In this episode we talk about Dark Matter, Gravity Waves, Gravitational Lensing and other Astronomy with WWU astrophysicist Dr. Kenneth Rines.
Dr. Rines succeeded in teaching the guest host, Dr. Regina’s brother and local actor, Ruben Chen science (Regina could not). We had a great time learning about things in the universe that still confuses scientists today.
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Speaker: Here we go.
[? Blackalicious rapping Chemical Calisthenics ? ]
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? I’m every element around
Dr. Regina: Welcome to Spark Science where we explore stories of human curiosity. I’m Regina Barber DeGraaff, astrophysicist and pop culture enthusiast. Today we’re going to talk about dark matter and dark energy, maybe gravitational waves, and planet 9.
But before we do that and before I introduce our wonderful guest today, I want to tell the viewers that we have a guest host. If you have listened to past shows, you know that the only guest hosts I’ve had are people related to me and today is no different.
My guest host today is an actor. He actually has an IMDB entry and he is a hotel manager, my little brother, Ruben Chen. How’s it going?
Ruben: It’s going well. Thank you very much. I can add the IMDB page entry, that’s singular. One entry.
Regina: Who got you into acting? I just want our listeners to know like who helped you and supported you and made you want to do that to start with?
Ruben: It was my wonderful sister Regina Barber.
Regina: Oh, that’s right. I forgot. [Joke/joking.]
So, let’s introduce our guest today. Our guest is my colleague, somebody who I’ve known for a good amount of time, lives at work down the hall from me, Dr. Ken Rines. Welcome.
Dr. Ken Rines: Hello. Thank you.
Regina: How would you describe your work in like a couple of words?
Ken: I study what we can’t actually see with our eyes or with light. So, trying to find out what we can find out about the universe by watching galaxies move and studying how structures change in the universe.
Regina: That’s basically the theme of this show. We’re gonna talk about your suggestion, finding our way in the dark.
Ken: Right. Seeing what we can learn about objects in the universe using indirect techniques.
Regina: How did you get into this specific subset of astronomy? Let’s all go in the time machine and now I see like baby Ken.
Ruben: At six feet tall still. [Joke/joking.]
Regina: Yeah, six feet tall.
Ken: I was a little shorter back then.
[Laughing.]
Regina: Yeah. He was 5’8″ at baby.
[Laughing.]
Did you always love astronomy as a kid?
Ken: I do remember a really cool astronomy book that I had in maybe 4th or 5th grade that had lots of beautiful pictures and talked about black holes and neutron stars and it all sounded really cool but I somehow never made the connection as a kid that this is something that people actually discovered at some point. It took me many, many years until high school or college to figure out that everything in that book had been basically discovered by people going out and using telescopes and doing calculations to figure these things out.
Regina: Did you go to any space centers and stuff like that or science centers when you were a kid?
Ken: Local science museum a lot, but not really space centers.
Regina: I was never that lucky either.
Ken: I’d actually give a lot of credit to my high school teachers. I had a couple of great chemistry and physics teachers. They were not only great teachers, but they were so enthusiastic about science in general. They worked with some people at the local university. They actually put on physics demonstration shows for local school groups.
Regina: What? Where was this?
Ruben: Where did you grow up?
Ken: In Minnesota.
Regina: Okay.
Ken: I think they even performed once at Disney Land for a —
Regina: What?!
Ken: They managed to put on some pretty elaborate shows.
Ruben: That’s cool.
Ken: It was very interesting just the way they approached everything. One of the things that I remember each of them made a point to tell everybody in the class repeatedly how bad they were at science when they were in school.
Regina: Yeah, I do that a lot.
Ken: It was fascinating because they were outstanding teachers of science and did a great job communicating ideas and how exciting they were and working out the idea of science as a process. My physics teacher would always set up these experiments and basically he would show us how everything was set up and then he’d say, “Okay, now your job is to make a prediction. You have to predict what’s going to happen with this.” Then, we’d spend most of the class doing that and then at the end of the class we’d actually get to find out if our prediction worked.
One time our prediction totally failed so then he actually let a couple of us back into the classroom during our lunch hour.
Regina: Wow. You were that dedicated.
Ruben: Wow. Wow. Good for you.
Regina: I love that they went to Disney Land. Do you remember their names, these teachers?
Ken: My chemistry teacher’s name was Hank Ryan [sp?] and my physics teacher was John Barber [sp?].
Regina: Oh okay. Barber’s a good name. [Joke/joking.]
Ken: Yes, no relation.
Regina: No, no relation. No relation.
Ruben: This is why we can’t have nice things.
Regina: No, or nice names. [Joke/joking.]
So you have this awesome high school experience with really good science communicators and then you go to undergrad. Was it different? Was it a different way that they taught science?
Ken: For undergraduate, I actually moved from Minnesota down to Houston, Texas, so a very different environment.
Regina: No, it’s the same. Totally same environment. [Sarcasm.] What are you talking about? I’ve never been to either.
Ken: The best is one winter break, I’d get on the airplane in Minnesota where it was 20 below zero. You get off the airplane in Houston and it was like 80 degrees.
Regina: Right, and you’re like what is happening?
Ken: Yeah, it was a very different vibe, certainly.
Regina: Vibe is a good word. [Laughing.]
Ken: It was at Rice University, which is a mid-size university, not as small as some small liberal arts colleges, but not as big even as Western, which is sort of middle sized, but still the introductory physics classes were 150 students in a big auditorium.
Regina: Ugh.
Ruben: Oh wow.
Ken: It was surprising how different that was from the high school classes even. It was still fun, but it wasn’t quite as engaging or interactive. Interactive would be the biggest thing there.
Regina: Did you get to do any research related to what you’re doing now in undergrad or was that all grad school?
Ken: Eventually I did a couple of summer programs after taking an astronomy class and realizing, hey this sort of got me back to that old book that I had read as a kid and realizing, oh wait, there were people that actually figured all these things out and there are people doing that now. Maybe you can actually get paid over the summer to do this. There were a couple summer internships like that. I was lucky enough to do a couple of those, one at Northwestern looking at gamma rays from the center of the Milky Way.
Regina: That’s awesome.
Ken: Then, one at the Smithsonian Observatory in Boston where studying X-rays coming from giant clusters of galaxies. Now I study the galaxies and the clusters of galaxies. So, similar objects, but different specific focus.
Regina: So, did you go into Rice thinking, “I want to be an astronomer” or was it finding your way?
Ken: A bit of finding my way. I’d sort of moved in high school in the direction of physics, because I was fortunate to have some really good math classes and get involved in some math programs. I was able to take really college level math classes as a high school student.
Regina: Which is always nice, but sometimes impossible.
Ken: The physics classes were really fun because I could really see there where the math classes were useful for that, whereas for high school chemistry at least, the math level isn’t as rigorous.
It was fun to see things like ideas in calculus directly used in the physics classes. The whole idea of this fundamental science and finding out what’s going on on the smallest scales, what the building blocks of the universe are.
Regina: So, Minnesota to Texas, and then you went to Harvard, which was totally the same as all those places, right? [Sarcasm.]
Ken: Absolutely, yes.
Ruben: You lost me at high school math.
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Regina: How was Harvard different from all these places? Very? [Laughing.] I don’t know. I just assume.
Ruben: Compared to Houston.
Regina: Another place I haven’t been.
Ken: Rice was a very good school and there were a lot of great students there. Many other physics majors much smarter than me that were there, so it was great to get that experience. Certainly, at Harvard, there were some of my grad student compatriots did absolutely amazing things, even in their thesis work. It was just a lot of fun.
The astronomy department has a special, unique feature that there is the Harvard Department of Astronomy, but then there is an institution — the Smithsonian actually has an astronomical observatory that’s located in the same place. So they have this giant center that has like 200 PhDs, large number of senior scientists doing all sorts of astronomy. Huge amount of science, especially astronomy, going on, all sorts of wavelengths, all sorts of objects.
Ruben: Influence is everywhere.
Regina: If I was there, I’d feel completely lost.
Ken: Even the building is famous for having many ways of getting lost, just walking around the building.
Regina: So, mentally you’re lost, physically you’re lost.
Ruben: Emotionally, you’re drained.
Regina: Okay, let’s get into then these definitions of some of your research and some of the stuff I think our listeners are really excited about: this idea of dark matter and dark energy. Why don’t you tell us more about your research and then kind of fill in the gaps of those definitions? My brother here, who knows a little less than me about this subject, can — [sarcasm.]
Ruben: I can spell “science.”
Regina: Good. I can barely. [Joke/joking.] If you’re lost, Ruben, please tell us.
Ruben: No, I like this. I don’t know, most people probably can’t see his face, but you’re smiling throughout all of this. It’s very engaging. I’m drawn into it, so by all means, I’m learning. I like this.
Regina: Tell us more about your research and fill in the blanks.
Ken: The basic idea of a lot of my research actually goes back to some of the physics ideas that I think I first learned in high school, just things like gravity is a force that pulls on things. We know that when you drop something on the earth, it falls towards the earth.
It can also do things where you can have an object going in a circle. So, the earth goes around the sun, because the sun is pulling on the earth with gravity. That same basic idea, you can apply that almost anywhere in the universe. So, you can figure out the sun and all the planets are going around the Milky Way galaxy. You can use that to figure out what that gravitational force is, which tells you how much stuff there is in the Milky Way.
Then, on larger scales, on these clusters where you have not just one Milky Way galaxy, but you have 50 or 100 Milky Way sized galaxies all orbiting each other. You could actually measure how fast they are orbiting each other and use that to figure out how much total stuff is in the cluster of galaxies.
The exciting part there is that you find out that when you add up all the matter that has to be there, there’s a lot more than you can account for from the stars that are in the galaxies, which is very weird, because we think most of the normal matter that we’re used to thinking of (atoms and molecules), almost all that matter is locked up in stars, or there are other ways of being able to see it. There’s a lot of stuff in these clusters that is not something you would find on the Periodic Table.
Regina: If we just take a step back for anyone who kind of hears the word “gravity” and then hears “stuff,” we need to just make sure that gravity itself is due to mass. It’s directly linked. These movements of objects, these kinds of orbits, the gravity that’s being exhibited or the movement that’s being exhibited tells us something about the mass related in that orbit or involved in that orbit, I guess we could say.
Ken: Roughly speaking, the more mass we have, the stronger the gravitational pull you have.
Regina: Right, that’s what I’m trying to say. See, you know what I’m saying.
Ruben: No, I totally got that.
Regina: Okay. I mean, the mystery is — when did this happen? When was this mystery or this question first asked? We’re looking at these orbits, we’re looking at these movements of galaxies in clusters and then we have this missing mass? When did that start? What year was that?
Ken: So, the first published evidence of that was by this guy Fritz Zwicky in 1933. It’s becoming a really old problem by now. He originally called it the missing mass, that there’s a lot more mass in these clusters than is apparent from just counting up all the stars in the galaxies. He said this is a problem.
Fritz Zwicky is a very entertaining astronomer. He had a very eccentric personality, very strong opinions, incredibly creative, he had all sorts of ideas about all sorts of different things about supernova, neutron stars. He was notoriously ornery.
Regina: Really? Is there stories?
Ken: A lot of people didn’t like him.
Regina: Wow. That is not what Cosmos told me.
Ken: Oh, he’s a very colorful character. I think there’s some stories that wouldn’t quite work on radio.
Regina: Oh, excellent.
Ruben: Fantastic. Let’s hear these stories.
[Laughing.]
Regina: During the break.
Ken: He had lots of amazing ideas. Some of them were amazingly far ahead of their time. Others of them were spectacularly wrong, but you take the good with the bad.
Regina: Right. It’s just volume. This is 1933 you said. Then, when did we start labeling this missing matter as dark matter?
Ken: That came mostly a few decades later, partly because Zwicky was such a colorful character. Many people sort of lumped this in, “well that’s Zwicky’s crazy idea. Maybe we shouldn’t put too much –.” A lot more people started to believe it with later work, especially by an astronomer called Vera Rubin, who studied individual galaxies.
Regina: Ruben’s like, “Yes.”
Ruben: I like this one.
Ken: She studied spiral galaxies like our own Milky Way and did the same type of exercise of, in this case, looking at stars going around galaxies, rather than galaxies going around a cluster of galaxies. So, doing the same basic type of analysis, but now applying it at a different scale where you can make the measurements — you could argue, you could make the measurements a bit more robustly there, at least at the time.
She was finding very similar thing that you found — that the speeds of the stars around the galaxy were so fast that you could only explain that by having much more mass there than you have just in all the stars. Again, this idea that there’s some missing mass that’s not glowing. You can’t see any light from it, so there’s some sort of matter there that’s not emitting light.
I’m not sure who first came up with the term “dark matter,” but that was when the whole community started to take it very seriously. Now you were seeing a similar phenomenon in different types of objects, which is always one of those things that’s great to see in science, where you get not just one piece of evidence, but a different piece of evidence that points towards the same thing.
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Ruben: Welcome back to Spark Science. We’re here today with Dr. Rines talking about dark matter and dark energy with your guys� favorite host, Ruben Chen.
Regina: Guest co-host.
Ruben: Yes, favorite first primary host.
Regina: Yes, my brother is great. Continue.
Ruben: Dr. Rines, just going into it, obviously, like I was saying earlier, I can spell the word “science.” I can probably spell “dark” and “matter” because that’s my fianc�s last name.
Regina: Yeah, it is actually.
Ruben: It is.
Regina: Who is also from Lynden.
Ruben: Who is also from Lynden.
Regina: My brother, just for listeners, is also from Lynden, obviously, because he grew up with me.
Anyway, go ahead. You were asking a question.
Ruben: Yeah. I’m not entirely lost, but going back to the viewers who are much like me. What is matter? How would you define matter?
Ken: That’s a great question. So, the physicist’s definition of matter would basically be something that interacts with gravity, so if you have something that has mass, something that has matter, that matter will interact with other bits of matter with a gravitational force and will pull on other bits of matter. That’s where the problem comes from is — we know that there’s something there, something that has mass, that you can say it has this many kilograms of stuff there. But, nobody actually knows what that stuff is and that’s where it’s utterly mysterious and it’s amazing how long standing this problem has been.
Ruben: Completely hypothetical.
Ken: Basically. So, there are lots and lots of ideas. The first suggestion was in 1933 and there have been decades of very smart people trying to think up creative ideas of what this matter could be.
Regina: Because we can’t see it.
Ken: Right, by definition you can’t see it or it wouldn’t be dark. It seems to behave in a way that it actually doesn’t interact with light at all. In astronomy, that’s what you usually do is you study light coming from distant galaxies.
Now, there are some particles that we know that act sort of like that. There’s a particle called a neutrino, which is involved in nuclear reactions. Our sun is powered by nuclear reactions in its core. So, the sun is producing these neutrinos at a tremendous rate and they’re going out in all directions. But, the neutrinos, they don’t interact with normal matter very often. They do very occasionally, but a neutrino could go through the entire earth and not interact with anything.
There’s a great statistic that there is something like 20 trillion neutrinos going through your body every second and not one of them actually interacts with any of your atoms.
Regina: I love it, because you’re gonna make conspiracy theories and will people be like, “That’s where cancer comes from.”
Ken: Oh, yeah. Well, because they never interact. That’s the amazing thing.
Regina: Yeah.
Ken: So, neutrinos are something — people actually suggested neutrinos as being a great candidate for dark matter. They have the great advantage that it’s a particle that we know exists. There’s lots of good evidence that neutrinos exist.
Regina: That was huge in the ’90s, right? It was like huge.
Ken: Yeah. But, there is one problem. First of all, neutrinos, they just don’t have enough mass to represent the dark matter. There are various estimates of how many neutrinos are out there and there are various ways of trying to figure out how much mass neutrinos have. There are now pretty good limits on what the mass can be.
So, neutrinos exist, but they don’t seem to have enough mass to make up dark matter. They might have a small amount of mass, which leads to some other interesting stories, but it turns out that that small amount of mass isn’t enough to explain the orbits that you see in galaxies, or the orbits you see of galaxies going around clusters.
Ruben: So, dark matter is not the evil matter, because I was pulling bizarro world. Like, there’s matter and then there’s dark matter.
Ken: Yeah, so another thing it’s not would be antimatter. So, that’s another thing that you’ll hear about sometimes.
Regina: Like bizarro Superman.
Ruben: That’s what I was thinking of.
Regina: But he’s not evil; he’s just confused. Let’s be nice to him. He grew up in a different environment and he doesn’t understand our environment. He’s not evil. I’m just saying.
[Laughing.]
It’s not antimatter, which you can explain to our listeners as well.
Ken: Antimatter is — there are particles that we know about. Atoms are made of protons, neutrons, and electrons. For every particle, like a proton, there’s an anti-particle. So a proton has an anti-particle called an anti-proton, creatively enough [sarcasm.]
[Laughing.]
Regina: Right. We’re good at naming things. [Sarcasm.]
Ken: There’s a big difference between antimatter, like that, and dark matter. Because antimatter — if you have an anti-proton and a proton, if they ever meet each other, they annihilate in a giant burst of energy.
Regina: So they definitely interact.
Ken: Yes, they interact very strongly. They produce two gamma rays, two particles of light that have a lot of energy. So, if you had a pocket of antimatter somewhere out in space, that pocket of antimatter would be interacting with regular matter, creating tremendous numbers of gamma rays since you’d be able to see some part of the sky glowing with gamma rays because of that antimatter.
We know it can’t be antimatter, we know it can’t be neutrinos. There’s this whole list of things that it can’t be. Again, particle physicists get very creative in their ideas and they say, okay, maybe there’s some type of particle that we don’t know about, we don’t know exactly what it is. It might be related to super-symmetry ideas, maybe vaguely related to string theory but no clear prediction on exactly what that would be.
So, just like particles have anti-particle partners, the idea with super-symmetry would be that each particle also has a super-symmetric particle that is similar to it.
Regina: Okay, that doesn’t annihilate?
Ken: Right.
Regina: Okay, got it.
Ken: So, you’d have a proton and then a super-symmetric partner of a proton. Or, an electron —
Regina: That’s just something else that we don’t really know what it is.
Ken: Right. An electron has a super-symmetric partner called a selectron. The names get absolutely horrible.
Ruben: Those are cool. I like those names.
Regina: So, first they’re just really bland and then they become horrible is what you’re saying.
Ken: Right. There are a lot of these super-symmetry particles. So, one popular idea has been that one of those super-symmetry particles might represent dark matter.
Regina: I do want to bring us back to what we were talking about before the break, because some of our listeners might just be like “Why can’t, let’s say planets, or this new Planet 9, why can’t other matter that is matter that we’re used to but just doesn’t emit light because it’s not a sun or something, how come that can’t make up for the dark matter?” I do know the answer, but I would like you — you can kind of elaborate on that, because I hear that a lot.
Ken: Oh yeah. Again, a few decades ago, this was a very contentious question about whether dark matter could be explained by things like planets that are dim matter, they’re not completely dark, but they don’t give off a lot of light. So if you had lots of free floating planets, that could explain where that missing mass is, or where at least dim matter, if not completely dark.
But there are other ways of detecting a lot of those things that astronomers have spent tremendous amounts of effort trying to detect evidence of things. Like, if you have free floating planets or very dim stars or white dwarfs or solar mass black holes, all sorts of things like that, they actually create gravitational lensing signals. So, if one of these particles goes between us and a distant star, you’ll see that background star get brighter for a short period of time and then it gets dimmer again.
So, a bunch of astronomers made a big survey to monitor thousands of stars and try to look for these little flickers. They did find some of the flickers. But then, when you figure out how much mass that represents, it’s a tiny fraction. It’s there, like neutrinos, there is mass there, but it’s not nearly enough to explain all of the dark matter.
Regina: Right.
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Regina: When you say it’s not neutrinos, it’s not these planets, what we’re really saying is that that is a so tiny fraction of what this unexplained matter could be.
Ken: Right. Almost all of the dark matter is something very weird that doesn’t show up as anything you find on the Periodic Table. It’s not atoms, it’s not molecules, nothing made of atoms or molecules, like planets or stars, which is very weird. That’s why the particle physicists get very creative, and then the experimental physicists, they also get creative and try to build new detectors, because some of the models say that, like neutrinos, these things won’t interact with normal matter very often. But, very occasionally, they will. So, if you build a really big detector and look really hard for evidence of these particles, maybe you would occasionally see some of these interactions.
It’s a fascinating idea. The experimental searches for dark matter particles have been going on now for decades, about 50 years now. They keep on finding nothing. It’s tremendously hard work for —
Regina: It’s a similar story to maybe the other thing I’d like to talk about today. We can kind of link it to when you said lensing — gravitational waves. I remember being in grad school, I went to WASU, Washington State University. There’s a good amount of people there that work with LIGO, which is —
Ruben: I was hoping you were actually talking about Lego.
Regina: Laser Interferometer Gravitational-Wave Observatory. So, I remember presentations from LIGO, quarter after quarter, I’m like, we’re gonna detect gravitational waves. We’re gonna do it. We’re so close. I don’t want to say decades, it probably was though, decades of work of just like nothing was happening. Finally, just this last week, something happened.
So, before we go into the definition of what gravitational waves are, let’s take a step back and talk about lensing and talk about maybe space. You’re nodding your head because I think you know where I’m going with this.
So, let’s talk maybe about what is lensing, and then we can talk about gravitational waves.
Ken: Right. Well, gravitational lensing brings us back to the dark matter idea very well. In the same way that gravitational lensing — the basic idea, the classic picture is that you try to picture space as being an infinite rubber sheet. Then you put bowling balls or golf balls on the rubber sheet and they create distortions. Then if you send other things close to the bowling ball, their path will get distorted a little bit.
Regina: It’s like that thing at the mall, the thing where you put coins in, and you drop the coin in and it kind of goes around and around. Then it gets sucked into —
Ruben: It pulls it in.
Regina: Right. Or, if you have enough velocity, it would stay there for a while, like it’s gonna orbit around for a while.
Ruben: I’ve wished that for years; it never happens.
Regina: Well yeah. There’s a lot of wobble in stuff.
Ken: Or, if you’re a particle of light, your path would get bent. Instead of going in a straight line past that little well, your path would get deflected a little bit.
Ruben: Or get pulled.
Ken: Right. So that creates this distortion. For our cluster of galaxies, it actually works very similar to the distortion that you see if you break a wine glass and look through the stem of the wine glass. You can see that it’ll stretch out objects that are behind it. So, things will get stretched out and make little circles around the stem of the wine glass.
So, a big cluster of galaxies does the same thing, because it has a lot of mass, so it creates a lot of distortion in space-time. So, then background galaxies, there’s light from galaxies that are very far away that gets bent by that gravitational disturbance and it gives you a signal that you can measure.
Basically, the more mass of the cluster is, the more distortion you get on the shape of the background galaxies.
Regina: Sometimes it can give you a distorted image from the background galaxy or sometimes it can give you multiple images of that background galaxy, which are kind of — I dunno — a halo — I’m moving my arms around in a circle. But, like haloing around the massive galaxy cluster.
Just for our listeners, when we keep on saying galaxy cluster, what we mean is that we right now live in the Milky Way galaxy, but the Milky Way galaxy is right next to other galaxies like Andromeda Galaxy, which you can actually see next to Cassiopeia if you look up in the sky.
So, we have a whole bunch of galaxies kind of around our own galaxy. In the universe, there is a lot denser clumps of galaxies than what we live in right now. That’s what we’re talking about, just to clarify.
Ken: Right. The Milky Way is in a small group of galaxies that has two big galaxies and a few dozen small galaxies. Then these clusters have, instead of two Milky Way sized galaxies, they have several dozen, or a hundred Milky Way sized galaxies.
Ruben: Much larger.
Regina: Yeah.
Ken: Yeah, much bigger. They have probably thousands of these dwarf galaxies.
Ruben: Does that mean more distortion?
Regina: Right, exactly.
Ken: Bigger distortion.
Ruben: Yes, I understood that.
Regina: He’s like learning something here.
Ruben: I should take a class from you.
Regina: You could.
Ken: With the gravitational lensing for the clusters, one of the really cool things there is one of these things that we like to do in science, is when you have an idea, especially a weird idea like, “Hey this cluster is filled with dark matter that is made of some weird stuff that we’ve never seen before,” you’d like to figure out, can you actually get multiple lines of evidence.
So, now you have the same object, you have the same cluster of galaxies, and you can figure out, you can measure the speeds of the galaxies going around and you can use that to figure out how much dark matter there is. But then you can also look at this and if you can measure that gravitational lensing effect, you get a totally independent way of trying to measure how much stuff is in the cluster, how much dark matter it has.
Regina: Like you just said, more mass means more distortion, so if there’s a lot of distortion, then you know there’s a lot of mass there.
Ken: Then you can do the really tricky thing is to see if you can get the same answer using both techniques. By and large, you get basically the same answer, that you need the same — both measures tell you that the clusters have the same amount of dark matter. That’s one of those great things where it says, okay, either that dark matter really is real. We have multiple lines of evidence that give us the same answer, or nature is extremely creative in its ways of confusing us.
[Laughing.]
Regina: I like that answer. That’s very important. These distortions can give us mass, like you were saying. This is probably new for a lot of people too that not just the planets go around the sun, but like you said, the stars also go around the center of the Milky Way. Galaxies like the Milky Way also orbit around other galaxies.
Ruben: Everything’s moving.
Regina: Everything’s moving. That’s something that’s very new for our students.
Ruben: So, the earth is not flat.
Regina: The earth is not flat.
[Laughing.]
I can’t believe that’s gaining momentum right now.
Ruben: It’s gaining a lot of momentum. It hurts me.
Regina: It’s because X-Files came back on, I think conspiracy theories are just like rising.
Ruben: Mulder and Scully are just like, “The earth is flat.” [Joke/joking.]
Regina: No, they would never say that. So, we talk about this idea of lensing, like I said, with the distortions. When I learned about gravity waves, it talked very much about these very massive objects moving around and then they’re sending ripples in space. Help me describe that better. [Laughing.]
Ken: Right. So, the cartoon example is, going back to the rubber sheet, if you had now two bowling balls, so each bowling ball is making its own distortion on that rubber sheet. Now, those bowling balls are orbiting each other, so they’re going in circular orbits around each other.
Regina: As Dr. Rines is doing this with his hands. He’s orbiting the two objects, the two bowling balls.
Ken: If you move the bowling ball around on the rubber sheet, it’s going to shake the sheet and it’s going to send little distortions that are going to travel outward.
Ruben: Ripples.
Regina: Yeah.
Ken: Ripples, exactly. Sort of like dropping rocks in a still pond. You can see the ripples go out.
Regina: Right. But now you’re moving the rocks and you’re doing this and making those ripples.
Ruben: But you’re still moving your hands, you can’t see that —
Regina: We all are now.
Ruben: Simultaneously.
Ken: So those ripples are traveling out, they’re actually carrying away energy from the system. So there was actually a long debate. This is one of the reasons why people debated a long time if LIGO would ever see anything, because they didn’t actually know if you have two black holes orbiting each other, it wasn’t clear if black holes would eventually merge or if they would just orbit each other for a very, very long time where you would never see them actually merge.
The big excitement — this is just on Thursday — February 11, 2016, the dawn of gravitational wave astronomy. So it’s a whole new era, a totally different way of looking at the universe.
Regina: So many happy astronomers. Just to clarify too, black holes are supermassive. Well, there are supermassive black holes, but black holes have a lot of mass. So, that’s why when they’re moving around, they are, like you said, more mass, more distortion. That’s why you’re saying two orbiting black holes.
Ken: Yeah. Also, these black holes were very close to each other. What happened is they were slowly losing energy, radiating energy away in these ripples. Then they got closer and closer together as they did that. Then eventually they merged. When they merged, that produces this characteristic signal that has been described as a chirp.
Regina: It’s very uneventful though.
Ken: So, there are these gravitational waves that get higher in frequency. So, when we talk about sound waves, if you have a higher frequency, that’s a higher pitch. Sort of like a “vwoop.”
[Laughing.]
Ken: If you drop water into — listen to water dropping, you hear a little “bloop.” That’s effectively what the signal that they heard on this gravitational wave observatory.
Regina: Which, I don’t know if we want to get into explaining that observatory, but we’re gonna take a quick break. When we come back, we’re gonna talk about finding objects using gravity, like let’s say Planet 9, or maybe even in history with some famous planets. Finding things using gravity and then we’ll talk about pop culture, because I love it.
[? Beastie Boys singing Intergalactic ?]
? Jazz and A.W.O.L, that’s our team
? Step inside the party, disrupt the whole scene
? When it comes to beats, well, I’m a fiend
? I like my sugar with coffee and cream
? Well, I gotta keep it going keep it going full steam
? Too sweet to be sour to nice to be mean
? Well, on the tough-guy style I’m not too keen
? Trying to change the world, I’m going to plot and scheme
? Mario C. likes to keep it clean
? Gonna shine like a sunbeam
? Keep on rappin’, ’cause that’s my dream
? Thank Moe Dee for ‘Sticking to Themes’
Regina: We usually end our show talking about pop culture and I think it’s a really easy way to talk about the popular stuff that’s happening right now related to — Ken, you said finding things or detecting things or inferring objects through gravity.
I know that there’s this very famous story about one of the funnier planets. Planet 9 is like getting a lot of press. This idea that there’s this other planet in our solar system that we didn’t know about and we found it. How did we find it and how does that relate to astronomy history?
Ken: That’s one of the fun things because nobody has found it yet.
Regina: Ah hah. So it’s just hype.
Ken: Well, hopefully not, but we’ll find out. That’s where astronomy is a lot of fun, because there are new things happening every day. Partly, it links to this history in astronomy of finding new objects by weird things that you notice in orbits. So, the most recent announcement was basically that some other astronomers had made this discovery and discovered all of these large things not quite as big as Pluto, but things that are probably maybe dwarf planet size, so not as big as Pluto, but fairly massive things in the outer solar system.
Regina: There’s a small dwarf planet in between Mars and —
Ken: Jupiter.
Regina: Yes, Mars and Jupiter. What is it, like a third of Pluto in size? What is the proportionality? I don’t remember. It’s smaller.
Ken: I forget off the top of my head. Yeah, it’s about 300 kilometers in diameter.
Regina: I keep on thinking like a third or a quarter or something like that.
Ken: Right. Ceres, which is the largest asteroid in the asteroid belt, and so that’s —
Regina: Which is still pretty big.
Ken: Yeah. It’s the largest asteroid in the solar system. There’s Pluto, which is also very far away. So, Ceres is mostly made of rocks, like most asteroids are made of rocks. Pluto is made of both rocks and a lot of ice. So a lot of these new objects are sort of like Pluto, that they are made of some mixture of ice and rocks. Some of them have very weird orbits.
So, a few years ago some astronomers basically pointed that out and said, “Hey, we found some of these dwarf planets, they have these weird orbits.” They sort of speculated, well maybe you could make a model where they get their weird orbits if they interact with a massive planet that’s very far out in the solar system.
The announcement a month ago was a more detailed model where a couple of astronomers looked into this and figured out they could in fact make dwarf planets have those weird orbits if you had a Neptune mass planet that’s in the very, very outer solar system.
Regina: Right.
Ken: One of these things where it’s dim matter, it’s not dark matter, because it would emit some light. But, so little light that no one has been able to see it so far.
Regina: Right. It would be really hard to detect through photometry [sp?].
Ken: Yeah. You’d love to take a picture of it. I think most astronomers, even the people who authored this publication where they said, here is our model, where we say, you really do need to have this planet in there to produce these weird orbits in the dwarf planets. Even they would say that we really have to get a picture of that planet to confirm that theory.
It’s a fascinating prediction right now, so they’re trying to get time on one of the biggest telescopes in the world and one of the biggest optical telescopes to look at this from the ground. Maybe in the future, you might be able to use an inferred telescope from space to see this planet.
But, so far it’s too dim to have been detected. It’s one of those really exciting things where there’s a good possibility that it exists, but there’s no confirmation yet.
Regina: This has happened in history of weird orbits and then people saying, well there must be something there and then actually finding something.
Ken: Right, so historically, there were many planets that were known for thousands of years by people being able to see them with their naked eyes. Then, William Herschel discovered planet Uranus just by looking for things in the solar system. Then, by making very careful observations of the orbit of Uranus, they noticed — a couple different astronomers noticed that Uranus’ orbit had some weird stuff. One way of trying to explain those differences from the expectation would be if it was getting tugged on by some unseen matters, some at the time, dark matter that was exerting a gravitational pull on Uranus.
There was a French astronomer, Le Verrier, who actually made a prediction, got in touch with an astronomer and said, you should put your telescope at this position.
Regina: Right now.
Ken: Yes, at this time, look right here. I forget the astronomer who observed it, but found Neptune within one degree of the prediction.
Ruben: Oh, wow.
Ken: So, it’s this amazing confirmation of using these anomalies from gravity and then finding matter that had been previously unknown.
Regina: Many people confuse dark matter and dark energy. What is the difference? Before we finish up gravity waves, talk about Interstellar, and pop culture, I want to talk about this idea of dark energy. Give us your best definition of that and why it’s not dark matter, or maybe it is.
Ken: It’s almost certainly not. Dark matter is one of these things that’s totally bizarre. It makes up most of the total matter in the universe, the stuff that interacts with gravity and we have absolutely no idea what it is. Dark energy makes dark matter sound like we know what we’re doing. Dark energy is even weirder.
About in 1998, there were some astronomers that were studying supernova and discovered that — we’d known for a long time that the universe is expanding, so the space between galaxies gets larger and larger with every year. What they found is that, you’d expect that the galaxies would actually be slowing down, because they’re pulling on each other by gravity.
But instead, the astronomers studying the supernova found that the distance between galaxies is actually getting larger and at an increasing rate. They’re accelerating apart from each other. Very bizarre observation. Basically, in desperation to try to explain what that is, something might be doing that that could be associated with the vacuum of space-time. When you don’t understand something, you say we’re gonna call it this thing and then put dark at the front of it.
[Laughing.]
Regina: It’s what we’ve learned from this episode.
Ken: Yes. In this case, there’s an idea that it might be associated with energy of the vacuum, so then it got the name dark energy, because it doesn’t emit light, doesn’t interact in ways that you can see it easily, other than its influence on making galaxies accelerate apart from each other.
Now, that does actually intersect with my own research at some level, because one of our ultimate goals is to try to measure how clusters are growing with time. Because, as the universe evolves, you have the Big Bang, galaxies are moving apart from each other, and then you sort of have this battle between galaxies moving apart because the whole universe is expanding, and then gravity trying to collect things together and form groups of galaxies, form clusters of galaxies. So, that sets up a competition between dark energy trying to pull things apart and gravity trying to pull things together.
If you can make measurements of the masses of clusters and make good enough measurements of that, you might actually be able to tell what’s going on with that competition and use that to measure how much dark energy is in the universe.
Whatever this dark energy stuff, the energy density of it is actually larger than not just regular matter, but also dark matter. 95-96% of the energy density of the universe is either dark matter or dark energy. So, it’s either the stuff that we don’t understand very well or it’s the stuff that we really don’t understand.
Regina: On that downer, let’s go on an upper and talk about pop culture.
[? Beastie Boys singing Intergalactic ?]
? Now when it comes to envy y’all is green
? Jealous of the rhyme and the rhyme routine
? Another dimension, new galaxy
? Intergalactic, planetary
? Intergalactic, planetary, planetary, intergalactic
? Intergalactic, planetary, planetary, intergalactic
? Intergalactic, planetary, planetary, intergalactic
? Intergalactic, planetary, planetary, intergalactic
Regina: So, how — and I ask every guest this. How is your science represented on TV and movies? Is it represented well? Are there things that are done well and things that are done horribly? I just mentioned gravity waves again, but that was represented in Interstellar, not in the way that we described it earlier before our break.
What annoys me when I hear dark matter and stuff, I think of red matter, which happened in the Star Trek reboot, which was not explained at all. It was just like, red matter does this. The end.
Ken: Yes. Enter the plot device.
Regina: Yes, so that was bad representation. Can you think of any other bad ones or some maybe possibly good representations of your field? Or anything we’ve been talking about here.
Ken: There are certainly representations of astronomers and scientists in pop culture. You can go from the Big Bang Theory, where you have the highly stereotyped perceptions of what astronomers or physicists are like. Now, I have met people like the characters on that show. They do exist, but there are also many normal people.
Regina: Right. We’re normal.
Ken: Right. Like Gina. Very normal person.
Ruben: See it’s weird, because you say that, but when I see you both, I’m like, you guys are exactly like these people on the show.
Regina: Nobody that looks like me is on that show.
Ruben: There’s no Asians on that show.
Regina: There are no Asian-Mexican women on that show.
Ruben: You win this round.
Regina: Actually, the only people of color have accents on that show.
Ken: Probably the best sort of positive depiction I think would go — you have to go all the way back to the movie Contact.
Regina: Yeah, I agree.
Ken: That one, really, it’s not — obviously not completely correct. It’s a fictional portrayal, but it gets a lot of the spirit of how the science is done correct.
Regina: Except for the headphones, because you listened for radio waves.
Ken: Oh yeah.
Regina: I agree with that the depiction of Contact — I think it’s hilarious that Matthew McConaughey — we were talking at the break, that he’s in that movie and he’s in Interstellar. I think he’s found his niche.
Ruben: And in your Lincoln at home.
Regina: I want to actually ask you some questions, Ruben, my brother.
Ruben: I’m Ruben.
Regina: Your depiction of astronomers is me, your sister.
Ruben: Absolutely.
Regina: But anything else from TV — what do you think of when you think like dark energy, dark matter, or astrophysics from TV or movies. How are we contradicting that or maybe we aren’t?
Ruben: My knowledge of it is just so minimal, I do think Interstellar, Star Trek, we were talking about White Dwarf earlier. I was thinking Red Dwarf, I’m thinking BBC. So, those are where all my minds are going. My perception of astronomers in the movie world, I don’t think I have too many. It’s not like there’s astronomer action superheroes out there fighting crimes.
Regina: Well Doctor Light is an astrophysicist.
Ruben: Okay.
Ken: But, occasionally there’s an astronomer who discovers the asteroid that’s just about the hit the earth.
Regina: That’s true.
Ruben: Yes. You have the Armageddon moments where it’s like, “It’s twice the size of Texas.” And then they’re all gonna die.
Regina: But you don’t know his or her name. You just know Bruce Willis.
Ruben: I just know Bruce Willis, yes. Yes, just Bruce Willis.
Regina: From the movie though, I’m trying to think of anybody else.
Ruben: Owen Wilson is in that movie, Liv Tyler, Owen Wilson, Steve Buscemi. See, I guess I did know some of them.
Regina: You are the actor, so I don’t know these things. I think you’re right that like the essence of astronomers isn’t totally portrayed well, but we all are different. It would be nice to see not the stereotype of the scientist, the crazy, introverted, don’t-talk-to-people scientist.
Ken: Yes. Some of us are like that, not all of us.
[Laughing.]
Regina: Other than Contact, I’m trying to think of — and Interstellar, and The Martian — The Martian we just talked about, we just reviewed that movie. That got a lot of praises for being fairly accurate.
Ruben: A great book too.
Regina: Yeah, it’s a good book. But, I can’t think of anything when you’re dealing with this mysterious thing called dark matter, or this very, very mysterious thing called dark energy. It almost lends itself to being a plot device or something crazy in Star Trek. I can’t even think of anything.
Ken: There’s a series of children’s books by Philip Pullman. I think dark matter is one of the plot devices there. It’s one of those interesting things where, on the one hand, it’s nice that it is tied to this real scientific idea, but the way it gets used in the novels is totally unlike what dark matter actually is.
Regina: I do want to end though on — even if it has nothing to do with astronomy, even if it has nothing to do with dark matter, what is your favorite pop culture right now? That’s what I’m gonna ask. I’ve been asking a lot of my guests that.
Ken: Maybe the Neil Degrasse Tyson rap battle about the flat earth. That’s been an entertaining thing.
Regina: It is, right?
Ruben: The flat earth thing is everywhere. Everywhere.
Regina: I think there’s a lot of conspiracy theories associated with dark matter and dark energy too. So, it’s — with great mystery comes great controversy. I mean, flat earth, there’s no mystery there, so I have no idea what that’s about.
Ken: Yes.
Regina: Yeah. With that, I want to say thank you Ken for being here. Thank you for enlightening us about a lot of stuff. Actually, learned a lot or maybe were just reminded of a lot of things. Thank you for coming. Ruben, thank you for being an awesome guest host. I hope you had fun.
Ruben: It was a lot of fun.
Regina: You’ll come back probably another time when Jordan is not available. I want to thank you.
Ken: Thank you for having me.
[? Beastie Boys singing Intergalactic ?]
? We’re from the family tree of old school hip-hop
? Kick off your shoes and relax your socks
? The rhymes are spread just like a pox
? ‘Cause the music is loud like an electric shock
Regina: Thank you for joining us. We just spoke with Dr. Ken Rines about the dark universe. Our show is entirely volunteer run and if you’d like to help us out, click on the button “donate.”
Ruben: If there’s a science idea that you’re curious about, send us an email or post a message on our Facebook page, Spark Science.
Regina: Today’s episode, Finding Our Way in the Dark, was produced in the KMRE Spark Radio Studios located in the Spark Museum on Bay Street in Bellingham.
Our producers and engineers today are Eric Fabueta [sp?] and Nathan Miller [sp?] Our theme music is Chemical Calisthenics by Blackalicious and our feature song today is Intergalactic Planetary by Beastie Boys.
[? Beastie Boys singing Intergalactic ?]
? Intergalactic, planetary, planetary, intergalactic
? Intergalactic, planetary, planetary, intergalactic
? Intergalactic, planetary, planetary, intergalactic
? Another dimension, another dimension
? Another dimension, another dimension
? Another dimension, another dimension
? Another dimension, another dimension
? Another dimension, another dimension
? Another dimension, another dimension
[? Blackalicious rapping Chemical Calisthenics ?]
? Lead, gold, tin, iron, platinum, zinc, when I rap you think
? Iodine nitrate activate
? Red geranium, the only difference is I transmit sound
? Balance was unbalanced then you add a little talent in
? Careful, careful with those ingredients
? They could explode and blow up if you drop them
? And they hit the ground
[End of podcast.]