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The Meridian - S01E02

Transcription of the second episode of the first season

Nic: 

Hi guys, his is season one, episode two, of the Meridian.  We are coming to you from Lund Observatory, in southern Sweden, on October 1st 2021, as we gear up to celebrate Culture Night this weekend.   

Crossing our local meridian in this episode we have Josefin Martell here, who studies impact craters on Earth and prepares for investigating samples from Mars. 

In each episode we also take a closer look at an astronomical object we find interesting.  This week we will be taking a closer look at the planet named Dimidium.  More about that later. 

 

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The intro scene includes background music and 24 high school students saying astronomical words like “Space missions”,  "Solar wind", "The big dipper", "Galactic dynamics", "Gravitational waves", "Exoplanets", "Black holes", "Betelgeuse", "Dark energy", "Near earth asteroids", "Jupiter", "Ground based telescopes" and more.  Slowly it fades to everyone saying “The Meridian”.   

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Nic: 

Hi Rebecca. 

Rebecca: 

Hi Nick, how are you? 

Nic: 

Yea, Im not too bad. How are you? 

Rebecca: 

I'm good. I'm actually super excited about the Culture Night that's happening this week. 

But before talking about that, I want to tell you about the IAU 100 hours.  Have you heard about it? 

Nic: 

I have not. What’s it about? 

Rebecca: 

So IAU is the International Astronomical Union.   And it was sort of huge during the International Year of Astronomy in 2009. They sort of started this event that lasts for a 100 hours of only doing astronomy.  

Nic: 

Oh wow, OK yeah.  

Rebecca: 

And this year we're actually a part of that event. By having this podcast. 

Nic: 

Oh, that's so cool. Are we the only Swedish people to apply for this? 

Rebecca: 

I think so, actually, but you know, we're not just anyone, right? 

Nic: 

No, we're very important people. But what else have we got going on then? 

Rebecca: 

We have the Culture Night that's happening tomorrow and partly the planetarium will be open where I work.  So it's part of this sort of exhibition with Artificial Intelligence.  And actually Anna has produced this show about the ESS. so that's going to happen. 

So if you want to come, you have to sort of pre book a ticket, but it's it's for free and you can do it on the web page at Vattenhallen. 

Nic: 

Yeah, and I heard also that Daniel, who works at our office is going to be helping out with something called the Laser show. 

Rebecca: 

Yeah, he's part of the physics and laser show. I actually used to be that too, but that was a long time ago.  It's sort of a classic happening at Culture night at Physicum.  Ao it's a physics and laser show. It's super cool.  Same thing there. I think you have to pre book a tickets but it's free. 

Nic: 

So elevated pitch.  If you're going to sell me the laser show.  What would you say? 

Rebecca: 

OK, so it's like physics experiments done in a very fun comedic way, but you know, still, science. And then the laser show is just it's like, I don’t know, 10-15 minutes of just like 1000 lasers going everywhere and coordinated with this, you know, awesome movie music. 

Nic: 

That sounds awesome. It sounds like a lot of fun, and that's not the only person who's performing tonight that works with astronomy.  We also have Eric. 

Rebecca: 

Right, yeah, and I think it's saw him in the corridors, maybe she's sort of... 

Nic: 

Eric, Eric.  Do you want to come and join the PodCast? 

Eric: 

Hi Nick  

Nic: 

Hi Eric, how are you? 

Eric: 

I'm good, thank you. 

Nic: 

So I hear you're performing during Culture Night.  What exactly are you are you doing? 

Eric: 

Oh yeah, right. Uh, so when I'm not doing astronomy. I'm a musician and play in a band called Leading Edge.   We’re playing music that is like this Indie-Folk post-folk kind of style.  

Nic: 

Nice OK and you guys are on Spotify. 

Eric:  

We are on Spotify and we have a few songs there. We also have a Facebook page of course that you can cheque out if you want more information about what we do. 

Nic: 

And so when are you actually playing? 

Eric:  

So we're playing at 11 in the evening. Yeah, we're playing at the Stadsteater or the City Theatre downtown. 

Nic: 

Yeah, and you need a ticket or anything like that to come and see? 

Eric: 

Uh, no I don't think so. 

Nic:  

OK, well how long have you been playing music for? 

Eric: 

Uh, I've been playing for 10-12 years, but with the band that started in 2015. 

Nic: 

Nice and you play the guitar? Are you the lead singer? 

Eric: 

I'm the drummer, I'm the guy hiding in the back. 

Nic: 

Alright yeah, but you know they're essential, and they're also probably the coolest people in the band so... 

Eric: 

Thank you. 

Nic: 

Rebecca.  What is on your Twitter feed right now? 

Nic: 

Rebecca!  What is on your Twitter feed right now? 

Rebecca: 

All right, so it’s this telescope tournament that's been going on for... Well, it was for like a month or so actually. 

Nic: 

And I missed it? 

Rebecca: 

Yeah, I guess you missed it. This was it was quite interesting. I guess astronomers are not really sport geeks in general, but really, this sort of brought us all together. So this guy named Ori Fox. I don't know who it is. He started this telescope tournament where you got to vote for various telescopes. 

It started off with a battle between the Hubble and FUSE and Hubble won. and then it was TESS and Kepler.  That was a hard one. 

Nic: 

OK, yeah right exoplanets, it probably would have been one of the ones I picked. 

Rebecca: 

Yeah, which one would you have picked? 

Nic: 

I'd probably go with Kepler. 

Rebecca: 

Yeah, Kepler actually won. I think I voted Kepler, but then you know.  Hubble and Kepler had a battle-off. 

Nic: 

Oh no, yeah. And what happened to Kepler? 

Rebecca: 

Yeah, well it was struck down by Hubble.  So this has been like following us on Twitter for a couple of weeks and actually it was the final battle-off between NASA/ESAs Hubble and the ESA telesckope GAIA. 

Nic: 

Oh wow, OK I can imagine that got a bit tense. 

Rebecca: 

Really, so that's sort of what I've been looking at now. Like the comments from sort of American based astronomers and European based astronomers have been like arguing for these various telescope. But actually Gaia won. 

Nic: 

OK, and did you vote for Gaia? 

Rebecca: 

Yeah, of course. I think I would be a bad Lund observatory astronomer if I didn't vote for Gaia. 

Nic: 

OK, so in the the flag of Europe to you know...Rebecca: 

But also I've been working with Gaia and Gaia is an amazing telescope. We have Paul coming in the last episode to actually talk about Gaia. I hope. 

So yeah, that really happened, but yeah, so kudos to this Ori Fox guy who I don't really know who it is. But yeah, he says he works on the James Webb Space Telescope. 

Nic: 

Oh, that's launching soon, isn't it? That's like 18th of December. 

Rebecca: 

Yes, we finally got a date. You know all fingers and toes crossed here. 

But yeah, it's got a date for launching in you say, uh, middle of December. So right before Christmas and I guess a lot of us will be nervous about that, right? 

Nic: 

Do you think it's going to actually launch, or do you think we're going to... 

Rebecca: 

Oh yeah, I guess it could be like bad weather or so, but I think it will launch. But also this is sort of, I guess an American - European thing.   I really hope that at least the rocket, which is an Arian 5 rocket, stays intact, because otherwise we might get s*** for it. 

Nic: 

Yeah, yeah, exactly I hope it goes up there too. I've been waiting for this so long and obviously it's not. It wasn't part of the tournament either, so... 

Rebecca: 

No, exactly. 

Nic: 

You know, it might have been a different story if we had James Webb against ESAs Gaia sattelite at that point, would you have... ? 

Rebecca: 

I I don't think so. 

Nic: 

You still would have voted for Gaia? 

Rebecca: 

Yeah, of course I would have voted for Gaia. I'm a sucker for Gaia. It's it's an amazing telescope. It's been doing beautiful science and.... Ah, you know: ESA. 

Nic: 

Yeah, look, I probably would have voted for Gaia to - no offence to any of you Hubble fans out there.  Just yeah, I guess... 

Rebecca: 

Although James will actually have some Swedish instruments on it, or like Swedish collaborating instruments. 

Nic: 

So then that might have shifted the balance a little bit. 

Rebecca: 

Perhaps.  We'll have to ask this guy to making another tournament. I guess in a couple of years or so. 

Nic: 

Yeah, I think I could be a fan of Telescope tournaments,  you know. 

Rebecca: 

I'll let you know if I see anyone. 

Nic: 

Maybe maybe it will even be put in the Olympics at some point, who knows. 

 

 
---------------------- Scene change with music.   

 

Rebecca: 

And now I would like to welcome to the mic Josefin Martell, a researcher visiting us from the Department of Geology here at Lund University. 

Welcome Josefine. 

Josefin: 

In thank you and thank you for having me. I'm really excited on being a guest astronomy podcast. 

Rebecca: 

Yeah, and you know. Likewise, we're super excited to have a geology researcher here. So tell us a little about yourself? And why are you studying geology? 

Josefin: 

Yeah, so I'm in the research...  in the field of planetary geology, but this is of course really interdisciplinary. So in order to understand the formation of the planets and our solar system, you need researchers from astronomy physics and also biology.  And yeah and why I study geology, it's really a coincidence. I would say.  So geology isn't its own subject here in Sweden, so when I I wasn't really sure what it was to be honest I just followed a friend to her class. 

And I thought, well, why not? And then the first semester we learned about volcanoes and mass extinctions and climate change.  And it was just like all of these really exciting topics. And then we also had a guest lecture on planetary geology, and I think that was when it kind of fell into place for me, because I've always been really interested in space. 

And I took some astronomy classes and now I got to like combine it. 

Rebecca: 

Oh, that's so cool. So why did you go with geology and not astronomy? As an astronomer, I'm sort of like:  Why did you pick the one? 

Josefin: 

I don't know. Actually it just happened and I thought like why it took like one class and then I thought, well, this is so interesting. 

I mean, I've always been interested also in Earth and why it looks the way it does and and I mean Earth is also a planet. And right now, as in Astro-geology or planetary geology, you put Earth into a larger context. 

You apply what you know about Earth, so volcanoes and all the features you see. But then you turn to the extraterrestrial objects and you use the knowledge you have about Earth and apply that to those objects. 

Rebecca: 

Oh that's cool. Yeah, 'cause Earth we can sort of study in detail and then we can apply that to other planets. 

Josefin: 

Yeah, exactly, but there are also features on Earth. So for example, impact craters. That's the dominant geological features on the rocky planets in our solar system, but on Earth we have very few impact craters. 

So if you would just turn to the Moon, for example, you see that it's full of craters, and also if you would see an image of Mars, you would also see that it's full of craters, but on Earth we have discovered around 200 impacts in total and those are not even like craters, so there is one creator in US which is called Meteor Crater. 

Its a very suitable name, because it's really a meteor crater, but that that one you may see it as like a feature in the desert, but most impact structures we would say on Earth they are, I mean, maybe it's a lake that is like a depression and then you would look for like at the rocks and then you would find tracers that tells you that this lake or this depression was formed by a meteorite impact, but it's not obvious in the landscape in the same way. 

Rebecca: 

Oh, that's so cool. So you can sort of just be out walking, hiking in the forest, and you could be sort of walking in a previous meteor crater. 

Josefin: 

I mean, I guess you could. I mean, we tend to go for... Maybe if there's some kind of geological features that stands out, so let's say a circular lake. 

But then there are many, many processes on Earth that can create circular features so you can also... I think meet your creator, for example. First they thought it was the result of a volcanic eruption. 

But then there was some clever person that started to look at the rocks and that was the same for the moon. They thought that this they were like remnants from volcanic activity. 

But then when they brought back the Apollo samples, they could see that OK, these rocks have been subjected to super high pressures and temperatures, and that only happens when you have these meteorite impacts. 

Rebecca: 

Right, yeah, 'cause you sort of did this as a part of your PhD, right? You looked at this lake in Småland, and that you actually sort of confirmed was a meteor crater, right? 

Josefin: 

Yeah, so I would stay in the community we already know that it was the result of a meteorite impact because they found these high pressure minerals so minerals that you...  And also like features in minerals that you only get when you have these super high pressures during a very short period of time. 

But that lake has been a bit controversial. I would say like if you go there, it's called Mien. You would see on all the signs. It says that it could be the result of a volcano – a volcanic eruption.  Which is not true. 

But for some reason they just keep the signs and I don't know. Maybe it it keeps some kind of-  it becomes more mystical. 

Rebecca: 

Right. 

Josefin: 

Maybe that there is something we need to solve - but I mean, it's really what we found was also traces of one of these high pressure minerals that you only get from meteorite impacts, so I kind of wanted to, I don't know, I think it's good when the public knows a little bit of what we are doing at the department.  And of course, it's really difficult if you just see this sign and you don't know anything about high pressure minerals. How can you know if it's the result of a volcano or a metiorite crater. 

Rebecca: 

So you're, like myself and Nic, at PhD student, so I'm curious, what is your PhD project about and are you working on any exciting projects right now? 

Josefin: 

So first of all, since I'm a planetary geologist, I study planetary materials. So I look at meteorites, but also so called impactites. 

And an impactide is basically a rock that have been created or modified during an impact.  So you can find that on all planets, but I look at terrestrial impactites. 

So what is happening is that if a meteor hits the surface of a planet in high enough speed and form a crater, and the energy from this meteor is transferred to the rocks so that they can melt and deform in various ways, and the meteor itself gets vaporised. 

And in rare cases, pieces and traces of the meteorite can be preserved within these impactites, so physical pieces are really rare, but you can find certain elements that are common in meteorites. For example Iridium. 

Rebecca: 

Right, these like heavy elements. 

Josefin: 

Yeah, and they are not so common on the surface of the Earth.  You can you can look for anomalies in for example in Irridium and this is how they discovered this dinosaur killer layer on Earth. 

There is this clay layer that you can find on several places on Earth, that formed when this meteorite hit the Earth around 66 million years ago, and in this clay you have this Iridium anomaly that comes from the impacting asteroid. 

Rebecca: 

Cool, is it just Iridium or is it other heavy elements as well? 

Josefin: 

You can get other platinum group elements as well.  But usually you tend to like go for the Iridium. 

Rebecca: 

Ah, that's so cool. 

Josefin: 

So yeah, so I look at that and but also meteorites are really interesting. They're often referred to as time capsules from the early solar system. I guess you also know a lot about Meteor meteorites. 

Rebecca: 

Some, but I would say here you're really the expert. 

Josefin: 

Yeah, so I mean they can give us a lot of information about like passt geological activity on other planetary bodies.  And we have meteorites from Mars, so that's the only physical material we have right now. 

The Perseverance mission, which is now on Mars. They are drilling for samples that will.... The plan is to return them back to Earth.  But right now we only have the metiorites from Mars. 

Rebecca:  

Do you have one of those? 

Yes, I do. So I am studying one of those right now, so I don't know if you know about the European Spallation Source. 

Rebecca: 

We actually have a a person from the ESS coming here speaking in a couple of weeks. 

Josefin: 

That sounds super exciting. I want to listen to that episode.  So they have this neutron source and what I do is at the moment I look at both my impactites and my meteorites and I try to create these 3D models of them.  So I use both X ray tomography and neutron tomography. 

And it's kind of similar to what you would do in the hospital. So if you want to see if you have a fracture in your arm, you would scan your arm of course, and then you would see the bone, but the flesh around it will be transparent. Which is great if you're looking for a fracture, and that's because... yeah, different densities and different elements attenuate in a different way, so they will pop up on an image and the heavier they are in the periodic system or the periodic table, the more they will pop up on your image. So for example, hydrogen does not show up if you scan your rock – or your arm - with X rays. 

So if you're interested in biological material or in this case - so a rock is obviously not made up by the same things as a body, a human body.  So if you have your rock and you're interested in clay minerals, for example, something that contains a lot of hydrogen, then X rays are not the best method to use. And that's when you can use neutrons instead because they interact differently with matter. 

So to just keep it simple, I use different methods, so it's so it's my PhD is rather method based and hopefully this can also be so if you have a really rare metiorite, right?  If you have a martian metiorite, you wouldn't want to crush it. The first thing we do.  

Because they're valuable. And all samples from sample return missions - you want to preserve them as pristine as possible. 

Rebecca: 

And I guess like this is just a I, I guess from me, but I guess sort of the shape of the rock could say tell you something as well, perhaps? 

Josefin: 

Absolutely yeah. So the three dimensional shapes. So even if you cut your sample and study it in the microscope. This thin section you can cut out. You would still only get a 2D view of the sample. 

So if you have fractures extending through the rock and you want to see like what it looks like inside, so it's really good to have these 3D models.  So, so yeah, that's it. Now ESS is not up and running for... 

Rebecca: 

No, of course it's a couple of years left. 

Josefin: 

Right, yeah? So we have to go to other neutron sources, but, I mean, hopefully hopefully at the ESS they can also do these experiments. 

Rebecca: 

Yeah, OK. And so you talk about sample return missions, but your meteor, your meteor or is not from one of those, right? 

Josefin: 

No, exactly so this is a meteorite from Mars that was ejected from Mars, so it was a rock laying calmly and nicely on Mars. But then there was an impact. 

And this material was ejected up in space.  And at some point they fell down on Earth.  And the one that I look at fell down on Antarctica.  And then a scientist picks it up and then we can study it. So that's the difference. So we haven't returned any samples ourselves. 

Rebecca: 

Has that been..   so that hasn't been done at all yet? 

Josefin: 

No, so that's one of the goals of this mission right now that they are drilling for samples on specific places that they have determined are extra interesting.  And then they will bring those drill cores back. 

Rebecca: 

Oh wow, I think that's so cool that actually sort of a rock has been ejected up from the surface of Mars and then landed here. 

Josefin: 

Yeah, that we can find them. That's great, but then also of course there are limitations to that. So one problem is that.  If it falls down on Antarctica and lies there for a long time, it will become contaminated. 

So that's also why it's so nice with these pristine samples that we will get from the sample returns because they have not been altered in any way. 

Rebecca: 

But I guess Antarctica is still like a pretty cold place, right? It's not much living stuff there. 

Josefin: 

Yeah it is.  And that's usually... I mean you many meteorites. You find them on Antarctica and in deserts because it's easier to look for them there. 

Rebecca: 

So does that as well happens or the other way around? Do we have rocks from the Earth being like... on Mars? 

Josefin: 

That's an excellent question, and I don't know if there are any earth rocks on Mars, but there are on Moon for example.  So there have been rocks that were blasted off Earth at some point and then fell down on the Moon. 

Rebecca: 

Right, OK, so you mentioned that there are like robots right now on Mars sort of drilling to get these samples. What are like the instruments on Mars right now and what are they sort of looking at? 

Josefin: 

But there are so many instruments on this rover, but for example, there is the Mastcam that takes this nice footage.  And a lot of geologists are looking at those footage because it can give us an idea of the landscape and we want to interpret like how did it form. 

Rebecca: 

So you can still get a lot of info without actually getting samples back to Earth. 

Josefin: 

Absolutely. So, for example, if you see sedimentary deposits that can give you a hint of: Did we have a water in this place? 

Rebecca: 

Yeah, because I've seen from pictures on Mars that this sort of looks like it's been these streams or flood beds, like structures. 

Josefin: 

Yeah, and that is because we can compare it to what we see on Earth. 

Rebecca: 

Hmm, ah, of course yeah, that's cool. So what would you like to achieve or find out with your research. What's your dream discovery? 

Josefin: 

I mean, everything is really a group effort, so I don't have like a perfect answer to that, but I hope that the research that we do can be for example helpful when you get these samples back from Mars and you want to study them without contaminating them. 

So as soon as you you bring them out of the containers, the sample containers there is a risk of contamination. So if you're interested in... I guess the most difficult thing is they want to find these biosignatures on Mars and as soon as you expose them to anything on Earth, there will be a risk of contamination. So the less destructive things you do in the beginning the better. So I hope that the neutorn - X ray - tomography thing that we're doing could be helpful in that, and I mean, I'm really excited about the life in universe thing.  

I mean, I think it would be amazing if they could detect any biosignatures. 

Rebecca: 

Yeah and I guess as you say your work here to create this method is really a step towards perhaps actually be able to discover life or life signs on a rock or something.  

Josefin: 

Yeah, I mean, I hope it's a little piece of the puzzle. Then, of course you have people from these different disciplines and... biologists, for example, are extremely important.  I don't know that much about biology to be honest. So I mean they will have to do their thing. But yeah, I think it's really a group effort when it comes to that. 

Josefin: 

And yeah, like the missions, right now they are kind of focused on finding biosignatures.  But first we need to like study the rocks we have and see like what methods can be used and how can we apply these methods on extraterrestrial samples. 

Rebecca: 

I think this is really cool.  And you sort of touched upon it in the the beginning like how you went to this class and then you sort of discovered geology in a way.   'Cause, as you say, we don't really do geology much here in Sweden like I remembered, I didn't have much of it in school.  It was sort of just like a couple of hours or something. I haven't really gotten in touch with geology that much, So what really draws you to this specific area of research? 

Josefin: 

I mean, first of all, geology is really a broad field, so as a geologist you can work with... I don't know volcanoes, glaciers, climate reconstructions, the physics and the chemistry of Earth and natural resources.  So I mean it. It it kind of, it's it's basically everything in nature, so. So it's really really a broad field, and I think everyone could actually find something that they're interested in. Like, why does the landscape look the way it does?  

But space has always been to me, like, the most fascinating field.  When I was little I was dreaming about being an astronomer. So I mean, now I'm also able to like look at physical material which is really nice. 

You can also use of course orbital data and things like that, but it's also great to be able to like hold in your hand physical material and... I don't know. It's easy to become a bit philosophical. Also, when it comes to geology and I guess everything you do as well, like where do we come from? Why? 

How did the solar system form? And then you have these massive processes like an impact event, which is super violent.  And then you have the rock in your hand.  And you look at the Super tiny minerals and you can still see traces of these enormous events. 

And then we have these enormous timescales as well, so billions of years or millions of years. I mean, you get a bit confused when you're thinking about it, but it's also... It's also fascinating. 

Rebecca: 

Now, but I guess like geology and astronomy really share something in common. They're having these huge timescales that we're like, oh, but you know, a couple of million years ago, that's not that far away, or long away, and that's really how we think, and we have that together, I think. 

Josefin: 

Yeah definitely yeah.  

Rebecca: 

So I actually looked it up and most craters on Mercury, the planet, are actually named after famous writers and artists and composers.  And two of them are named after Swedes.  One after August Strindberg and also one after Ulrika Pasch, who is apparantly a Swedish painter. 

So I am sort of curious, do you have like a favourite impact crater in the solar system and or which  planet or moon is it on? 

Josefin: 

So, I've been thinking about this because I guess as an impact researcher you should have a favourite.  And I guess there's there's so many that would be interesting to study scientifically, but I think I would go with more of a mainstream answer and choose one on the Moon. 

So there is this one, the Tycho crater, which is very prominent crater. If you look up to the sky in the night you will see it has these bright rays going from the centre and it's quite a young crater. 

So now we have the timescales again, but it's 108,000,000 years old.  That's really young. 

Rebecca: 

How do you know that it's that age? 

Josefin: 

So they have been dating samples from the Moon, and from this specific crater that they have been analysing. So it has been studied already, but I think that one - first of all is really beautiful and it's also one of the, I don't know, like one of the only geological phenomena that you can see everywhere on Earth. 

And like I think people during all times have also looked upon it and been thinking. I mean it's inspired, you said fiction before it has inspired a lot of fiction and people from other fields.  And you don't have to travel far like Grand Canyon to see something amazing. You can only look up and you would notice this this crater, so I think I would go for the Tycho crater, 

Rebecca: 

That's true.  Right.  I guess it’s named after Tycho Brahe. 

Josefin: 

Yeah, maybe I should say Tycho... Tycho crater, yeah? 

Rebecca: 

 I know which one you mean.  It's like the super bright one that you actually see. I hadn’t really thought about that as a huge impact crater, but of course it is. 

Josefin: 

Yeah, and the rays you see. That's part of the ejecta material. So since it's so young, it's still preserved, so it's like when the impact takes place there will be a lot of material ejected up from the ground, and you will see it as these rays basically.  And they haven't disappeared because it's so young. 

Rebecca: 

And also I guess we don't have a lot of wind and stuff on the Moon that could erase it. 

Josefin: 

Exactly, yeah, so that's why we have so many, we can see so many craters on other planets because they don't have plate tectonics, at least not as far as we know, but not as active on as on Earth. 

And also we have weather on Earth and large oceans. Everything is there to just destroy. 

Rebecca: 

So would you say that Earth is a bit boring as an impact crater scientist,  

Josefin: 

Mmm... I mean, I think Earth is amazing, but if you're interested in impact craters, maybe it's not the best place. 

Rebecca: 

Yeah, 'cause you mentioned tectonics and I think I read like a couple of weeks or months ago. Perhaps that maybe Venus have tectonics. Do you know anything about that? 

Josefin: 

No, I'm not updated on that, but I know of course that they are discussing it. But then the question is like if it had plate tectonics at some point, but either way it is not as active as on Earth. 

Rebecca: 

Right, do you have a favourite planet?  Or is it the moon? You seem very... 

Josefin: 

I mean, I like the Moon, uhm.  Because it's the one you see, but I mean I also love Earth. I don't know. Maybe I should have like a great answer.  I go by looks I think. I think Saturn is pretty so then I like that one.  

Rebecca: 

I think there's also, sort of, spoken as a true geologist.  

Josefin. 

Maybe.  Do you have a favourite planet? 

Rebecca: 

I guess it's Jupiter, but it's the first one I saw through a telescope, so it was really a big experience for me. Like actually seeing one of the ... 

Josefin: 

I think I saw that I took an astronomy course at this department a couple of years ago and we were able to visit the telescope that you have on the roof and we actually got to see Jupiter. 

Yeah, that was amazing because you see it in pictures in books and then you're like oh, of course it exists.  But it's not until you actually see it that you're like. Wow, it actually exists. 

Rebecca: 

You can see these storms that it has and the colours and like it. Yeah that that was a great experience. 

Josefin: 

I think everyone should see that at some point. 

Rebecca: 

So actually we have Culture Night happening this weekend and usually we have star gazing taking place. But because of the pandemic that's not happening. 

But I still encourage anyone who has, you know, use a pair of binoculars or anything to go out. And yeah, look at the Moon and perhaps look at the Tycho crater and just enjoy space. 

Josefin: 

So, when does the moon rise tonight? 

Rebecca: 

It's it's fairly late. You had to stay up until like 2-3 o'clock in the in the night, but you know, if you're a night owl, you can do it. 

Rebecca: 

It's worth it. Yeah, it's worth it, of course. 

And with that I'd like to wrap up and thank you so much Josefin for coming to this podcast. It's been quite pleasure to speak with you about your research. 

Josefin: 

Thank you for having me.  It was really fun.  

Rebecca: 

Yeah, thank you. 

 
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Nic: 

Looking through our telescopes we observe and study the Universe we live in.  We see planetary nebulae, globular clusters, star forming regions and much much more. 

Today we would like to spend a few minutes taking a closer look at one of the many wonders of the Universe.  Here to assist us with that we have Katrin Ros, the editor of the magazine Populär Astronomi.  Welcome. 

Katrin: 

Thank you Nic. 

Katrin: 

How are you? 

Katrin: 

I'm good, thank you. How are you?  

Nic: 

Yea, not too bad, so tell us what's captured your interest today? 

Katrin: 

So today I thought we could talk about the planet, which name is, as you said in the beginning Nic, Dimidium. 

Nic: 

Oh yes, and there's another name for it too, I think. 

Katrin: 

Yeah, so most people have probably heard of it as 51 peg B. 

Nic: 

Yeah, yes I I've heard that quite a lot recently. From my own research as well. Why is it so interesting? 

Katrin: 

So well, it is a very interesting planet and this week it is 26 years ago since it was discovered and that makes it the very first exoplanet or extrasolar planet that was discovered around a sun-like star. 

Nic: 

Wow, yeah, I know it's kind of weird to think how far we've come since then. It was a...  it's a kind of a weird planet too, because it's a hot Jupiter, right? 

Katrin: 

Yeah, exactly so. Even though it's like an around the sun, like star, it's very different from the actual planets in our solar system, so it's a hot Jupiter, which means that it's, well, it's really hot. 

So it's actually around 1284 Kelvin surface temperature and that's really hot. That's sort of like lava on Earth, so throw a rock in there and it will melt. 

Nic: 

Yeah, so we won't be pitching a tent there anytime soon. 

Katrin: 

Not exactly, I don't think that's the planet we would go to if we want to live somewhere, no. 

Nic: 

Do you know why that was the first planet we detected, meaning if you have any kind of idea or... 

Katrin: 

No. Do you know? 

Nic: 

Well, I think... I guess with all the things that we have when it comes to exoplanet research use the bias that we have with our detection. 

So we used what's known as the radial velocity method to detect this planet, which basically is we detect the strength of the pull of the planet on its host star.  And that actually it sends a wobble in the star signal that we can detect and show that there's a planet there. 

The thing is, is that well, those signals are really exaggerated with really large planets which are really close to their star and so. 

Basically, the reason why we detected this one first. Well, you know among others is that it was the easiest to detect.  

It created the strongest signal and so, but also it's a lot weirder than any kind of thing that we know today. 

So yeah, it's kind of interesting when we sort of look at those kinds of planets and sort of it was almost like it was, it was definitely going to be the first type that we were going to see, but at the same time, yeah you, you know you want to find the next Earth really.  And then we see this crazy looking plant that we've never seen before and it kind of shatters our reality on the science that we have. 

Uhm, are there any other cool like facts that you know about the planet? 

Katrin: 

You've so just as you're saying, it's important that it's very close to its to its host star and that's why we could discover it so early.  And it's actually so close to its orbit is just four days. 

And to compare that to something we have our closest in planet Mercury, but that has an orbit of 88 days. So like this, this 51 peg B is a lot closer in to its star. 

Nic: 

Yeah, it'd be a lot quite a lot different to anything we have looked at. 

So then how does it relate to Jupiter then if we call it hot Jupiters, yeah . 

Katrin: 

Yeah, what's Jupiter? So it's called Jupiter, because it's basically the same size or half the mass of Jupiter. 

Nic: 

Oh OK, yeah. 

Katrin: 

But since it's so close into its star, we think that its radius is a lot bigger because it's sort of puffed up because it's so hot. 

Nic: 

How do you feel when it comes to like these like do this. These kind of discoveries excite you personally when you come like, well, you see a new exoplanet out there or hot Jupiter. 

Or you know, what do you think when these kinds of things happen? 

Katrin: 

Yeah, of course, it's super cool. I mean, I sort of remember before. We didn't know any exoplanets. 

We didn't know if there was any exoplanets out there, so I mean, this planet in particular. It's really really cool and special. I think it really like marks the start of the era of exoplanets as we know them. 

Nic: 

Yeah, it's it's kind of like really special to me 'cause I was one year old when this thing was detected. 

So you know, like I remember, like as a 6 year old looking at science programmes talking about, like, there are planets around other stars and, you know, being inspired to thinking maybe that I can do that kind of research and then you know now I'm living my 6 year old dream and actually studying these planets a little bit more. 

And I feel like that's the it's really cool too...  a really cool aspect of this field that it's so young.  Like... like Rebecca studies stars, which is a very, you know, old pursuit.  It's been around for 100 years, no offence Rebbecca. 

The stuff that....  the science we're doing with stars is really cool because we've developed these techniques that, you know, we can really understand stars right now. 

But planets is something that we're still learning to do. It's only as old as I am and I still don't really know what's going on in my life. So you know, like that's the... that's kind of like, you know, I'm still figuring out and wrestle severe figuring things out to. 

One thing I really think is cool, about 51 Pegasi B, that it has an atmosphere, and we know that it has an atmosphere.  

So my research with my supervisor, Jens Hoeijmakers, basically we look at these hot Jupiters, and because they're so close to their stars, light travels through their atmospheres quite a lot, and it actually gives us a good chance of detecting molecules such as carbon monoxide or water, which actually being proved to exist. 

Ultra-hot Jupiters, I think, one of the...  Well, what I really love about them is that they're almost like laboratories for us because we can see the light coming through and they sort of test... We can test our own theories our own understanding of the planets that exist around it.  

How far away is it though, do you know that?  I have no idea. 

Katrin: 

So it's about 50 light years away from us. 

Nic: 

50 light years. Is that a long distance or a short distance? 

Katrin: 

Yeah, Distances are weird in astronomy. 

Nic: 

Yes, yeah exactly. 

Katrin: 

It's , well, it's not the closest planet we have around us. It's not the closest star. The closest star is around 3-4 light years away from us. 

So, about 10 times as far away from us than that. 

Nic:  

Ten times this far. 

Katrin. 

But it is still sort of close. I mean, that's also why we could discover it. 

Nic: 

Yeah, so like I guess, you know.  If we talk about some people think that like 1000 light years is still what we call that the solar neighbourhood or around that kind of that range.  

So it's quite close. 

Still we can't really send a rocket there though or a satellite to observe it, because you know, it wouldn't get there. Well, we'd have to, you know, let other our grandchildren take up the mission if we wanted to, but and you know, it might get lost on the way there. 

But it's it's kind of cool, I think. And like, you know, maybe one day we might find a target that would be worth visiting, and then we have to start thinking about how we could possibly get there as well. 

Katrin: 

Yeah yeah, that would be awesome, definitely. 

Nic: 

Uhm, well, I think we might wrap up this conversation. So thanks Katrin for this week. It's been a lot of fun talking to you. 

Katrin: 

Thank you, Nic. 

 
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Rebecca: 

This second episode of the first season of the Meridian was hosted by Rebecca Forsberg and Nicolas Borsato.  Our guests today were Josefin Martell and Katrin Ros and our producer was Anna S. Arnadottir.   If you have any comments or questions about the show then feel free to reach out to us via our emails or via the LundObservatory account on Twitter. 

In our theme at the beginning of the show we could hear members of the 2021 Astronomic Youth Research School, which was held here in Lund back in July.   

The music we have heard is called Twilight and was composed by Stellardrone. 

You can find all of our episodes on www.astro.lu.se/TheMeridian and make sure you tune into next weeks episode, when we will be visited by Jens Hoeijmakers, who is an associate senior lecturer here at Lund Observatory working on exoplanets. 

Thank you for listening. 

Frida Palmer in front of telescope
Frida Palmér standing by the meridian circle (taken ca 1929)

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