Pythagorean Astronomy

In the 65 years since Sputnik 1 was launched in 1957, the number of artificial satellites in orbit has been increasing. In the last two years, the number of satellites has doubled, largely thanks to the huge "constellations" launched by companies such as SpaceX. The number of satellites has a detrimental impact on astronomical observations, both with professional telescopes and by amateur astronomers. Dr Meredith Rawls, from University of Washington, is planning observations with the Vera Rubin Observatory, while Professor Andy Lawrence is a Regius Professor at the Royal Observatory Edinburgh. With forecasts indicating up to 100,000 satellites in a matter of years, a 20-fold increase on today's numbers, there could be serious implications for astronomers around the world. But what has led to this increase in satellites? Dr Moribah Jah, co-founder and Chief Scientist at Privateer Space, explains why there are so many satellites being launched, and what the risks are both for satellites and down here on Earth

It's not often that a new astronomical phenomenon is named, but this month we have a new one. The name might not be that original, but there have been the first observations of something known as a "micronova". Lasting just a few hours, a micronova is much fainter than a typical "nova", making them much harder to detect, and much less likely to be picked up. Chris North and Edward Gomez discuss what causes these events. Coming closer to home, spaceflight has been busy, with two missions to the Space Station in April - one part of the normal rotation of astronauts, and the other a privately-funded mission from SpaceX. Does this mean that space travel is becoming routine? And is that even a good thing? Most of our exploration of space is, of course, done by robotic spacecraft, and NASA have just announced extensions to a number of their ongoing missions. Some of which have already been going for over 20 years - take a bow, Mars Odyssey! From rovers on Mars to lunar mappers, and from asteroid encounters to voy

With the invasion of Ukraine casting a shadow over the world, Chris North and Edward Gomez look at the impact of the war on astronomy and space science, mindful that these pale in importance when compared with the death and destruction taking place on the ground. From the international collaboration taking place on board the International Space Station, to the use of Russian rockets. Also at stake is the future of the Rosalind Franklin Rover, a European-Russian collaborative mission that was due to launch later this year. Elsewhere in the world, NASA have shown off their newest rocket - the Space Launch System, or SLS. The missions it allows should be impressive, but how does the huge price tag compare to other options? And finally, how does one de-detect a black hole? Sometimes in science, you have to take one step back to take two steps forward!

Back in September 2020, the new broke that an unexpected gas, phosphine had been discovered in the atmosphere of Venus. While plans for making further measurements are progressing, the theoreticians have been hard at work modelling the atmosphere, and trying to explain how life could possibly exist in such a harsh environment Dr William Bains, of Cardiff University and MIT, is part of a team who have developed a model that helps explain how microbial life might make the atmosphere of Venus more hospitable. On the way, it also solves a few other mysteries about our nearest planetary neighbour's atmosphere. From an excess of water and oxygen to the disappearance of sulphur dioxide, and potentially non-spherical particles, could this be the solution that solves all of the mysteries?

When a mysterious signal was found by an undergraduate student, Dr Natasha Hurley-Walker was perplexed. It was hiding in archival data from the Murchison Widefield Array (MWA), a large network of radio antennas in Western Australia. Based at the International Centre for Radio Astronomy Research, Natasha started to loop deeper. Repeating every 18 minutes, and initially found at only one frequency, the signal showed signs of being something astronomers have been searching for decades - radio transmissions from an intelligent species. It's not a much of a spoiler to say that it wasn't aliens (it's never aliens!), but repeating radio signals with this period hadn't been seen before, and were very hard to explain at first. This month, Natasha explains to Chris how the discovery unfolded, why it might have been aliens, why it wasn't aliens, what else it couldn't be, and what the current favourite theory is - something called a magnetar, but one which was behaving in a very unusual way.

The first interstellar object to be discovered was 'Oumuamua, detected in 2017. Joined by Comet 2I/Borisov a couple of years later, astronomers are eagerly awaiting further discoveries of such objects, which were ejected from other solar systems. We explore what the link is between these interstellar objects and the history of star formation around the galaxy, thanks to new research by Prof Chris Lintott, Dr Ted Mackereth and Dr Michele Bannister. Chris and Ted explain how these two seemingly disconnected fields have led to new hypotheses about what we might learn from future observations.

The world of astronomy is eagerly awaiting the launch of the James Webb Space Telescope later in December. The telescope is not without controversy, but is set to revolutionise observations of the cosmos. Prof Pete Hargrave was responsible for building a calibration source for MIRI, the Mid-Infrared Imager, while Dr Tim Davis will be observing nearby galaxies to study the roles of black holes. Meanwhile, Dr Mikako Matsuura is hoping to study the final stages of stars' lives, while Dr Subi Sarkar will be using the full range of wavelengths the telescope's instruments will capture to understand the composition of atmospheres of planets beyond our Solar System.

Back in 2015 the New Horizons spacecraft whizzed past Pluto on its way out of the Solar System. A few years later, as it continued on its way through the Kuiper Belt, it passed by a snowman-shaped object called Arrokoth. More recently, it's discovered two objects that are in fact four - binary objects comprised of two smaller objects orbiting each other. As Dr James Robinson, from the University of Edinburgh explains, the discovery of these objects is very useful for understanding the Kuiper Belt, and the different groups of objects within. In turn, that is important for understanding the formation of our Solar System. Closer in, the Lucy spacecraft has recently launched on its way out to the Trojan asteroids, location near Jupiter. The first mission to these unusual objects, Lucy will shed light on a type of object we've never seen before.

Way back in 1181 AD, astronomers in China and Japan recorded a "guest star" - something that we'd now call a supernova. Over 800 years later, astronomers made a connection between this ancient observation and more recent studies of a very unusual object that goes by the name of "Parker's Star". Prof Quentin Parker, from University of Hong Kong, explains how he and his team made the link, displacing a previously favoured object. And it seems that this was no common or garden supernova, but an incredibly rare "Type 1ax" supernova.

The last month or so has seen several cases of small things being discovered. The first is an asteroid, 2021 27PH, which gets closer to the Sun than Mercury. What could we learn about fundamental science from such an object? The second is one of the smallest exoplanets detected, at less than half the mass of Venus. It orbits very close to its star, and would have very high temperatures on its surface, so it's not a place to look for life (at least not as we know it). But finding planets so small, even around a relatively close star, shows just how sensitive these detection methods are getting. But the focus of this month is not planets or asteroids, but moons. Specifically, the formation of "exomoons" - moons orbiting planets around another star. Detected using the ALMA telescope array, this is the first time we've seen this happening, and has intriguing implications for our understanding of the formation of our own Solar System. Dr Stefano Facchini, from University of Milan, explains how this discovery was

In late June an interesting object was discovered heading inwards from the outer solar system, identified in archival images from a survey of the sky. It was initially thought to be worth keeping an eye on over the next decade or so, as it approaches the orbit of Saturn before heading back out to the outer reaches - a chance to keep an eye on a distant wanderer. Further observations have shown that 2014 UN271 (its official designation) appears to be active, with a coma and tail like a comet - unusual for an object so far from the Sun. If it is a comet, becoming Comet Bernadinelli-Bernstein, it could be the largest on record, possibly more than 100km across. This month Dr Meg Schwamb, from Queens University Belfast, explains where this objects fits in terms of the size and scale of the Solar System, while Dr Tim Lister, from Las Cumbres Observatory, explains what he and colleagues have found from those early follow-up observations. Find out what to expect over the next decade from this icy visitor, and how f

Our understand of the Universe has changed a great deal in the last 100 years. From Einstein's theories of relativity and measurements of the expanding Universe, to the discovery of the Cosmic Microwave Background and the mysterious Dark Energy. But what are the current mysteries and unknowns that we still want to uncover? And how much is our progress guided by technological developments? Dr Ian Harrison, currently at the University of Oxford, but shortly to return to Cardiff University, studies increasingly precise observations from many different telescopes and observatories, comparing them to theoretical predictions. Dr Samantha Stever, from Okayama University, and formerly an undergraduate here in Cardiff, works on the design and build of scientific instruments designed to make these incredibly precise measurements, including the LiteBIRD satellite currently being built. Between Ian and Samantha, we can journey from our early developments in theoretical understanding the Universe and the initial measur

This month, we're joined by two people who've just been elected to prestigious roles in science here in the UK. Professor Mike Edmunds has just become President-elect of the Royal Astronomical Society, while Professor Bernard Schutz has recently been elected a Fellow of the Royal Society. Both these societies have a long history, and we discuss their role in the development of science in the UK, and how it has changed. Mike and Bernard have both been here in Cardiff for nearly 50 years, and have seen the way science is done change significantly over that period. But what are their thoughts about the future of astronomy, and of science in general? What are the challenges facing the two societies, and science in general, in the aftermath of the Coronavirus pandemic? What do they think we should we do to protect future of science, and possibly humanity?

Last September, a team of scientists led by Professor Jane Greaves announced the detection of a rare gas, phosphine, in the atmosphere of Venus. With no plausible explanations of how it could be there, one possibility remaining was that it was being produced by some sort of microbial life floating in the cloud decks of Venus. The idea was seen as preposterous by some, and others even questioned the validity of the detection itself. This month, Jane gives an update on the process of double and triple checking their result, and what the latest is on this exciting process of scientific discovery. It even features 1970s spacecraft! And could there possibly be a spacecraft sent to Venus in just a few years?

Where were you on 28th February 2021, just before 10pm? If you were in parts of Wales, or the west of England, you may have seen a bright flash streaking in the sky. This was a fireball - a bright kind of meteorite which is a special sight in its own right. But this was a very special fireball, as the object that created it landed on the ground and has been found, collected and is under analysis right now. To add to the magic, it's also an incredibly special kind of meteorite, and includes some incredibly old material. To learn about the process of finding, collecting and studying these rare finds, as well as what they can tell us about the origins of the Earth, we hear from Dr Martin Suttle and Dr Helena Bates from the Natural History Museum.

The idea of life elsewhere is not a new one. Hundreds of years ago it was assumed that there were beings everywhere, before such views were considered heretical, and the determination that places like the Moon were dry airless worlds started to reduce the possible places life could thrive. But even as recently as the mid-20th Century, the idea of vegetation on the surface of Mars was not considered crazy. As the dry, arid nature of Mars became clear, and the hot, hellish surface of Venus was revealed, hope of finding life, or certainly intelligent life, all but disappeared. There was a flurry of interest in the mid-1990s, when a meteorite that originated on Mars seemed to show signs of fossils of tiny lifeforms. Those turned out to be the product of geology. But the search goes on, not just in our Solar System, but also beyond. This month, we are joined by Professor Abel Mendez, who is a physicist and astrobiologist at the University of Puerto Rico, based at Arecibo. We got on to shadow biospheres and techn

Over the course of the next month, we'll see the arrival at Mars of not one, not two, but three spacecraft: Nasa’s Perseverance Rover, with its little helicopter Ingenuity; the Chinese Space Agency's Tianwen-1 mission, which comprises an orbiting spacecraft, a landing platform and a rover; and the UAE's Hope mission, which is an orbiting spacecraft. In this episode we'll be hearing about the upcoming missions to Mars, as a bit of insight into the Chinese Space Programme. Of course, a sensible question is: why all the interest in Mars? It's a dead planet now – or certainly pretty dead – but perhaps that wasn’t always the way. To find out more I spoke to Dr Peter Fawden, whose expertise is the geological history of Mars. Peter is based at the Open University where he works on the imaging cameras of a future mission: the Rosalind Franklin Rover, due to launch in a couple of years. On Earth we can dig up rocks, or go to a cliff, perhaps by a beach, and look at the layers of rock, studying the order in which the

With the end of one of the craziest years in living memory, we start with astronomical reflections on the last 12 months - and how far we've come over the course of the last decade. A new results has been published about the structure of our own Milky Way Galaxy, using the emission from carbon monoxide gas. The results, from the SEDIGISM team, show that the galaxy is much more "flocculant", or fluffy, than previously thought. Cardiff-based team member, Dr Ana Duarte Cabral Peretto, explains how the survey of the galaxy was done, and what the results might mean. 00:00 - Reflections of the Year and Decade 08:00 - Galactic Structure

A show of two halves, this month, starting with watery moons. One isn't so surprising - Jupiter's icy Europa. Known to have an ocean under the thick ice shell, models suggest that the plumes that have been observed may not be from the global reservoir, but from smaller briny pools within the icy crust. The second moon is perhaps more surprising, being our own Moon. New measurements from the airborne observatory SOFIA have shown that there is molecular water within the rocks in some places on the surface, and not restricted to the permanently-shadowed craters. Lunar geologists Marissa Lo and Dr John Pernet-Fisher from the University of Manchester (and the Cosmic Cast podcast) explain why water on the moon is of so much interest. And what are we likely to learn when China's Chang'e 5 mission brings samples back from the Moon later this year. Moving further afield we return to Fast Radio Bursts - phenomena we've covered before a number of times on this podcast. We now have an example of a fast radio burst with

Chris North and Edward Gomez give a round-up of the month in astronomy. Towards the end of October, NASA's Osiris Rex spacecraft grabbed a sample from the asteroid Bennu. What happens next, and what might we learn from these samples? Chris and Edward discuss. There's also an update on Betelgeuse (however you chose to pronousne it), which is not estimated to be closer than previously thought - which means it's smaller? But we're still safe when it goes supernova. Right?! Further afield, telescopes around the world spotted a star getting spaghettified by a supermassive black hole - what an Earth does that mean? An finally, October is the month that Nobel Prizes are awarded. With Sir Richard Penrose, Reinhard Genzel and Andrea Ghez sharing the prize for discoveries related to black holes. (Crucially, recorded before the recent announcement regarding the Moon - but we have something to talk about next month!)