Starts With A Bang Podcast

When we search for life in the Universe, it makes sense to look for planets that are similar to Earth. To most of us, those signatures would look the same as the ones we'd see if we viewed our planet today: blue oceans, green-and-brown continents, polar icecaps, wispy white clouds, an atmosphere dominated by nitrogen and oxygen, and even the modern signs of human activity, such as increasing greenhouse gas emissions, planet modification, and electromagnetic signatures that belie our presence.But for most of our planet's history, Earth was just as "inhabited" as it is today, even though it looked very different. One fascinating period in Earth's history that lasted approximately 300 million years resulted in a planet that looked extremely different from modern Earth: a Snowball Earth period, where the entire surface, from the poles to the equator, was completely covered in snow and ice. This isn't just speculation, but is backed up by a remarkable, large suite of observational and geo

It might seem hard to fathom, but it hasn't even been ten full years since advanced LIGO, the gravitational wave observatories that brought us our very first successful direct detection, turned on for the very first time. In the time since, it's been joined by the Virgo and KAGRA detectors, and humanity is currently closing in on 300 confirmed gravitational wave detection events. What was an unconfirmed prediction of Einstein's General Relativity for a full century has now become one of the fastest-growing fields in all of astronomy and astrophysics.Here in 2025, we're now looking forward to the LISA era: where we're going to build our first gravitational wave detectors in space. They'll have far longer baselines (i.e., separations between the various spacecrafts/stations) than any terrestrial gravitational wave detector, enabling us to detect fundamentally different classes (and masses) of objects that emit gravitational waves. At the same time, the rise of artificial intelligence and

Out there in the Universe, each star represents an opportunity: a chance for a stellar system to develop that just might possess something remarkable. While we normally think about life, and intelligent life at that, as the grand prize the Universe has to offer, there are a wide variety of fascinating phenomena that are out there to consider. Whereas Mercury, for example, is the closest world to our Sun in our own Solar System, it still takes 88 days to make a complete revolution. In other systems, however, exoplanets can be so hot that they orbit their parent star in less than a single Earth day.In fact, we've discovered a few systems that are so extreme, the planets that orbit them are in the process of disintegrating: where the heat, winds, and radiation from the parent star actually blows part of the planet itself away. This doesn't just include a planet's atmosphere, which is what we see for giant worlds, but even the surfaces and interiors of rocky planets in the most extreme cases. At tempe

Sure, it's easy to look out at the Universe and take stock of what we find. Although spiral and elliptical galaxies house the majority of the Universe's stars, represented locally by galaxies like Andromeda and our own Milky Way, the overwhelming majority of galaxies are much smaller and lower in mass than we and our cousins are. These low-mass galaxies, the dwarf galaxies in the Universe, represent upwards of 97% of all the galaxies that exist.However, while most of the dwarf galaxies we know of are found as satellites around larger, more massive galaxies, they aren't good laboratories for helping us understand the Universe as it was long ago. Back during the first few billion years of cosmic history, it wasn't just dwarf galaxies that formed the majority of starlight in the cosmos, but isolated dwarf galaxies: dwarf galaxies that hadn't yet interacted with larger neighbors.We can best understand those early-stage galaxies by studying their late-time analogues: isolated dwarf galaxies in

Out there in the Universe, there are tremendous, uncountable numbers of planetary systems just waiting to be discovered. But stellar systems won't just consist of planets orbiting a parent star; there will be moons, asteroids, Kuiper belt-like objects, and many of them will be bound together into their own rich sets of systems, with both irregular and round bodies comprising these planetary systems.Here in our own Solar System, we have at least three notable large, terrestrial-sized bodies with impressive lunar systems of their own: the Earth-Moon system, the Mars-Phobos-Deimos system, and the Plutonian planetary system. Pluto, interestingly, is orbited by Charon, which is very large and massive compared to Pluto, an unusual and possibly unique, or most extreme, configuration of all known such bodies. But how did it get to be that way? That's the topic of this podcast, and the research focus of this month's guest: Dr. Adeene Denton.It's kind of amazing what variety can emerge in terms of survi

When it comes to stars, most of them, for most of their lives, behave in a very similar fashion to the Sun. In their cores, they undergo nuclear fusion, which provides energy and creates radiation, and that outward radiation pressure holds the star up, internally, against gravitational collapse. For most stars, this balance between the pressure from outward radiation and the inward force from gravitation is nearly perfect all throughout the star, leading to an equilibrium state. But some stars aren't in this kind of equilibrium at all. Instead, some internal process actually drives the star in a fashion that causes it to pulsate: overshooting equilibrium in both directions, as it alternatingly expands and cools, and then contracts and heat up in a cyclical fashion. These species of intrinsic variable stars, including Cepheids and RR Lyrae stars, are not only of profound importance when it comes to understanding stellar evolution, but for unlocking the secrets of the distant Universe. How do we understand thes

When we look out at our home galaxy, the Milky Way, we have to recognize that even though it's been growing and evolving for 13.8 billion years, we're only observing it as it is right now: a snapshot in time determined by the light that's arriving in our instruments right now. However, just like we're living "right now" in human history but can, through the science of archaeology, learn about historical events that happened many thousands of years ago (before recorded history) or even earlier, we can learn about the Milky Way's history through the astronomical equivalent: galactic archaeology. How do galactic archaeologists do it? They look at as much data as possible, across many wavelengths of light, including at many rare and obscure species of stars, in as many locations as possible and to the greatest precisions possible all at once. By combining these different lines of evidence, we can arrive at a coherent and compelling picture for how our little corner of the Universe grew up, including by reconstruc

In this Universe, there are a few objects that are just larger, and a few events that are just more powerful, than others. As far as size goes, the cosmic web creates some of the largest features ever discovered, with the largest galaxy filaments and the largest regions devoid of galaxies spanning as much as ~2 billion light-years. No robust, verified structure has ever been found that's larger. Meanwhile, as far as energy and power go, collisions of galaxy clusters are the most energetic events, outstripped only by the Big Bang itself. However, nearly rivaling galaxy cluster collisions are the strongest black hole jets ever seen, capable of emitting trillions of times the energy of a Sun-like star, but also capable of sustaining those energies over timescales of a billion years or more. Astronomers have just set a new record for the longest black hole jet with the discovery of Porphyrion, which spans a whopping 24 million light-years across! How did this jet and others like it come to be, and what effects do

It's hard to imagine, but it was only five years ago, in 2019, that humanity feasted our collective eyes on the first direct image of a black hole's event horizon. Thanks to the technique of very long baseline interferometry and the power of arrays of radio telescopes stitched together from all across the Earth, we were able to resolve the event horizon of the black hole M87*, despite the fact that it's an impressive 55 million light-years away.That was with radio interferometry, but historically, most telescopes have used optical light, not radio light. Does that mean that optical interferometry is possible? Not only is the answer a resounding "yes," but we've been performing it for decades. In fact, the most ambitious optical interferometry project of all-time is already under construction in New Mexico: the Magdalena Ridge Observatory Interferometer (MROI). With an array that will feature a total of ten separate telescopes all linked together, and with a maximum tunable distance of 340 meters between them

When you think of an active galaxy, what picture comes to mind? Do you think about a monstrous supermassive black hole feasting on tremendous stores of gas and other forms of matter? Do you picture an enormous disk of accreted matter, being accelerated, heated, and eventually shot out along two jets, each perpendicular to the disk itself? This common picture of active galaxies describes many of the most prominent ones, but isn't universal to them all. Some active galaxies aren't giant ellipticals, but just average-looking spiral galaxies. Some galaxies aren't in the process of a major merger, but seem to be powered by their own internal gas. And some of these black holes aren't ridiculously massive, with billions of solar masses inherent to them, but are rather much more modest. Some of these active galaxies actually show practically no signs of activity in visible light, but must be viewed in other wavelengths, such as with radio telescopes, to reveal their activity. Above, you can see galaxy

Right now, the Large Hadron Collider (LHC) is the most powerful particle accelerator/collider ever built. Accelerating protons up to 299,792,455 m/s, just 3 m/s shy of the speed of light, they smash together at energies of 14 TeV, creating all sorts of new particles (and antiparticles) from raw energy, leveraging Einstein's famous E = mc² in an innovative way. By building detectors around the collision points, we can uncover all sorts of properties about any known particles and potentially discover new particles as well, as the LHC did for the Higgs boson back in the early 2010s. But the LHC has a limited lifetime, and by the 2030s, will complete its data-taking runs. If we want to go beyond the LHC, we need to start planning for a new particle collider now, and there are four great options that can take us beyond the current frontier: a linear lepton collider, a circular lepton collider, a circular hadron collider, and a potentially new innovation of a circular muon collider. In this episode of the Start

On the largest of cosmic scales, the best description we have of our Universe is known as the ΛCDM model with an inflationary hot Big Bang: our consensus cosmology. It tells us that we have a Universe consistent with being made of about 5% normal matter, a little bit of radiation in the form of photons, around 0.1% neutrinos, and the rest made of the mysterious dark matter (~27%) and dark energy (~68%). Governed by General Relativity, this explains what we see on Solar System scales, where dark matter and dark energy are negligible, and on cosmic scales, where dark matter and dark energy are important. But on in-between scales, we aren't quite sure that this same "consensus cosmology" leads to a very successful description. It's long been known that, on galactic scales, rotating galaxies appear to obey a different force law: MOND, for MOdified Newtonian Dynamics. In MOND, the traditional Newtonian acceleration is replaced, at very low accelerations, by a combination of the Newtonian accelera

One of the most swiftly forgotten revolutions in all of science is our understanding of the Solar System out beyond Neptune. Although Pluto was discovered nearly a full century ago, it wasn't until the early 1990s that we even discovered the next object beyond Neptune that wasn't also part of the Plutonian system. And yet, in the 30 short years that have passed since then, we've learned so much more about the structure of the Kuiper belt and beyond, but we also face tremendous challenges in the quest to learn more thanks to an unwelcome intruder: the rise of satellite megaconstellations. Although the original team of Mike Brown and Konstantin Batygin continue to advocate for a novel, massive, undiscovered world located at hundreds of times the Earth-Sun distance, they're largely alone, as other scientists have weighed in and see no evidence for this hypothetical world. Nevertheless, more science must be conducted to know for sure, and in the meantime, the rise of satellite megaconstellations

Every January, I head to the American Astronomical Society's big annual meeting with an ulterior motive in mind. Beyond merely uncovering new scientific findings, gathering information for potential stories, and connecting with friends and colleagues, I also look to meet emerging junior researchers who are swiftly becoming not only experts, but leaders, in their particular sub-field of astronomy. One of the most popular research topics in astrophysics today is the connection between the dark Universe, including the only indirectly-observed dark matter and dark energy, and the observable components that astronomers routinely see: stars, galaxies, gas, plasma, and other forms of light-emitting and light-absorbing matter. The dark Universe, to date, is best revealed by looking at the luminous, electromagnetic signals that are imprinted onto the visible components of our cosmos. To better understand what scientists are investigating, I'm so pleased to welcome KeShawn Ivory to the podcast. KeShawn is a PhD

Have you ever wondered what the full story with the galactic center is? Sure, we have stars, gas, and an all-important supermassive black hole, but for hundreds of light-years around the center, there's a remarkable story going on that's traced out in a variety of elements at a whole slew of different temperatures. Imprinted in that material is a remarkable set of features that reveals the magnetic fields generated in our galaxy's core, with some of them spanning much greater distances than have ever been seen elsewhere. It's a testament to the power of multiwavelength astronomy, and in particular to the long wavelengths like the far-infrared, the microwave, and the radio portions of the spectrum that shows us these features of the Universe that simply can't be revealed in any other way. To help bring this story to all of you, I'm so pleased to welcome Dr. Natalie Butterfield, a scientist at the National Radio Astronomy Observatory (NRAO), to join us on this episode of the Starts Wit

All throughout the Universe, galaxies exist in a great variety of shapes, ages, and states. Today's galaxies come in spirals, ellipticals, irregulars, and rings, all ranging in size from behemoths hundreds or even thousands of times larger than the Milky Way to dwarf galaxies with fewer than 0.1% of the stars present here in our cosmic home. But at the centers of practically all galaxies, particularly the large ones, lie supermassive black holes. When matter falls in towards these black holes, it doesn't just get swallowed, but accelerates and heats up, leading to phenomena like accretion disks, jets, and emitted radiation all across the electromagnetic spectrum. When these conditions exist, we know we have what's called an active galaxy, and it isn't just the rest of the galaxy that's impacted by that central activity, but far larger structures in the Universe beyond.  Here to help us explore these objects and their impact this month is Skylar Grayson, a PhD candidate at the School of Ear

Up until the early 1990s, we didn't know what sorts of planets lived around stars other than our Sun. Were they like our own Solar System, with inner, rocky planets close to our star and large, giant worlds farther away? It turned out that exoplanetary systems come in a great variety of configurations: with planets of all sizes, masses, and distances from their parent stars. But some configurations are more common than others. There are lots of hot Earth-sized planets and lots of hot Jupiter-sized planets, but precious few "hot Neptune" worlds out there. Furthermore, there appear to be lots of Earth-sized and super-Earth-sized worlds at greater distances, as well as many Neptune-sized and mini-Neptune-sized worlds. However, there's a gap there, too: between the large super-Earths and the small mini-Neptunes. Where are these missing exoplanets? Or, rather, why are these classes of exoplanets so uncommon? That's what we're exploring on this episode of the Starts With a Bang podcast, fe

Happy new year, everyone, and with a new year comes a spectacular new podcast! We normally cover an intricate and underappreciated aspect of astrophysics on the podcast, but I had the opportunity to bring on a true expert in the field of quantum computing and just couldn't pass it up. You've likely heard a lot of noise about quantum computers and the benefits that they're poised to bring, with buzzwords like "P=NP," "quantum supremacy," and "quantum advantage" tossed around, but a lot of what you're likely to hear is hype, not actual science. Good thing I was able to get Dr. Riccardo Manenti as a guest for our podcast! Riccardo is the author of a state-of-the-art textbook on quantum computers, has his PhD from Oxford in Quantum Computing, and has been working for Quantum Computing startup Rigetti for several years now. Join us as he helps demystify some of the recent progress and problems right here on the cutting edge of this promising new arena of physics, right

It's hard to believe, but it was only back just a year and a half ago, in mid-2022, that we had yet to encounter the very first science images released by JWST. In the time that's passed since, we've gotten a revolutionary glimpse of our Universe, replete with tremendous new discoveries: the farthest black hole, the most distant galaxy, the farthest red supergiant star, and many other cosmic record-breakers. What is it like to be on the cutting edge of these discoveries, and what are some of the most profound ways that our prior understanding of the Universe has been challenged by these observations? I'm so pleased to welcome Dr. Jeyhan Kartaltepe to the program, who's not onlya member of the CEERS (Cosmic Evolution Early Release Science) collaboration, but who has spearheaded a number of novel discoveries that have been made with JWST. In the quest to understand not only what our Universe is and how we fit into that cosmic story, but also the story of how the Universe evolved and grew up

You might not think about it very often, but when it comes to the question of "how old is a star that we're observing," there are some very simple approximations that we make: measure its mass, radius, temperature, and luminosity (and maybe metallicity, too, for an extra layer of accuracy), and we'll tell you the age of this star, including how far along it is and how long we have to go until it meets its demise. This also operates under a simple but not-always-accurate assumption: that all stars of a given mass and composition have the same age-radius and radius-temperature-luminosity relationships. That simply isn't true! Stars vary, both over time as they evolve and also from star-to-star dependent on their rotation and magnetism. It's a funny situation, because just a few years ago, people had declared stellar evolution as a basically "solved" field, and now it turns out that we might have to rethink how we've been thinking about the most common classes of stars of