Latest / Daniel and Kelly’s Extraordinary Universe / Is all of space magnetized?

Transcript

Is all of space magnetized? · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Hey, Jorgey, I have a cool idea for a totally
0:11
Speaker 1: new gadget. Is it an automatic banana pelar? That's you,
0:16
Speaker 1: You're an automatic banana pelar. No, it's a space compass
0:20
Speaker 1: on nice, So I tell you where to find bananas, uh,
0:24
Speaker 1: your refrigerator. Now, like a compass on Earth right tells
0:28
Speaker 1: you where North is based on magnetic field. Right, So
0:32
Speaker 1: this space compass would use the Sun's magnetic field to
0:36
Speaker 1: tell you where you are in the Solar system. That
0:38
Speaker 1: sounds cool, But isn't that just like a regular compass.
0:41
Speaker 1: That's the genius part. There are no engineering or design costs,
0:45
Speaker 1: just cost to bananas. Anything I can do to cut
0:48
Speaker 1: out the engineers. Hi am or handy cartoonists and the
1:06
Speaker 1: creator of PhD comics. Hi, I'm Daniel, I'm a particle physicist,
1:10
Speaker 1: and I'm moonlight as an inventor of ridiculous things and
1:14
Speaker 1: ridiculous podcasts. Right, Let's see what I can make in
1:18
Speaker 1: a particle colliderary that I could sell on Etsy. Let
1:21
Speaker 1: see if we can collide science and bad puns and
1:24
Speaker 1: see if anyone will listen. Maybe I should list many
1:27
Speaker 1: black holes on my Etsy shop and see if anybody
1:29
Speaker 1: buys one. Are those for sale? Can you buy one
1:32
Speaker 1: from the LHC. Everything has a price, right, you give
1:35
Speaker 1: me a hundred billion dollars, I will give you a
1:37
Speaker 1: black hole. You would totally do it, wouldn't you. The
1:40
Speaker 1: l a C would totally do it. They'll take that
1:42
Speaker 1: money well after the check cash is yes. But welcome
1:45
Speaker 1: to our podcast Daniel and Jorge Explain the Universe, a
1:47
Speaker 1: production of I Heart Radio, in which we talk about
1:50
Speaker 1: all the things that we can do in the world
1:51
Speaker 1: and all the things that we can't do in this world,
1:54
Speaker 1: even if we have a hundred billion dollars. We zoom
1:57
Speaker 1: out into space and think about what's there, what's seeing?
2:00
Speaker 1: Why are things here? Why does the universe work the
2:02
Speaker 1: way that it does. Why doesn't it work some other way?
2:05
Speaker 1: All the things for sale and that you can get
2:07
Speaker 1: for free ad cern gift shop. Can you get a
2:10
Speaker 1: free superconducting magnet that you don't use anymore? No, we
2:14
Speaker 1: do not give those away. I think you can get
2:17
Speaker 1: a sticker though. A sticker is it a super conducting sticker? No,
2:21
Speaker 1: it might have a picture of a Higgs Boson collision
2:23
Speaker 1: on it, so it's pretty fun. Yeah, we like to
2:26
Speaker 1: talk about all the amazing things out during the universe,
2:29
Speaker 1: all of the things that are here on Earth and
2:31
Speaker 1: that we can discover and look closely at, and all
2:33
Speaker 1: the things that we can quite see that are out there.
2:37
Speaker 1: That's right, because humanity is taking a mental voyage of exploration.
2:41
Speaker 1: We are stuck here on Earth for the time being.
2:44
Speaker 1: What we'd like to understand what's out there? How do
2:46
Speaker 1: things work? So we use our telescopes and are clever
2:49
Speaker 1: ideas to probe the cosmos, And every time we do,
2:53
Speaker 1: we find something weird, somebody that shakes the very foundation
2:56
Speaker 1: of our understanding of how the universe works and what
2:59
Speaker 1: it's old with. Do you think humans have a kind
3:02
Speaker 1: of a version of fomo like fear of missing out?
3:04
Speaker 1: That's what we're always looking out into space, trying to
3:07
Speaker 1: find couder things. Yeah, maybe we're just stuck in a
3:11
Speaker 1: boarding corner of the universe and the real party is
3:13
Speaker 1: happening somewhere else at the center of the galaxy or
3:16
Speaker 1: in another galaxy, and if only we were there, we
3:19
Speaker 1: could be partner. Well, you know what they say, be
3:20
Speaker 1: careful about having an interesting life. Well, maybe the aliens
3:24
Speaker 1: are gathering together in some sort of like Universal Physics
3:28
Speaker 1: Conference and revealing the secrets to the universe, and we
3:30
Speaker 1: just weren't invited. Man, you do have fomo. I have
3:38
Speaker 1: fear of missing out on alien physics. What's the acronym
3:40
Speaker 1: for that, A phomo. But yeah, I would like to
3:42
Speaker 1: talk about all the amazing things out there. And turns
3:44
Speaker 1: out that there are a lot of very interesting things
3:47
Speaker 1: out in space, things you can't see, but that we
3:49
Speaker 1: can potentially feel. That's right, and humanity is busy building
3:53
Speaker 1: new kinds of eyeballs, ways to look at space, ways
3:57
Speaker 1: to hear messages from outer space to give us clue
4:00
Speaker 1: as to what's out there, and every time we do,
4:02
Speaker 1: we find something weird. Of course, there are planets, there
4:05
Speaker 1: are stars, there are galaxies, there are supernovas, but there
4:08
Speaker 1: are also other amazing things we can listen to. So
4:11
Speaker 1: to be on the podcast, we will be asking the
4:13
Speaker 1: question does space have a magnetic field? Now, Daniel, we
4:21
Speaker 1: have a magnetic field here on Earth, like the Earth
4:24
Speaker 1: has a magnetic field from the north pole to the
4:27
Speaker 1: south pole, and so compasses work and it helps protect
4:30
Speaker 1: us from cosmic race that are coming from space. And
4:34
Speaker 1: so I guess the question is does space have a
4:36
Speaker 1: magnetic field to like, is there, you know, like a
4:39
Speaker 1: universe wide or galaxy wide magnetic field. Yeah, it's a
4:44
Speaker 1: great question. And if you ask people this question, you know,
4:47
Speaker 1: maybe twenty years ago they would have said, how could
4:50
Speaker 1: the universe be filled with a magnetic field? Magnetic fields
4:53
Speaker 1: and need sources, right, they need magnets or spinning loops
4:57
Speaker 1: of charge or something. So what could possibly j generate
5:00
Speaker 1: universe wide magnetic field? That's absurd, right, And my favorite
5:04
Speaker 1: thing about physics is that things that were observed twenty
5:07
Speaker 1: years ago become reality and then accepted wisdom and then
5:10
Speaker 1: later eventually obvious. And you're like grumpy its students for
5:13
Speaker 1: not understanding it in a ten minute explanation, and the
5:17
Speaker 1: cutscene montage of physicists throughout his roy would be like,
5:20
Speaker 1: that's ridiculous. Wait, never mind, that's ridiculous. Wait never mind. Yeah, yeah,
5:26
Speaker 1: that can't be true. Oh, actually it is. And then
5:28
Speaker 1: to the students, why don't you understand this? So you're
5:31
Speaker 1: saying that there are magnetic fields in space? Yeah, and
5:34
Speaker 1: this is wonderful history of discovery. As we look further
5:36
Speaker 1: and further out into space, we discover magnetic fields where
5:40
Speaker 1: we didn't expect to see any and we're forced to
5:42
Speaker 1: come up with more and more ideas for what could
5:45
Speaker 1: be generating them. And this is giving us a fascinating
5:47
Speaker 1: window into how the universe was constructed and maybe even
5:52
Speaker 1: like solving deep problems and concerns we have about understanding
5:55
Speaker 1: how the universe expands. Sounds deep. It's quite a magnetic topic.
5:59
Speaker 1: Deep answers about deep space. Is magnetically attractive to this topic? Well,
6:03
Speaker 1: I feel kind of positive and negative about it, but yeah,
6:06
Speaker 1: I guess the idea is that, you know, we have
6:07
Speaker 1: a magnetic field here on Earth. You know, I have
6:09
Speaker 1: a compass. It tells me which way is north. But
6:11
Speaker 1: as I imagine myself floating out into space, I would
6:14
Speaker 1: imagine that that compass doesn't work. Like you know, if
6:18
Speaker 1: you're way far from the Earth, where would it point
6:21
Speaker 1: to you. It wouldn't point to the north or the south.
6:24
Speaker 1: But you're saying that a compass in space would be
6:26
Speaker 1: pointing somewhere. Yeah, a compass in space would be pointing somewhere.
6:30
Speaker 1: And I think it's useful to sort of take a
6:32
Speaker 1: mental journey from the Earth and think about the magnetic
6:35
Speaker 1: fields as you get further and further away from our
6:37
Speaker 1: Earth and Solar system and galaxy and think about where
6:40
Speaker 1: those magnetic fields come from, and that will help us
6:43
Speaker 1: understand where they're not coming from or what we're confused about. So,
6:48
Speaker 1: as usual, Daniel was wondering how many people out there
6:51
Speaker 1: knew that there are magnetic fields in deep space? That's right,
6:55
Speaker 1: and so I asked folks to pontificate on this question.
6:57
Speaker 1: And if you'd like to participate and answer questions you
7:00
Speaker 1: are unprepared for, please write to us at questions at
7:03
Speaker 1: Daniel and Jorge dot com. Think about it for a second.
7:06
Speaker 1: If there are magnetic fields in space, where do you
7:09
Speaker 1: think they would be coming from. Here's what people had
7:12
Speaker 1: to say. I guess this could be a definition problem
7:14
Speaker 1: of what deep spaces. If you mean like nothing in
7:18
Speaker 1: this space or quote unquote nothing possibly not, but a
7:23
Speaker 1: few mean like are there magnetars out there? Then yeah,
7:27
Speaker 1: there's magnetic fields and deep space. I guess so as
7:32
Speaker 1: long as there are electro magnetic forces, there are magnetic fields.
7:36
Speaker 1: I would say yes, because I think you mentioned on
7:39
Speaker 1: a previous podcast about nuance that photons travel through the
7:45
Speaker 1: electro magnetic field. I think Earth has one right for protection,
7:50
Speaker 1: but in deep space. Would it be like a field
7:54
Speaker 1: that attracts or repels objects, Possibly, but they would probably
7:59
Speaker 1: be extra dream we weak. Yes, of course, should be
8:04
Speaker 1: magetive fields. I don't know by deep space, like if
8:06
Speaker 1: it's an a void, probably not, because I think magnetic
8:11
Speaker 1: fields require like matter and energy to be there. But
8:15
Speaker 1: around nebulas and stuff, then yes, I would say there's
8:19
Speaker 1: magnetic fields alright. A lot of very um cautious answers.
8:23
Speaker 1: We even seem to think that there are magnetic fields,
8:26
Speaker 1: but nobody seem to have an idea where they come from. Yeah,
8:28
Speaker 1: people think that there are things out there, like magnetars
8:31
Speaker 1: and stars, etcetera. They create magnetic fields. But we're talking
8:35
Speaker 1: about out in deep space, far from any concrete source,
8:39
Speaker 1: things that aren't obviously generated by some spinning little particle
8:44
Speaker 1: or moving current of charge. Well, I see, we're talking
8:47
Speaker 1: about like way out there where there's nothing around you. Yeah, exactly,
8:51
Speaker 1: because I imagine if you're in your Earth, then there's
8:54
Speaker 1: a magnetic field here, and maybe other planets have them,
8:57
Speaker 1: and maybe other objects have them. But like if your
9:00
Speaker 1: own space but nothing around you, would there still be
9:02
Speaker 1: a magnetic field. Yeah, and anywhere you find a magnetic field.
9:05
Speaker 1: You get to ask the question where did it come from?
9:07
Speaker 1: What's making it? Right? And that lets you investigate like
9:10
Speaker 1: the source and the history and the understanding of like
9:13
Speaker 1: what's going on inside. You know, Like when you discover
9:16
Speaker 1: the Earth as a magnetic field, you get to ask, well,
9:18
Speaker 1: what's making it? And that reveals a fascinating picture of
9:21
Speaker 1: what's going on inside the Earth. It's not just like
9:23
Speaker 1: a cold static blob. It's called like massive currents of
9:28
Speaker 1: liquid metal. That's a pretty cool realization. So discovering magnetic
9:31
Speaker 1: fields is an awesome clue that leads you to understanding
9:34
Speaker 1: what's going on around because it's cool to think that
9:36
Speaker 1: the Earth isn't just like a you know, like your
9:38
Speaker 1: average kitchen magnet that you know, it's static and it's
9:41
Speaker 1: just it just hasn't a magnetic field to it like
9:44
Speaker 1: the one from Earth. It's because we have like a
9:47
Speaker 1: generator inside of the Earth, like a living moving you know, dynamo. Yeah,
9:52
Speaker 1: there's energy. They're right. Those liquids are flowing and they
9:55
Speaker 1: create a magnetic field, and then the magnetic field makes them.
9:58
Speaker 1: Liquids flow more because are charged and they get pushed
10:01
Speaker 1: by the magnetic field and so it builds on itself. Yeah,
10:04
Speaker 1: we call that a dynamo. So that's pretty awesome. We
10:06
Speaker 1: have a little magnetic engine inside the Earth that's powering
10:09
Speaker 1: this magnetic field, and that lets you wonder. Every time
10:12
Speaker 1: you find a magnetic field, you can ask like, where
10:14
Speaker 1: is the energy coming from to create this magnetic field.
10:17
Speaker 1: So it's like finding out that there's something happening in
10:20
Speaker 1: an empty room and you're like, well, what's going on
10:22
Speaker 1: in the walls, and so that's kind of what's happening
10:25
Speaker 1: out in space. So Daniel step us through. Maybe for
10:28
Speaker 1: those who are not super familiar with what a magnet is,
10:32
Speaker 1: remind us where they come from and what do we
10:34
Speaker 1: know about magnetic fields. Yeah, so magnetic fields are fun,
10:38
Speaker 1: and in our universe, we don't have pure sources of
10:42
Speaker 1: magnetic fields, like you have a pure source of an
10:44
Speaker 1: electric field, which is just an electric charge like an
10:47
Speaker 1: electron or a positron. They can just create an electric
10:50
Speaker 1: field around them, but we don't have that in our universe.
10:53
Speaker 1: That would be called a magnetic monopole. Instead, we can
10:56
Speaker 1: only create dipole fields, and these are created by like
10:59
Speaker 1: moving elect charges spinning in a circle for example. So
11:02
Speaker 1: a ring of current can make a magnetic field. That's
11:05
Speaker 1: an electro magnet. You can also have metals that are magnetized,
11:09
Speaker 1: and there the magnetic field comes from the spin of
11:11
Speaker 1: the electrons. There's a electrons moving around in a circle
11:14
Speaker 1: around the nucleus or actually having a weird quantum spin themselves.
11:19
Speaker 1: So fundamentally, magnetic fields always come from some electric charge
11:23
Speaker 1: that's in motion. And maybe that's the motion of the
11:26
Speaker 1: liquid inside the Earth, or conductive plasma in the sun
11:30
Speaker 1: or something else. But they always have this same kind
11:32
Speaker 1: of source as far as we're aware, Like, it doesn't
11:34
Speaker 1: seem to be like a fundamental property of the universe
11:39
Speaker 1: or of matter or of charge. It's like you need
11:42
Speaker 1: something to be happening to have a magnetic field. Yeah,
11:45
Speaker 1: and now all of space has the capacity to have
11:47
Speaker 1: magnetic fields, right, All of space we think of has
11:50
Speaker 1: quantum fields in it. Right. Those fields are like possibilities
11:54
Speaker 1: for charge. It's like, you know, there are slots there
11:57
Speaker 1: and at any point in space you can put energy
12:00
Speaker 1: into the magnetic field or the electric field, or the
12:03
Speaker 1: Fermion fields or the Higgs field or whatever. Every point
12:06
Speaker 1: in space has these fields, but sometimes have zero value
12:10
Speaker 1: and some of the fields can actually go down to zero,
12:12
Speaker 1: and the magnetic field is one of those. So all
12:14
Speaker 1: of space has the capacity for a magnetic field, but
12:17
Speaker 1: we're interested in, like, what's creating energy in that magnetic field?
12:21
Speaker 1: Where is that coming from? In cases when there is
12:23
Speaker 1: a magnetic field like around the Earth. Wait, are you
12:25
Speaker 1: saying that there's a quantum magnetic field, just like there's
12:29
Speaker 1: an electric field for the electron. Absolutely, all these fields
12:32
Speaker 1: are quantized, and in fact it's very close connection between
12:35
Speaker 1: electricity and magnetism, and in quantum field theory we just
12:38
Speaker 1: treat those two as one. But yes, absolutely, the magnetic
12:42
Speaker 1: field is quantized, and one quantum of the electromagnetic field
12:46
Speaker 1: is of course a photon of the electromagnetic field. Yes,
12:50
Speaker 1: because in quantum mechanics we think of electricity and magnetism
12:53
Speaker 1: is just two sides of the same coin. Classically we
12:56
Speaker 1: see to have slightly different phenomena, but we understand there
12:59
Speaker 1: very closely related did so we think of them as one,
13:01
Speaker 1: and a photon actually is an electric field and a
13:04
Speaker 1: magnetic field sort of oscillating and supporting each other. It
13:08
Speaker 1: goes from a magnetic field to an electric field back
13:10
Speaker 1: to a magnetic field creating each other. A photon is
13:13
Speaker 1: sort of this amazing cycle of energy flowing between one
13:17
Speaker 1: of the fields and the other. See. But I think
13:18
Speaker 1: what you're saying is that, you know, unlike a matter
13:21
Speaker 1: field or like a force field, magnetic field can't just
13:25
Speaker 1: like have energy on its own, like you're saying, it
13:28
Speaker 1: sort of needs activity in another field. You know that
13:30
Speaker 1: for it to have any kind of activity. That's what
13:33
Speaker 1: we've seen so far. All the magnets that we have
13:35
Speaker 1: seen have a source right there, are not constant, they're
13:39
Speaker 1: not fixed. The magnetic field comes from the emotion of
13:42
Speaker 1: a charged particle. We'll talk later about whether it's possible
13:45
Speaker 1: for space to just sort of have a magnetic field
13:48
Speaker 1: on its own. That would be fascinating, all right, So
13:50
Speaker 1: we know that the Earth has a magnetic field, and
13:52
Speaker 1: we know that the Sun has a magnetic field, right
13:55
Speaker 1: because I guess it's it has kind of a stuff
13:58
Speaker 1: inside of it flowing in circles and creating some sort
14:01
Speaker 1: of current. That's right in the Sun. We think that,
14:03
Speaker 1: similar to the Earth, is just like flowing currents of
14:06
Speaker 1: charred stuff creating the magnetic field, and the Sun's magnetic
14:09
Speaker 1: field is very very powerful, much more powerful than the
14:12
Speaker 1: Earth's magnetic field. And if you are on the surface
14:14
Speaker 1: of the Sun, your compass would be much more effective
14:17
Speaker 1: than the compass on the surface of the Earth. Don't
14:19
Speaker 1: recommend doing any hikes on the surface of the Sun,
14:22
Speaker 1: of course, and you'll need more than a compass if
14:24
Speaker 1: you do. Being lost in the surface of the Sun
14:26
Speaker 1: is the lease of your problems. That's right. And the
14:29
Speaker 1: Sun's magnetic field is actually really fascinating. We have a
14:32
Speaker 1: whole episode plant about that because it's all sorts of
14:35
Speaker 1: weird mysteries, like, unlike the Earth's magnetic field, it flips also,
14:39
Speaker 1: but it does so on a very regular cycle, like
14:41
Speaker 1: every eleven years boom, it flips over the north and
14:44
Speaker 1: the south. The Earth's magnetic field flips very irregularly and
14:47
Speaker 1: much more rarely. But the Sun is like clockwork, so
14:50
Speaker 1: it's got a fickle field. So and also the galaxy
14:54
Speaker 1: as a magnetic field, I guess because the galaxy is
14:56
Speaker 1: kind of spinning, right, it's got a lot of stuff
14:58
Speaker 1: going around in a circle. Is that what's generating the
15:01
Speaker 1: magnetic field for the galaxy. So we have some understanding
15:04
Speaker 1: of the Earth and the Sun's magnetic field. The galaxies
15:06
Speaker 1: magnetic field is where we start to be a little
15:08
Speaker 1: bit confused, like we don't really understand why the galaxy
15:13
Speaker 1: has such a strong magnetic field. You know, if you
15:16
Speaker 1: give the galaxy sort of a seed, a magnetic field
15:19
Speaker 1: that begins, then the spinning, you're right, can make that
15:22
Speaker 1: magnetic field stronger because you're slashing around big, heavy stuff
15:26
Speaker 1: that can support it. But without that seed, you don't
15:29
Speaker 1: get a very strong magnetic field just from the spinning.
15:32
Speaker 1: The magnetic fields are interesting that way that they can
15:34
Speaker 1: be enhanced more easily than they can be created. Like
15:37
Speaker 1: you make a magnetic field, it organizes the magnets around
15:40
Speaker 1: it and builds on itself, but you need that initial seed,
15:43
Speaker 1: and we don't know where that initial seed for the
15:46
Speaker 1: galaxies came from. It's actually very similar to the problem
15:49
Speaker 1: we have with supermassive black holes. It's like you can
15:52
Speaker 1: have a big black hole in the center of a galaxy,
15:54
Speaker 1: but how does it get that big? And we have
15:56
Speaker 1: the same problem with the galactic magnetic fields that we
15:59
Speaker 1: don't really understand how they got so strong, how they
16:02
Speaker 1: started and then got strong. Are their galaxies without a
16:05
Speaker 1: magnetic field, or did they all have them. They all
16:08
Speaker 1: have them, and they're actually important for forming stars because
16:12
Speaker 1: the magnetic field helps channel all the gas and dust
16:15
Speaker 1: and keep it together and not as diffuse, and that
16:17
Speaker 1: helps of course collapse it into forming stars and all
16:20
Speaker 1: that kind of stuff. And so it's pretty important part
16:23
Speaker 1: of being a galaxy as having a magnetic field. It
16:25
Speaker 1: it helps you evolve in the way that we expect.
16:27
Speaker 1: And there's some variation of course in magnetic field galaxy
16:30
Speaker 1: to galaxy, but they all have them, and then having
16:32
Speaker 1: stars makes you more attractive to in magnetic yeah, exactly.
16:35
Speaker 1: All right, so let's get into what else has a
16:38
Speaker 1: magnetic field out in space, But first let's take a
16:41
Speaker 1: quick break. All right, Daniel, we're talking about magnetic fields
16:56
Speaker 1: in space, and we know that things have them, like
16:59
Speaker 1: the Earth in the Sun and the galaxies. But the
17:02
Speaker 1: question is does space, like empty space, like the space
17:05
Speaker 1: between where there's nothing, does that have a magnetic field.
17:09
Speaker 1: And so we were at the point of galaxies that
17:12
Speaker 1: have magnetic fields, but then the galaxy clusters happening that
17:16
Speaker 1: fields too. Yeah, it's amazing. You take your compass, right,
17:19
Speaker 1: you're on Earth that has a field. You zoom out
17:22
Speaker 1: the sun controls your compass, you zoom out to the galaxy,
17:25
Speaker 1: and your galaxy then controls where your compass points. But
17:28
Speaker 1: then as you leave your galaxy, you can ask, like,
17:30
Speaker 1: are there magnetic fields between galaxies in these galactic clusters?
17:35
Speaker 1: And so it's a very recent paper where people were
17:38
Speaker 1: studying this and trying to measure magnetic fields between galaxies,
17:42
Speaker 1: and to their frankly great surprise, they found that there
17:44
Speaker 1: are magnetic fields between these galaxies. They are these like
17:49
Speaker 1: filaments of gas between the galaxies that they used to
17:52
Speaker 1: understand whether they're magnetic fields. And there are magnetic fields there,
17:56
Speaker 1: and nobody knows what meaning, kind of like iron filings,
18:00
Speaker 1: Like we're seeing things move around in between galaxies that
18:03
Speaker 1: seem to be moved around by a magnetic field. Yeah,
18:07
Speaker 1: it's really hard to measure magnetic fields for something else
18:10
Speaker 1: you're looking at. Right, we can't take a compass and
18:12
Speaker 1: like go out there and say, well, what's the magnetic
18:15
Speaker 1: field here between the galaxies because we can't get there,
18:18
Speaker 1: we can't send a probe. So all we can do
18:20
Speaker 1: is try to understand the impact of the magnetic field
18:23
Speaker 1: on the stuff we're looking at. And so, like you say,
18:26
Speaker 1: you can look at iron filings on the table and
18:28
Speaker 1: see the magnetic field lines. But here, we can't toss
18:31
Speaker 1: iron filings between the galaxy. So we have to find
18:33
Speaker 1: something that's already there and use it as our indicator,
18:38
Speaker 1: like if it if it allies or it falls into
18:40
Speaker 1: some sort of funny pattern, then that would tell you
18:43
Speaker 1: there's a magnetic field there. Yeah, and actually our best
18:46
Speaker 1: indicator are not objects like that, but electrons. Electrons as
18:50
Speaker 1: they whizz through space are bent by magnetic fields that
18:54
Speaker 1: tend to curve around magnetic fields. Just like particles that
18:57
Speaker 1: hit the Earth, they hit our magnetic force field, they're
19:00
Speaker 1: spiraled up around those lines towards the north pole in
19:03
Speaker 1: the South pole, which is what causes the Northern and
19:05
Speaker 1: Southern lights. In the same way, these electrons out there
19:09
Speaker 1: in deep space, if they feel magnetic fields, they tend
19:12
Speaker 1: to bend. And anytime a charge particle bends, it gives
19:15
Speaker 1: off a photon. It radiates a photon that's sort of
19:18
Speaker 1: like a signal for how it's happening. And we can
19:21
Speaker 1: capture those photons and say, oh, look, electrons over here
19:25
Speaker 1: are bending, so there must be a magnetic field. Interesting,
19:28
Speaker 1: But how do you tell if they're bending, like can
19:31
Speaker 1: you see it on a telescope or do you have
19:33
Speaker 1: to somehow measure there's spin or how do you tell
19:36
Speaker 1: their bending? We can't see the electrons directly at all.
19:39
Speaker 1: These are electrons that are like a billion light years
19:41
Speaker 1: away or millions of light years away. We don't ever
19:43
Speaker 1: see the electrons. We only see the photon they give
19:46
Speaker 1: off when they bend. And those photons have sort of
19:49
Speaker 1: a characteristic signature that have like a certain energy you
19:52
Speaker 1: would expect, and you look at patterns, and if there
19:55
Speaker 1: are magnetic fields, you then expect to see like a
19:57
Speaker 1: coherent pattern of electrons all giving off this same kind
20:01
Speaker 1: of photon when they go through this region. What what
20:05
Speaker 1: you mean? What how does it change the light that
20:07
Speaker 1: it's meaning just from its velocity or it's a fundamentally
20:10
Speaker 1: different these photons. When an electron gets bent, right, when
20:13
Speaker 1: it changes direction, how does it do that? To do
20:15
Speaker 1: that and conserve energy and momentum, it has to sort
20:18
Speaker 1: of push off by shooting off a photon, and so
20:20
Speaker 1: a magnetic field induces this. It says, al right, electron,
20:24
Speaker 1: kick off a photon and change directions, and that's how
20:27
Speaker 1: like all the energy momentum of the original particles preserved,
20:30
Speaker 1: and we see that photon, and can we distinguish those
20:33
Speaker 1: photons from like any other random photon. Well, a photon
20:37
Speaker 1: is a photon, is a photon. They're all just photons.
20:40
Speaker 1: But that was a pretty deep statement, huh. But these
20:43
Speaker 1: tend to happen at characteristic energies, Like we know how
20:45
Speaker 1: fast electrons tend to be moving and how strong these
20:48
Speaker 1: magnetic fields are, and so that predicts the energy of
20:51
Speaker 1: those photons. And again we expect them to be sort
20:54
Speaker 1: of coherent. We expect to see like these kind of
20:56
Speaker 1: photons all coming from the same direction if there is
20:59
Speaker 1: a big athnic field there. But I'm glossing over a
21:02
Speaker 1: lot of technical details. It's a really hard problem. They
21:06
Speaker 1: build this amazing antenna to try to capture these photons,
21:09
Speaker 1: and it took them years of data analysis to like
21:12
Speaker 1: remove all the noise and understand if these really photons
21:14
Speaker 1: from electrons far away. It's a difficult problem, but I
21:18
Speaker 1: guess the main point is that you look out into
21:20
Speaker 1: this sky into space, yes, and the way that we
21:22
Speaker 1: look out into space is sort of awesome. I was
21:25
Speaker 1: talking earlier about every time we opened a new eyeball,
21:27
Speaker 1: we see something amazing in space. Here, we're looking into space,
21:30
Speaker 1: not with visible light with these are in telescopes or
21:33
Speaker 1: eyeballs in a literal sense that we're using to look
21:36
Speaker 1: out into the universe. These are radio frequency antennas, but
21:40
Speaker 1: they're still photons, right, It's still light. It's just a
21:42
Speaker 1: higher frequency, that's exactly right. Radio waves are electromagnetic radiation,
21:47
Speaker 1: which means that pulses in them are photons. And so
21:50
Speaker 1: these are just photons with really really long wavelength, too
21:53
Speaker 1: long for you to see with a visible eye or
21:55
Speaker 1: for us to see with hubble. So the way they
21:57
Speaker 1: do it is they have twenty thousand and tennas that
22:00
Speaker 1: they spread across Europe. What really big device because these
22:05
Speaker 1: wavelengths are so long, they can be like kilometers in
22:08
Speaker 1: wavelength that you need a really big device to capture them.
22:11
Speaker 1: Twenty Yeah, that's a lot. It's a lot. Do you
22:14
Speaker 1: need a grad student for each one? Or how does that?
22:17
Speaker 1: How do you keep trying them and how do you
22:19
Speaker 1: keep them clean? It's a lot of work, right, And
22:21
Speaker 1: these things are just like sitting out in the field
22:23
Speaker 1: somewhere anywhere they can put one. Basically, they put one
22:26
Speaker 1: it's a really awesome distributed device because you we never
22:29
Speaker 1: take like all of Europe and turn it into a telescope,
22:32
Speaker 1: though I'm sure some astronomers I wish you would. But
22:34
Speaker 1: you can just sort of like embed these telescopes across
22:38
Speaker 1: the continent and then stitch it together into effectively a
22:41
Speaker 1: virtual telescope. That's did they try to disguise as cell
22:45
Speaker 1: phone towers, disguise as trees, but that these guys and
22:49
Speaker 1: is like satellite TV on rooftops. It's a great program.
22:52
Speaker 1: It's called Low Far l O F a R. And
22:55
Speaker 1: they have this awesome program and they really did a
22:58
Speaker 1: lot of work. And one of the hard things is
23:00
Speaker 1: that when radio waves come through the atmosphere, they get
23:03
Speaker 1: fuzzy because the atmosphere interacts with radio waves and so
23:07
Speaker 1: basically the picture was like crystal clear across millions of
23:11
Speaker 1: light years and then it gets to our atmosphere and boom,
23:13
Speaker 1: it gets fuzzed. So they have to solve that problem,
23:16
Speaker 1: which is pretty cool. They put like things up in
23:18
Speaker 1: the sky, or they used sources of radio in the sky.
23:22
Speaker 1: They saw how those were fuzzed, and then they try
23:24
Speaker 1: to unfuzzed their signal in the inverse way. So it's
23:28
Speaker 1: a really clever data analysis just to see this picture
23:31
Speaker 1: of the magnetic fields between galaxies. Did you say the
23:34
Speaker 1: project is called Loafer? Yes, it sounds kind of app
23:38
Speaker 1: for an astronomer, don't you think. I love my astronomy colleague,
23:43
Speaker 1: and so I will refraining from criticizing their acronyms. But
23:45
Speaker 1: I guess maybe a question is how strong are these
23:48
Speaker 1: magnetic fields? Like you know, I know the one here
23:51
Speaker 1: on Earth is enough to move a compass and deflect
23:53
Speaker 1: cosmic rays. But how strong is the one in from
23:56
Speaker 1: the Sun or the galaxy or are the How strong
23:58
Speaker 1: are these fields that you see between galaxy? These are
24:01
Speaker 1: not really very strong compared to the kind of things
24:03
Speaker 1: we feel on Earth or from the Sun. We're talking
24:06
Speaker 1: a few micro gals, which is a million times weaker
24:09
Speaker 1: than the Earth's magnetic field. These are really very weak
24:12
Speaker 1: magnetic field. But you know, there's a lot of space there,
24:15
Speaker 1: and so if you add them all up, it's a
24:18
Speaker 1: lot of magnetism, even though it's spread out pretty thin.
24:22
Speaker 1: All right, I guess the big question then is where
24:25
Speaker 1: are these magnetic fields coming from? Like, if I'm out
24:27
Speaker 1: there between galaxies, there's really literally nothing around me, right,
24:32
Speaker 1: Like there's no rotating black hole or there's no planet
24:36
Speaker 1: or electrical current, So how could it possibly have a
24:39
Speaker 1: magnetic field. So let's get into that question, But first
24:42
Speaker 1: let's take another quick break, all right, Daniel, So space
24:54
Speaker 1: has a magnetic field. Like if you go out there
24:56
Speaker 1: in space between galaxies, far from anything and you took
25:00
Speaker 1: out a compass, it would move, it would point somewhere,
25:03
Speaker 1: it would point somewhere. Yeah, the space between galaxies has
25:06
Speaker 1: a magnetic field. And this is something we only recently learned,
25:09
Speaker 1: like this is the paper from this summer twenty twenty
25:12
Speaker 1: and kind of mind blowing. And you know, the history
25:16
Speaker 1: of this research is like, well, let's check over here,
25:18
Speaker 1: Oh there is a magnetic field. Okay, well let's check
25:20
Speaker 1: over here. Oh my gosh, there's a magnetic field over
25:22
Speaker 1: there also. And so we basically never failed to find
25:26
Speaker 1: a magnetic field wherever we looked, which of course raises
25:29
Speaker 1: two questions. You know, one is like how far out
25:31
Speaker 1: does it go if you go out into like the
25:33
Speaker 1: massive voids in between superclusters where there's just nothing and
25:38
Speaker 1: nothing from billions of light years? Are there magnetic fields there? Also?
25:42
Speaker 1: And what could be generating all these magnetic fields. Are
25:45
Speaker 1: there magnetic fields out there in the middle of nowhere,
25:47
Speaker 1: So we don't know yet. We've looked out there between
25:50
Speaker 1: galaxies and we've seen magnetic fields between galaxies, like inside
25:54
Speaker 1: a galactic cluster, but it's pretty tricky to see things
25:57
Speaker 1: where there's nothing like. Our strategy or looking for magnetic
26:01
Speaker 1: fields relies on there being at least some matter there,
26:04
Speaker 1: some like thin filaments of gas like the ones that
26:06
Speaker 1: connects galaxies. You know, the space between galaxies isn't totally empty.
26:11
Speaker 1: There are a few particles there that we can use
26:13
Speaker 1: to trace the magnetic fields, and the way we talk
26:16
Speaker 1: about if we're looking deep into the void, it's much
26:18
Speaker 1: harder to tell if there are magnetic fields there. So
26:22
Speaker 1: we don't know the answer to that question yet. If
26:24
Speaker 1: there are magnetic fields deep deep out there in space,
26:27
Speaker 1: really far from anything in the megavoids. But we have
26:30
Speaker 1: ideas for how to look for the like there are
26:32
Speaker 1: no iron filings out there in the middle of nowhere,
26:35
Speaker 1: so you can't tell that's right. We need to come
26:37
Speaker 1: up with another technique for measuring those magnetic fields, and
26:40
Speaker 1: people have ideas, but to me, the big question is like,
26:42
Speaker 1: what could be making those magnetic fields? Like, what's the
26:45
Speaker 1: possible source? You mean the ones between galaxies are the
26:48
Speaker 1: ones in deep space both, right? And it might be
26:52
Speaker 1: the answer is the same. We have some understanding for
26:54
Speaker 1: what causes the magnetic field inside the galaxy that we
26:57
Speaker 1: don't quite know how we got started. We think the
26:59
Speaker 1: galaxies are powered by the spinning, but between the galaxies,
27:02
Speaker 1: like what could make those magnetic fields? It's just too big,
27:06
Speaker 1: too strong, too consistent between the galaxies to be coming
27:10
Speaker 1: from the galaxies themselves. Could it be like from the
27:13
Speaker 1: spinning of the galaxies, you know, like galaxies and the
27:16
Speaker 1: galaxy cluster could be spinning around maybe a common point
27:19
Speaker 1: and that's what's generating the field. It might contribute, and
27:23
Speaker 1: also like particles and gas ejected from the galaxies and
27:26
Speaker 1: all that craziness, But the cluster magnetic fields are too
27:30
Speaker 1: strong to be explained by all of those Sometimes they're
27:33
Speaker 1: even stronger than the galactic fields themselves. And also remember
27:37
Speaker 1: the galaxies take a long time to orbit the galactic center,
27:41
Speaker 1: and there's all these particles between the galaxies, but those
27:45
Speaker 1: aren't again, not enough to make these magnetic fields. And
27:48
Speaker 1: so we really have nowhere to look to to say,
27:51
Speaker 1: what's created this magnetic field, whereas the dynamo or the
27:54
Speaker 1: mechanism that's powering this thing. Is there a pattern to
27:57
Speaker 1: these fields in the inside of the clusters, like to
28:00
Speaker 1: these fields kind of point everywhere? Is it kind of random?
28:03
Speaker 1: Or like you know, like if I were out there
28:04
Speaker 1: in space between galaxies, would my compass go wild or
28:07
Speaker 1: would it be like I think I know where the
28:10
Speaker 1: center of the cluster is. Well, we've only begun to
28:13
Speaker 1: map this out, and we can only see it so
28:15
Speaker 1: far where there are particles in these very thin filaments
28:19
Speaker 1: of particles that stretched between the galaxy, So we don't
28:21
Speaker 1: have a great map yet. We're really only beginning to
28:24
Speaker 1: explore this, and so what we need is a better
28:26
Speaker 1: technique to give us a map for where all the
28:29
Speaker 1: magnetic fields are, even like far away from any of
28:31
Speaker 1: the galactic clusters, and based on the shape of those
28:34
Speaker 1: we might get an idea for where it could be
28:37
Speaker 1: coming from within a cluster, But out out between clusters,
28:41
Speaker 1: we don't know even if there are magnetic fields. We
28:43
Speaker 1: know that galaxies have fields and galaxy clusters have fields,
28:47
Speaker 1: and now we've learned that there are fields between clusters.
28:51
Speaker 1: But beyond that we don't know. There could be magnetic
28:54
Speaker 1: fields out there in deep space. We don't know. So far,
28:56
Speaker 1: everywhere we've looked there have been magnetic fields, all right.
29:00
Speaker 1: So that's a big mystery. So what could it be.
29:03
Speaker 1: Where could these magnetic fields come from? Well, nobody really
29:07
Speaker 1: has a great idea except for this one sort of
29:10
Speaker 1: super bonker idea which might explain it. And it's a
29:13
Speaker 1: fun idea because it also sort of solves another puzzle
29:16
Speaker 1: along the way. And that idea is that magnetic fields
29:20
Speaker 1: were created all through the universe during the Big Bang,
29:25
Speaker 1: like when things were hot and nasty and crazy in
29:27
Speaker 1: the very early universe, when there was just a lot
29:29
Speaker 1: of energy all around, some of it got dumped into
29:33
Speaker 1: the magnetic field and it just sort of never went away.
29:36
Speaker 1: And so this is energy left over in the magnetic
29:39
Speaker 1: field from the very early moments of the universe and
29:42
Speaker 1: now it's just stretching through the whole universe. Like maybe
29:46
Speaker 1: back when the universe was super dense and small, maybe
29:49
Speaker 1: it had like a spin to it, or it had
29:51
Speaker 1: a little bit of a magnet effect into it that
29:53
Speaker 1: then got blown up just like you know, space itself
29:58
Speaker 1: or the energy of the univer during the Big Bank.
30:01
Speaker 1: That's right, and today we only can make magnets by
30:04
Speaker 1: moving electrical charges. But you know, the magnetic field is
30:07
Speaker 1: just a quantum field. If you can somehow get energy
30:10
Speaker 1: into it, then that energy can just stick around like
30:13
Speaker 1: magnetic fields don't decay, they just stay. Like if you
30:16
Speaker 1: pour energy into a magnetic field, it doesn't necessarily leak
30:20
Speaker 1: out into another kind of energy. It can just hang out.
30:23
Speaker 1: And so the question is like, is there some way
30:25
Speaker 1: in the very early universe for energy to have like
30:28
Speaker 1: poured into this magnetic field bucket and then just gotten
30:31
Speaker 1: stuck there. I think you're saying that maybe the universe itself,
30:35
Speaker 1: the fabric of it, is magnetized. Yes, exactly. That's the
30:39
Speaker 1: really deep question. And people have always thought like, of course,
30:42
Speaker 1: not how could you have a universe spanning magnetic field,
30:45
Speaker 1: But it could be that one was made in very
30:47
Speaker 1: early times and now it feels all of space, even
30:50
Speaker 1: where there's nothing, there could be magnetic fields left over
30:54
Speaker 1: from the Big Bang, And people have been working furiously
30:58
Speaker 1: on It's called magneto genis on ideas for how in
31:02
Speaker 1: those very early moments in the universe when there was
31:04
Speaker 1: energy slashing around and you know, bubbling around, and so
31:07
Speaker 1: much energy that you couldn't even really think of like
31:09
Speaker 1: particles being formed. It was just like these hot fields
31:12
Speaker 1: bouncing around that some of it could have slashed over
31:15
Speaker 1: into the magnetic field and got stuck there. Wow, NATO genesis. Yeah,
31:19
Speaker 1: I like how you guys have a need to name it,
31:21
Speaker 1: you know what I mean. Like somebody was probably writing
31:23
Speaker 1: a scientific paper and they kept having to write the
31:26
Speaker 1: phrase where the magnetic field of the universe comes from?
31:29
Speaker 1: And so they said, you know, let's just give it
31:30
Speaker 1: a two word, cool sounding name. Oh no, it's one word, man,
31:34
Speaker 1: It's a single word. Nothing hyphens. It's it's like German.
31:39
Speaker 1: It's just one long word to describe your idea. All right.
31:42
Speaker 1: And so the itast and maybe the whole universe has
31:44
Speaker 1: a magnetic field. Does that mean that maybe you could
31:47
Speaker 1: use a compass to make your way around the universe? Yeah, exactly.
31:50
Speaker 1: It could give you like directionality. There could be like
31:53
Speaker 1: primordial flows and directions just left over from you know,
31:58
Speaker 1: whatever randomly was happening in that moment it in their
32:00
Speaker 1: early universe. And and really the only way to tell
32:03
Speaker 1: is to look where there's nothing, like there's already magnetic
32:06
Speaker 1: fields out here on Earth, so we can't search for
32:08
Speaker 1: these like primordial magnetic fields. What we need to do
32:11
Speaker 1: to look for them is to get really far away
32:13
Speaker 1: from everything, so far away from any physical source like
32:17
Speaker 1: moving charge, that the only way to have the magnetic
32:20
Speaker 1: field would be if space itself had left over magnetic fields.
32:24
Speaker 1: What you're saying, that's the only way we can tell.
32:26
Speaker 1: That's the only way we can tell. We have to
32:27
Speaker 1: remove all the other sources. We have to go into
32:30
Speaker 1: these voids and look for magnetic fields there between superclusters
32:33
Speaker 1: of galaxies, far away from any source, because there's nothing
32:36
Speaker 1: there for us to look at, that's right, And so
32:39
Speaker 1: there's nothing there to cause magnetic fields in a conventional way.
32:42
Speaker 1: And so if we find magnetic fields there, then we
32:44
Speaker 1: can say, oh, they're probably left over from the Big Bang.
32:47
Speaker 1: So that's really the leftover question is like, are there
32:50
Speaker 1: magnetic fields deep in the voids of space? Can we
32:54
Speaker 1: measure them? How can we figure that out? All right?
32:56
Speaker 1: So I guess the question is how could we figure
32:58
Speaker 1: that out without going out there? And we can we
33:01
Speaker 1: have some clever ideas. It's a lot harder. Right, if
33:03
Speaker 1: you don't have particles that are getting bent and shooting
33:05
Speaker 1: us radiation, then what you can do is look for
33:09
Speaker 1: the impact on photons, like photons that fly through these voids.
33:14
Speaker 1: Photons are magnetic objects right there, wiggles in the electromagnetic field,
33:19
Speaker 1: and so if they move through a magnetic field, it
33:22
Speaker 1: changes their polarization. You know how light has different kinds
33:25
Speaker 1: of polarization and basically like how its phase is spinning
33:29
Speaker 1: and you can block them with your sunglasses and it
33:31
Speaker 1: changes when it reflects, etcetera. Well, the photons have this
33:35
Speaker 1: little like track for how much magnetic field they have
33:37
Speaker 1: gone through, and so we can look at these photons
33:40
Speaker 1: and try to understand, like, how is their polarization changed,
33:44
Speaker 1: because photons they're not bent by magnetic fields, but you're
33:48
Speaker 1: saying they do sort of aligned to the magnetic field. Yeah, exactly,
33:52
Speaker 1: they aligned with the magnetic field. And they think that
33:55
Speaker 1: maybe these voids aren't totally empty. There might be a
33:58
Speaker 1: few sort of dust grains that get aligned with the
34:01
Speaker 1: magnetic fields and help support it and it could enhance it,
34:05
Speaker 1: and that as the photons fly through, they don't change directions,
34:08
Speaker 1: just changes their polarization. Basically, you can think about like
34:11
Speaker 1: the photon spinning. We talked about how the electron has
34:14
Speaker 1: a spin, it can spin up or down. The photon also,
34:17
Speaker 1: being a quantum particle, has a spin and so it's
34:20
Speaker 1: spin can change as it flies through these magnetic fields.
34:23
Speaker 1: This is even harder to do than the low far
34:26
Speaker 1: measurement that was looking for like characteristic photons from electrons bending.
34:30
Speaker 1: This is even more subtle and actually can't be done
34:33
Speaker 1: with low Far. They have to build something totally new
34:35
Speaker 1: to do this, done with high far, not low far.
34:39
Speaker 1: They're building in a ray that's an entire square kilometer
34:42
Speaker 1: dedicated just to radio antennas, and that's gonna be really
34:45
Speaker 1: good for this measurement. It's called the square kilometer array.
34:48
Speaker 1: It's gonna come online in T seven and it's gonna
34:51
Speaker 1: look at photons that have passed through these voids from
34:54
Speaker 1: you know, galaxies on the other sides of these bubbles
34:57
Speaker 1: to see if their light is spinning in a way
34:58
Speaker 1: that tells us whether they there are magnetic fields there.
35:02
Speaker 1: So it like if you see them all aligne one way,
35:05
Speaker 1: it would be suspicious, yeah, exactly. Or if you see
35:07
Speaker 1: patterns or something yeah, if you see patterns, well, we
35:10
Speaker 1: don't know the directions of those magnetic fields, right. If
35:13
Speaker 1: the magnetic fields are all aligned, it tells you that
35:16
Speaker 1: maybe it was made in the early universe during this moment,
35:19
Speaker 1: or maybe if they're like curved up like a ball
35:21
Speaker 1: of yarn, it tells you they were made in a
35:23
Speaker 1: different way. Or if they're all aligned like a corkscrew.
35:26
Speaker 1: The patterns of those magnetic fields are like a fingerprint
35:29
Speaker 1: to tell us how and when they were made in
35:31
Speaker 1: the early universe. So that would be fascinating data. If
35:34
Speaker 1: you could like know right now the direction of all
35:37
Speaker 1: the magnetic fields all through the universe, that would tell
35:39
Speaker 1: us a lot about what happened during the Big Bang, really,
35:42
Speaker 1: because these fields could be different depending on something that
35:46
Speaker 1: happened in the Big Bang, Like are there different kinds
35:49
Speaker 1: of magnetic fields? They're not different kinds of magnetic field,
35:52
Speaker 1: but depending on how the energy and when the energy
35:55
Speaker 1: got into the magnetic field, they would arrive in different patterns,
35:58
Speaker 1: you know, like did it it s law in there
36:00
Speaker 1: before there were particles or maybe after protons were formed,
36:04
Speaker 1: or even maybe billions of years later. There are different
36:07
Speaker 1: mechanisms were sort of getting the energy into the magnetic fields,
36:10
Speaker 1: and they leave different fingerprints on those magnetic fields. It's
36:14
Speaker 1: like clues at a crime scene, like a picture. It's
36:16
Speaker 1: like having a picture of what happened exactly. And you
36:19
Speaker 1: know that picture of the cosmic microwave background radiation, and
36:22
Speaker 1: it tells us like where the photons were that came
36:24
Speaker 1: out of that hot plasma. That pictures so much information
36:27
Speaker 1: about the nature of that plasma, what was going on
36:29
Speaker 1: inside it, and how things were bouncing around in it.
36:32
Speaker 1: We've extracted so much knowledge from that. This would be
36:34
Speaker 1: like a magnetic equivalent, but it might look back even further.
36:38
Speaker 1: That plasma we're talking about is like four thousand years
36:41
Speaker 1: after the beginning of the Big Bang. This magnetic picture
36:44
Speaker 1: might tell us about things that were happening you know,
36:46
Speaker 1: milliseconds or nanoseconds afterwards, and so it could be very fascinating,
36:51
Speaker 1: a big clue about the origin of the universe. Yeah, exactly.
36:55
Speaker 1: And there's another really fun way that we might be
36:57
Speaker 1: able to see magnetic fields. We look at these weird
37:01
Speaker 1: stars called blaze oers. Blazers are stars that have really
37:05
Speaker 1: high energy gamma rays, and these gamma rays sometimes when
37:09
Speaker 1: they're flying along through space. Remember they're just high energy photons.
37:12
Speaker 1: Sometimes they split into an electron and a positron and
37:15
Speaker 1: then they go back to being in a photon is
37:17
Speaker 1: a thing that photons do. They sometimes split and then
37:20
Speaker 1: come back. But electrons and positrons are charged particles, and
37:24
Speaker 1: so if there's a magnetic field there, then when the
37:27
Speaker 1: photon splits into the electron and positron, it's more likely
37:31
Speaker 1: to get broken apart, to separate, to get pulled apart
37:34
Speaker 1: by the magnetic field, and not recombine if it's going
37:37
Speaker 1: through a magnetic field to them, if it's going through
37:40
Speaker 1: a magnetic field exactly. So what we do is we
37:43
Speaker 1: look at blazeers and that can tell us whether there's
37:46
Speaker 1: a magnetic field between us and the blaze are. If
37:49
Speaker 1: we're sort of missing some of the high energy gamma
37:52
Speaker 1: rays from these blazers, that's suggests that they're basically getting
37:55
Speaker 1: filtered out by a magnetic field that's between us and them.
37:59
Speaker 1: It's sort of like magnetic lensing. Wow, I guess that
38:02
Speaker 1: the overall strategy is, since there's no stuff there is,
38:07
Speaker 1: to look at how these magnetic fields would affect light itself. Yeah, yeah, light,
38:12
Speaker 1: that's passing through it will get affected in all sorts
38:14
Speaker 1: of weird different ways, and that's going to carry information
38:17
Speaker 1: about where the magnetic fields are. So these are like,
38:20
Speaker 1: you know, crazy ideas. People are having to answer a
38:23
Speaker 1: question that ten years ago or twenty years ago people
38:25
Speaker 1: thought was crazy, you know, like why would you even
38:28
Speaker 1: worry about magnetic fields and the voids. Well, now it's
38:30
Speaker 1: a deep and fascinating question. It seems frankly kind of
38:33
Speaker 1: likely that there are magnetic fields there. I feel like
38:37
Speaker 1: we have to update now. The Boy Scouts training do
38:40
Speaker 1: not just include reading a compass and Earth. Now they
38:43
Speaker 1: should be trained about how to read a compass and space.
38:46
Speaker 1: What to do if you were lost in a Super Bowl,
38:49
Speaker 1: you know, be prepared. You never know give up, give
38:52
Speaker 1: up or give up. You're billions of light years from Earth.
38:57
Speaker 1: You have no chance. A compass is not going to
38:59
Speaker 1: save your life. Let's be realistic here, Step one, build
39:01
Speaker 1: twenty thousand telescopes out of twigs and merit badges. All right, Well,
39:08
Speaker 1: let's say that they do find a magnetic field of
39:12
Speaker 1: the universe out there in the voids of space between
39:15
Speaker 1: galaxy clusters, and let's say it has a pattern. What
39:18
Speaker 1: what does it mean? What would it tell us about
39:21
Speaker 1: I don't know what we know about the origins of everything. Well,
39:24
Speaker 1: it would give us sort of a picture as to
39:26
Speaker 1: the early universe, which I'm sure could answer all sorts
39:28
Speaker 1: of questions we can't even imagine asking right now. You
39:32
Speaker 1: know about how the universe went from like super duper
39:34
Speaker 1: hot to only just super hot to only just hot,
39:37
Speaker 1: and all these transitions, and we broke that down in
39:40
Speaker 1: an episode recently about the first two seconds of the universe.
39:43
Speaker 1: There are all these transitions where you go from like
39:45
Speaker 1: too hot to have particles, to be having these kind
39:48
Speaker 1: of particles, to having those kind of particles, and a
39:50
Speaker 1: lot of that is just speculations. So it would be
39:52
Speaker 1: really awesome to have like an image captured from one
39:55
Speaker 1: of those moments, you know, like an ultrasound to the
39:58
Speaker 1: whole universe as it was a be You all like
40:00
Speaker 1: to keep those pictures of when we were hot, for sure,
40:05
Speaker 1: minor photoshop dea. But also it's a really cool idea
40:08
Speaker 1: because it solves an outstanding puzzle we have in cosmology.
40:12
Speaker 1: What's the puzzle? Well, the puzzle is how fast is
40:15
Speaker 1: the universe expanding? You know, we look out into the universe,
40:18
Speaker 1: and we see the galaxies are moving away from us,
40:21
Speaker 1: and that they're moving away from us faster and faster
40:24
Speaker 1: every year. That's something we call dark energy. This is
40:26
Speaker 1: the accelerating expansion of the universe, and we use that
40:30
Speaker 1: to measure something we call the Hubble constant, which tells
40:33
Speaker 1: us basically, how fast the galaxy is accelerating away from us.
40:37
Speaker 1: It's like a kilometer per second per millions of light years.
40:41
Speaker 1: How fast that velocity is increasing, right, because it's changing, right,
40:45
Speaker 1: the expansion is changing. Yeah. And the interesting thing is
40:49
Speaker 1: that when you look and you're trying to measure this
40:51
Speaker 1: rate of expansion, and you measure it today using the
40:54
Speaker 1: expansion of galaxies and they use clever tricks to try
40:57
Speaker 1: to measure it in the early universe, you get a
41:00
Speaker 1: different number. And this is interesting because it tells us like, well,
41:03
Speaker 1: we don't really know how fast the universe is expanding,
41:05
Speaker 1: and we don't know if it's expanding at the same
41:07
Speaker 1: rate now as it was before, or is there more
41:10
Speaker 1: dark energy than there was before. We had a whole
41:12
Speaker 1: podcast episode about this, it's called the Hubble tension, like
41:15
Speaker 1: how fast is the universe expanding? We got two measurements
41:18
Speaker 1: that disagree. But yeah, they're different by about ten percent,
41:22
Speaker 1: but that's statistically significant. Like they're two teams are both
41:26
Speaker 1: pretty confident in their measurements, and so the question is like, well,
41:30
Speaker 1: what explains it? And you know, one measurement uses the
41:33
Speaker 1: expansion of the universe, that's the Late Times measurement, and
41:36
Speaker 1: the other one looks at the very early universe, those
41:39
Speaker 1: blobs we were talking about in the cosmic microwave background,
41:42
Speaker 1: and looks at the shapes of those blobs and the
41:44
Speaker 1: distances between them, and because the speed of the expansion
41:47
Speaker 1: sort of controls how many blobs you get and how
41:50
Speaker 1: far apart they are, and they make a measurement. So
41:53
Speaker 1: it's like the Early Days measurement versus the Late Days measurement,
41:56
Speaker 1: and they don't quite agree. So maybe they're saying that
41:59
Speaker 1: there is a universal magnetic field. Maybe that's kind of
42:03
Speaker 1: where the difference went. Yeah, exactly. The folks who analyzed
42:06
Speaker 1: their data from the very early universe assumed no magnetic field.
42:10
Speaker 1: But if you add a magnetic field to the very
42:13
Speaker 1: early universe, then it turns out you can have a
42:16
Speaker 1: larger Hubble constant, but it looks smaller and so essentially
42:20
Speaker 1: they did account for that in their early measurements. And
42:23
Speaker 1: so if the Hubble constant is actually the one we've
42:26
Speaker 1: measured in the late universe, it would give you exactly
42:29
Speaker 1: the picture you see in the early universe if there
42:31
Speaker 1: was a magnetic field. And so it's sort of like
42:34
Speaker 1: solves so that it corrects the tension. And it's very
42:36
Speaker 1: nice way. Now, who would be right then, the late
42:40
Speaker 1: measurers or the early measurers. Who would get bragging? Right?
42:44
Speaker 1: I'm sure everyone would find a way to brag, But
42:46
Speaker 1: this would suggest that the measurement by the expansion team,
42:49
Speaker 1: the folks who were looking at the actual expansion in
42:51
Speaker 1: the universe right now, sort of the late measures would
42:54
Speaker 1: be correct, all right. Well, and coincidentally they're the ones
42:56
Speaker 1: funding these new experiments. Everybody just wants to know the answer.
43:02
Speaker 1: But you know, that's exactly what we hope for. When
43:04
Speaker 1: we do a measurement, two ways that we think should agree.
43:07
Speaker 1: When we see a discrepancy, we think, well, maybe you
43:09
Speaker 1: made some silly mistake. But once you've crossed all those
43:12
Speaker 1: possibilities off, then the other possibility is maybe there's some
43:15
Speaker 1: new science going on here. We didn't account for maybe
43:18
Speaker 1: two different set of assumptions. One of them must have
43:21
Speaker 1: a mistake if the results don't agree. And that's exactly
43:24
Speaker 1: what we found. And so it's not like anybody screwed
43:27
Speaker 1: up here. It's just revealed something new about the universe.
43:30
Speaker 1: And so again this is still an idea, like, we
43:33
Speaker 1: don't know that there are magnetic fields all through space,
43:35
Speaker 1: but if there were, it would solve this problem very nicely.
43:38
Speaker 1: All right, Well, I think it seems like the answer
43:41
Speaker 1: is stay tuned. The answer is that there are magnetic
43:43
Speaker 1: fields here on Earth and the Sun and the gaxies
43:46
Speaker 1: and the galaxy clusters, which is already pretty amazing, but
43:49
Speaker 1: there might be an even bigger, universe wide cosmic magnetic field. Yeah, exactly.
43:55
Speaker 1: It's incredible that we keep finding magnetic fields everywhere we look,
43:59
Speaker 1: despite our ex pectations, and that's pretty fun. It's fun
44:02
Speaker 1: to see surprises out there in the universe and then
44:04
Speaker 1: to have to try to explain them to me. That's
44:07
Speaker 1: much more exciting than finding what you expected. It's finding
44:10
Speaker 1: what you didn't expect and then having to change your
44:13
Speaker 1: concept of the universe, bending your concepts to the data itself.
44:17
Speaker 1: I guess my question, Daniel is that if the universe
44:19
Speaker 1: has a magnetic field, does that mean it has a
44:21
Speaker 1: north and a south pole? And would you find a
44:25
Speaker 1: universal Santa clause in the north pole? That would be
44:27
Speaker 1: quite a gift. Jokes aside, though, we don't know the
44:30
Speaker 1: pattern of that magnetic field, and so we don't know
44:32
Speaker 1: it's orientation if it's totally balanced, so if it's curled
44:34
Speaker 1: up in all sorts of ways. But that's exactly the
44:37
Speaker 1: kind of question we'd like to ask. We'd love to
44:39
Speaker 1: see that picture so we can ask those questions. We
44:42
Speaker 1: need a special array, like a Santa array to be finally,
44:45
Speaker 1: the term that all right, well it's it's again. It's
44:48
Speaker 1: just another one of these crazy measurements and ideas that
44:52
Speaker 1: tell you that there are invisible things out there in
44:54
Speaker 1: the universe that we can't immediately see, but are there
44:58
Speaker 1: and are part of the history and origin of how
45:01
Speaker 1: things came to be the way they are. That's right,
45:02
Speaker 1: And so the universe is filled with mystery. So there's
45:05
Speaker 1: lots of room for your creativity and your curiosity and
45:09
Speaker 1: vast enigmas waiting to be solved. You just need a
45:12
Speaker 1: compass to help us find them. Thanks for joining us.
45:14
Speaker 1: We hope you enjoyed that. See you next time. Thanks
45:25
Speaker 1: for listening, and remember that Daniel and Jorge explained. The
45:28
Speaker 1: Universe is a production of I Heart Radio. Or more
45:31
Speaker 1: podcast from my heart Radio, visit the I Heart Radio
45:34
Speaker 1: Apple Apple Podcasts, or wherever you listen to your favorite shows.
45:44
Speaker 1: Ye