Episode 26: Dr. Kaitlin Rasmussen on Exoplanets And how to find ’em

Image: Crop of “Dwarf star spectra (luminosity class V) from Pickles 1998,” used according to a CC BY-SA 4.0 license. (Source: Wikimedia Commons)

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[there are some differences between time stamps and the final audio due to editing, but it is approximately accurate]

Charles 0:00
Hello, this is Assigned Scientist at Bachelor’s. I’m Charles and I’m an entomologist.

Tessa 0:04
And I’m Tessa and I’m an astrobiologist.

Charles 0:07
And today as our guest, we have Kaitlin Rasmuson. Dr. Kaitlin Rasmussen got her bachelor’s degree in astrophysics from Florida State University in 2015 and her PhD in nuclear astrophysics from Notre Dame in 2020. She currently studies exoplanet atmospheres at University of Michigan with a focus on improving the statistical techniques behind separating planetary from stellar spectra. Kaitlin, welcome to the show.

Kaitlin 0:30
Hello. Great to be here.

Charles 0:32
It’s great to have you. So to begin with, we normally like to ask people, what’s your background in science? How did you get interested in science?

Kaitlin 0:38
So I was just one of those little kids that were always completely obsessed with space when I was, you know, three, four years old. I think space was one of those things that kind of stuck with me a little bit, even as I was, you know, not really considering being a scientist until I graduated high school.

Kaitlin 1:08
S in middle school, I wanted to be a musician slash band teacher. And so I wasn’t very focused on my math and science classes, I was actually a horrible student. But when I was a senior in high school, I took a music education internship at an elementary school where I was the assistant band teacher. And I realized that public school teachers are treated really, really horribly and you know, administrators will be jerks to you and parents can be jerks to you, and even kids are jerks sometimes. I realized that it wasn’t the career path that I wanted to take.

Kaitlin 1:13
So as I graduated high school, I realized that, you know, I had all these opportunities before me. And I just kind of had this epiphany that I could do whatever I wanted now that I wasn’t tethered to music anymore. In this kind of state of mind, I wandered into a Walden books that was in my hometown, and at the front of the bookstore, they had Stephen Hawking’s The Grand Design, it was a brand new book at that time, and I, I picked up a copy. And I started reading it and I turned… it made me remember that I used to be really into space and the universe. And even though I had only really just sort of casually engaged with that kind of stuff through, you know, the Discovery Channel, and the Science Channel and stuff, specials like that on, you know, exoplanets, black holes, those really fun, interesting topics, it made me realize that I had really actually cared a lot about space throughout my whole entire life.

Kaitlin 2:42
And I started reading the textbook, and it had… I started reading the chapter on gravity, and well, while I was in the, in the bookstore, and the chapter on gravity explained that, you know, gravity is actually just mass bending space time. And that effect that we, that we feel is… it’s not just an abstract thing that goes down. It’s a real, real force, caused by sheer mass of things way larger than us in the universe. And that just really struck me and I sort of made me realize that maybe this was something I could actually do with my life. So naturally, I went home and downloaded the book. I did not buy it. I did buy it later.

Tessa 3:26
Spoken like a true millennial.

Kaitlin 3:28
Yeah, yeah, I downloaded it. But yeah, I read that whole textbook cover to cover. And I realized that it was so accessible and well written that I was able to, like, envision myself doing this kind of research. And so I decided to change my major from music education to astrophysics, and I am still here today.

Charles 3:52
Fantastic. Music teaching to astrophysics seems like a very easy switch, very straightforward. So could you tell us more about the research that you’re doing now?

Kaitlin 4:03
Yeah. So I, as you said, I got my PhD in nuclear astrophysics, which in layman’s terms is basically just the origin of the elements on the periodic table. But I actually, I’ve always wanted to study exoplanets. Even before I knew I wanted to be an astronomer, I just found the field of exoplanets to be completely fascinating and always cutting edge and always something new going on. So I was really fortunate to actually switch fields into exoplanets for my postdoc.

Kaitlin 4:33
What I do right now is I study a class of planet called hot Jupiters. So hot Jupiters are really fascinating because there’s no analogue for them in our own solar system. Hot Jupiters are Jupiter sized, but they’re actually very, very close to the sun. They orbit on periods of less than 10 days and they’re tidally locked, kind of the way the moon is tidally locked to the earth. So they’re really very fascinating sort of astrophysical laboratories all in one object because you have this very hot 1000s of Kelvin day side and a very cool, you know, maybe only 1000 Kelvin night side. And so there’s a lot of differences that arise in these extreme environment that are both in this the same object. And so using stellar spectroscopy, we can analyze the starlight that come from the star and also the starlight that come from the star and then bounces off of the planet and is sort of incorporated into the remaining starlight that comes to us. So we can actually study the light that comes from the planet, and that can tell us a lot of information about things you couldn’t even imagine like the magnetic field of the planet, things like the the temperature gradient, what it’s made out of, you can measure the velocity that the planet is rotating at just by looking at the starlight that comes reflected back from it, which I think is just incredible. So basically, we can actually get a sense of what the climate is like on a hot Jupiter, despite the fact that it is just a tiny speck going around a star that we probably can’t even see in the sky. I just think that’s incredible.

Charles 6:06
The first question that comes to my mind will likely sound uncharitable, but it isn’t. But it’s, it’s basically the idea of… are we only interested in exoplanets because they’re in space and space is cool, or is there another motivating factor behind the questions that we ask about these other sort of celestial objects?

Kaitlin 6:31
So there’s definitely a lot of motivations for why people study exoplanets. For example, my supervisor, she knows everything about meteorology, so she’s kind of interested in in hot Jupiters from a fluid dynamics and meteorology standpoint. I’m personally interested in hot Jupiters because I think they’re a way for us to learn how to study planets so that we can take that information and then start studying smaller planets when bigger telescopes become available. But yeah, some people study exoplanet just because exoplanets are really, really awesome. Some people study exoplanets because they think that we’re going to need to leave the earth one day and that we’re going to have to move to one and so we want to know what the climate is going to be like.

Charles 7:18
What you said about learning how to study planets so that we can apply it to smaller planets when more technology becomes available… could you talk more about how relatively recent technological advancements have made even the studying of very, very large exoplanets possible where maybe it wouldn’t have been before?

Kaitlin 7:36
Yeah, absolutely. So the instrument that we use to study hot Jupiters and, in the future, things like smaller Neptune-type planets and super Earths, an earth sized planet, that… it’s all because of spectrographs. Spectrographs basically are like big prisms. So the white light comes through from the star and it goes through the prism and it gets broken up into all the colors of the rainbow. One thing that you will see if you actually look at the sun, or if you look at a star, is that it’s not just a perfectly smooth rainbow, there’s actually a dark band in it. And the dark bands are caused by the electron transitions of the things that are in the light.

Kaitlin 8:14
So like in the upper layers of a star, you have all the elements of a star – like iron, and carbon and copper and that kind of stuff. And so the electron transitions of these elements kind of shows up as dark patches, where every element is unique, it has its own fingerprint.

Charles 8:32
Could you describe what you mean by electron transition?

Kaitlin 8:35
Yes, I can. Yeah, as we learned in school atoms are made of protons and neutrons and electrons, electrons sort of live in what we call orbitals. So they kind of have an average distance around… in the, in the Bohr model, you will see they have like an average distance around the nucleus. If you apply something like electricity to an atom, the electron can actually jump up from one orbit to another orbit. So when an electron does that it’s absorbing a little bit of light, where the energy of the light corresponds to the distance that it is jumping up in it orbital.

Charles 9:13
So orbitals are basically a description of the energy of electrons?

Kaitlin 9:19
Yes. So when you have transitioned between these orbitals, what happens is that a photon of this very specific energy can be caught so that it won’t show up in the spectrum, and so when you have less light at some part of the spectrum, you get this dark band. That’s how we actually identify that there are different elements and stars, going all the way back to Cecilia Payne and her thesis back in like 1925 when we figured this all out. We basically identified the fact that these fingerprints of elements are visible in every star, every star has its own unique set of elements that are present in it.

Kaitlin 9:54
The way we can actually apply this to exoplanets is in a number of ways. So, we can do spectrographs to see how fast a planet is moving because when planets orbit their stars, the star orbit the planet as well, around the center of the center of mass. And so if a star is sort of wiggling back and forth, the lines that are in that spectrum will also blue shift and red shift because the star is moving closer and farther away, just by a little tiny amount. And we can actually see that in a spectrograph – we measure the motion of the lines as the planet orbit the star, and then we can say, Oh, this must be a planet of such and such mass limit, and it has such an such orbital parameters. And that’s one of the methods that we actually use to confirm planets.

Kaitlin 10:42
Now, where the tricky part comes in is when you actually want to study what the planet is doing with a spectrograph. So then you have a spectrum, so a set of dark lines from the star, and then you have a totally different spectrum of the light emitted from the planet, bcause planets are made of different things from stars, stars being largely hydrogen and helium, and planets are usually made out of weird stuff, like there’s a lot of water in them and there’s carbon monoxide, and just a whole bunch of, a whole bunch of simple gases that you don’t find it stars because stars are too hot to have things like carbon monoxide in them.

Charles 11:17
Well, this is interesting. If we could step sideways for a moment to the composition of planets.

Kaitlin 11:22

Charles 11:22
Because when I think of planets, I think of… well, Earth, first of all, because I live here, and then also basically large collections of rock in space, but I imagine that’s not quite correct.

Tessa 11:41
Well, think of, like, Jupiter.

Charles 11:44
Sure. So I’m hoping, potentially both of you could tag team and describe what we really mean when we say planet and what the, like physical reality of a planetary body is.

Kaitlin 12:00
Yeah, so there’s basically there’s gas giant planets and then there’s rocky planets, as far as you know, we’re aware of, those are the two major types of planet. And they both have to do with the, the way that they form. So we think the planets form according to something called the core accretion model, which is where you start with your star and you know, little baby star, and it’s got a disk made of dust around it. And what the dust does is, it sticks to itself, and it slowly become bigger and bigger – it, you know, it rolls into pebbles, the pebbles mash together…

Tessa 12:00
It clumps.

Kaitlin 12:00
Yeah, clumps. So if a planet in the it’s in the inner part of the solar system, where there is not a whole lot of gas, the core of the planet will just build up and build up in that it’ll just kind of sit there and maybe it’ll smash into other planetesimals and eventually create rocket planets.

Tessa 12:50
And the reason that there’s less gas closer to the stars, because the light of the stars literally pushed the gas out further out into the solar system.

Kaitlin 12:57

Charles 12:58
Oh, see, I was gonna ask if it was because the sun was being very greedy and gobbling the gases up for itself.

Kaitlin 13:03
I think it may actually be a combination of those two, I’m not a planetary formation person. But out in this far solar system, you have this reservoir of cold gas that’s available for the planetesimal to just start to gobble up and accrete onto themselves, then they become bigger and bigger, and you get Jupiter sized planets and, you know, Uranus and Neptune.

Charles 13:24
Oh, I know how this works, because I’ve read the Locked Tomb trilogy books by Tamsyn Muir. And that’s I mean, that’s essentially how the large like beasts…

Tessa 13:38
Oh, the resurrection beasts?

Charles 13:39
Yeah, yeah, the resurrection beasts… That’s basically what they’re doing, right?

Tessa 13:42
Yeah, yeah. Except, you know, it’s gas instead of like, souls.

Charles 13:46
Sh sh shh shh shh. That’s how they’re made. Well, so this is interesting. So there are these two categories of planets, right, and I am taken to understand from the demotion of Pluto that got everybody all bothered, that the boundary line for planet is based broadly on size. So is it possible that there are third, or fourth, or 17th categories of planets that we just don’t know about yet?

Kaitlin 14:18
Well, there are definitely categories of planets that are not found in our solar system, there are a planet called mini Neptunes which are a rocky core with a very thick atmosphere, we think, and they’re very common in the universe, but we don’t have any in our own solar system. And then there’s also, you know, kind of super Earths, which are 10 times the mass of the planet Earth. But again, we don’t have any super Earths in our solar system. So there are there are other categories of planet that we just can’t look at through a small telescope.

Charles 14:51
Well, then another question, are there kinds of planets that we can imagine but which could not actually physically exist? Does that make sense? Like, are there boundaries around what kind of planets there could be in the universe?

Tessa 15:06
I know at a certain point size becomes an issue because, like, if you make Jupiter big enough, eventually it gets so hot in the core and the pressure is so high that it starts undergoing fusion and basically becomes a star. So you know, you have at least one cut off in terms of size. The other thing I’d say is probably just, like, scarcity of materials, it’s unlikely that you’re going to find a planet entirely made out of say, I don’t know, titanium, just because titanium isn’t that common in the universe, it’d be hard to get enough of it in one place to form a whole planet.

Charles 15:38
Watch there be an egg on your face when we discover titanium planet.

Kaitlin 15:42
There’s actually a certain scientist who I have a feud with, Avi Loeb, who proposes that there are diamond planets… that there are planets where somehow they’re entirely made of carbon, and then because of the pressure in the core, the core becomes diamond. You know, I just have to disagree with that.

Charles 16:01
That’s, I mean, while we’re all being silly… when I was a kid, I had an OC that was a spacefaring superhero, and he found an opal planet. So…

Kaitlin 16:11
Opal planet, wow.

Tessa 16:12
No, actually, that’s not… that, that would be more plausible, I think, than a diamond planet because silicon and, and oxygen are both pretty common and hopefully was just silicon and oxygen in mutual configuration. Yeah, you could do that.

Charles 16:28
Yeah. Okay. So planetary sidestep, we can step back into the original thing we were talking about,

Kaitlin 16:33
I think we were talking about the spectra of planets.

Tessa 16:37
Yeah, what you can learn from it, how you measure it, etc. You talked about electron orbitals as well

Kaitlin 16:42
So to, to continue that, basically, spectrographs are the thing that we know everything…. ono everything, many things about the universe just because of this amazing technology. Basically, when you look at a planet with a spectrograph, one thing gets really difficult is that the star has a spectrum. And the planet has a spectrum. And they’re mixed together and the planet spectrum because as we said, the planet can be made out of strange things like carbon monoxide, and water and methane. And that kind of stuff, the spectrum of that planet looks a whole whole lot different, just because molecules have their own electron transition based on the fact that their molecules are not singular atoms. So they have these really complicated electron situation going on. So this leads to sort of features in the spectrum that can be very difficult to identify, just because there’s so many electron transitions. There’s lots of lines in the spectrum. My job as a scientist, the reason I was hired is to figure out how to make this separation better, basically, to say, How can we actually know that we’re sure that we’re really looking at a planet spectrum? And it’s not just a loose fit to a model? It’s a good fit to a model, you know, how can we get rid of noise? How can we get rid of the Earth atmosphere? One bird, we’re doing this because the atmosphere has its own lines in the spectrum, mostly water and o h. And that’s another barrier that we have to get through one be tried to look at a planet spectrum. Yeah, that’s, that’s part of my job is the statistical methods of figuring this out? It’s, it’s quite a problem. Well,

Charles 18:18
How do we do those things?

Kaitlin 18:20
Well, usually, we use a technique called cross correlation. Cross correlation is basically if you take a data set, you know, just a one dimensional set of numbers. And then you sort of slide it across another one dimensional data set where the two data sets match really well, there will be a peak in what’s called the cross correlation function. And so that’s actually how we measure exoplanet atmospheres. If we say, okay, we generated this nice model of what we think the planet looks like. And we’re going to slide it across a real data set and see if there’s a peak in the cross correlation function at the place we expect it to be.

Charles 19:00
Well, as somebody who has never enjoyed statistics, better you than me.

Kaitlin 19:06
Well, I’m I’m not a big fan of statistics either.

Charles 19:09
[laughing] You chose the wrong job.

Kaitlin 19:12
Yeah, I… statistics is my hammer and exoplanets are the nail.

Charles 19:17
Well, I mean, there you go. I imagine a lot of this comes back to computational power.

Kaitlin 19:24
Yeah, it actually does, yeah.

Charles 19:25
Yeah, so how were people… basically before you could use computers for a lot of this stuff? How were people doing your job?

Kaitlin 19:35
Oh, they weren’t, yeah. This is a very new field. Exoplanets have only been around since the 90s.

Charles 19:41
I feel like I should know this by now. But it’s probably good that I keep forgetting it, because then I can ask people.

Tessa 19:46
Yeah, first one was discovered in 1995, 51-Pegasus B.

Charles 19:51
Yep. So what was that like?

Tessa 19:54
Seven year old Tessa was very excited, let me tell you.

Charles 19:58
You big nerd. Okay. So 1995… discovery of the first exoplanet. Can we talk, can we talk about this? Because that sounds interesting.

Kaitlin 20:07
Yeah, there was actually just a Nobel prize that was awarded last year or the year before that, to DDA Kalos. And Michael Mayer, who made the first radial velocity observation of 51 Peg B, like I mentioned earlier, they use the fact that exoplanets, especially big exoplanet that are close to their star, cause their star to wobble a whole bunch. And if you can get a spectrograph that’s precise enough, you can actually measure that wobble. It’ll, it’ll look like a nice little sine curve when you look at it, all the all the data points together. And that’s how they discovered the first exoplanet.

Charles 20:41
So was it truly just that the discovery and description of exoplanets really was literally impossible before increasing computer power in the 90s?

Kaitlin 20:52
I wouldn’t say computer power, but it definitely had to do with the precision that the spectrographs were available at because spectrographs have resolution. You know, it’s like a TV. And they’re basically just cameras that capture spectra. And so like camera technology had to catch up and catch up until we could get the resolution to detect very minute changes in spectral features going back another 70 years.

Charles 21:19
I think you said that spectrographs were developed in 1925.

Kaitlin 21:24
Oh, stellar spectroscopy was developed in 1925. But Isaac Newton actually invented the spectrograph.

Charles 21:31
Well, there you go. But so stellar spectroscopy. How did… basically what was happening before that came on the scene?

Kaitlin 21:41
And finally, my useless knowledge of the history of spectroscopy comes in handy. All right. So Isaac Newton put a glass prism to the sun, and then he sent the sunlight through that prism on to a bar of wax. And so in that way, he noticed that some colors of the Sun are brighter than other colors of the sun. So because the sun is yellow, that’s the brightest color of the sign. And so he noticed that the yellow part of the light that was coming through melted the wax the most and so that was kind of the beginning of the idea that starlight is complex, not just white light that come out. It’s, you know, light of all colors all across the electromagnetic spectrum. So that was the beginning of spectroscopy.

Kaitlin 22:24
And then in the 1800s, people started to actually have the technology to do this with stars, they had better telescopes. And so they were able to look at right local stars like Vega and Arcturus and that kind of thing. And they were able to send that dark light through a prism. And then they kind of noticed that there were dark patches in the prism, it wasn’t just wasn’t just a clean rainbow. And so that that was a mystery for a very long time. It was actually Cecilia Payne, who came along and did to paint a potion she married later, she came along and her graduate thesis in 1925, focused on the fact that she sort of compared this new field of electron orbitals with basically this was sort of its own separate field. And she compared it with the fact that stars had these unique spectral features. And she came to the conclusion that the sun must be made out of hydrogen and helium, mostly, just because those are the biggest most obvious features in the spectrum.

Charles 23:25
Because this was like a hot time for chemistry too.

Kaitlin 23:27
Yeah, yeah, that’s true.

Charles 23:29
It wasn’t just the roaring 20s for people who like to go drink

Kaitlin 23:32
Yeah. It was also the roaring 20s for Cecilia Payne-Gaposchkin, my personal idol.

Charles 23:39
Nerds can party too, we just party in a real boring way. I am a big history of science nerd. So I… your quote unquote, useless knowledge of spectroscopy is great for me. I love having historical interludes. And so, following her publication in 1925, was there like an explosion of new research using that technique?

Kaitlin 24:02
Yeah, yeah. So after Cecilia Payne-Gaposchkin established that the lines in stellar spectra correspond to elements being present in stars, the field really did explode. And people just looked at every star they could possibly look at, they started to notice things like, oh, not all stars are made out of the same material. And sometimes stars had really weird and unexpected elements in them, like the discovery of technetium in a star – that was really interesting because technetium is not a long lived element. So if it had been in the natal cloud that the star was born in, it would have decayed, and we wouldn’t see any of it. But sometime in the, I want to say the 40s, maybe they discovered technetium in a star. And so that kind of established the fact that there are nuclear reactions actually happening in stars, that are producing these exotic elements that can be seen with a spectrograph.

Charles 24:59
Did we just know not know what was happening inside of stars for this point?

Kaitlin 25:04
Yeah, yeah, we actually for a long time, we had no idea that nuclear fusion with behind the powering of stars and there’s actually a really infamous paper… well, famous infamous called “B Squared FH,” which stands for Burbidge, Burbidge, Fowler and Hoyle. And it is the instrumental paper that set off the field of nuclear astrophysics. So basically, in one paper, these four people who had just kind of gotten together over a summer and they were like, let’s figure out nuclear astrophysics, let’s figure out where all these reactions are coming from and how they’re possible. And so these four people sat down, and they just figured it out. And they laid down the principles of nuclear astrophysics. They said, here’s the proton proton chain that happened during the main sequence of a star. And, you know, here is something called neutron capture. Nobody had ever even thought of that before. They said that neutron capture was responsible for the formation of heavy element of beyond iron, they said that there must be different versions of neutron capture happening, there must be slow neutron capture and rapid neutron capture that were responsible for elements all the way up to uranium being president DARS. This was probably the most the most impactful paper I can really think of.

Charles 26:21
Well, why “infamous,” then?

Kaitlin 26:23
Oh, well, it just very famous. And it’s, it’s just a remarkable paper, because it actually, you know, 70 years later, after it was written in 1957, it actually it came true. But we actually did figure out where neutron capture happened in the universe. I, I guess I don’t really know what I mean by infamous but it is a truly remarkable paper.

Charles 26:46
I guess if anything is big enough, at some point, it becomes infamous.

Kaitlin 26:50

Charles 26:51
Just because anybody can get mad at anything.

Kaitlin 26:53

Charles 26:54
That’s wild. Everything I learn about space and space science is so wild. Y’all are having a good time. You’re doing some fun stuff.

Kaitlin 27:01
We, we really are, yeah.

Charles 27:03
I, just, it’s so wild to me how much we didn’t know about space. Because it’s just up there. Like, it’s always been there. You look up and there’s space. You know what I mean?

Kaitlin 27:19
Yeah, it’s the human constant you know?

Charles 27:21

Kaitlin 27:22
It’s the oldest science.

Charles 27:24
It’s… well… because that’s a whole… I mean, I don’t disagree with you. But that’s a whole conversation about what’s science and what’s old.

Kaitlin 27:35
Yeah, that’s, that’s true. But I mean, you had to have astronomy before you could have agriculture. You know, you had to figure out when to plant your crop for the year.

Charles 27:43
You’re not wrong. You’re not wrong. Here’s a question. Are there any misconceptions about your field or about space in general, that you would like to correct people on?

Kaitlin 27:55
I think that there’s a lot of misconceptions about the field of astrobiology, which I am kind of tangentially part of because I study exoplanets. I think that a lot of people think that astrobiology is about finding a new planet to live on. And it’s really just the search for other life out there in the universe. I think that when people think of astrobiology, they’re like, oh, we’re going to discover that Proxima Centauri B is habitable. And then Elon Musk is going to take us there. First of all, Elon Musk is not gonna take you anywhere. Let’s be clear about that. But yeah, astrobiology is really the search for other life in the universe, which is on its own fascinating. We don’t, we don’t need to say… we don’t need to bring capitalism into it. It’s its own great thing.

Charles 28:41
“We don’t need to bring capitalism into it” is something that you could say about everything, constantly, all the time.

Kaitlin 28:48

Charles 28:49
Unless you’re talking about problems, in which case, you do need to bring capitalism into it.

Tessa 28:53
So I want to ask you about sort of what a major focus of your current research is on which happens to be sort of the next generation telescope… not the one everybody’s heard of, but a different one that actually started its life, so I hear, as a spy satellite.

Kaitlin 29:07
Let’s see… is that one the Nancy Grace Roman space telescope?

Tessa 29:11

Kaitlin 29:11
Yeah. Yeah, that one, uh, that is a really interesting backstory for a telescope. I don’t know all the details. But you’re right. It was like a spy satellite that some institution with like, well just turn this over to the government to be a space telescope. And now we’vem got a great infrared photometer and got to do a lot of really cool science, it’s going t what we call the microlensing way of finding exoplanets. So basically, what happes is that when you point a telescope at a really crowded part of space, like if you point it towards the like the Galactic disk, where there’s a pure density of stars, what you’re going to see is that there are rogue planets out there that do not have they don’t have stars, they were kicked out of their solar system by some dynamic process. And so they’re just out there and what happens Is that when one of these planets crosses in front of these stars, and this happens pretty frequently because the dehler density is just so high is that you get a little flash of light when the planet is right in the center of the star. And this is because of the stuff that Einstein predicted that light bends around massive bodies. And so what’s happening is when this planet crosses in front of the star, the light bench perfectly around it, and so you get like a sharp point in your vision or in the camera, and so you can actually discover rogue exoplanet in this way. So we expect to find a lot of planets without stars with the Nancy Grace Roman based telescope, it definitely a fascinating and super important tool for the future of our field. And I’m sure it does other stuff besides exoplanets, but, you know, exoplanets is the best.

Tessa 30:51
So are there any particular element instruments or telescopes that you do work with out of curiosity, or is your stuff mostly theoretical?

Kaitlin 30:58
So I work with the Magellan telescopes, which are in Chile at the Las Campanas Observatory, so they are 6.5 meter telescope. So they’re like 20 feet across, they’re gigantic, they’re wonderful, I love them, they can be remotely operated now that there’s the pandemic. So they weren’t, they kind of shut down, like they alternate shut down. So it’s been hard to use them for the last year, because you know, you want to keep the crew safe and everything. But those are the telescope that I use primarily.

Kaitlin 31:26
And then in the future, the telescope I’m really excited about it called the European Extremely Large Telescope, ELT, and that is going to be a 40 meter telescope. Just mind mind blowingly big. And it’s going to have a spectrograph called medische on it, and medische is just absolutely top notch, like really super high resolution, and it’s going to be on a gigantic telescope to we’re going to get really good signal at planet and what we’re going to be able to do with the metal spectrograph on the ELT, if we’re going to actually be able to get spectra of Earth sized planets – Jupiters, or hot Jupiters, can be easy to measure, because they’re very big, and they emit their own light. But Earth sized planets are difficult because they don’t really emit a whole lot of light, they just reflect it. And this is a lot less light than get emitted from a hot Jupiter. So when you want to study an earth-sized planet you just need a whole lot more photons than when you need to study a Jupiter sized planet. And a 40 meter telescope is what you need to study Earth sized planets.

Charles 32:29
Well, I have two questions. One is, do different telescopes develop like fandoms? Do you get people were like really ride or die for a specific telescope?

Kaitlin 32:40
I think the telescope operators are probably ride or die for their telescopes. I mean, I’m a huge fan of Magellan telescopes, but I don’t know if I would do a ride or die for them. But a lot of people do get pretty attached to their, their preferred telescope. Yeah.

Charles 32:56
Well, and then on a somewhat more somber note, I think I saw something recently about the proposed construction of a telescope on Mauna Kea again?

Kaitlin 33:07

Charles 33:07
Like that was put to bed, the land protectors protected the land, and they weren’t going to develop it. And now it seems to have come up again, as… and what struck me the first time and what strikes me again now, is… why is it so important to the people to whom it’s important to build a telescope there specifically?

Kaitlin 33:32
So that, that’s the really frustrating thing, is, you know, not only does the land belong to the Native Hawaiian people, and they obviously shouldn’t build, build a big telescope, they’re against their wishes. But there’s an alternate site for the TMT that just is good in the Canary Islands, and they just won’t move it to the the alternate site, even though it got perfectly good seeing, there’s already the infrastructure there, you know, it it’s not a contested site, you know, it doesn’t belong to somebody else that doesn’t want a telescope built there. There’s a there’s a perfectly good other site and that they can’t get the collaboration of people on the the telescope committee to, like, commit to building this telescope in the alternate location.

Charles 34:18
Well, is… because I got the impression that it’s something about clearness in the sky and height.

Kaitlin 34:28

Charles 34:28
Like, are these things that really… how much do these things really affect the efficacy of telescopes?

Kaitlin 34:36
Well, they’re very important. In the case of Hawaii… Hawai’i is very humid and cloudy until you get up above, up through Mauna Kea, where, you know, the seeing is really good, there’s low humidity, they’re rarely clouds up in that level. So we did so in the case of having telescopes on Hawai’i, it is an excellent location and it is the kind of conditions necessary, you can’t build someplace in a really humid location which is why the Atacama desert is a really popular place for telescopes, because it’s very dry it’s very high up, the Chileans are welcoming to having telescope built there. They have great astronomical institutions in Chile that support the telescope. Yeah, the the conditions under which you build a telescope are, are super important. But the TMT can be built somewhere else and still have good conditions.

Charles 35:24
As a side note, is this part of how like, because I know that Pluto was first described by a guy up near, like, the Lowell Observatory in Flagstaff… is, is part of why that was possible, just the skies are so gosh darn clear in Arizona?

Tessa 35:45

Charles 35:49
And I do want to I do want to include, I think all three of us are in agreement. Don’t build TMT on Mauna Kea.

Kaitlin 35:58

Charles 35:59
Find another place. I just am so struck, like, the stubbornness of people who want to go against, like native sovereignty to build a telescope has really confounded me. And I just didn’t understand like, why is this location so uniquely well suited to a telescope that they have to disrespect the people who live there?

Kaitlin 36:22
Yeah, there is, there’s there’s other better locations, and it just has the honestly part of it. This is this is all hearsay. But part of it is that some of the collaboration members would rather travel to Hawaii to observe than to the other side of the world to the Canary Island to observe it. Exactly. Like that’s, that’s a terrible reason to, you know, enforce colonialism, you know.

Charles 36:51
So there’s that. I don’t know how much of that I’m gonna keep in but probably at least… because it feels weird to talk about space and like, not acknowledge it.

Kaitlin 37:02

Charles 37:03
And so the the final thing that we do in our podcast is ask our guests to weigh in on one or several of some recurring questions, which I believe I sent to you. So which one… s… would you like to answer?

Kaitlin 37:18
I think I would like to talk about what I would be doing if an apocalypse happened.

Charles 37:25

Kaitlin 37:25
I liked it. I don’t know what exactly it would be, but I imagine it’d be something like… knock out all the electricity grids like all over the world. You know, like maybe a coronal event from the sun or something just knocked out all electricity.

Charles 37:42
A, a different kind of coronal event, am I right?

Kaitlin 37:47
Yeah, I think that if that happened, I would probably have to go back to my farm person roots. I grew up on a horse farm in Maryland. And so I know how to do things like birth, livestock and garden and that kind of stuff. So I think I would probably do well on a farm straightforward. Valid. Yeah. workable.

Charles 38:12
I love it. Yeah. So, Tessa, weren’t you also gonna do farming?

Tessa 38:16
Yeah, because I also grew up on a horse farm all the mines was in Virginia. Oh, wow. And I was also I was going to focus on composting especially because I actually do have some background in microbial ecology, which actually lends itself to you know, making sure your compost pile is correctly tuned to maximize the, you know, rate of aerobic decomposition. That’s cool.

Charles 38:40
And I was I was gonna start cricket farming, so we can all team up. Have a little farm nice livestock crickets. Composting, we’re gonna need a gardener. I think Caitlin was gonna garden.

Kaitlin 38:55
Yeah, I’ll take care of the gardening.

Charles 38:57
I was actually thinking of a different Caitlin, but I’m not gonna stop you. Yeah, well, we got a real plan, so the only problem is that we’re so far away from each other. And if we don’t have electricity, I think it’s gonna be tough getting from Arizona, to Michigan, from Michigan to Arizona.

Tessa 39:14
Eh, we can make it work.

Charles 39:16
We can make it work. Yeah. Well, Kaitlin, thank you so much for coming on.

Kaitlin 39:25
Yeah, absolutely.

Charles 39:26
It’s been great having you on, and if people want to find out more about you or your research, where should they look?

Kaitlin 39:55
Oh, well, I am very very active on Twitter @toomanyspectra. I also have a website which I do not update in case anybody wants my CV. I am in the job market next year.

Charles 40:10
I actually have the CV open, it’s beautiful.

Kaitlin 40:13
Thank you put a lot of effort into that CV.

Charles 40:17
Yeah, it is apparent.

Kaitlin 40:20
So yeah, I honestly think that Twitter is the best way to find out more about me and my life and what’s going on.

Charles 40:26
Wonderful. I am on twitter @cockroacharles.

Tessa 40:29
I am on Twitter @spacermase.

Charles 40:33
The show is on twitter at ASAB pod or at our website where we post show notes and transcripts for every episode asabpodcast.com

Tessa 40:41
And until next time, keep on science-ing.

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