1: buy knowledge about the universe. We have enough money. It's
• 21:16
  Speaker 1: just a question of do we have the will, do
• 21:18
  Speaker 1: we want it enough right?
• 21:19
  Speaker 2: Do we want to buy it or do we want
• 21:21
  Speaker 2: to just leave it in our shopping cart for.
• 21:24
  Speaker 1: A while, wait till the price goes down.
• 21:27
  Speaker 2: Yeah, wait for that sale. That's Cosmo Amazon sale in
• 21:32
  Speaker 2: the sale on solar sales. But yeah, scientists, get on it, because,
• 21:35
  Speaker 2: let's face it, Daniel is not getting any younger, and
• 21:39
  Speaker 2: he really wants to do these pics is before he dies.
• 21:42
  Speaker 1: You know, I'm not the only one who's not getting
• 21:44
  Speaker 1: any younger. That's true of literally everybody.
• 21:47
  Speaker 2: You seem especially to want to see these pictures.
• 21:49
  Speaker 1: I do want to see these pictures. Absolutely, Yes, Congress,
• 21:52
  Speaker 1: please send us one hundred million dollars we can spend
• 21:54
  Speaker 1: on this.
• 21:55
  Speaker 2: Or let's freeze Daniel and when we finally get the
• 21:59
  Speaker 2: pictures back, well.
• 22:01
  Speaker 1: Wake them up the frosty. That sounds pretty good. I
• 22:06
  Speaker 1: do have fantasies about freezing myself and waking up every
• 22:08
  Speaker 1: hundred years just to get like updated on physics. That
• 22:11
  Speaker 1: would be pretty cool.
• 22:12
  Speaker 2: Oh interesting, but just you, not your family.
• 22:17
  Speaker 1: Everybody else has to stay awake so they can do
• 22:19
  Speaker 1: the physics and then I can get updated. Right, that's right.
• 22:22
  Speaker 2: Yes, I think it sounds like you need to start
• 22:24
  Speaker 2: like a cult. Maybe you used to start by having
• 22:26
  Speaker 2: a podcast.
• 22:27
  Speaker 1: Perhaps maybe that was the plan the whole time.
• 22:32
  Speaker 2: Maybe you read the numbers in our listener question titles.
• 22:36
  Speaker 2: You'll get instructions for how to how to join, how
• 22:39
  Speaker 2: to join the cult, and mix the kool aid?
• 22:42
  Speaker 1: Don't cult leaders usually like solicit donations from their members though,
• 22:45
  Speaker 1: we should have gotten on that.
• 22:46
  Speaker 2: Oh yeah, maybe that's in the instructions or maybe you
• 22:48
  Speaker 2: should have put that in the instruction.
• 22:50
  Speaker 1: Yeah, that's right, it's banking information.
• 22:53
  Speaker 2: All right. Well, thank you Charles for that question. Let's
• 22:55
  Speaker 2: get to our next question. This one is kind of
• 22:58
  Speaker 2: also about space prodes, but from a different perspective, so
• 23:02
  Speaker 2: let's dig into that. But first let's take a quick break.
• 23:17
  Speaker 2: All right, we're answering listener questions here today, and our
• 23:20
  Speaker 2: next question comes from Ted.
• 23:23
  Speaker 1: Hi, Daniel and Joge.
• 23:24
  Speaker 2: Here's my question.
• 23:25
  Speaker 3: I've always been fascinated by the voyager space probes and
• 23:29
  Speaker 3: their journey through our Solar System out into interstellar space.
• 23:35
  Speaker 3: I believe it will be around forty thousand years until
• 23:38
  Speaker 3: Voyager one will reach the proximity of another star. I've
• 23:43
  Speaker 3: always wondered if another civilization has sent a voyager like
• 23:48
  Speaker 3: probe in our direction and it passed through our Solar system,
• 23:53
  Speaker 3: would be a even be able to detect the presence
• 23:57
  Speaker 3: of an object that size be If we were able
• 24:01
  Speaker 3: to detect it, would we be able to intercept it
• 24:05
  Speaker 3: and bring it back to Earth so that we could
• 24:07
  Speaker 3: retrieve its gold record or the equivalent audio medium that
• 24:11
  Speaker 3: the alien civilization who sent it had included?
• 24:15
  Speaker 1: Thanks?
• 24:16
  Speaker 2: All right, pretty cool question. Basically, I feel like that
• 24:20
  Speaker 2: question is couldn't Alien have probed us?
• 24:22
  Speaker 1: Yeah, this is a fun question. Couldn't Alien have probed us?
• 24:25
  Speaker 2: Or?
• 24:25
  Speaker 1: If alien probes arrive, could we even see them? To me,
• 24:28
  Speaker 1: this is a really dark scenario that like an alien
• 24:31
  Speaker 1: voyager probe could pass to the Solar System and we
• 24:34
  Speaker 1: could not spot it. Oh my god, what a tragedy.
• 24:37
  Speaker 2: Well, maybe if we assume that you're assuming we want
• 24:40
  Speaker 2: to meet these aliens.
• 24:43
  Speaker 1: I don't need to assume that I want to meet
• 24:44
  Speaker 1: these aliens. I already know that somebody sends us a probe.
• 24:47
  Speaker 1: I want that thing. Oh my gosh, wouldn't you want
• 24:49
  Speaker 1: to see it?
• 24:50
  Speaker 2: But I guess the question is how likely is it
• 24:52
  Speaker 2: that maybe we haven't seen a probe that has come
• 24:55
  Speaker 2: near us? Or maybe that's the main point, is it?
• 24:57
  Speaker 2: It depends on how close to us it flew.
• 24:59
  Speaker 1: Well, we're definitely sure we have not yet seen any
• 25:02
  Speaker 1: alien probes. I mean, unless the government has some secret
• 25:04
  Speaker 1: program and is captured in an alien probe and is
• 25:06
  Speaker 1: studying it at Area fifty nine or Area sixty two
• 25:09
  Speaker 1: or whatever. But let's assume that we have not yet
• 25:11
  Speaker 1: captured any alien probes. I think it's a fun question
• 25:14
  Speaker 1: to explore, like could we see an alien probes? Like
• 25:17
  Speaker 1: if one hundred aliens shot their probes in our solar system,
• 25:20
  Speaker 1: what fraction of those could we see right?
• 25:23
  Speaker 2: And seeing them meaning like we see them with their
• 25:26
  Speaker 2: naked eye right or with some sort of radar.
• 25:29
  Speaker 1: Yeah, we have a lot of technology to spot these things.
• 25:31
  Speaker 1: I mean, number one, if they somehow still have power
• 25:34
  Speaker 1: after their ten thousand year journey to our solar system
• 25:38
  Speaker 1: and they're broadcasting, then yeah, we're going to spot them.
• 25:40
  Speaker 1: You know, because any signal like that we will capture.
• 25:43
  Speaker 2: Wait, why would they need to have been space that long?
• 25:45
  Speaker 2: Couldn't they do the same thing we just did in
• 25:47
  Speaker 2: the first question, And maybe the probe is only twenty
• 25:50
  Speaker 2: years old.
• 25:51
  Speaker 1: Yeah, it's possible. And space craft can have like nuclear
• 25:54
  Speaker 1: powered batteries, they can last four decades, and so it's
• 25:57
  Speaker 1: certainly possible that you know, they send a solar sale
• 25:59
  Speaker 1: or they have some even better technology and it gets
• 26:01
  Speaker 1: here and it still has power. But broadcasting takes a
• 26:04
  Speaker 1: lot of energy, and so it seemed unlikely to me.
• 26:07
  Speaker 1: But that's possible, and that would be easy, right if
• 26:09
  Speaker 1: an alien probe comes and is sending signals in some
• 26:13
  Speaker 1: band that we're monitoring, yeah, we're going to spot that.
• 26:15
  Speaker 1: I think the harder thing is some like dead relic
• 26:18
  Speaker 1: of an ancient civilization that's floating through our solar system.
• 26:21
  Speaker 1: Could we spot that?
• 26:23
  Speaker 2: Well, it's sort of I feel like it's the same problem,
• 26:25
  Speaker 2: Like it could also be a probe, but maybe it's
• 26:27
  Speaker 2: sending laser signals back to its own planet that we
• 26:31
  Speaker 2: can't see, right, so it.
• 26:32
  Speaker 1: Could be silently spying on us.
• 26:34
  Speaker 2: Yeah, yeah, so I guess the question is if something
• 26:37
  Speaker 2: that was not naturally occurring, like a meteorite was flying
• 26:41
  Speaker 2: around us, around the Earth, Could we first of all
• 26:44
  Speaker 2: spot it and could we tell that it is not
• 26:48
  Speaker 2: an asteroid?
• 26:49
  Speaker 1: What media clue would be its trajectory? Like, we monitor
• 26:52
  Speaker 1: a lot of things in the Solar System and we
• 26:55
  Speaker 1: measure their orbits, mostly because we're curious about whether they're
• 26:57
  Speaker 1: going to slam into the Earth. Has been monitoring asteroids
• 27:01
  Speaker 1: and comets and all sorts of stuff, and most of
• 27:03
  Speaker 1: those orbits are consistent with having gone around the Sun
• 27:06
  Speaker 1: a bunch of times. But sometimes, very rarely, very occasionally,
• 27:10
  Speaker 1: we see something that clearly is coming into the Solar
• 27:13
  Speaker 1: System that was not gravitationally bound by the Sun. The
• 27:16
  Speaker 1: most famous example is O Muamoa, which is a rock
• 27:20
  Speaker 1: that came from another Solar system just like drifted through ours.
• 27:24
  Speaker 1: We spotted that because of its weird trajectory. That's what
• 27:26
  Speaker 1: made it different from all the other rocks in the
• 27:29
  Speaker 1: Solar system.
• 27:30
  Speaker 2: Right, Like, maybe Omo was an alien probe from an
• 27:33
  Speaker 2: alien civilization.
• 27:35
  Speaker 1: Right, Yeah, now you're sounding like a vilobe, right, That
• 27:37
  Speaker 1: was his other claim.
• 27:38
  Speaker 2: I'm just saying, maybe I'm necessarily after thorough analysis, I
• 27:42
  Speaker 2: can tell, let's say, alien probe.
• 27:45
  Speaker 1: Yeah, exactly, And that's what makes these things so exciting, Right,
• 27:47
  Speaker 1: they're coming from another solar system. Are they just a
• 27:50
  Speaker 1: chunk of ice or rock, or are they actually a
• 27:52
  Speaker 1: relic from another civilization, et cetera, et cetera. And so
• 27:55
  Speaker 1: we want to study these things. But the exciting thing
• 27:57
  Speaker 1: is that we can usually tell if something is interstellar
• 28:01
  Speaker 1: or if it's part of our solar system. So these
• 28:03
  Speaker 1: things stand out because of their motion and because we're
• 28:06
  Speaker 1: trying to track things moving in our solar system. We're
• 28:08
  Speaker 1: pretty good at spotting those things.
• 28:11
  Speaker 2: M I thought you were going to say that we
• 28:13
  Speaker 2: could tell it's an alien pro because maybe it's not
• 28:15
  Speaker 2: going in a straight line or maybe not going in
• 28:18
  Speaker 2: a natural sort of gravitational orbit line.
• 28:22
  Speaker 1: Absolutely, that's an important factor as well. Like number one
• 28:25
  Speaker 1: is where do we think it came from? Number two
• 28:27
  Speaker 1: is is it moving gravitationally? Like If it's moving as
• 28:30
  Speaker 1: if the only forces on it are due to gravity,
• 28:33
  Speaker 1: gravity the Sun and Jupiter, etc. Then that makes it
• 28:36
  Speaker 1: more likely to just be like a rock or a
• 28:37
  Speaker 1: chunk of ice. But if it's thrusting, if it's accelerating,
• 28:41
  Speaker 1: if it's deviating from a gravitational path, then it's almost
• 28:44
  Speaker 1: certainly not natural. Although in the case again of Omuamua,
• 28:48
  Speaker 1: that thing was not just moving gravitationally. There was a
• 28:51
  Speaker 1: little bit of thrust, though now we're pretty sure that
• 28:54
  Speaker 1: was due to ice boiling off the back of it
• 28:56
  Speaker 1: as it left the Solar System, which provided a little
• 28:58
  Speaker 1: push hmmm.
• 29:01
  Speaker 2: Or I guess you know, just sort of how we
• 29:02
  Speaker 2: do it with our space probes. We basically only do
• 29:06
  Speaker 2: small corrections every once in a while, right, Like we
• 29:09
  Speaker 2: when we plan out the navigation of our space pros,
• 29:12
  Speaker 2: we try to make it as natural as possible, right,
• 29:14
  Speaker 2: because that saves you the most amount of energy.
• 29:17
  Speaker 1: Exactly. We're very sparing with our use of that fuel
• 29:19
  Speaker 1: because you can't put a lot on board. It makes
• 29:21
  Speaker 1: the thing heavy and you have a long way to go.
• 29:24
  Speaker 1: It's a voyager, for example, still has a little bit
• 29:26
  Speaker 1: of fuel left, even decades and decades after it took off,
• 29:30
  Speaker 1: because mostly its trajectory was determined by gravitational slingshots around
• 29:34
  Speaker 1: Solar System objects.
• 29:36
  Speaker 2: So it's possible we may not be able to detect
• 29:39
  Speaker 2: this probe by studying its path.
• 29:41
  Speaker 1: That's right, though, if it comes from outside the Solar System.
• 29:44
  Speaker 1: I think we would identify it as a non Solar
• 29:46
  Speaker 1: system object, but that depends on whether we can see it.
• 29:50
  Speaker 1: Like we can see stuff in the Solar System, but
• 29:52
  Speaker 1: we can't see everything. You know, the Sun is bright,
• 29:54
  Speaker 1: but it doesn't light up all of space in the
• 29:57
  Speaker 1: way that you can see every rock. Rocks have to
• 29:59
  Speaker 1: be like shiny enough and big enough and oriented the
• 30:03
  Speaker 1: right way for the light to bounce off of them
• 30:05
  Speaker 1: and come to Earth. There's a lot of dark rocks
• 30:07
  Speaker 1: in the Solar System we've never seen.
• 30:09
  Speaker 2: Before, right, and a lot of tiny rocks that we
• 30:12
  Speaker 2: just can see. They're too small for us to even notice.
• 30:15
  Speaker 1: Yeah, exactly, And most of the stuff we've seen in
• 30:16
  Speaker 1: the Solar System is bigger than like the Voyager probe.
• 30:19
  Speaker 1: We can see smaller rocks, but they have to be
• 30:21
  Speaker 1: kind of brighter. So we've seen all the big rocks
• 30:24
  Speaker 1: in the Solar System. We're very confident about that. But
• 30:27
  Speaker 1: as the rock size gets smaller and smaller, then the
• 30:30
  Speaker 1: fraction of them we've seen starts to drop pretty quickly.
• 30:32
  Speaker 1: So certainly is possible for an interstellar probe to enter
• 30:36
  Speaker 1: the Solar System. And if it's dark enough and small
• 30:38
  Speaker 1: enough for us to not notice.
• 30:40
  Speaker 2: Yeah, I mean, omoom Wo was huge and we still
• 30:43
  Speaker 2: can definitively tell right, we can't get a closer picture
• 30:46
  Speaker 2: of it.
• 30:46
  Speaker 1: Oh mum Woo was pretty big and we couldn't study definitively.
• 30:49
  Speaker 1: One reason is that we didn't really identify it until
• 30:52
  Speaker 1: it was already past its point of closest approach, so
• 30:55
  Speaker 1: zipping away from us in the Solar System. If we
• 30:58
  Speaker 1: spotted these things sooner, and we could identify them before
• 31:00
  Speaker 1: for they had their closest approach to Earth, then there's
• 31:02
  Speaker 1: a possibility we could like rapidly launch something to intercept it,
• 31:06
  Speaker 1: or at least come near it and like snap a
• 31:08
  Speaker 1: bunch of quick photos. But oh Mumu was so frustrating
• 31:12
  Speaker 1: because it's basically too late to launch anything to go
• 31:15
  Speaker 1: sample it or take pictures of it. It was already
• 31:17
  Speaker 1: zipping on its way out of the Solar System.
• 31:19
  Speaker 2: And oh, I feel like we just happened to have
• 31:21
  Speaker 2: seen it. Is it possible we've missed other o'mu moos
• 31:25
  Speaker 2: in the near past or will miss them in the
• 31:28
  Speaker 2: near future.
• 31:29
  Speaker 1: It's certainly possible. Omoomu is something we spotted pretty soon
• 31:32
  Speaker 1: after we turned on a new set of telescopes, the
• 31:34
  Speaker 1: pan Stars telescopes, which are excellent at this So now
• 31:38
  Speaker 1: that we have those guys operating and we're building more
• 31:40
  Speaker 1: of these things in the future, I think we're just
• 31:43
  Speaker 1: increasing our chances of spotting these things. But there's always
• 31:46
  Speaker 1: a chance that we miss them. Right, you have to
• 31:47
  Speaker 1: be looking in the right place at the right time,
• 31:49
  Speaker 1: and we have a tiny number of eyeballs scanning a
• 31:52
  Speaker 1: very large solar system. We should definitely be spending more
• 31:55
  Speaker 1: money on telescopes.
• 31:57
  Speaker 2: Well, here's a question. What if the Aliens designed a
• 32:00
  Speaker 2: stealth space prow Could they do that? Could they design
• 32:04
  Speaker 2: it in a way that maybe doesn't reflect light or
• 32:07
  Speaker 2: reflects it, you know, like maybe it has weird angular
• 32:10
  Speaker 2: mirrors in its surface that would make it super duper
• 32:15
  Speaker 2: hard to spot.
• 32:16
  Speaker 1: Yeah, exactly, you basically just paint the thing black and
• 32:18
  Speaker 1: it's invisible. If it absorbs the radiation instead of reflecting it,
• 32:22
  Speaker 1: then it's gonna be very very hard for us to
• 32:23
  Speaker 1: see it.
• 32:24
  Speaker 2: M what if they paint it infinite black or infinite dark, then.
• 32:28
  Speaker 1: They're going to owe you license because.
• 32:30
  Speaker 2: That'shactly, Maybe I sold them to paint.
• 32:34
  Speaker 1: Maybe you're an alien, And this whole question is just
• 32:37
  Speaker 1: to try to figure out how to sneak by our defenses.
• 32:40
  Speaker 2: Yes, that's my cult. Then I'm starting, but I want
• 32:43
  Speaker 2: to hide the code for sending me money. Just got
• 32:46
  Speaker 2: to hoorhead Han dot com and use the Venmo coat.
• 32:51
  Speaker 2: All right, So it sounds like the answer for Ted
• 32:53
  Speaker 2: is that, yeah, it's totally possible. Then an alien species
• 32:56
  Speaker 2: has sent approach to us and taking pictures of us,
• 33:00
  Speaker 2: study does and we could have maybe not noticed at all.
• 33:03
  Speaker 1: It is possible. I think it's not likely unless they're
• 33:05
  Speaker 1: trying to hide it because we have pretty good telescope
• 33:08
  Speaker 1: scanning the solar system. So I think at least it
• 33:10
  Speaker 1: helps me sleep better at night to think that we
• 33:12
  Speaker 1: have a pretty good chance of spotting an alien voyager.
• 33:15
  Speaker 2: But well, I guess also, I mean, usually we only
• 33:18
  Speaker 2: have a pretty good view of half of this guy, right, Like,
• 33:20
  Speaker 2: what if they're smart enough to come at us from
• 33:22
  Speaker 2: the sun.
• 33:23
  Speaker 1: Yeah, it would be much more difficult if it comes
• 33:24
  Speaker 1: from behind the sun and then around the sun and
• 33:27
  Speaker 1: then straight at us. You know, like a fighter pilot
• 33:29
  Speaker 1: coming in from the sun.
• 33:31
  Speaker 2: Yeah, exactly.
• 33:32
  Speaker 1: If you're intentionally sneaky, it would not be hard to
• 33:35
  Speaker 1: go unnoticed. But if you're friendly and you're trying to
• 33:38
  Speaker 1: advertise your existence, then it's not that hard to build
• 33:41
  Speaker 1: something which with a good probability of being seen.
• 33:43
  Speaker 2: But technically, I think the answer is it is totally possible.
• 33:46
  Speaker 1: It is totally possible.
• 33:48
  Speaker 2: Yes, we've been probed, well, probe up.
• 33:50
  Speaker 1: There was it up the intellectual wazoo.
• 33:52
  Speaker 2: Yes, yes, that's right, it's a family friendly podcast. All right, well,
• 33:57
  Speaker 2: thank you Ted for that question. Now let's get to
• 33:59
  Speaker 2: our last question, and this one is about splitting the electron,
• 34:03
  Speaker 2: so that's not split hairs about it. Let's get to it.
• 34:06
  Speaker 2: But first let's take another quick break. Robert answering listener
• 34:22
  Speaker 2: questions here today, and our last question comes from Inyaki.
• 34:26
  Speaker 5: Hi Danielle lan Jorge. I was curious about the possibility
• 34:30
  Speaker 5: that in certain specialized state of matter, electrons can splinter
• 34:35
  Speaker 5: into a fraction of their whole, splitting the electron chart,
• 34:38
  Speaker 5: what will be amazing? Thank you, very great podcasts.
• 34:43
  Speaker 2: All right, interesting question. It seems to be about this
• 34:47
  Speaker 2: idea that they have in certain field to physics where
• 34:51
  Speaker 2: you have like fractional electrons.
• 34:53
  Speaker 1: Right. Yeah. I think that this question is stimulated by
• 34:57
  Speaker 1: a bunch of news articles that came out that were
• 35:00
  Speaker 1: little sensationalist about something that was discovered in condensed matter
• 35:04
  Speaker 1: physics that led people to believe that the fundamental electron
• 35:07
  Speaker 1: that we know and love has somehow been split into
• 35:10
  Speaker 1: sub electrons with fractions of an electric charge. WHOA.
• 35:14
  Speaker 2: That was actually in the news.
• 35:16
  Speaker 1: There was a bunch of popular science news articles describing
• 35:19
  Speaker 1: these studies and giving people that impression. I know because
• 35:22
  Speaker 1: I got like ten emails from listeners asking about it.
• 35:26
  Speaker 2: What were some of the headlines.
• 35:27
  Speaker 1: Here's one from MIT News that says, quote, electrons become
• 35:31
  Speaker 1: fractions of themselves.
• 35:32
  Speaker 2: WHOA, that is pretty sensational and from MIT.
• 35:38
  Speaker 1: And it says in the article, in very special states
• 35:40
  Speaker 1: of matter, electrons can splinter into fractions of their whole. WHOA.
• 35:44
  Speaker 2: That does sound like you're splitting the electron. So what's
• 35:48
  Speaker 2: really going on here?
• 35:49
  Speaker 1: So first of all, number one, we have not split
• 35:52
  Speaker 1: the electron. Okay, that's not what has happened here. Instead,
• 35:55
  Speaker 1: they've created some new kind of funky material that displays
• 35:59
  Speaker 1: some new weird property, and there's like a layer of
• 36:01
  Speaker 1: condensed matter theory interpretation on top of that that says
• 36:04
  Speaker 1: that it's sort of like if you had fractional electrons.
• 36:08
  Speaker 2: I feel like that was a lot of legalise there
• 36:11
  Speaker 2: in your explanation there. So what was the experiment was
• 36:15
  Speaker 2: it that they did?
• 36:17
  Speaker 1: This is the whole field of physics, soft mataphysics or
• 36:19
  Speaker 1: condensed mataphysics that tries to build new, weird kinds of
• 36:23
  Speaker 1: materials in order to force electrons and other particles to
• 36:27
  Speaker 1: do weird quantum stuff. So in this case, they're using
• 36:29
  Speaker 1: graphene to these regular lattices of carbon. They use it
• 36:34
  Speaker 1: because it has strange electronic properties, like the electrons sometimes
• 36:37
  Speaker 1: can only move basically in two dimensions in between the
• 36:41
  Speaker 1: layers of graphene. So what they do is they make
• 36:44
  Speaker 1: structures of graphene. So they have like five layers of graphene.
• 36:48
  Speaker 1: And you remember, to make these layers of graphene is
• 36:50
  Speaker 1: actually quite tricky, use like Scotch tape the stuff. Yeah,
• 36:53
  Speaker 1: to put like thin layers of graphine off and actually
• 36:56
  Speaker 1: have these super thin like two dimensional stuff. And what
• 36:59
  Speaker 1: happens when you build these things is electrons behave in
• 37:02
  Speaker 1: new weird ways. Now, this is not changing what the
• 37:05
  Speaker 1: electron is. The electron is not being split, The electron
• 37:08
  Speaker 1: is not new. We're not looking inside the electron. What's
• 37:11
  Speaker 1: happening here is that we're putting a new interpretation on
• 37:13
  Speaker 1: what we're seeing. This is what we call quasi particles.
• 37:17
  Speaker 1: You know, particles are like ripples and fundamental quantum fields.
• 37:21
  Speaker 1: Quasi particles are things that obey the same mathematics as particles,
• 37:25
  Speaker 1: but are ripples in things that are not fundamental fields.
• 37:29
  Speaker 1: Like for example, sound is a ripple in air, right,
• 37:32
  Speaker 1: but air is not like a fundamental field in the universe.
• 37:35
  Speaker 1: It's just a bunch of atoms. But still you can
• 37:37
  Speaker 1: talk about sound in terms of like phonons, particles of
• 37:41
  Speaker 1: sound moving through the air. So you can use that
• 37:44
  Speaker 1: kind of mathematics to talk about ripples in stuff that
• 37:48
  Speaker 1: are not fundamental quantum fields. So when you make electrons
• 37:52
  Speaker 1: operate in this weird way inside graphene, then what you're
• 37:55
  Speaker 1: doing is you're making them operate in a way that
• 37:57
  Speaker 1: they create these quasi particles, some of which have fractional
• 38:01
  Speaker 1: electric charge. But they're not like new fundamental particles we're
• 38:05
  Speaker 1: discovering in the universe. It's just like a layer of
• 38:07
  Speaker 1: mathematical interpretation on top of the complicated stuff that the
• 38:11
  Speaker 1: electrons are doing underneath.
• 38:13
  Speaker 2: Right. I think We've done a few episodes on this,
• 38:15
  Speaker 2: and the idea is that, you know, sometimes it's sort
• 38:19
  Speaker 2: of like things like bubbles in water, right, Like a
• 38:21
  Speaker 2: bubble in water is not really a particle of something
• 38:25
  Speaker 2: or water. It's just sort of like the absence or
• 38:28
  Speaker 2: a little void of water and it sort of behaves.
• 38:30
  Speaker 2: It looks like a thing because it's moving through the
• 38:32
  Speaker 2: water and it's bubbling up, and you think, oh, there's
• 38:34
  Speaker 2: a little circle that moves up, But it's not actually
• 38:37
  Speaker 2: a particle or a thing. It's just sort of a
• 38:40
  Speaker 2: void of water molecules that's moving together as if it
• 38:45
  Speaker 2: was a thing.
• 38:46
  Speaker 1: Yeah, exactly, And let's take that example and run with it.
• 38:49
  Speaker 1: Say you try to then measure properties of that void
• 38:51
  Speaker 1: and you're like, well, what is the mass of it?
• 38:53
  Speaker 1: And you're like, oh, well, compared to the water, there's
• 38:55
  Speaker 1: no mass there. So we could imagine having like negative mass.
• 38:58
  Speaker 1: Could we use negative mass in our mathematics to describe
• 39:02
  Speaker 1: the motion of these things? And that's essentially what's happening here,
• 39:05
  Speaker 1: is that they're adding a layer of mathematics on top
• 39:08
  Speaker 1: of this condensed matter experiment where lots of electrons are
• 39:11
  Speaker 1: swooshing around and obeying weird mathematics quantum mechanics, and in
• 39:15
  Speaker 1: that mathematics they use fractional electric charges. That doesn't mean
• 39:18
  Speaker 1: they've seen any fundamental particles with fractional electric charges. It
• 39:23
  Speaker 1: just means that, like when the electrons get together, they
• 39:26
  Speaker 1: do a complicated dance, and you can interpret that at
• 39:28
  Speaker 1: a sort of a higher level when you zoom out,
• 39:31
  Speaker 1: as if there were least quasi particles with fractional electric charges.
• 39:36
  Speaker 2: Yeah, the way I understand it, it's sort of like
• 39:38
  Speaker 2: you have this layer of graphene, right, and you have
• 39:41
  Speaker 2: these electrons kind of on the surface of that layer,
• 39:44
  Speaker 2: and they're just moving around like in a two dimensional table,
• 39:47
  Speaker 2: and sometimes you get these bubbles in that sea of electrons,
• 39:51
  Speaker 2: and those bubbles then have like a fractional charge of
• 39:55
  Speaker 2: the electrons. Is that sort of a good way to
• 39:56
  Speaker 2: look at it.
• 39:57
  Speaker 1: That's a good way to look at it. They're actually
• 39:58
  Speaker 1: a p probate using the quantum Hall effect, which is
• 40:01
  Speaker 1: a complicated effect that electrons can do when you have
• 40:03
  Speaker 1: an electric current one direction in a magnetic field and
• 40:06
  Speaker 1: another direction. And so they're observing not just the quantum
• 40:10
  Speaker 1: Hall effect, but the fractional quantum Hall effect. That's what
• 40:13
  Speaker 1: this experiment is actually about. But you're right, essentially, they're
• 40:17
  Speaker 1: looking at the emergent behavior of a bunch of electrons
• 40:20
  Speaker 1: doing weird things. And you know, all these popular science
• 40:23
  Speaker 1: articles that are talking about it, none of them really
• 40:25
  Speaker 1: explain what the quantum Hall effect is because it's really
• 40:28
  Speaker 1: complicated and kind of a mess to understand if you're
• 40:31
  Speaker 1: not deep into condensed matter theory. So I totally understand
• 40:34
  Speaker 1: like why they didn't dig into the details of it,
• 40:36
  Speaker 1: But I think it's a little misleading to write that
• 40:38
  Speaker 1: they've split the electron into fractional charges because they really
• 40:41
  Speaker 1: haven't done that.
• 40:43
  Speaker 2: Well. I think maybe what they mean then is sort
• 40:45
  Speaker 2: of like they created something that behaves like a particle
• 40:48
  Speaker 2: that has the fractional charge of an electron.
• 40:51
  Speaker 1: Yes, that's right.
• 40:52
  Speaker 2: So then you maybe get into a little bit of
• 40:54
  Speaker 2: philosophy of like is that actually a thing or not
• 40:57
  Speaker 2: a thing? How do you even know that electrons are
• 41:00
  Speaker 2: a thing?
• 41:01
  Speaker 1: Yeah, electrons are a thing and they have a certain charge.
• 41:04
  Speaker 1: We don't know that they're a fundamental thing, right, totally
• 41:07
  Speaker 1: find a zoom out and say, look, here's the thing,
• 41:08
  Speaker 1: even if it's made out of other stuff, Like we
• 41:10
  Speaker 1: call the proton a thing. It has a charge, but
• 41:13
  Speaker 1: it's actually made of other charge things inside of it. Right,
• 41:16
  Speaker 1: It might also be true of the electron, And that
• 41:19
  Speaker 1: would be very exciting. If you could take the electron
• 41:21
  Speaker 1: apart into little bits and show that it's a charge
• 41:25
  Speaker 1: of negative one comes from other little fractional charge bits,
• 41:28
  Speaker 1: that would be very cool. That would fundamentally change our
• 41:30
  Speaker 1: understanding of the nature of reality. That's not something we've
• 41:34
  Speaker 1: done here today. That would be huge milestone.
• 41:37
  Speaker 2: But I wonder if it's possible that, you know, maybe
• 41:39
  Speaker 2: the electron fields are not quite what we expect, and
• 41:43
  Speaker 2: when they mix together they somehow do create these sort
• 41:46
  Speaker 2: of things that are fractional charge and maybe they're just
• 41:50
  Speaker 2: as real as the electrons.
• 41:51
  Speaker 1: Yeah, and this is totally a fascinating and valuable direction
• 41:55
  Speaker 1: of research. But it's not asking what is the electron
• 41:57
  Speaker 1: field made out of? Fundamentally, what is it's nature. It's
• 42:01
  Speaker 1: asking what complicated stuff can the electron field do under
• 42:04
  Speaker 1: certain conditions. This is not telling us anything about the
• 42:07
  Speaker 1: nature of the electron. It's telling us about the complexity
• 42:11
  Speaker 1: that arises when a bunch of electrons come together. And
• 42:14
  Speaker 1: so that's fascinating totally worthwhile.
• 42:16
  Speaker 2: Right.
• 42:16
  Speaker 1: The whole field of candense matter physics is basically that
• 42:19
  Speaker 1: what complicated stuff can a bunch of tiny particles do
• 42:21
  Speaker 1: when they get together, And it turns out, Wow, they
• 42:23
  Speaker 1: can do all sorts of amazing complicated stuff bananas, an
• 42:26
  Speaker 1: ice cream and people and superconductors and all that stuff.
• 42:29
  Speaker 1: It's glorious. But none of that tells us anything about
• 42:32
  Speaker 1: the nature of the electron itself, which is I think
• 42:35
  Speaker 1: what this article was suggesting.
• 42:36
  Speaker 2: Could it maybe could it? You know, by finding out that, oh,
• 42:39
  Speaker 2: these are electron fields makes in a weird way that
• 42:41
  Speaker 2: we didn't think of before. Maybe they're not fundamental.
• 42:46
  Speaker 1: Yeah. Absolutely. By exploring what the electron field is doing,
• 42:50
  Speaker 1: you might see some discrepancies from your predictions that point
• 42:53
  Speaker 1: towards clues that tell you that you're understanding the electron
• 42:55
  Speaker 1: field is wrong. Yeah. Absolutely. That also is not what's
• 42:58
  Speaker 1: happened here. Like the fraction quantum Hall effect was predicted,
• 43:02
  Speaker 1: it's understood theoretically, it had never been seen before experimentally,
• 43:06
  Speaker 1: So that's cool, But again, it doesn't tell us anything
• 43:09
  Speaker 1: new about the electron field itself. That doesn't mean again,
• 43:12
  Speaker 1: this is not a valuable area of research. And if
• 43:14
  Speaker 1: they see something weird and unexpected, they could lead to
• 43:17
  Speaker 1: a discovery that does help us unravel what the electron
• 43:20
  Speaker 1: field is. But this is more about like what do
• 43:23
  Speaker 1: electrons do when we combine them into weird ways than
• 43:26
  Speaker 1: like what is the electron itself?
• 43:28
  Speaker 2: All right? Well, then to ask for Nyiki is that
• 43:31
  Speaker 2: they did not split the electron, or at least Daniel
• 43:34
  Speaker 2: doesn't like an interpretation of the results, But it may
• 43:37
  Speaker 2: I'll be telling us a little bit more about the
• 43:41
  Speaker 2: nature of the electron and what it can do, and
• 43:43
  Speaker 2: what it's made out of, and whether it could maybe
• 43:45
  Speaker 2: be split in the future exactly.
• 43:47
  Speaker 1: And questions of the fundamental nature of the universe are
• 43:50
  Speaker 1: not the only valuable science questions. We can do science
• 43:53
  Speaker 1: at the tiniest scale to try to reveal what are
• 43:55
  Speaker 1: the basic units of the universe, but there's still a
• 43:58
  Speaker 1: lot of really important open questions about what those basic
• 44:01
  Speaker 1: units do when they come together and how they make
• 44:04
  Speaker 1: the complexity of our world. Science is valuable at all
• 44:06
  Speaker 1: sorts of different scales, from like psychology all the way
• 44:09
  Speaker 1: down to particle physics. All of it is teaching us
• 44:11
  Speaker 1: something about our wonderful universe.
• 44:13
  Speaker 2: Now, does that include cult studies.
• 44:15
  Speaker 1: Also, absolutely, yes, can two podcasters raise millions of dollars
• 44:21
  Speaker 1: to fund their interstellar probe? That's a fascinating question of science.
• 44:25
  Speaker 2: Yes, and the answer is hidden in the numbers of
• 44:29
  Speaker 2: our listener question titles.
• 44:32
  Speaker 1: And in Jorges Venmo code. Yes, that's right.
• 44:36
  Speaker 2: I'll give you the answer if you pay. How about that?
• 44:39
  Speaker 1: Oh man, you better come up with the answer then.
• 44:44
  Speaker 2: All right. Well, thanks to all of our question askers
• 44:46
  Speaker 2: for these great questions, and thanks to all of you
• 44:48
  Speaker 2: for listening to our listener questions.
• 44:51
  Speaker 1: Thanks to everybody who writes in with their questions. I
• 44:54
  Speaker 1: love reading them, I love answering them. Please don't stop
• 44:57
  Speaker 1: sending them, and don't stop being curious about the universe.
• 45:00
  Speaker 1: Your personal curiosity about science and about the universe that's
• 45:04
  Speaker 1: pushing forward the whole human project of science and exploration
• 45:08
  Speaker 1: of our gospels.
• 45:09
  Speaker 2: That's right, Daniel, I think you're saying, don't stop believing.
• 45:12
  Speaker 2: Just listen to that feeling. All right, Well, weeled you
• 45:16
  Speaker 2: enjoyed that. Thanks for joining us, See you.
• 45:18
  Speaker 1: Next time for more science and curiosity. Come find us
• 45:25
  Speaker 1: on social media, where we answer questions and post videos.
• 45:29
  Speaker 1: We're on Twitter, disc org, Insta and now TikTok. Thanks
• 45:33
  Speaker 1: for listening and remember that Daniel and Jorge Explain the
• 45:36
  Speaker 1: Universe is a production of iHeartRadio. For more podcasts from iHeartRadio,
• 45:41
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• 45:45
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