Speaker 1: Hey, Daniel, what's your feeling about the Moon?
Speaker 2: I guess I don't have that many strong feelings. Does
Speaker 2: anyone Do you like it? Do you dislike it? I mean,
Speaker 2: I guess I'm generally pro moon, although if it's made
Speaker 2: out of white chocolate, I'm not going to be very
Speaker 2: happy about it.
Speaker 1: Oh what if it was would you want to nuke
Speaker 1: it out of the sky?
Speaker 2: Oh? Man, that sounds like a disaster. It would cause
Speaker 2: a shower of molten white chocolate all over the earth.
Speaker 1: Yeah, a lot of people would be happy.
Speaker 2: That sounds like a disaster movie.
Speaker 1: To me, it sounds like you have really charged feelings
Speaker 1: about the moon and white.
Speaker 2: Chocolate, both positive and negative.
Speaker 1: Hi am Jorhemy Cartoonist'm the author of Oliver's Great Big Universe.
Speaker 2: Hi, I'm Daniel. I'm a particle physicist and a professor
Speaker 2: at UC Irvine. And you couldn't pay me enough white
Speaker 2: chocolate to take a trip to the moon.
Speaker 1: Can we pay you some money to eat white chocolate?
Speaker 2: I guess it depends on the amount of white chocolate
Speaker 2: and the amount of money.
Speaker 1: Wait, you would have wanted to go to the moon?
Speaker 1: Why not?
Speaker 2: I mean, I don't take trips to Antarctica, and I'm
Speaker 2: pretty sure the Moon is like less cozy than Antarctica.
Speaker 1: It's not about coziness, It's about the adventure, you know,
Speaker 1: excitement being someplace interesting.
Speaker 2: Yeah again, still don't take a lot of trips to
Speaker 2: Antarctica for the same reason.
Speaker 1: Have you been to Antarctica? How do you know you
Speaker 1: won't like it.
Speaker 2: I've never been to Antarctica, but I've been to some
Speaker 2: places that are sort of Antarctica adjacent, and I wasn't
Speaker 2: a fan.
Speaker 1: I've been to the Arctics Circle that was pretty exciting.
Speaker 1: I've been on a glacier.
Speaker 2: I know. I'm trying to hook you up with a
Speaker 2: trip to Antarctica to visit the physics experiments there, but
Speaker 2: no luck yet.
Speaker 1: M Are you just trying to get rid of me?
Speaker 1: Are you hoping that some sort of a freak accident
Speaker 1: will happen while I'm there.
Speaker 2: I think that's a conversation you should have with your
Speaker 2: therapist about your paranoia. I thought you wanted to visit
Speaker 2: the South Pole. I don't know.
Speaker 1: There's all very suspicious, Daniel. I mean, of all the
Speaker 1: places you could send me to Hawaii, Fiji, do you
Speaker 1: want to send me to the most remote place on Earth.
Speaker 2: There's also an awesome physics experiment in the south of France.
Speaker 2: Maybe you want to visit that one.
Speaker 1: Yeah, let's do it. I'll take it. Is a podcast paying.
Speaker 2: Everybody chip in crowdsource Jorgees trip to the South of France.
Speaker 2: We'll see how many contributions we get.
Speaker 1: There you go, We'll kickstarted. But anyways, welcome to our podcast.
Speaker 1: Daniel and Jorge Explain the Universe, a production of iHeartRadio.
Speaker 2: In which we get all charged up about the mysteries
Speaker 2: of the universe. We are very positive about the idea
Speaker 2: that humans can understand the nature of the universe that
Speaker 2: we live in, and not just a few humans operating
Speaker 2: on the forefront of science. Everybody. We love taking these
Speaker 2: crazy ideas that scientists have developed and explaining all of
Speaker 2: them to you.
Speaker 1: It's right because we are attracted to the deep mysteries
Speaker 1: of the universe, and we are also repelled by our
Speaker 1: deep ignorance of the things. We don't know about how
Speaker 1: things work.
Speaker 2: But what we definitely do know is that the universe
Speaker 2: is controlled by forces. There are pushes, there are pulls,
Speaker 2: there are tugs. Everything that happens out there in the
Speaker 2: universe is the result of forces in balance and out
Speaker 2: of balance.
Speaker 1: Wait, are you sure about that? I mean, I feel
Speaker 1: like we need for a long time about the force
Speaker 1: of gravity, but now I hear that there's no just
Speaker 1: a thing as the gravitational force.
Speaker 2: You're right, of course, that gravity is not a force.
Speaker 2: It's just the curvature of space time, which gives the
Speaker 2: illusion of a force if you're not aware that space
Speaker 2: is curved in front of you and causing things to
Speaker 2: move in a way you might not expect. We can
Speaker 2: still actually describe a lot of that in terms of
Speaker 2: pseudo forces. So for the spirit of today's conversation about
Speaker 2: pushes and pulls and what's tugging on the moon and
Speaker 2: what's not, doesn't really make a difference if gravity is
Speaker 2: a force or the curvature of space time.
Speaker 1: I wonder it could it be that we eventually find
Speaker 1: out that the other forces in nature are also just
Speaker 1: distortions of space and time or are we pretty sure
Speaker 1: those are forces forces?
Speaker 2: No, you're absolutely right, and that is an active idea
Speaker 2: people are working on. Einstein spent many, many years trying
Speaker 2: to explain electromagnetism in terms of additional curvature of space time.
Speaker 2: He thought maybe that force is actually also a pseudo force,
Speaker 2: just the result of space being curved in additional ways.
Speaker 2: He never made it work, and one reason is that
Speaker 2: he didn't understand the weak force, which is crucially related
Speaker 2: to electromagnetism, So he sort of didn't have the whole picture.
Speaker 2: But there are people working on that right now. They
Speaker 2: just haven't succeeded yet.
Speaker 1: I guess Einstein felt he was kind of forcing it
Speaker 1: at some point. He didn't want to push it.
Speaker 2: I think he went around the wrong curve.
Speaker 1: He felt like he couldn't pull it off.
Speaker 2: It wasn't a grave enough matter.
Speaker 1: But it does seem like in our everyday lives, like
Speaker 1: things are governed by these laws of nature that seem
Speaker 1: to pull and push on things. And that's kind of
Speaker 1: what physics it's all about, right, the push and pull
Speaker 1: of the universe.
Speaker 2: That's right. And the universe as we see it is
Speaker 2: shaped by lots of different forces. Stuff in the universe
Speaker 2: is mostly built out of the more powerful forces, the
Speaker 2: strong force, electromagnetism. But the overall shape of the universe,
Speaker 2: the way the Solar System is, the shape of the Earth,
Speaker 2: the structure of the galaxy and beyond is mostly dominated
Speaker 2: by the weakest force, gravity.
Speaker 1: As our gravity is what gives the universe its structure.
Speaker 1: If it wasn't for gravity, we wouldn't have planets, right,
Speaker 1: or suns or galaxies, and we wouldn't be here. I mean,
Speaker 1: be nice to be lighter than what we are, but
Speaker 1: without gravity, we and none of us would exist.
Speaker 2: That's right. It's gravity that causes the Sun to burn
Speaker 2: because it squeezes all that gas together, giving it the
Speaker 2: high temperature and density needed to ignite fusion. It's gravity
Speaker 2: that forms the structure of the Earth. It's gravity that's
Speaker 2: formed the Moon. It's gravity that's formed everything that we
Speaker 2: see out there in the universe. But that doesn't mean
Speaker 2: that gravity is the only force at play in our
Speaker 2: Solar system.
Speaker 1: Yeah, there are other forces, some of which play an
Speaker 1: equally important role in our existence. If it wasn't for
Speaker 1: the electromagnetic force, like, none of our atoms would hold together,
Speaker 1: and so we also wouldn't be here.
Speaker 2: That's right. You're basically built out of the electromagnetic force.
Speaker 2: All of your atoms and molecules are bonded together using
Speaker 2: electrons and electromagnetism. So basically every structure you're familiar with,
Speaker 2: is an electromagnetic structure.
Speaker 1: I feel like we're saying we're basically everything. Everything is
Speaker 1: everything made out of everything, due to everything.
Speaker 2: It is an incredible balance of all those forces.
Speaker 1: Yeah, and sometimes that force pulls and pushes on things
Speaker 1: in ways that you don't quite expect.
Speaker 2: And so we think that gravity is the dominant force
Speaker 2: remaining in the solar system, but that's not always the case.
Speaker 1: And so on the podcast, we'll be tackling the question
Speaker 1: what's the electrical charge of the moon? Interesting question, like
Speaker 1: the moon has as a plug in it?
Speaker 2: Is the Moon a battery? And if we travel there,
Speaker 2: can we use it to recharge our phone?
Speaker 1: There you go, that'd be important. Does it have a
Speaker 1: USBC connector a USB connector lightning port, the USB Moon
Speaker 1: connector Yeah, that's what I want to know before you
Speaker 1: send me to the Moon.
Speaker 2: You know, the way it is with USB, there's always
Speaker 2: some new shape you've never seen before.
Speaker 1: Yeah, Well, hopefully the Moon has a stand under plug.
Speaker 1: But this is an interesting question to ask about the moon,
Speaker 1: like the idea that the moon has a charge at all.
Speaker 2: Yeah, because we're very familiar with the Moon having a mass,
Speaker 2: which is sort of like a gravitational charge. You you're
Speaker 2: thinking about gravity as a force and a Newtonian sense,
Speaker 2: but it's weird to think about the Moon having like
Speaker 2: an electric charge, like it being overall positive or negative.
Speaker 1: Hmm. Well, I'm positive we'll get to the bottom of this,
Speaker 1: but as usual, we were wondering how many people out
Speaker 1: there had thought about the Moon having a charge or
Speaker 1: what that charge could be.
Speaker 2: Thanks very much to everybody who volunteers for this fun
Speaker 2: segment of the podcast. One of my favorites. I love
Speaker 2: hearing your voices. Please join the group right to meet
Speaker 2: at questions at Danielanjorge dot com.
Speaker 1: So think about it for a second. Do you think
Speaker 1: the Moon has a charge? Here's what people had to say.
Speaker 3: I would think planets and moons get their charge from
Speaker 3: their cores, you know. In Earth's case, I think the
Speaker 3: iron core gives it a magnetic field. But then again,
Speaker 3: I guess the charges would cancel out and make it neutral.
Speaker 2: So I don't know.
Speaker 3: I don't think the Moon has a core or an
Speaker 3: electric field as far as I know, so I guess
Speaker 3: maybe you can call that neutral too.
Speaker 4: I feel like the Moon should have a total electrical
Speaker 4: charge of zero. It's probably different locally depending on what's
Speaker 4: getting hit by the solar wind and being ionized at
Speaker 4: the dust particular level, but that's probably a zero overall.
Speaker 5: I'm not sure about the electric charge of the Moon
Speaker 5: because it doesn't have more to love in it, I think,
Speaker 5: but since it's spinning, it might have a really small,
Speaker 5: undetectable amount. But I'm not sure about it.
Speaker 6: Otherwise, I would have guessed that the electrical charge of
Speaker 6: the Moon would be zero because I thought that all
Speaker 6: electrical charge balanced out. But you're asking the question, so
Speaker 6: I'm guessing it's not zero. I'm not sure though. Maybe
Speaker 6: it has something to do with the Earth's magnetic field.
Speaker 6: But I'm really not sure. I'm not too sure what
Speaker 6: the charge of the Moon would be, but I imagine
Speaker 6: it has the same charge as the Earth.
Speaker 1: I believe that the electrical charge of the Moon is zero,
Speaker 1: just us on Earth. All the positive and negative charges
Speaker 1: should balance, all right, some charge answers here.
Speaker 2: Consensus seems to be a zero charge for the Moon.
Speaker 1: Well, it's not positive or negative. It's just kind of there.
Speaker 2: The Moon just neutral. Just kind of me.
Speaker 1: Just kind of mad, as the kids say these days.
Speaker 1: But the moon is a pretty interesting object out in
Speaker 1: our night sky. It's big, it's about the quarter of
Speaker 1: the size and diameter.
Speaker 2: Of the Earth, right, Yeah, I think that sounds right.
Speaker 1: Yeah, And it's out there in orbit around the Earth.
Speaker 1: And so the question is does it have an electrical charge?
Speaker 1: Why would it have an electrical charge? Or should it
Speaker 1: have an electrical charge?
Speaker 2: I think the listeners had the right spirit. That ended
Speaker 2: up mostly getting the wrong answer because a simple model
Speaker 2: of the solar system suggests that it shouldn't have any charge,
Speaker 2: that it should be basically neutral.
Speaker 1: Well, maybe let's take a step back and talk about
Speaker 1: the charge of things in general, Like do I have
Speaker 1: a charge? An overall charge me like my body? Or
Speaker 1: I guess where does a charge come from? Do I
Speaker 1: have to add up all my electrons and then add
Speaker 1: up all my protons and if there's an imbalance, then
Speaker 1: I have an overall charge? Is that kind of what
Speaker 1: having a charge means?
Speaker 2: Yeah, You're made out of charged objects, the quarks, the
Speaker 2: electrons that are in your body. They all have electric charges,
Speaker 2: and some of them are positive and some of them
Speaker 2: are negative, and so you add them all up. It's
Speaker 2: like a big accounting and if you have more positives
Speaker 2: the negatives. Then you're positively charged, and you're made up
Speaker 2: of charged out of the molecules. Sometimes you have ions
Speaker 2: inside your body which have electrical charges, but the electromagnetic
Speaker 2: force is very, very powerful, and so it tends to
Speaker 2: try to neutralize things.
Speaker 1: But would you say that's an overall way to define
Speaker 1: my charge or define the charge of something like if
Speaker 1: it has more electrons than protons, which are made out
Speaker 1: of quarks, then it has a negative charge.
Speaker 2: Yeah. That's the definition of the charge of an object
Speaker 2: is the sum of all the charges of its particles.
Speaker 1: So if I have excess electrons somehow inside of me,
Speaker 1: then I'm going to be negative charge, which means that
Speaker 1: if you put me in front of a whole bunch
Speaker 1: of electrons, am I going to be repelled by those electrons?
Speaker 2: Yeah? Exactly. If you're negatively charged and then like a
Speaker 2: cloud of electrons comes by, you're going to be repelled
Speaker 2: from those electrons and they will be repelled by you.
Speaker 2: Or if a cloud of protons comes by, you would
Speaker 2: be attracted to those protons and they would be attracted
Speaker 2: to you. And that's sort of the reason why most
Speaker 2: stuff in the universe is very close to electrically neutral,
Speaker 2: because electromagnetism is very strong, and if you do have
Speaker 2: an overall charge, it tends to cancel itself out by
Speaker 2: slurping up the opposite charge.
Speaker 1: Right Like, if I have just a whole bunch of
Speaker 1: electrons floating in space, I guess, first of all, they
Speaker 1: would repel each other and fly away from each other.
Speaker 1: But second of all, they would probably attract protons from
Speaker 1: around them, and then they would quickly become neutral in
Speaker 1: terms of charge exactly.
Speaker 2: And that's just what happened in our universe when things
Speaker 2: cooled down very early on. There were protons and there
Speaker 2: were electrons, and they were all flying around. The whole
Speaker 2: universe was charged. It was a plasma, which is just
Speaker 2: a gas of charged particles. We think overall it was neutral,
Speaker 2: but like individual electrons and protons of course had charge,
Speaker 2: but they also had a lot of energy, were moving
Speaker 2: really really fast, too fast for electromagnetism to sort of
Speaker 2: capture them. But then when the universe cooled down, eventually
Speaker 2: they were captured by each other, and protons electrons came
Speaker 2: together to make neutral hydrogen. Then the whole universe was
Speaker 2: filled with neutral gas.
Speaker 1: Oh, that's an interesting question. Is the universe overall charge? Like,
Speaker 1: is the total number of universal electrons the same as
Speaker 1: a number of protons?
Speaker 2: Yeah, great question. We don't know. We think that charge
Speaker 2: is concerned in the universe, meaning it can't change. So
Speaker 2: when the universe was born, there was a number which
Speaker 2: is a total charge and that hasn't ever changed. We
Speaker 2: think probably that was zero just due to symmetry arguments,
Speaker 2: but the whole thing is very fuzzy.
Speaker 1: And poorly now probably zero. Interesting.
Speaker 2: Yeah, in the same way that we think like matter
Speaker 2: and antimatter were made at the same rates in the
Speaker 2: very early universe, although now we have a lot more
Speaker 2: matter than antimatter, which is not something we understand. We
Speaker 2: think that positrons and electrons were made at the same
Speaker 2: rate in the early universe, that we started overall with
Speaker 2: zero charge and created equal amounts of positive and negative
Speaker 2: charge particles.
Speaker 1: All right, So now let's get to the moon. And
Speaker 1: now the question we're asking today is is the moon
Speaker 1: positively or negatively charge overall? And you said that the
Speaker 1: simple model of the moon says that it should be neutral,
Speaker 1: So why is that?
Speaker 2: Well, go back to our simple history of the universe.
Speaker 2: The universe is filled with neutral gas. And what happened
Speaker 2: after that is gravity took over. Right, Electromagnetism is neutralized out,
Speaker 2: it's not really pushing and pulling on everything anymore. And
Speaker 2: now gravity, the weakest force by huge amount, right, like
Speaker 2: trillions and trillions of times weaker than electromagnetism, finally has
Speaker 2: a chance to influence things. And it takes millions and
Speaker 2: billions of years, but it pulls together planets and stars
Speaker 2: and moons and forms the structure of the universe. The
Speaker 2: weird thing about gravity is that it can't get canceled out.
Speaker 2: There's only one charge for gravity. There's positive mass, there's
Speaker 2: no negative mass, and so gravity forms this structure and
Speaker 2: it's still the thing that dominates the universe because it's
Speaker 2: still around. Unlike electromagnetism, it doesn't get neutralized or canceled out.
Speaker 2: So the simple model of the universe is everything neutralizes
Speaker 2: and then gravity takes over, and it's basically just the
Speaker 2: gravity of neutral objects. So the Earth, the Moon, everything
Speaker 2: should be basically neutral.
Speaker 1: M I think you're saying that the Moon was basically
Speaker 1: formed out of rocks, and way before those rocks formed
Speaker 1: the Moon, those rocks were already electrically neutral.
Speaker 2: Mmmmm exactly. And if the Moon had like a really
Speaker 2: big positive charge and the Earth had a really big
Speaker 2: negative charge, what would happen is that they would slur
Speaker 2: particles off of each other and neutralize that.
Speaker 1: Wait wait, wait, do you mean slur particles like pull
Speaker 1: the electrons out of their rocks?
Speaker 2: I mean you would hear this giant sucking sound like whew.
Speaker 2: Quite literally.
Speaker 1: I thought there was no sound in space. What kind
Speaker 1: of misinformation are you giving out of here?
Speaker 2: There is sound on Earth. And if the Moon was
Speaker 2: sucking electrons off the Earth, we would hear it. Yeah,
Speaker 2: the Moon was positively charged and the Earth was very
Speaker 2: negatively charged, then the Moon would suck electrons off the
Speaker 2: Earth until it was roughly in balance. Because electromagnetism is
Speaker 2: very powerful.
Speaker 1: Why would the Moon give up its electrons whatever they're
Speaker 1: like embedded inside of their atoms.
Speaker 2: I'm saying, if somehow the Moon was positively charged, like
Speaker 2: I had a bunch of protons that didn't have electrons
Speaker 2: to match it. They were hanging out on the Moon,
Speaker 2: and the Earth had an excess of electrons like hanging
Speaker 2: out in the atmosphere, then those electrons would get sucked
Speaker 2: off the Earth to the Moon. The protons might also
Speaker 2: get sucked off towards the Earth, but electrons are lighter,
Speaker 2: so they would move further than the protons.
Speaker 1: But I guess we're sticking to the model where the
Speaker 1: Moon and the Earth were made out of neutral rocks,
Speaker 1: and so that's what you're saying. That's a simple model
Speaker 1: of how things got to be.
Speaker 2: Yeah, so that simple model tells you that the Moon
Speaker 2: should either be totally neutral or very close to neutral,
Speaker 2: because anything else would have gotten balanced out early on,
Speaker 2: and any large deviation from that later on would be
Speaker 2: balanced out.
Speaker 1: All right, Well, that's the first approximation. But as usual,
Speaker 1: we know that physics and nature likes to surprise this.
Speaker 1: So let's find out if that's really the case. Is
Speaker 1: the Moon charged or not? Dig into that, But first
Speaker 1: let's take a quick break. Right. We're asking the question
Speaker 1: is the moon charged? Like is it amped up?
Speaker 2: What else is going on with the moon to give
Speaker 2: it positive or negative charges?
Speaker 1: M All right, Well you said that the simple bottle
Speaker 1: is that the Moon is made out of rocks, and
Speaker 1: by the time those rocks got made, they were pretty
Speaker 1: electrically neutral. Because that's kind of how the universe works,
Speaker 1: and so what makes us think that maybe the universe
Speaker 1: is not neutral.
Speaker 2: Well, I think probably the whole universe is neutral. But
Speaker 2: the Moon, it turns out, is more complex because that
Speaker 2: simple story we told where you have like just a
Speaker 2: bunch of gravitational rocks floating in space is not everything
Speaker 2: that's happening in the Solar system. There's a lot more
Speaker 2: going on, and specifically, the Sun is pumping out a
Speaker 2: huge amount of positive and negatively charged particles. The solar wind,
Speaker 2: which is essentially a stream of plasma flowing through the
Speaker 2: Solar system, has big impact on everything.
Speaker 1: You mean, we're all getting kind of showered by sun rays,
Speaker 1: which not only include light, but also little tiny particles,
Speaker 1: right like little quarks and electrons.
Speaker 2: Exactly, mostly protons and electrons. A few positrons are also created,
Speaker 2: and the Moon is going through this essentially soup of
Speaker 2: electrons and protons, and that has a big effect on
Speaker 2: the charge of the Moon.
Speaker 1: But what isn't the Sun throwing out both positive and
Speaker 1: negative charges. So basically the solar wind is neutral too,
Speaker 1: isn't it.
Speaker 2: The solar wind is overall neutral, But fascinatingly, the backside
Speaker 2: of the moon tends to attract electrons more. Electrons stick
Speaker 2: to the backside of the Moon more than protons do
Speaker 2: because electrons are lighter and faster.
Speaker 1: Wait wait, wait, wait, go back a little bit. What
Speaker 1: does that mean. What do you mean electrons are different?
Speaker 2: Well, electrons and protons have opposite charges, but they don't
Speaker 2: have the same mass. Protons are much much more massive
Speaker 2: than electrons are, right, and so that affects their velocity.
Speaker 2: They come out of the Sun with the same energy,
Speaker 2: but they have a lot more mass, so they're moving
Speaker 2: much more slowly and it takes a bigger force to
Speaker 2: accelerate them. And so electrons come out of the Sun
Speaker 2: moving faster, and so there's just like a greater flux
Speaker 2: of them hitting the Moon than the.
Speaker 1: Protons, a greater flux.
Speaker 2: So there's like more electrons per second per square meter
Speaker 2: hitting the Moon than there are protons.
Speaker 1: So wouldn't that mean that the Sun is making more
Speaker 1: electrons than protons.
Speaker 2: It's making the same number. But because the electrons are faster,
Speaker 2: more of than are getting out to the moon. Like,
Speaker 2: the protons don't have as much energy, so they don't
Speaker 2: always get out to the moon, and they certainly don't
Speaker 2: get out as rapidly.
Speaker 1: Wait wait, wait, so you're saying that, what do you mean,
Speaker 1: like some of the protons don't make it out to
Speaker 1: the moon, like they get stuck somewhere.
Speaker 2: Some of them get stuck. They just like exist in
Speaker 2: the outer layers of the Sun.
Speaker 1: Like the Sun is punet electrons and protons. But some
Speaker 1: of the protons that don't get very far they maybe
Speaker 1: get stuck back into the Sun you're saying, or they
Speaker 1: get it's trapped into orbit with the Sun.
Speaker 2: Yeah, exactly. And there are electrons and protons that do
Speaker 2: make it out there by the Moon. But again the
Speaker 2: electrons are moving faster and so they just tend to
Speaker 2: hit the Moon more.
Speaker 1: But then what would that mean that the center of
Speaker 1: the solar system it has a positive charge, if you know,
Speaker 1: if there's more electrons leaving it than protons, that.
Speaker 2: Does tend to make the Sun more positive than negative.
Speaker 2: There's a lot of other processes happening at the same
Speaker 2: time that affect the overall charge. For example, the streams
Speaker 2: of electrons end up creating a positive charge at the
Speaker 2: core of the solar system, but that in turn makes
Speaker 2: an electric field that tends to accelerate positive charges away
Speaker 2: from the Sun, which ends up helping to balance that out.
Speaker 2: So you see how electromagnetic effects tend to neutralize themselves.
Speaker 2: The key takeaway is not that the Sun is throwing
Speaker 2: out electrons which are hitting the Moon, but just more generally,
Speaker 2: that the Sun fills the solar system with charged particles
Speaker 2: which are then around to interact with the Moon. So
Speaker 2: that's a whole other topic we can dig into, like
Speaker 2: what is the electrical charge of the Sun. Turns out
Speaker 2: to be much more complicated even than the electrical charge
Speaker 2: of the moon.
Speaker 1: Hmmm. But I guess it does have a positive charge
Speaker 1: because you know, the Sun is so sunny all the time.
Speaker 2: I've never seen the Sun be negative. That's true.
Speaker 1: There you go, all right. So then the idea is
Speaker 1: that the Sun is positive and negative charges in the
Speaker 1: solar wind, but more electrons make it out to where
Speaker 1: we are, and so are basically weed the Earth and
Speaker 1: the Moon are getting showered by more electrons than protons.
Speaker 3: Mm hmm.
Speaker 2: But this turns out to be a dominant effect only
Speaker 2: on the back side of the Moon. The backside of
Speaker 2: the Moon, you have this like sheath of plasma, these
Speaker 2: protons and these electrons that have come along from the
Speaker 2: solar wind and they're hanging out there and more the
Speaker 2: electrons end up on the Moon than the protons. So
Speaker 2: the backside of the Moon is negative. But there's a
Speaker 2: very different process that dominates on the other side of
Speaker 2: the Moon, on the sun facing side of the moon.
Speaker 1: Wait wait, wait, so okay, so I'm the Moon and
Speaker 1: I'm facing the Sun and I'm getting showered by electrons
Speaker 1: and a little bit of protons. Now what you're saying
Speaker 1: that the electrons stick to my backside, why would that be?
Speaker 2: The electrons will also stick to your front side. But
Speaker 2: there's another process on your front side that's even more powerful.
Speaker 2: That's forcing the front side to become positively charged, and
Speaker 2: that's the photoelectric effect. Photons from the Sun, really high
Speaker 2: energy particles hit the Moon and they eject electrons. This
Speaker 2: is the same experiment that Einstein wather bo fries for
Speaker 2: explaining if you shine light on a piece of metal,
Speaker 2: you'll give energy to electrons and eject electrons from the metal,
Speaker 2: making it overall positively charged. The same thing happens on
Speaker 2: the sun facing side of the mo Moon, making that
Speaker 2: side positive and the backside ends up negative.
Speaker 1: Okay, So I'm the Moon and I'm getting hit by
Speaker 1: sun rays. So forget the electrons for now, I'm just
Speaker 1: getting hit by sunlight, which are photons. And you're saying
Speaker 1: it's kicking off the electrons off of the rocks facing
Speaker 1: the sun. But where are those electrons going? Are you
Speaker 1: saying they're flying off into space?
Speaker 2: They're flying off into space exactly. The Moon doesn't have
Speaker 2: a significant atmosphere as what they call an exosphere we
Speaker 2: talked about once on the podcast, so they don't like
Speaker 2: run into other particles. It's basically collisionless, so they just
Speaker 2: fly out into space.
Speaker 1: Yeah, okay, Well what's kicking them off into space?
Speaker 2: The photons, right, Photons are coming in hitting those rocks,
Speaker 2: giving those electrons a boost so they have enough energy
Speaker 2: to leave the rocks and also leave the Moon.
Speaker 1: Okay. So you're saying, like the moon's getting a little
Speaker 1: bit of a sunburn, and the sunburn basically makes the
Speaker 1: surface of the Moon facing the sun positively charge. Okay,
Speaker 1: so now my sun facing side is positively charge. And
Speaker 1: you're saying, now I'm getting a shower of electrons from
Speaker 1: the Sun.
Speaker 2: That's right. At the same time, you have a shower
Speaker 2: of electrons from the sun, and your backside tends to
Speaker 2: attract those electrons. Those electrons end up in this plasma
Speaker 2: sheath that's around you. Plasma member is just a mix
Speaker 2: of protons and electrons.
Speaker 1: So it would in the front facing side, which is
Speaker 1: positively charged, wouldn't that attract the electrons hitting me and
Speaker 1: make them stick to me more?
Speaker 2: It does do that, Yeah, and that limits the overall
Speaker 2: positive charge of the front side. Right. The more positively
Speaker 2: charged she gets, the more it pulls electrons back out
Speaker 2: of the solar wind and out of this plasma. So
Speaker 2: this isn't a huge effect. It's self limiting. As we
Speaker 2: talked about, electromagnetism can be neutralized, and anytime you build
Speaker 2: up a big charge, it tends to limit itself. But
Speaker 2: there's a constant process here. You're constant getting bombarded by
Speaker 2: more and more photons where it's generating more of a
Speaker 2: positive charge, so it sort of comes into balance.
Speaker 1: Oh, I see, so getting electrons knocked up into space
Speaker 1: by the sunlight, but I'm also getting showered by electrons
Speaker 1: from the sun. But maybe those two are not the
Speaker 1: same amounts, and so overall I have a little you're
Speaker 1: saying overall, I'm still left with a little bit of
Speaker 1: a positive charge in my sun facing side.
Speaker 2: Yes, exactly, your sunburn side is positively charged.
Speaker 1: Okay, so then what happens.
Speaker 2: And on the backside, as we talked about, you're negatively charged. Wait,
Speaker 2: why so the front side gets charged because it's being
Speaker 2: hit by these photons, right, that doesn't happen on the backside.
Speaker 2: The backside of the Moon is dark. Photons don't make
Speaker 2: it there, right, and so there's no photons to drive
Speaker 2: it positively charged. All you have are the protons and
Speaker 2: the electrons floating around in this plasma. And the electrons
Speaker 2: are much higher velocity and they tend to hit the
Speaker 2: Moon's surface and stick more.
Speaker 1: Wait, I thought that this is not facing the Sun,
Speaker 1: and most of this stuff is coming from the Sun
Speaker 1: to where is my backside of the moon catching all
Speaker 1: this stuff?
Speaker 2: There's a gravitational effect here, right, You have this like
Speaker 2: solar wind that's washing over the Moon, and then some
Speaker 2: of the protons and the electrons get pulled around on
Speaker 2: the backside, and you have this plasma of electrons and
Speaker 2: proto hanging out on the backside because of gravity. And
Speaker 2: then the electrons get pulled down to the Moon more
Speaker 2: than the protons because electrons are faster moving and lighter.
Speaker 1: So you're saying the backside of my moon sucks electrons
Speaker 1: in through gravity.
Speaker 2: Yeah, And also the electrons are moving faster and they
Speaker 2: end up hitting the backside of the moon.
Speaker 1: M all right. So then and more electrical than positive
Speaker 1: because that's just what the solar wind is made out
Speaker 1: of it.
Speaker 2: And because electrons are lighter, right, they are easier to
Speaker 2: pull down, And so you end up with this positive
Speaker 2: charge on one side and this negative charge on the
Speaker 2: other side. And then there's this threshold, this terminator region
Speaker 2: right at the edge of darkness and light where it's
Speaker 2: totally neutral between the positive and the negative. So this
Speaker 2: is like a ring of neutrality on the Moon between
Speaker 2: the positive these charged sun facing side and the negatively
Speaker 2: charged dark side.
Speaker 1: Hmmm, that's super interesting. But I wonder, like, isn't the
Speaker 1: Moon rotating with respect to the Sun, so r and
Speaker 1: d these surfaces and positive negative surfaces rotating all the
Speaker 1: time and changing.
Speaker 2: Yes. Absolutely. As the moon rotates, a different part of
Speaker 2: it comes into contact with the photons, and so a
Speaker 2: different part of the moon becomes positive and negatively charged.
Speaker 2: This charging and discharging times are very very quick, and
Speaker 2: so like fractions of a second, so there's not like
Speaker 2: a lag between the charge of the moon and which
Speaker 2: part the Sun is hitting.
Speaker 1: So when I look at the moon, whether it's like
Speaker 1: full moon or half moon, basically when I see it,
Speaker 1: I should imagine that the part that we can see,
Speaker 1: the light side, is positively charged and the dark side
Speaker 1: is negatively charge no matter what phase of the moon
Speaker 1: it is in.
Speaker 2: Exactly, if you can see half of the moon and
Speaker 2: half of it is lit, then that side is positive
Speaker 2: and the dark half is negative. Then as it rotates,
Speaker 2: those charges change. So if you're just standing on the
Speaker 2: surface of the moon, the surface you're standing on goes
Speaker 2: from being positively to negatively charged from daytime to nighttime.
Speaker 1: Hmmm, that sounds super interesting. See what do you want
Speaker 1: experience that yourself? I mean, you talk so excitedly about it.
Speaker 1: Wouldn't it be great to be there?
Speaker 2: I think it's super fascinating, But I think it could
Speaker 2: also be unpleasant. I mean we're talking about like up
Speaker 2: to forty five hundred volts of static electricity.
Speaker 1: Wait what, yeah? That much?
Speaker 2: Yes, it's so powerful that it causes like dust to
Speaker 2: levitate on the surface of the Moon. If your dust
Speaker 2: develops a charge, it can repel the surface of the moon.
Speaker 2: You have like electromagnetic levitation happening on the surface of
Speaker 2: the moon.
Speaker 1: That just makes it sound more exciting, Daniel, I.
Speaker 2: Think it's exciting for other people to go and take
Speaker 2: pictures and tell me all about it while I stay
Speaker 2: in the comfort of southern California.
Speaker 1: I see charge neutral on your couch.
Speaker 2: The astronaut saw this. You can see dust levitating like
Speaker 2: a meter off of the Moon's surface if you go
Speaker 2: for a.
Speaker 1: Walk, meaning that there is like if you're in the
Speaker 1: light side, there's just a lot of it's just a
Speaker 1: lot of electrons floating and things. Everything's negative charge, which
Speaker 1: makes the dust repel the rest of the dust which
Speaker 1: makes it float.
Speaker 2: Yeah, it can repel the surface. So if you're standing
Speaker 2: on the surface of the moon and it's daytime, so
Speaker 2: you're in the lift part, the surface is positively charged.
Speaker 2: So if you can have a rock be also positively charged,
Speaker 2: then it will repel the surface of the moon. You
Speaker 2: just got to like rub the rock and brust some
Speaker 2: electrons off of it, just that hard. You can do
Speaker 2: that with like a rag then it will be positive
Speaker 2: and it can float. It's not something we experienced like
Speaker 2: down here on Earth very often, like unless you're in
Speaker 2: a magnetically levitating train.
Speaker 1: M And I guess the same would happen in the
Speaker 1: dark side too, right, I mean, the same effect would
Speaker 1: happen in the dark side, like you might see dust floating,
Speaker 1: but for the opposite reason.
Speaker 2: Yeah, exactly. And so if you plan to like have
Speaker 2: your house plants levitate, then you have to switch from
Speaker 2: positive to negative charge as the day goes into night.
Speaker 1: Mmm. Right, like a dawn and a dust things would
Speaker 1: fall to the ground.
Speaker 2: Sounds like a good problem for the engineers.
Speaker 1: Yeah exactly, or just you know, a handy man with
Speaker 1: a hammer and a nail. All right, Well, it sounds
Speaker 1: like the moon has at all times a positively charged
Speaker 1: side and a negatively charged side at all times. But
Speaker 1: maybe the question is does it overall have a positive
Speaker 1: or negative charge? So let's dig into that. But first
Speaker 1: let's take another quick break. All right, we're asking charge
Speaker 1: questions about the moon. Does the moon have a charge?
Speaker 1: And it sort of does? I guess it depends on
Speaker 1: which side of the moon you're in. If you're in
Speaker 1: the light side being hit by sunlight, then things are
Speaker 1: positively charged where you are, and if you're in the
Speaker 1: dark side, things are negatively charged by a lot. You
Speaker 1: said about forty five hundred volts.
Speaker 2: It can be up to that. Yeah, that's the largest
Speaker 2: that they've measured.
Speaker 1: Wow, So why doesn't it just act like a giant battery?
Speaker 1: And you see these you know, sparks or currents going
Speaker 1: through the moon.
Speaker 2: You don't get lightning storms on the moon, right, There
Speaker 2: isn't like another layer there to discharge from. And I
Speaker 2: think it depends also on the distance over which you
Speaker 2: have this voltage, but it can potentially be dangerous for
Speaker 2: stuff on the moon if you have like electrical equipment
Speaker 2: up there. That's very sensitive.
Speaker 1: M But I guess if the light side and the
Speaker 1: darks are so differently charged, why doesn't the charge equalize,
Speaker 1: Like why don't you get a whole bunch of electrons
Speaker 1: from the backside rushing to the front side.
Speaker 2: Some of that does happen, right, This is self limiting,
Speaker 2: and so this is like the result of a balance
Speaker 2: of all these processes. If you turned off the solar wind,
Speaker 2: for example, then eventually the moon would just neutralize. But
Speaker 2: the solar wind is constantly making this happen, and really interestingly,
Speaker 2: when the solar wind is stronger, like when you have
Speaker 2: solar storms, these effects grow more dramatic. Then the moon
Speaker 2: is more charged, or when the moon passes through like
Speaker 2: the magnetic tail of the Earth, which tends to focus
Speaker 2: the solar wind, then it also gets more powerful. So
Speaker 2: it sort of depends on the solar weather.
Speaker 5: Mmm.
Speaker 1: Interesting, Okay, so then the light side is positively charged
Speaker 1: and dark side is maked charged. But does it have
Speaker 1: a charge overall or does it all balance out to
Speaker 1: zero for the whole mood?
Speaker 2: So this is really interesting question, like philosophically, like do
Speaker 2: you really mean exactly zero? Because I think that's pretty
Speaker 2: unlikely for the number of protons and the number of
Speaker 2: electrons to be exactly matched to each other. It's like
Speaker 2: flipping a billion coins and getting fifty percent heads exactly.
Speaker 2: I think it's unlikely. So I'm sure the moon has
Speaker 2: some overall charge, but I bet it's very very close
Speaker 2: to zero because it's mostly made of neutral stuff, and
Speaker 2: then the surfaces are a little bit charged, but one's positive,
Speaker 2: one's negative, So I think overall it's going to be
Speaker 2: very close to zero.
Speaker 1: But here, you're just speculating, or yes.
Speaker 2: I'd be pretty confident that if you added up every
Speaker 2: single particle on the Moon, it would not come out
Speaker 2: to a perfect balance of zero.
Speaker 1: Right, But I guess would it be negative or positive?
Speaker 1: What do you think it would be?
Speaker 2: If I had to guess, I'd probably lean negative because
Speaker 2: I think the effects of the sun light probably taper
Speaker 2: off more quickly near the terminator region as the sun
Speaker 2: sort of gets low in the Moon's sky, So overall
Speaker 2: that might be a little bit weaker than the effects
Speaker 2: on the negative side. But I'm really not sure.
Speaker 5: Hmm.
Speaker 1: I see, like, if the sunlight effect kicking off electrons
Speaker 1: off of the rocks is not as strong as like
Speaker 1: the idea of being showered by a whole bunch of
Speaker 1: electrons from the sun, then overall it would have a
Speaker 1: negative charge. Yeah, exactly, But it's not quite clear, right, Like,
Speaker 1: maybe maybe the sunlight does kick off more electrons than
Speaker 1: get absorbed from the silver wind.
Speaker 2: Mm, And this is not something we know the answer to.
Speaker 2: There are folks who study the charge of the Moon,
Speaker 2: and they make some measurements from things orbiting the Moon,
Speaker 2: but mostly they have models that describe like these plasmachines
Speaker 2: and on these processes we talked about the photo electric effect,
Speaker 2: and they try to match them up with a few
Speaker 2: measurements they make. But we don't have a whole lot
Speaker 2: of measurements on the surface of the Moon, and we
Speaker 2: have some measurements from Apollo astronauts. We're not sure that
Speaker 2: they were always working in like typical conditions, and as
Speaker 2: we know, this is like constantly changing throughout the day.
Speaker 1: Throughout the seasons as well, right like as it interacts
Speaker 1: with the Earth.
Speaker 2: Maybe also yeah, and it's probably not a coincidence, but
Speaker 2: most of the Apollo astronauts tend to visit the Moon
Speaker 2: under pretty normal solar conditions, Like if there's going to
Speaker 2: be a big solar storm, then you're probably not going
Speaker 2: to launch your astronauts up to the Moon. And so
Speaker 2: we tend to have measurements during intervals of less extreme
Speaker 2: space weather.
Speaker 1: But I wonder if you could measure some other charge
Speaker 1: of the Moon from a distance, could you? Or you
Speaker 1: mentioned earlier, some signists are trying to do that. How
Speaker 1: are they doing that and what kind of effect are
Speaker 1: they using to measure this?
Speaker 2: What they're doing is basically measuring the particles that come
Speaker 2: off of the moon. Like you have something orbiting the moon.
Speaker 2: You can collect particles, you can count, like how many
Speaker 2: electrons are being pushed off of the positive side, how
Speaker 2: many electrons are being lost on the negative side. Basically,
Speaker 2: where are the particles and where are they going? And
Speaker 2: then compare that to the model you have of what's
Speaker 2: going on on the surface, and try to constrain it
Speaker 2: and say, by measuring this many protons per second per
Speaker 2: square centimeter up here, then how many are actually being
Speaker 2: attracted to the moon or being pushed off of the moon.
Speaker 1: Or I guess maybe to bring it down to Earth.
Speaker 1: Like if I had an apple in front of me,
Speaker 1: how would I measure whether it has a positive or
Speaker 1: negative charge?
Speaker 2: So the overall charge you can measure quite easily from
Speaker 2: a distance. Right, you just have a test particle, You
Speaker 2: put an electron near it, and you see the force
Speaker 2: on that electron, and that will tell you the charge
Speaker 2: of the apple.
Speaker 1: What do you mean you test the force of an electron.
Speaker 2: So if the apple is charged, it will create an
Speaker 2: electric field, and that electric field would push or pull
Speaker 2: on other charged particles. So if you want to measure
Speaker 2: the charge of the apple, you basically need to measure
Speaker 2: the strength of the field that it creates, and you
Speaker 2: can do that by putting another particle in that field.
Speaker 2: So if you have an electron, for example, and you
Speaker 2: drop it near some object and you watch that electron move,
Speaker 2: it'll tell you what the strength of the field is
Speaker 2: moving through is because you'll see it bend or accelerate
Speaker 2: or whatever, and that'll tell you the charge of the
Speaker 2: object that made that field.
Speaker 1: Could you do that with the Moon? Also? Like could
Speaker 1: we not just like drop an electron near the Moon
Speaker 1: and then figure out if it's positively or negatively?
Speaker 2: Yeah, it's a cool question, and you could do that
Speaker 2: if like there was a total vacuum, right, But everywhere
Speaker 2: around the moon is a plasma. There's lots of positive
Speaker 2: negative particles, So you can't just like isolate the moon.
Speaker 2: And it comes down a little bit too like definition,
Speaker 2: Like what do you mean by the moon? Do you
Speaker 2: mean just the rocks that are made up you mean
Speaker 2: also the exosphere? Do you mean this plasma sheet that
Speaker 2: surrounds it as well?
Speaker 1: Yes, to all of it. I mean I mean just
Speaker 1: like if you stand away from the Moon a good
Speaker 1: distance away, is it is it does overall have a
Speaker 1: negative or positive charge. I mean, I thought that's kind
Speaker 1: of what we're asking in this episode.
Speaker 2: Yeah, I don't know if anybody's actually tried to measure
Speaker 2: the overall charge of the Moon in that way. I'm
Speaker 2: pretty sure it's close to zero. And we've measured the
Speaker 2: charges on various sides of it and these processes and
Speaker 2: understood that pretty well, and that all comes together to
Speaker 2: tell you the story that the Moon is very likely
Speaker 2: overall zero. But I don't know about an actual direct measurement,
Speaker 2: Like we're talking about here dropping electrons somewhere near the
Speaker 2: Moon and seeing what happens to them.
Speaker 1: It sounds like somebody needs to go there, I know.
Speaker 2: All right, everybody chip in for Jorges trip to the Moon.
Speaker 1: Yeah, there you go, I'll pay for the electrons, now
Speaker 1: go drop them off. All right. Well, what does this
Speaker 1: mean about the Moon in general in kind of how
Speaker 1: things are going in our solar system?
Speaker 2: Well, it makes the Moon an even less pleasant place
Speaker 2: to visit, because all the dust on there is very
Speaker 2: very charged up, and it makes it really a pain,
Speaker 2: like the dust tends to stick to everything. All the
Speaker 2: experiments they did on the Moon and all the equipment
Speaker 2: they brought came back like coded with this terrible regolith dust.
Speaker 2: Everything on the Moon tends to stick because it all
Speaker 2: gets charged up and it's a big mess.
Speaker 1: Wait, why would dust stick if it's negatively charged? Wouldn't
Speaker 1: be repelled by something neutral? Or would he care about
Speaker 1: something neutral like my clothes?
Speaker 2: For the same reason that like a balloon will stick
Speaker 2: to your hair if you rub it enough. You know,
Speaker 2: you are effectively shedding charges, and so you're building up
Speaker 2: an overall electromagnetic force. And so the same thing happens
Speaker 2: on the Moon all the time.
Speaker 1: I see. So it's not easy to get rid of
Speaker 1: this dust.
Speaker 2: Yeah, exactly, But there are some positive sides. The fact
Speaker 2: that the moon surface can be positively or negatively charged
Speaker 2: might help us develop technology to explore or live on
Speaker 2: the Moon. Is a group trying to build a levitating glider.
Speaker 2: They're like, Hey, if dust can float on the Moon
Speaker 2: using electromagnetism, why can't we build a device that like
Speaker 2: floats on the moon, basically flying cars on the Moon? Mmm?
Speaker 1: Like, use the fact that the surface of the Moon
Speaker 1: is very charged, you know, positively on the light side,
Speaker 1: negatively on the dark side, to maybe do like a
Speaker 1: mac left train.
Speaker 2: Yeah, except in this case would be like electro lev
Speaker 2: I suppose the idea is to use an ion engine.
Speaker 2: An ion engine is where you take like a neutral atom,
Speaker 2: you know, a proton and an electron, you break them down,
Speaker 2: you accelerate one of them and shoot them out the
Speaker 2: back of the engine. So say, for example, you shoot
Speaker 2: the electrons out the back of the engine. That's like
Speaker 2: you're propellant. So you have a little rocket that's shooting
Speaker 2: electrons the back and it gives you a little bit
Speaker 2: of thrust. That's an ion engine. Well, one consequence of
Speaker 2: throwing electrons out the back of your engine is now
Speaker 2: your engine becomes positively charged. So if you're trying to
Speaker 2: levitate over a positively charged surface, that gives you an
Speaker 2: extra little boost. So you run your little engines, but
Speaker 2: they don't have to be as powerful as normal because
Speaker 2: now they're getting positively charged, so they're getting repelled by
Speaker 2: the surface. So if you're going to build a little
Speaker 2: glider to explore the Moon, you can take advantage of
Speaker 2: this effect.
Speaker 1: I see, figure out how to get rid of all
Speaker 1: your electrons so that your car is positively charged, which
Speaker 1: would make it float a little bit above the positively
Speaker 1: charged moon.
Speaker 2: Floor exactly, But then you're like Cinderella and you have
Speaker 2: to watch out for the sunset because then your car
Speaker 2: is going to slam into the surface.
Speaker 1: When you get to the dark side, then the whole
Speaker 1: surrounding floor turns negative exactly.
Speaker 2: But then you just got to flip your ion engines
Speaker 2: the other way and shoot the protons out of it
Speaker 2: instead of the electrons, so it can work on either side.
Speaker 1: But would that be enough gosh, I know the gravity
Speaker 1: is lower on the Moon, but would it be enough
Speaker 1: to actually make something flow?
Speaker 2: Potentially? They're working on the technology and they've tested one
Speaker 2: on Earth where they have like a one kilogram object
Speaker 2: who was able to levitate a centimeter above the surface,
Speaker 2: and they speculate that on future missions to very low
Speaker 2: mass moons, very small moons, you might want a flyer
Speaker 2: instead of a rover because rovers get stuck on surface effects,
Speaker 2: and helicopters can be pretty tricky if there isn't enough atmosphere.
Speaker 2: So they're thinking about developing these electrically levitating gliders for
Speaker 2: exploring future small moons. We might want to figure out
Speaker 2: if there's like alien life on or just figure out
Speaker 2: what's on them.
Speaker 1: I see, just to get around, because I guess wheels
Speaker 1: can only get you so far.
Speaker 2: Yeah, exactly. The glider doesn't get stuck in a crevass,
Speaker 2: then it's easier to get over hills. You know. We
Speaker 2: have these cool helicopter on Mars now and they're developing
Speaker 2: one to fly on some of the moons of Jupiter.
Speaker 2: But those are really good in higher atmosphere environments, and
Speaker 2: this would work in a very low atmosphere environment moon.
Speaker 1: All right, Well, it sounds like the answer to our
Speaker 1: question today what's the electrical charge of the moon, is
Speaker 1: that it depends on what side of the Moon you're in.
Speaker 1: If you're in the light side, the charge is positive.
Speaker 1: You're in dark side, it's negative. If you're in the
Speaker 1: dusks or twilight zone, then things are neutral. But overall
Speaker 1: it sounds like it's still kind of a mystery what
Speaker 1: the charge of the whole moon is.
Speaker 2: We think it's probably pretty close to zero, but we
Speaker 2: don't have direct measurement using jorgees.
Speaker 1: Electron right, right, and by we Daniel means Daniel.
Speaker 2: That's right. I've not yet sent jorget to measure the
Speaker 2: charge of the moon, so I don't have that data.
Speaker 2: Nobody knows the exact charge of the.
Speaker 1: Moon right now, all right, but I think it's another
Speaker 1: interesting example of how complex things can get in the universe.
Speaker 1: You know, you might think that something like the Doing
Speaker 1: is just floating out there in space and it's made
Speaker 1: out of neutral rocks, and so it must have a
Speaker 1: neutral charge. But you know, there's so much going on
Speaker 1: in the Solar system with the solar wind and gravity
Speaker 1: and light and the photo electric effect, that things can
Speaker 1: I get complicated and a little bit charged up.
Speaker 2: Yeah, there's a lot more going on than just gravity
Speaker 2: that shapes our solar system and our galaxy. These winds
Speaker 2: affect our solar system, but there are also galactic winds
Speaker 2: radiation from the center of the galaxy that shape the
Speaker 2: structure of the galaxy and the star formation. So electromagnetism
Speaker 2: still has things to say about the structure of the universe.
Speaker 1: All right, Well, we hope you enjoyed that. Thanks for
Speaker 1: joining us. See you next time.
Speaker 2: For more science and curiosity. Come find us on social
Speaker 2: media where we answer questions and post videos. We're on Twitter,
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Speaker 2: remember that Daniel and Jorge Explain the Universe is a
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