The Urban Astronomer Podcast

This episode features an interview with Dr Julia Healy, from ASTRON, where she works as part of the MHONGOOSE survey team. When this interview was originally recorded early last year, she hadn't yet submitted her PhD thesis, but has since graduated and earned the title "Dr". Julia completed her Bachelor of Science, specialising in Astrophysics and Physics, at the University of Cape Town in 2013. She went on to complete a Bachelor of Science Honours in Physics in 2014 and a Master of Science in Astronomy in 2017, also at UCT. In 2017 she began a double degree PhD programme at the University of Cape Town and the University of Groningen (in the Netherlands), which she submitted in March 2021 and later defended in a public ceremony in Groningen in August 2021. I am now a postdoctoral fellow based at ASTRON (the Dutch National Radio Observatory) working as part of the MHONGOOSE survey team. The MHONGOOSE (MeerKAT HI Observations of Nearby Galactic Objects: Observing Southern Emitters) survey is one of the large survey project run on the MeerKAT radio telescope.

This is episode 60 of the Urban Astronomer podcast! Is that a milestone? Sure, but we'll save the party hats for episode 75. Today we'll just get on with the job at hand, and bring you a science explainy bit. Today's question: How can astronomers be so certain about what things in space are made from? On Earth it's relatively easy to send geologists out to different places with their hammers, and have them collect samples from interesting rock formations and bring them back to the lab for analysis, but astronomers hardly ever get to do that with planets, comets, the Sun and distant galaxies. So how do they know, and how can they sound so confident? Listen below to find out!

This episode of the Urban Astronomer Podcast features an interview with Dr Imogen Whittam, an astrophysicist at Oxford University

It's another Science Explainy Bit episode, and today we answer a question asked by another podcaster while interviewing us for their show. The host wanted to know how the view of southern skies compares to that of the northern hemisphere. I gave a quick answer before we moved on to another topic, but I would have liked to give a more detailed and complete answer. Which brings us to this episode, in which I describe how there really isn't a single sky for the North or the South. But the sky in the USA does still look different to what we have here in South Africa, and I explain why.

The Urban Astronomer interviews noted South African amateur astronomer Carol Botha about her science outreach work. Carol has become quite well known on Slooh, the robotic telescope and astronomy service which I know quite well because I've provided a few video streams of eclipses and the like for them over the years. Be warned though, this is a long episode so make some popcorn and find a comfortable seat before you start!

Today's episode is the first Science Explainy Bit of the season, and it's another basic, classic topic: Leap Years. As a reminder, I love looking at the questions that seem simple because we think of them as the sorts of things that children ask their parents, but the thing about these questions is that they never are simple. These are things that took humanity centuries or longer to figure out, and that most of us still don't really understand because we first asked these questions as kids ourselves, and got the sort of answer which people give small kids, and nobody ever asked again! Last season we talked about about the tides and what happens if you shoot a gun in space, and why it is that we sometimes see the Moon during the day when we all expect to see it at night. And today, we talk about how leap years, how they relate to Easter and politics, and why they even exist. A few weeks back, we were featured as guests on Podcast Insider, the official podcast of the Blubrry podcasting platform. Although this show doesn't live on their hosting platform, we do use their software to make it all work on our own servers, and it was a bit of an honour to be invited onto their show. Give it a listen here.

At long last, the third season of the Urban Astronomer Podcast has kicked off! We thought the last season went so well that we've decided to keep things much as they are, with perhaps the occasional news segment added in whenever something interesting has happened. So for the most part, that means twelve episodes, alternating between interviews with people who have some sort of a connection to South African astronomy, and science explainy bits where I answer the questions that listeners like you have emailed to me at podcast@urban-astronomer.com Tony Lelliott 3:23 But this episode is all about the Interview with Dr Lelliott. Tony is an Honorary Assoc. Professor at Wits University. He has spent much of his career researching science communication, and has a special interest in astronomy, and human evolution. You can follow him on twitter at @drtoeknee

Since our last episode aired, in early December last year, I've had people ask me when the third season will begin. Well the good news is: Soon! Guests have been booked, interviews will be recorded over the next few weeks, and science explainy bits... well. That's where you come in! If you've got questions you'd like to hear answered in one of the Urban Astronomer Podcast Patented Science Explainy Bits then why not put them in an email and send to podcast@urban-astronomer.com for me? It's your questions that make those segments work. If you're worried that your questions might be too basic or simple for me, then please send them anyway. Those questions usually have the best answers and they are my favourite to work with! Anyway, we launch towards the end of March. Don't miss it!

The Urban Astronomer Podcast's season 2 finale examines the colours of stars, and ponders what it's actually like out in space

In this episode, we interview Nicole Thomas, a PhD student at the University of the Western Cape with an interest in the evolution of galaxies, and the super-massive black holes that lie within. We recorded this conversation only a week ago, and I really enjoyed speaking to her. I found her childhood interest in how the universe worked very relatable, and especially her need to understand what's going on underneath it all. Sadly, this is the final interview with a real astronomer of this season of the Urban Astronomer podcast, but I'm especially happy with this one so I hope you'll enjoy it. Nicole Thomas Nicole is a PhD student at the University of the Western Cape, and the Square Kilometer Array. She recently completed a stint at the department of Astrophysics as Oxford university, thanks to the UK-SA Newton Exchange Fund Links Nicole on Twitter Astro Molo Mhlaba Cosmic Soundscapes - a website containing audio recordings derived by NASA scientists, from radio signals detected by Solar System objects

Episode 10 of Season Two answers listener questions: What happens when a spaceship shoots its gun in space, and why is Venus so hot?

This is episode 9 of the 2nd season of the Urban Astronomer Podcast, featuring an interview with Dr Tana Joseph.  It's been an interesting two weeks since the last episode - I've settled further into my new home and adjusted from rural to suburban life. What I gained in access to basic utilities and saving several hours off my commute has been paid for with a loss of the sky - not to light pollution, but to a canopy of trees shading the entire property! Regular listeners would be expecting this episode to feature Nicole Thomas. Unfortunately, for the second time this season, my recordings of the interview that we made months ago, are unusable. I made the recording within Skype and downloaded it within the 30 day period. But when I tried to import it into this episode, I found that it was an empty file. Now I've been a loyal user of Skype for over a decade, but it just isn't good enough for me anymore. All my serious technical problems with interviews have been Skype related. In future, I'll be using different technology. But for all the Nicole fans out there, don't worry. She will be back in a future episode. Dr Tana Joseph Dr Joseph is an astrophysicist with a special interest in extra-galactic X-ray binary star systems. She is also the founder and owner of AstroComms, a STEM consultancy and communications company. I found her very easy to speak to, but unfortunately the sound quality isn't so great. Again, thank you Skype! You can find Dr Joseph on Twitter here, and you can learn more about AstroComms here.

In this eighth episode of the second season, I defend my defense of the Ptolemaic geocentric system of crystal spheres! I hadn't even realized till I started recording that this is our 50th ever episode. I really should be so blown away that I've kept things going this long, but I'm not, somehow? Perhaps it's just become a habit, and I stopped noticing milestones! But anyway, 50 episodes, I think that's pretty amazing and I'm very proud to have made it this far. I'd like to thank every one of you for sticking with me for this long, and I'd also like to ask you to please let me know what you'd like me to do for the next fifty episodes! Why I defended the Geocentric system 2:30 Today's science explainy bit is not a question that anybody specifically sent to me. Rather, it's something that people are generally quite curious to know: How am I, tireless crusader for the truth, able to justify my constant apparent defense for the old Ptolemaic system of a universe made from crystal spheres centered on the Earth? I think I make a pretty good argument, and you'll find it in this episode. Announcements 28:20 I didn't want to stop this story with Copernicus because I think things get REALLY interesting when Galileo uses a telescope to properly disprove the geocentric model. He is a total heel about it, and the Church, desperately trying to protect itself from the reformation, sees Galileo as another troublemaker. As we all know, they tried hard to suppress him... it's all just too fascinating, especially when you look more carefully and learn just how complicated Galileo's relationship with the church and the elites really was! I don't really have space to fit this in this season, unfortunately, but if enough of you mail me at podcast@urban-astronomer.com to ask for it, I'll record it as a special bonus episode! Last episode, I mentioned that we're trying out a new community on the Flick app. It's kind of like a social media network centered around podcasting. To me, it feels a lot like a classic web forum. To try it out, click the link at the bottom of the sidebar on urban-astronomer.com. Use the "urbanastronomer" join code. You'll see existing conversations for each episode. There's another one to introduce yourself, or you can start your own! It's still early days, but the team behind Flick are working extra hard to build this thing, but even at this stage it feels like a great place for me to meet and chat with each one of you. It's completely free, it is uncluttered with non-podcasty stuff, and I look forward to seeing you there!

In Episode 7 of the second season of the Urban Astronomer Podcast, I chat with Dr Jarita Holbrook of the University of the Western Cape about her interest in cultural astronomy. This was one of the longer and more interesting interviews of my career, and our conversation continued for some time after the microphones were turned off! Unfortunately, the audio quality isn't as good as I'd hoped. There's a terrible echo on my voice which comes and goes as the recording plays. I've done my best to clean it up, but it was just a bad recording and there's only so much I can do! Still, we're all clearly audible and I believe the content is good enough to justify publishing. Dr Jarita Holbrook 1:18 Dr Holbrook is a professor of physics at the University of the Western Cape. She has a special interest in cultural astronomy. She is an expert on African Indigenous Astronomy and the principal investigator of the Astronomy & Society group at UWC.  Her intellectual interest in African cultural astronomy has resulted in academic positions in applied anthropology and women and gender studies before her returning to physics. She's also a documentary film maker, whose 2017 film "Black Suns:  An Astrophysics Adventure" won the Jury Prize at the Art of Brooklyn Film Festival. Announcements 37:30 Last weekend I presented a talk at ScopeX on Orbital Mechanics. I used Kerbal Space Program to demonstrate some of the more unintuitive aspects of maneuvering through space. It went pretty well, although I ran out of time and had to cut myself short! I was really excited to meet people who do actually listen to the show. One of them, Heystek Grobler, is a researcher at the Hartebeesthoek Radio Astronomical Observatory. The radio telescope from this observatory is less than a half hour's drive from where I live, and I've always wanted to pay them a visit and record an interview for this show. Somehow that never happened, but hopefully Heystek will agree to chat to us in Season Three, and tell us a little about the history of the observatory, and what sort of work he does there. I'm trying out a new app which creates communities around podcasts. It's called Flick, and is driven through an app on your phone or tablet. I've created a group especially for the Urban Astronomer Podcast. If you'd like to try it out then you can tap the link on your mobile device. They've promised all sorts of interesting functionality in future versions of the app. I think it has a lot of potential. But like anything online community, it can only work if people actually join in and participate. I'm there most days, so if you have questions and would like to chat in a format that's a little more intimate than Twitter, or more immediate than email, why not give it a try? Links Dr Holbrook on Facebook Trailer for Black Suns: An Astrophysics Adventure Science Tourist on YouTube

In episode 48 of the Urban Astronomer Podcast, we're doing another Science Explainy bit! These segments are where you get to hear my droning voice explain some fundamentals and answer listener questions. Today we get asked why it always is that planets orbit in the same plane, and why the Moon can be seen during daylight. If you like what you hear, don't forget to tell a friend about the show, and make a small donation on our Patreon account. Why do planets orbit in the same plane? 1:50 This question was asked by Matthew du Plessis, one of our Twitter followers. He wants to know why planets always seem to orbit their star in the same direction, and why those orbits are always aligned within the same orbital plane. We take a look at how solar systems are formed in the first place, to show why this alignment is inevitable. I make reference to this video: Why can I sometimes see the Moon during the day? 12:29 This question came from Anzet du Plessis, also on Twitter. She wants to know why it is that the Moon is sometimes visible during the day. I think a bit about how small children never seem to be surprised by this, yet older kids and adults often are. And of course, I also answer the question! Announcements 18:35 This weekend, on Saturday 14 September, I will be at ScopeX, at the Military History Museum in Johannesburg. ScopeX is an astronomy and telescope fair held every year. It is packed with amateur telescope making displays, science shows, commercial telescope vendors. There are also public lectures in the auditorium. I will be presenting a talk on Orbital Mechanics, demonstrated through the medium of Kerbal Space Program. So basically, I'll be playing video games to demonstrate the physics of space travel! Other speakers include Case Rijsdijk, president of the Astronomical Society of South Africa, Dr Pieter Kotze of the Hermanus Magnetic Observatory, Prof Roger Deane of the University of Pretoria, Martin Heigan, who is the section director of ASSA, and David Rogers who will be speaking on "Fifty Years after Apollo - with so much going wrong, how did they get it right?" If you are in the area, please do come along. The museum does charge a small entrance fee, with discounts for students, scholars and pensioners, but it's not much and they need the support. It's a great day out for the family, there's a lot to see and do, there are prizes to be won, including cameras and telescopes, and of course you'll meet fellow space and astronomy enthusiasts who've flown in from all over the country! It's one of the highlights of the local astronomy calendar, and i'm really looking forward to meeting you there! One Last Thing 20:55 I announced last episode that I've joined the team at the Weekly Space Hangout, and I now have a date for my first episode! I'll be on the air, live, on 18 September, with Fraser Cain, Kimberly Cartier, and whoever the special guest will be! Longtime listeners will remember that time I experimented with unscripted content, and if you enjoyed hearing me flounder along speaking from the top of my head, well... you'll love this! Follow my twitter account at @uastronomer for updates closer to the time on who I'll be sharing the mic with, the exact time we'll be broadcasting, and the link to watch it. I'm nervous as all hell, but I also think it's gonna be a ton of fun and I'm looking forward to having you loyal listeners with me, for moral support if nothing else!

This is episode five of this season of the Urban Astronomer Podcast. As usual, this being the 4th show of the month, we have an Interview episode today, and this is the one that gets us back to our scheduled order of things. You'll remember two episodes ago, we were supposed to interview Dr Rosalind Skelton of the South African Astronomical Observatory. Unfortunately, I messed up somewhere and the recordings we'd made well in advance of the show were lost. Luckily we were able to shuffle the slot with another guest, also from SAAO. Anyway, I've spoken to Dr Skelton again and this time everything went as planned. Dr Rosalind Skelton 2:01 Dr Skelton is a SALT Astronomer at the South African Astronomical Observatory in Cape Town. She is part of the team of astronomers who manage the SALT telescope operations and observe on behalf of all the SALT partners. Her research within the field of galaxy formation and evolution currently concentrates on the impact of mergers on the growth of galaxies, the mechanisms that shut down star formation in galaxies, environmental effects within groups and cluster of galaxies and large but faint “ultra-diffuse” galaxies. ScopeX 30:12 In a few weeks, on 14 September, I will be at ScopeX, at the Military History Museum in Johannesburg, South Africa. ScopeX is an astronomy and telescope fair held every year It is packed with amateur telescope making displays, science shows, commercial telescope vendors, and public lectures in the auditorium. I will be presenting a talk on Orbital Mechanics, demonstrated through the medium of Kerbal Space Program. So basically, I'll be playing games to demonstrate the physics of space travel. Other speakers include Case Rijsdijk, president of the Astronomical Society of South AFrica, Dr Pieter Kotze of the Hermanus Magnetic Observatory, Prof Roger Deane of the University of Pretoria, Martin Heigan, who is the section director of ASSA, and David Rogers who will be speaking on "Fifty Years after Apollo - with so much going wrong, how did they get it right?" Name an Exoplanet 31:41 The IAU have assigned South Africans to come up with a name for an exoplanet and its star, which have the official designatons of WASP 62 and WASP 62b. You can enter as either a private individual, or as a school or other organization. If one of your suggestions is chosen for the shortlist, you will win something. The prize for individuals is fully paid a trip to Sutherland, for a tour of SAAO's telescopes. Organizations, however, get a 6" telescope, a selection of astronomy books for their library, and training on how to use it all. Suggested names have to comply with standard IAU naming rules Links Contact Dr Skelton Dr Rosalind Skelton's website Name an Exoworld competition website

Welcome to another Science Explainy Bit episode of the Urban Astronomer Podcast. Today we try to figure out just what an "orbit" actually is. Is it really as simple as they said in primary school? How does gravity, which normally pulls things down, work to keep the Moon in space? Download this episode now, to find the answer, and also learn a little about my upcoming appearance at ScopeX! What is an Orbit? (1:28) This turns out to be quite a simple topic - much simpler than why planets are always round, which we covered last month. In fact I struggled to stretch the core idea out long enough to fill an episode! All I really want to do here is explain how things stay up and why they go around, without resorting to the inaccurate "Centrifugal Force" explanation. You know the one? Where you ask people to fill a bucket, and then spin it around? The bucket swings around them without spilling any water, and then you wave your hands and say "That's how orbits work, except that there's no handle on the bucket, just gravity". The truth, however, is so much cooler than that, so if you want to skip straight to the answer, click the timestamp above! ScopeX (14:48) ScopeX is an annual telescope and astronomy expo held in Johannesburg, South Africa. It features a huge display of amateur-built telescopes, commercial stands where you can buy telescopes, binoculars and cameras. There are also science shows and robotics displays. One of the highlights for me has always been the series of public lectures, in the auditorium. This year I will be giving the final talk of the day, where I'll talk about orbits. It won't just be a repeat of what you've heard here, though. I'll dig deeper, into the world of orbital mechanics and showing the strange, intuitive maneuvers that are needed to move around in space. And to make it easy to understand, I'll do it through the medium of video games! If you'd like to attend, it's on 14 September from 9am to 9pm at the Museum of Military History in Saxonwold, Johannesburg. My talk starts at 3pm, and you're welcome to come introduce yourself afterwards!

Welcome to the 3rd episode of the Urban Astronomer Podcast, season 2, featuring Dr Daniel Cunnama. We almost didn't make it this week, thanks to a major technical hitch, but we worked around it and here we are. If you listened to the last episode, then you're probably expecting this to be an interview episode, featuring Dr Rosalind Skelton of the South African Astronomical Observatory. I spoke to her in June last year and we recorded an interview specifically for this episode. But when I came to actually produce the thing, the recording was gone! The gods of technology turned their back on me and gremlins ate it. So, no Ros today. Instead, I was lucky enough to get Dr Daniel Cunama to stand in for her. Daniel also works at the South African Astronomical Observatory (SAAO), although in a different role, and I'm very lucky that his recording was still intact! So that's what we'll be playing in this episode, and Dr Skelton will appear in a few weeks in a later episode after we've re-recorded her interview. Dr Daniel Cunnama Daniel is the Science Engagement Astronomer at the SAAO. Daniel has a background in computational physics and physics simulations, who has worked for the Square Kilometer Array  and SAAO. He is also a co-host of The Cosmic Savannah podcast. If your favourite part of Urban Astronomer is astronomer interviews, then I'd definitely recommend their show! Links Daniel on Twitter The South African Astronomical Observatory The Cosmic Savannah Podcast

Welcome to the second episode of this second season of the Urban Astronomer Podcast! Two of Two, sounds like it should be special... and it kinda sort of is, because this week we're presenting the first of our unique patented Science Explainy Bits! Now to be clear, it's the name that's new, not the science explaining, because I've done explainy stuff for science concepts before on this show, back in our super-extended 42 episode long first season. I got quite a lot of feedback from listeners like yourself telling me how much you enjoyed my explanations, but I'll be honest, I'm dubious because I'm just this guy with a website and a podcast, so I'm not sure why you're trusting me to get these things right! I'm not a professional research astronomer, I don't even have a PhD! But you all seem to trust me anyway, and you have explicitly asked for more so.. yeah, sure, just promise me you're not using these segments as exam prep, and if you were planning to cite me in a paper, that's your own fault! This episode makes reference to an earlier explainy episode on the tides. That episode sounded quite a bit different than this one, because it was recorded off-the-cuff, with no script or notes at all. It was also strangely popular, so if you're interested you can play it back here.

This is Episode 1 of our brand new second season! This is the 43rd episode since the podcast was first launched, back in February 2017, and I'm thrilled to be back on the air with you. The New Season We're mostly keeping things the same, but there are some important changes. From the beginning, I've always been pretty disorganized in how I ran the show. There was no fixed schedule or plan, so I'd release episodes as they became available. This meant that new episodes would only come out whenever it was convenient for me. Listeners like you would never know in advance when the next one would be coming out. At the end of Each episode, I'd make a promise for the next release date, but these dates were always based more on hope and ambition than on any real plan. And while this was all very charming and artisanal, it wasn't how I wanted to present myself. So now we have seasons! Everything is planned in advance, content is written and recorded to a fixed schedule, and you get your episodes when you expect them. Which, in this case, means every fortnight, for 12 episodes. But aside from these changes to scheduling and process, everything else should be much the same. Some episodes will be interviews with interesting people connected to South African astronomy. Others will be loaded with the Science Explainy Stuff that so many of you have written to ask about. Apparently those are very popular, so you're going to get a lot more of them. The only thing that I've had to cut, sadly, is the space mission updates. Clem Unger, my friend and part-time co-host, has unfortunately had to step back for a while. He was always far more interested in the various spacecraft traveling out in the Solar System, exploring and doing science, and knew far more about the subject than me. So, until he's able to rejoin the show, we're going to be silent on that subject. Dr Wendy Williams This episode features an interview with Dr Wendy Williams, a radio astronomer from Cape Town who currently works in the Netherlands, for the university of Leiden. She works with the LOFAR array, which scans the skies at the same range frequencies as used by broadcast TV, air liners, and police radios. We spoke about her current research, she taught me how these arrays of radio antennas work together to create an image, astronomy development in Africa, and more. But before I play you that interview, a quick note on audio quality. Since we were in opposite hemispheres at the time of our conversation, I had to get creative with the recording. Audio quality isn't as good as I'd have liked. I think we're still quite audible, but you can definitely tell we weren't in the same room! Coming Up Next week's episode, which airs on the 16th of July, features the first in a new series of science explainy bits, where I answer a question you might never have thought to ask: Why are planets always round, and never some other shape? If you think you know, or would like to take a guess, go ahead and tweet your ideas to @uastronomer and I might read them out before I give the answer!