Nic: 

Welcome, this is season one episode three of the Meridian, a podcast exploring the ins and outs of what's happening here at Lund Observatory. 

This episode is airing on the 8th of October 2021, but if there are any listeners out there discovering the Meridian at a later date, then we just want to welcome you and hope that you find our banter entertaining. 

Now crossing our local Meridian in this episode we have Jens Hoijmakers, a planetformation specialist from the Netherlands. Jens, moved to Lund about a year ago in the autumn of 2020 after accepting a position as an associate senior lecturer here at the observatory. 

In every episode we also pick out one astronomical object to explore in more detail, and this week we'll be taking a closer look at a comet. This comet is named after its first two discovers Michael Giacobini and Ernst Sinner. But 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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Rebecca:

Hello Nic. 

Nic: 

Hey Rebecca. 

Rebecca: 

How are you? 

Nic: 

Yeah, I'm good, yeah... Actually I think one of the topics that we haven't really covered is the name of this podcast. Like why did we call this the Meridian? 

Rebecca: 

Right, yeah, we actually had sort of a. 

Nic: 

A brainstorm of ideas, right, I think. 

Rebecca: 

Yeah exactly, we had a brainstorm of ideas to come up with this name so I think I suggested like ‘Science Chat’ and ‘Talking to an Astronomer’. 

Nic: 

Yeah, then we like help with like Talking Space Dust or Astro in a Nutshell 

Rebecca: 

Yeah, yeah, and I don't know our producer and I tried to make sort of an acronym out of LUND because, well, we're astronomers. We like acronyms, but... 

Nic: 

Yeah exactly, and we're really bad at acronyms, so you know. So like what like LUND is spelled, L-U-N-D. Just you know if you're like me and you can't spell. So ‘long, unconventional night discussions’. 

Rebecca: 

Yeah, and many more that I didn't think was flying as well as the Meridian. 

Nic: 

With the Meridian so you came up with the Meridian, right? 

Rebecca: 

I think, Anna came up with it and I think it's a great name because we actually have a Meridian here in Lund. It's a kind of telescope that's called the Meridian Circle. 

Nic: 

Yeah, it's the one that can only point towards South, right? 

Rebecca: 

Exactly so you you can only sort of adjust the height of it, but you can't adjust the. 

Nic: 

Yeah, like the whether it points, East or West 

Rebecca: 

Exactly exactly. 

Nic: 

So like wouldn't that block? You from seeing objects in the night sky. 

Rebecca: 

Yeah, you could sort of think that way, but the the idea is really that you have this telescope pointing at South, just an imaginary circle really that goes from South to North. Yeah, you probably have heard of the GMT, which is where we have a Meridian circle going through the Grenich Observatory and that's where we set, you know, time to be zero or... 

Nic: 

Right, so you have GMT plus one or two. Depending on where you live. 

Rebecca: 

Yeah exactly, we're plus one here in Sweden and Australia is at? 

Nic: 

Plus nine if you're in Sydney. It depends on where you live. 'cause really big country, yeah. 

Rebecca: 

Right, of course it's. I forgot no. So really so you have this line going. From a North to South or South to North doesn't matter and you point your telescope towards that line basically, and then as the Earth rotates around its axis, you will have stars crossing. 

Nic: 

And also it's almost all Stars crossing, right? 

 Rebecca 

Uh, yes. 

 Nic 

On the night sky. So I think - or the way I understood is that basically if an object is going to appear on the night sky eventually it's going to track through the line that points from north to south and and so since you can move your telescope up and down, eventually it comes across and you can - what you record the time when it crosses that point? 

 Rebecca: 

Point, yeah, so you need to like be two astronomers to actually handle this telescope, you have one sort of sitting and looking through the ocular, saying like OK, no star crosses and then you have someone actually reading out like OK. Which angle are we at now and what is the hour,  like the stellar time. 

Nic: 

Right, I guess, and I guess that the idea is that because the earth rotates. Quite consistently is that you can somehow use mathematics to backtrack and create a coordinate for that. 

 Rebecca: 

Yeah, so that's really what you use in Meridian for to set the positions of stars. 

 Nic: 

Right, and so I guess since you know we have such a large growing fan base of this, we you know it's going to be inevitable that every astronomer and scientist is going to, you know, cross our Meridian. 

 Rebecca: 

Yeah, of course. Yeah, that's what we're hoping. 

Rebecca: 

Yeah, but you know, as I said, we use it to, or we used to use it for determining positions of stars and actually one who used it a lot was Frida Palmere. Have you heard of her? 

 Nic: 

Oh yes, she has really cool pants, right? 

 Rebecca: 

Yeah exactly, there's a picture of her on our our page at the and astronomy page and she was the first woman PhD in astronomy in Sweden. 

 Nic: 

That's awesome, yeah. 

 Rebecca: 

Yeah, so yeah she has this super cool pan standing by the Meridian. I think he's 23. 

 Rebecca: 

When that picture was taken, yeah, yeah no. I think he's so cool. So this was like in the yeah I think she finished in 1939. So it's a fairly long time ago. 

Nic: 

Yeah, I guess it's also really interesting back in those days we had all these huge international collaborations working together because, well, there's just so much cool stuff to see Lund Observatory wasn't the only one who were taking measurements. We got a section of the sky. Because it was an international collaboration to sort of map where all the stars and the objects were in the night sky. So yeah, you know, Frida Palmer was able to contribute. 

 Rebecca: 

Yeah, no, you're right, and that's really how we work today, right? Having these large collaborations of international people. 

 Nic: 

Yes, definitely. I think we're all part of those. 

Jens: 

And for all the. 

Nic: 

Aspiring astronomers out there you too can wear cool pants. 

 

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

 

 Rebecca: 

And now I'd like to welcome to the mic Jens Hoijmakers market researcher here at Lund Observatory welcome. 

 Jens: 

Thank you very much. 

Rebecca: 

Very much. I'm so happy to have. You here today I here today 

Jens: 

I'm also very happy to be here. In fact, it's quite special still. for me to be here, I was recently. I recently came to Lund. About a year ago, actually, but. Because of the pandemic, I have been out of the country for most of this. 

 Rebecca: 

Right, yeah? 

 Jens: 

So I just arrived back a few weeks ago and I really feel now that we can start as Corona is leaving us, hopefully to really start start work. Here and get settled and and do amazing science. 

 Rebecca: 

Yeah, I look so much forward to see the work you can do here. Where did you come from before getting here? 

 Jens: 

So I studied in the Netherlands. I did my bachelors, masters and PhD in Leiden University, Leiden is a small city. Between Amsterdam and The Hague, more or less, but. 

 Rebecca: 

Oh yeah, it's like Michiel.  

Jens: 

I think we yeah. Michiel was also in Leiden. That's right. Yeah, we didn't have a lot of overlap I think he was there a bit earlier than me. Or maybe I was a student and. I he was more more ahead of me I I think. 

Uhm, Leiden is a very famous city for its university though, so it has a very highly ranked university and it's also very strong in astronomy. They brag that they are the 5th or the 10th or something in the world. I don't know how those rankings go, but it's very famous. Astronomy Institute is one of the oldest observatories. 

Rebecca: 

Oh, I didn't know that that's actually very cool. 

 Jens: 

Yeah, yeah it has. It has an old like really old observed to building in the city centre as well. They don't use that anymore for outreach. So the point is that it's it's. A very established place. I really enjoyed my studies there. I spent, well, it's nine years there in total. And did my PhD and moved on to Switzerland. For a post doc for three years or actually four years. But I ended it a year earlier to come here. 

 Rebecca: 

All right, OK. 

 Jens: 

There I spent. Essentially half my time and in the observatory of Geneva, and Geneva is famous for the discovery of the first exoplanet. 

 Rebecca: 

Right, yeah in 1995. 

 Jens: 

In 1995 exactly the people who discovered it well. Nobel Prize two years ago. They were actually doing it right there. And so, so that is quite a. That's quite an interesting place to be as well. They have a relatively large section on exoplanets. They develop a lot of instrumentation for exoplanet research and so so walking around there as well was very interesting.  

Half the time I was there and half the time I was in in Bern. University of Bern, which also has an interesting history but more in the in the context of the exploration of the solar system they have developed especially in the Apollo programme. I think that they're still very proud of some instruments that went along to the Moon missions, but they're a bit more. Focused on the solar. System there. 

 Rebecca: 

Because you work on exoplanets right? And an exoplanets, they it's a fairly new field I'd say, but it seems you said you discovered. Oh well, they discovered the first one in 95. How far have we come since then? Can you sort of take us through the subject?  

Jens: 

Yes. Exoplanets is a new field. Of course, in the sense that we've only been discovering planets for about 25 years, and if you compare that with the rest of let's say mainstream astronomy, if you talk about stars or galaxies, you can trace back a lot of our thinking about 100. Years when people were first really starting to develop more advanced instrumentation too, and also more advanced methodology, I would say to study astronomical objects. In that sense exoplanets is a relatively new field, but over the last. 25 years it has really exploded in terms of activity I think. I think it's fair to say that. About a third of all of astronomy these days is about exoplanets, so there's a lot of work going on.  

There's a lot of developments going on, so on on the one hand, I would say 25 years sounds like not a lot, but on the other hand, a lot has happened and especially in the last last years. I think this is really one of those fields that is. Currently growing exponentially with a lot of new things happening all the time. And I, I would say that there there is, there is not a better time, let's say to be doing exoplanets than today,  

But that has been. True also, five years ago, the feild was exploding and five years from now, hopefully we're still, you know, making new discoveries going going further than we could before, and this is very much driven by technological advancement. So there are telescopes that are being being developed designed specifically for exit planets, and every time a new telescope or Space Telescope, for example, becomes operational, we are able to see again a step further and see smaller planets. See cooler planets that are harder to to study, and I think every time we are surprised by what we see and we see new, interesting, interesting phenomena. 

 Rebecca: 

Yes, I wanna you know back up a bit and. Yeah, talk about your research with it. Exoplanet atmospheres, right? So how did you come into that subject? 

 Jens: 

When I was starting my studies like my research studies during master PH.D. exoplanets were quite routinely being discovered. We're talking about sort of 2011, 2012, 2013. 

 Rebecca: 

Was this sort of the Kepler era? 

 Jens: 

Exactly this is right at the end of the. Kepler era where we were starting to count the number of exoplanet discoveries in the thousands. 

 Rebecca: 

Yeah, exactly. 

 Jens: 

There was really still a fresh field there was only few people even doing it. And every exoplanet discovery before that was a press release essentially and at this moment we started. Really in bulk that. Hundreds of planets were being sort of discovered. All the time. And what was it's not fair to say lagging, but it was still a bit more difficult. To do was the atmospheres, and I think in the end a large.  

A large component of this of this, or a large driver of this field. Is to find planets that are like Earth planets that may have life on them. I mean this is a very very classical classical way of thinking about the direction of this field, right. And I would say that this is one of the most important things that we're going to be doing in astronomy. Finding planets like Earth or seeking out whether there are planets like Earth and the question of extraterrestrial life is, of course, it's of course always, always there. 

That's not exactly what we're working on right now, right? But that is the direction where we're going. That's sort of. The target that we have on. The horizon. 

Rebecca: 

So do you know what you'd look for if you're looking for Earthlike? 

 Jens: 

Well, yes, depending on what you mean by Earth. Like if you say we're looking for an earth like planet in the sense that it looks like earth, then we know exactly what to look for, but that is not exactly always what we mean and depending on who you talk to, Earthlike may mean something very different. I think Earthlike planets are planets that are rocky and sort of the same size as the earth, and they have an atmosphere and they may have sort of a similar. Maybe temperature or something like that. I think in our book Venus would be an earth like planet even though it is not very habitable and it is, I would say, not very Earthlike it. 

I mean, it's earth like in the sense that it has the same composition and sort of size and matters, but that's. Where the comparison. Stops the thing with exoplanets is that we see only very. Global, we only get very global. Pictures of what these plants are like and plants are very complicated objects. 

What I really. Like about about astronomy, is that actual astronomy? The study of stars is that you can take a piece. Of paper and. You can write down in a couple of equations how star works. I mean, I think that is spectacular. For planets you cannot do this. Planets are very complicated systems. They are maybe chaotic systems in the sense of how they're, how they're weather and climate works, and how everything interacts with each other. 

 There's no real prescription of a planet if you give me a basket of elements, metals and rocks and ices or water, gas, whatever and I put it all together. I cannot predict to you what this planet is going to look like. Now or a billion years from now? Because it's a very chaotic interplay of a lot of different processes. 

 Rebecca: 

No, I guess only if we look at the solar system we have, you know, like 8 planets that are totally different. 

 Jens: 

Exactly, or if you talk about if you talk about climate change, for example, we are on Earth. We've got millions of sensors trying to track what's. Happening and we. Have a hard time understanding what our climate is. Going to do 50 years from now. 

 Rebecca: 

Right, yeah? 

 Jens: 

Right so that already tells you. That planets are difficult, difficult things to. Grasp and how you name things matters you. You can call it an Earthlike planets like Venus. Yes, and if you are in the solar system, that doesn't make any sense because there's only one Earth-like planet. 

There's rocky planets, but they're all extremely diverse and we're starting to see this in the field of our exoplanet discovery , that there is a very wide diversity in the planets that they're out there. I think that forces usto constantly rephrase a little bit, the questions that we're asking in the terms that we're using - and what was an earth-like planet and maybe five years ago, doesn't pass like one soon anymore. 

And I think that is very exciting because it's very dynamic and maybe to come back to your original question, which is why you do exoplanet atmospheres.   It is because, in part, because it is so incredibly dynamic that when I was starting there was almost no studies of exoplanet atmospheres. I mean the first explant atmosphere was observed in 2002. 

Rebecca: 

Like the first detection of it? 

Jens: 

The first detection of it. But then there was only a handful of people in the world actually doing that and it took a couple of years for the field to mature for different groups to start start to align their thinking. Methodologies. People had no idea actually what they were looking at.  You can trace a lot of the theory that we're using back to the early 2000s, but it really picked up speed, I would say, with observations of Hubble and the Spitzer Space telescope at the end of the first decade of this of this century. 

2008, 2009, you start to see really the first papers that are discussing the details. A bit more people going after each other, you know?  Seeing different things, trying to reconcile different ideas.  And it really started. I would say to mature only then just the methodology and the first sort of exploration of exoplanets. 

And these exoplanets are really gas giants. They are what we call hot Jupiters, which are sort of Jupiter sized gaseous planets that are in very close orbits around their stars. 

Orbital periods of days rather than years and temperatures that are higher than 1000 degrees or 2000 degrees is also very common. 

Planets completely unlike that we have in the in the solar system, but those are observationally the easiest to to study. 

They're not even that common in the universe, but they are easier to detect and study and that's why we're focusing on those. 

Rebecca: 

Just for our listeners that might not know: Why are they easier to detect? 

Jens: 

Because said they are larger and hotter, so in astronomy it is usually easier to detect things that are hotter and larger because they emit more light, more radiation. 

And for these planets it's a little bit more peculiar, because a technique that we use to study them is the fact that they sometimes go in front of their stars. 

And then they block the starlight. And of course, when the plan is larger then that will also help.  So it generally helps us if planets are larger or more massive.  More heavy or hotter and so those just happened to be the plans that we were studying first.  We're not studying rocky earth-like planets so much because we can't really detect them because they're difficult to see. 

So we studied the planets that we can instead, and we try to learn as much as we can and as we learn how to interpret these observations, we will be developing new technologies to be able to do that better and then that will allow us to go and see smaller planets as well. And that also adds to this dynamicisim, right. 

Right, if you are in this field in 2010, there's a handful of planets where we can observe their atmospheres or hints of their atmospheres.  There is now more and more planets being discovered, and sometimes there's planets in there that are really favourable for us and then we will all target that one and we learn a little bit more and then we go back and we learn new things and have new discussions. Have new problems to solve. 

And that makes it very, I think, very interesting.  It is a field that is really picking up more and more speed as more and more things are being discovered, there is thousands of people researching exoplanets these days, whereas in 2010 it was more like dozens. 

So it is really. I think it's really a spectacular field. And of course the end goal is also very very interesting. Of course it's one of the biggest questions that humanity has had. Is there life outside of Earth? Are there planets like the Earth out there? And the answer to that question is yes, and there's one about about, you know, extra actual life. That is of course, something. 

That's the million dollar question of a lot of...  I maybe even all of science.  One of these questions that people have been... That's the first question that people have when they think about exoplanets. 

Oh, is there life out there?  

Rebecca: 

It joins a lot of fields together also.  It joins biology and chemistry.... 

Jens: 

Exactly exactly, it's really the outcome... I think it's going to be the outcome of a lot of our scientific endeavours that we are doing right now. 

It's not something that is around the corner. I think. I've been saying for 10 years that 20 years from now we will know. 

It's it is technologically very difficult but we are inching closer towards answering questions like this. 

And it's going to take decades more, but we will get there and I think that is also very exciting. 

 Rebecca: 

Yeah, it really is. So what sort of stuff are you working on right now? Do you have any exciting projects that you're working on right now? 

Jens: 

Yeah, absolutely absolutely. 

I mean, as I say this, this field is like it's like going forward so so quickly.  Everything you are working on has to be. It's also a bit of a downside actually, because if you're doing something that is boring. 

Then you don't make an impact because a year from now you'll be you'll be behind the curve, but absolutely. 

We are constantly trying to see new themes. One of the things that I'm actually specialised in is the atmospheres of the hottest planets.  So you've got, you know, these gas giants that are heated because they're so close to their star.  They’re thousands of degrees. 

We've got planets that are even 3000 or 4000 degrees. 

 Rebecca: 

That's like harder than some of the stars I'm working with. 

Jens: 

Exactly, that is hotter than maybe even most stars, right? 

So these are planets that are very close to very hot stars and when that happens their atmosphere starts to resemble the atmosphere of a star a little bit in the sense that the entire gas is no longer molecular.  If you think about the atmosphere of the Earth, for example, the atmosphere is composed of molecules. You've got nitrogen, which is N2. You've got oxygen, which is 02. You've got CO2.  Those are all molecules.   

Rebecca: 

Water. 

Jens. 

Water of course.  Yeah exactly, and this is true for all the planets in the solar system. So Jupiter for example, is mostly composed of hydrogen, which is H2 - molecular hydrogen. 

But if you go to stars, for example, they also are made of hydrogen, but that is atomic hydrogen. 

And these planets are so close to their stars that all of these molecules fall apart as well and they become atoms. 

And that is interesting because all of those atoms are detectable with spectrographs.  So they create spectral lines that when you work on stars you also you also use those of course, all the time. 

Which means that suddenly we have new tools.  Or new, let's say, probes to interrogate these atmospheres with. 

You do the same thing when you study stars, you take a spectrograph and you take the starlight and you disperse it and you see based on all of the absorption lines of all of these different elements, what the star is made of, how the star works and we can do the same thing for planets, which is actually one of the main ways we study their atmospheres.  

You can do that if the atmosphere has molecules in it, but then you very often have to go to infrared wavelengths so you have to use infrared instruments, and those are typically a little bit harder to use.  To observe with. They are also a little bit  less developed than than instruments at visible wavelengths. 

 Rebecca: 

Yeah, the infrared field is not really up to speed with the optical. 

Jens: 

Exactly. It's a little bit more tricky observations there, whereas we have, I think, 100 years or almost -  experience observing things in optical wavelengths.  And that makes it that these this particular class of planets, even though they are not interesting at all from the point of view of life, because it's it's very it's very hot. They're never going to... They are not even earth-like.  They are gas giants. 

But the fact is that we have a lot more observable signals that we can use. 

And in that way get more of a detailed understanding of what the atmospheres are like, and that's that's - I mean, this type of planets, I've been working on for now, three years and right now we are seeing a lot of these planets having commonalities, but also some differences in the things that we see and we don't... 

We thought that we sort of had an idea of what these planets should look like and maybe we got that right 50% of the time and the other 50% is a bit of a problem for us to solve.  

So currently I'm preparing and also executing a lot of new observations of these types of objects and try to put together what they have in common and what they don't and whether we can explain that using more advanced and deeper observations and also more sophisticated models, which are also very important to to interpret this type of data. 

Rebecca: 

Yeah, 'cause really when the first time we sort of put spectrographs that telescope then looked at stars we saw that oh they have different spectral types. You can sort of group them into stars having more hydrogen or having more of whatever element. 

Do you mean that you sort of are starting to do that with planets now?  You can sort of group them in spectral types or elemental types. Or is that sort of what you’re going for? 

Jens: 

I think the comparison is interesting.  It's not exactly about grouping them. I think, when we were first doing this for stars, we essentially had to invent a new field of science. 

 Rebecca: 

Yeah, that was basically when Astrophysics was born. 

Jens: 

We had no clue. We had to invent astrophysics – literally. 

In some sense, that is what we are going to have to do again, and I think it is accurate to say that plants don't allow themselves to be grouped in that way. 

Stars, as I said, you can take a piece of paper and write out a couple of equations that govern essentially 95% of what you see in a star. 

For plants this is not the case, which means that every single one of them is a unique animal, and only because we don't see the details, we only see these planets at a global sort of scale. If we're lucky initially, that is when they allow themselves to be grouped, but I predict that once we have bigger telescopes and we're going to look at all of these planets in more detail than we can right now, we're going to see a lot of differences and you don't need to go far to sort of understand that point, because in the solar system -what planets....  You can you can group rocky planets and gas giants, but then you've got two types of gas giants because you've got Jupiter and Saturn, which are a bit different from Uranus and Neptune, which we call ice giant, right? 

And then Mars and the Earth and Venus and Mercury. They're nothing alike either.  So.I think the more you zoom in, the more you're going to see the differences and the more work we will have to make sense of all of that. 

 Rebecca: 

Right, so speaking of new telescopes, and there are a lot of new telescopes and instruments coming online in the next few years, a lot of them which will be beneficial for your field. Are there any ones you're more excited about or? 

Jens: 

Yeah, definitely. As I said, this field is driven by technological advancement.  The telescopes that we used initially, which are the Hubble Space Telescope, the Spitzer Space Telescope mostly also all ground based telescopes, they were not designed to do exit planets. Exoplanets didn't exist when these things were being designed and developed and launched. 

So we had to repurpose these instruments. These telescopes these facilities for the type of observation that we wanted to do. I think Kepler was the first telescope that was really designed specifically for exoplanets, but discovering them. 

Now we have advanced for 15-20 years and we are now starting to see new instrumentation that is specifically designed for studying, exoplanets not just detecting them. 

And one of  the main developments in this in this area is the launch of the James Webb Space Telescope.  Fingers crossed it's going to be launched in a few months.  This is a project that has been on the drawing board and being developed for decades. It's been delayed a lot. 

But it is now finally going to be launched and it is really going to revolutionise, I think, what we know about exoplanets.  

If you think about astronomy there's a lot of, you know, nice, beautiful imagery that you can find of galaxies and nebulas. I think 9 out of 10 - those have been made by Hubble. 

Hubble has been extremely successful in revolutionising what we could see in the universe. 

James Webb is going to do that all again, I think for for wider astronomy, but also for exoplanets. 

Where we're going to have unprecedented detail with which we can study planets, and I predict that all of the theory and the models and the things that we think we know about planets all are going to go out of the window by the time that we first aim James Webb at some planet because the detail that we're going to see is just going to be too much.  Compared to what we think we understand and that's very exciting, right? That's how science progresses. 

So James Webb is one of the things I'm really looking forward to. I also hope to observe with this instrument, with this telescope in the future. 

Another very very important big project that's coming up is the European Extremely Large Telescope - the ELT which is being built in in Chile. 

And this is a telescope with a diameter, a mirror diameter, of 39 years. This is by far the largest telescope that we've ever built. 

It is going to be online, sort of. In the mid 2020s. And it also has instrumentation that is designed -  optimised - for studying exoplanets as well. 

It also is going to give us unprecedented views on exoplanets, in a way that's a little bit orthogonal, a little bit complementary to what James Webb is going to do from space, and I think those two together are going to really drive this field forward over the next few decades, actually. 

Rebecca: 

Right, yeah, sort of as a wrapping up question, I wanted to sort of ask you if you had unlimited time on say James Webb or the ELT -  What would you point it at and what would you do with it? 

Jens: 

I think that... So one of the main limitations that we have when we observe anything in in astronomy is that we have to compete. We compete with colleagues for executing the best idea using the limited amount of time that a telescope or facility has. 

That is true for any telescope that we can propose time for. 

So the way this works is that these these facilities are operated by some organisation and they basically decide what's going to happen. They decide how they're going to improve instruments, what they're going to. And then they ask the scientific community to come up with ideas to execute. And then there is always more ideas than they can't execute, so they choose the best ones and this Is a way to select or to make sure that these instruments facilities are used in the best possible way. 

That is good in the sense that it keeps us competing with each other to make the best ideas possible, to to carry out the best science possible. 

It also means that we will try to do the best possible science for the cheapest amount of time, or the least amount of time. The cheapest type of proposal. And that means that we may miss opportunities.  

So if you ask me - Given unlimited time, I would do things that I couldn't do when I'm so limited in having to come up with ideas that you can execute in small amounts of time or resources. 

And what I would focus on I think is to do a lot more repeat observations. Very often we look at a planet once and then we never repeat that again because it's already been observed. Let's look at something else right now because you have to you know, come up with new things. 

Rebecca: 

So it's hard to sort of put that proposal through saying I want to look at it again. 

Jens: 

What if planets change and one thing we … well in the case of atmosphere - is what if their atmospheres change? 

There is...  on Earth with the concept of weather where if you look at the Earth one day, it may be all cloudy and maybe a couple of months later you know the the weather may have changed or things like climate change. You can imagine that the climates of these very hot gas giants are a lot more volatile, there's a lot more things going on. What are things change?  

We think we understand the planet based on observations taken in one day and then five years later, we would do the same observation and we come up with different answers. 

We are, I think, at risk of not being able to do that because of this model, in which time is distributed to scientists. 

So I would, I would really go for exoplanet weather. 

Observe a planet 10 times in a row or 20 times in a row and see if you can see differences.  Or not. 

And what does that tell you about how these climates actually work, and how repeatable are the observations that we are going to take with James Webb once this thing is flying. 

And we might observe a planet once and then that's going to be our final answer for what this plan is like. Well, maybe not. 

Maybe yes, maybe often yes, but maybe sometimes not.  

Are we going to make mistakes by looking at planets only once or twice and never again? 

I think that is one of the things I would like to test. Another thing, of course, is how the more time you have, the more detail you can see. The longer you look at something, the more sensitive you become. 

So there is a bit of a tug between looking at more objects.  Or looking at.a few objects, but more often.  Simply to go deeper to see more detail. 

And there's of course a couple of objects out there that I think are my personal favourites where I would like to spend a little extra time on.. 

Rebecca: 

Yeah, thank you so much for that answer. I hope you get to discover exoplanet weather sometime and also, I'd like to thank you for crossing our Meridian and joining this podcast. 

Jens: 

Thank you very much for the invitation. I really liked it, I think you really do an amazing job 

Rebecca: 

Thank you. 

 

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Nic: 

Looking through our telescopes we can observe and study the Universe we live in.  We see radio bursts, hot Jupiters, moons with Vulcanos, 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. 

Katrin: 

Thank you Nic. 

Nic: 

Tell us Katrin, what has captured your interest today? 

Katrin: 

So this week I'm bringing you a comet named 21P or Giacobini-Zinner 

Nic: 

Awesome, so tell me something about it. 

Katrin: 

So this is a periodic comet, so it means that it's coming back into the inner solar system every 6.6 years, actually. 

Nic: 

So can you see it? 

Katrin: 

No, I'm sorry right now you cannot see it at all, actually. So right now it's at this furthest point, so it's outside of Jupiter's orbit. 

Nic: 

Oh wow, yeah. 

Katrin: 

So it's very, very faint. You would need a very big telescope to be able to look at it right now. 

Nic: 

Oh well, that's a bit disappointing. 

Katrin: 

You can maybe wait 4 years. 

Nic: 

So in four years time, it'll be bright enough for me to look at? 

Katrin: 

Yeah, With binoculars or a small telescope, you could see it then.  For then it's closest to the Earth. 

Nic: 

OK, so I guess there's more light reflecting off it and we get to see it like that. 

Katrin: 

Yeah, yeah that's true. 

Nic: 

OK, so like what's the deal with it? Like why is it such a cool object to talk about? 

Katrin: 

So right now we cannot see it at all, but we can see something else that comes from it.  

So this weekend it's the Draconids meteor shower, so there's a lot of meteors coming up this weekend and how they are connected to this comet is actually that the comet has this periodic orbit, and when it comes close to this to the Sun, it leaves behind a lot of ice and dust. 

Like small material and then the Earth right now. This weekend is travelling through this path in space, so we see all of this space debris coming into the atmosphere. 

Nic: 

Yeah, so they look like, basically like a lot of shooting stars in the night sky? 

Katrin: 

Yeah, exactly exactly. 

Nic: 

Oh, that sounds so awesome. So so, when what exactly is it going to happen? Like is there a specific date? 

Katrin: 

So it's this weekend 8th to 9th of October. That's the best time to look at it. 

Nic: 

OK cool, awesome.  Why do many showers occur so often in the night sky like. It seems that like , you know, we've seen shooting stars all the time, but is there something driving that process forward? 

Katrin: 

Yeah, so I mean we can see shooting stars quite often, just like one happening here and there. But there are a few times of the year when the Earth's orbit is going through a specific path that is left behind a certain comet. 

So we have this one - the Draconids - now coming up and then maybe you know about the one in the end of summer.  So in August we have the Perseids. And that's maybe the biggest one, actually. 

Nic: 

OK, right now so you can watch it again later on in life and that's is that done by the same comet? Or is that done … ? 

Katrin: 

No, that's another one. So each of those meteor showers are coming from different comets, so we have a few of them actually, but this is one of the good ones this weekend. So yeah, go out to look at it. 

Nic: 

Right, OK, yeah, OK sounds good so I don't know if you know, but are there a lot of comets in our solar system then like that do this a lot? 

Katrin: 

Yeah, there are a lot of comments, but not all of them leaves visible meteor showers behind and not all of them are comes so close to us that we are crossing their path so. But this is one of the ones that that do and that has like a pretty short orbit as well. We have the we have ones that are go very much further out in the solar system as well and then takes like hundreds or thousands of years to come back again. 

Nic: 

OK so periodic comets mean something element that has an orbit around the Sun or something like that. So are there non periodic comets that exist? 

Katrin: 

There are even potential comments from outside of the solar system. So yeah, there there are.  

I mean comedy is basically just an icy body that comes close to the Sun.  And then it leaves behind a bit of this ice and us when it's melting basically. 

Nic: 

Right, OK, so we really could have comments that have come from alien systems. Basically shooting through that, yeah. 

Katrin: 

Yeah we can. We have had two of them that we think actually more or less. 

Nic: 

Oh, really. 

Nic: 

That's so cool. 

Katrin: 

Yeah it is, right? 

Nic: 

Right, I never thought of that. So yeah, wow, so if you keep your eyes on the night sky you might see something that no one's ever seen before - I guess. 

Katrin: 

That's possible. That's possible. Keep looking. 

Nic: 

Yeah, OK wow, that's something really nice to think about. Well, thank you for coming in this week, Katrin.  It was really awesome. 

 Rebecca: 

Yeah, thanks for having me. 

Nic: 

No worries 

 

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Nic: 

Thie third episode of the first season of the Meridian was hosted by Rebecca Forsberg and Nicolas Borsato.  Our guests today were Jens Hoeijmakers and Katrin Ros and Anna was our producer.  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 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 by Laura Hrastar from MAX IV, so tune in then to learn more about the world class large laboratory we have here in Lund! 

Thank you for listening.