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 Starts With A Bang podcast, Dr. Cari Cesarotti joins us to discuss all of these options and much more, as we look ahead to the future of particle physics.

The serious question isn't whether we should build one (we definitely should), but which approach will be most fruitful in pushing our suite of knowledge beyond the known frontiers. There's an entire Universe to explore at the subatomic level, and those of us curious about the Universe want to know what's out there better than ever before! Follow Cari's attempts to support the future of a muon collider on Twitter @muoncollider.

(This image shows the expected signature of a Higgs boson decaying to bottom-quark jets around the collision point inside a muon collider. The yellow lines represent the decaying background of muons, while the red lines represent the b-quark jets. Credit: D Lucchesi et al.)

Starts With A Bang #108 - A Future Particle Collider

Launched in May 2024, ESA’s Earth Explorer EarthCARE mission has already been delivering remarkable data. Its four instruments have brought us groundbreaking insights into clouds, aerosols and Earth’s energy balance. The mission is being featured in an immersive installation called Hakuryu, which is Japanese for White Dragon, at the Living Planet Symposium in Vienna and here’s the accompanying sonification of atmospheric data downloaded from the EarthCARE satellite.

EarthCARE data transformed into a dragon’s song for peace

Every day, the Sun sends out bursts of energetic electrons into space. As these electrons collide with other charged particles, they produce radio waves—captured by the Radio and Plasma Waves (RPW) instrument on ESA’s Solar Orbiter spacecraft.

This track is a sonification of one six-hour data segment from a five-year dataset compiled by a team at Radboud University and Paris Observatory. Each drop in pitch represents electrons travelling further from the Sun, where fewer particles are left to interact with—causing the radio frequency (and now sound) to drop.

Listen for the distinctive “pyoong” sounds—real solar radio bursts, each starting sharp and fading low. The data has been sped up for your ears; that dramatic burst at the centre? It lasted three hours in space.

Credit: ESA & NASA/Solar Orbiter/RPW, sonification by Katerina Pesini
Acknowledgements: Philippe Zarka (IDL script), Alan Loh (Python script), Dimosthenis Bitzilos (video editing support)

Sound of a Solar Storm: Radio Bursts from the Sun

Perhaps the strongest evidence we've ever acquired in support of the Big Bang has been the discovery of the leftover radiation from its early, hot, dense state: today's cosmic microwave background, or CMB. While there were many competing ideas for our cosmic origins, only the Big Bang predicted a uniform, omnidirectional bath of blackbody radiation: exactly what the CMB is.

But it turns out the CMB encodes much more information than just our cosmic origins; it allows us to map the very early Universe from when it was just 380,000 years old, and gives us vital information about what has happened to light from that time over its 13.8 billion year journey to our eyes. It encodes information about our cosmic expansion history, about dark matter and dark energy, about intervening galaxy clusters, and about the material here in our own galaxy, along with much more. It is, arguably, the richest source of information from any one single observable in our entire Universe.

Here to guide us through what CMB scientists are working on here in 2025, including what we've learned and what we're still trying to find out, I'm so pleased to welcome Dr. Patricio Gallardo to the show. We've got more than an hour and a half of quality science to go through, and by the end, I bet you'll be more excited about the upcoming Simons Observatory, designed to measure the CMB to higher precision than ever before, than you knew you should be. Enjoy!

(This image shows the Large Aperture Telescope's colossal, 6-meter primary and secondary mirrors at the Simons Observatory in February of 2025. The telescope has already seen first light, and will soon begin delivering new CMB science as never before. Credit: M. Devlin/Simons Observatory)


Starts With A Bang #119 - The CMB

How PFAS From A Military Base Has Sickened Nearby Residents

Adam Aleksic Responds To Callers' Words

Out there in the Universe, somewhere, a second example of an inhabit world or planet likely awaits us. It could be some other planet or moon within our own Solar System; it could be a spacefaring, interstellar civilization, or it could be an exoplanet around a different parent star. Although the search for life beyond Earth generally focuses on worlds that have similar conditions to Earth, like rocky planets with thin atmospheres and liquid water on their surfaces, that's not necessarily the only possibility. The truth is that we don't know what else is going to be out there, not until we look for ourselves and determine the answers.

And yet, if you've been paying attention to the news, you might think that super-Earth or mini-Neptune type worlds, such as the now-famous exoplanet K2-18b, might be excellent candidate planets for life. Some have even gone as far as to claim that this planet has surefire biosignatures on it, and that the evidence overwhelmingly favors the presence of life within this planet's atmosphere. But the science backing up that claim has been challenged by many, including our two podcast guests for this episode: Dr. Luis Welbanks and Dr. Matthew Nixon.

Beyond the breathless and sensational claims, what does the actual science concerning K2-18b in particular, and of biosignatures on exoplanets in general, actually teach us? What does the evidence indicate, and if we are going to find inhabited exoplanets, what will it take for us to actually announce a positive detection with confidence and less ambiguity? That's what this episode of the Starts With A Bang podcast is all about; I hope you enjoy it!

(When an exoplanet passes in front of its parent star, a portion of that starlight will filter through the exoplanet’s atmosphere, allowing us to break up that light into its constituent wavelengths and to characterize the atomic and molecular composition of the atmosphere. If the planet is inhabited, we may reveal unique biosignatures, but if the planet has either a thick, gas-rich envelope of volatile material around it, or alternatively no atmosphere at all, the prospects for habitability will be very low. ⁠Credit⁠: NASA Ames/JPL-Caltech)


Starts With A Bang #120 - Exoplanet biosignatures

It's hard to believe, but it was only back in the early 1990s that we discovered the very first planet orbiting a star other than our own Sun. Fast forward to the present day, here in 2025, and we're closing in on 6000 confirmed exoplanets, found and measured through multiple techinques: the transit method, the stellar wobble method, and even direct imaging. That last one is so profoundly exciting because it gives us hope that, someday soon, we might be able to take direct images of Earth-like worlds, some of which may even be inhabited.

Although it may be a long time before we can get an exoplanet image as high-resolution as even the ultra-distant "pale blue dot" photo that Voyager took of Earth so many decades ago, the fact remains that science is advancing rapidly, and things that seemed impossible mere decades ago now reflect today's reality. And the people driving this fascinating field forward the most are the mostly unheralded workhorses of the fields of physics and astronomy: the early-career researchers, like grad students and postdocs, who are just beginning to establish themselves as scientists.

In this fascinating conversation with Dr. Kielan Hoch of Space Telescope Science Institute, we take a long walk at the current frontiers of science and peek over the horizon: looking at the good, the bad, and the ugly of what we're facing here in 2025. It's a conversation that might make you hopeful, angry, and optimistic all at the same time. After all, it's your Universe too; don't you want to know what comes next?

(This composite image shows a brown dwarf star, center, with the first directly imaged exoplanet, 2M1207 b, in red alongside it. This image was acquired in 2004 by the Very Large Telescope in Chile, operated by the European Southern Observatory. In the years and decades since, dozens of more exoplanets have been directly imaged, with hundreds more expected in the next decade. Credit: ESO/VLT.)



Starts With A Bang 121 - Direct exoplanet imaging

It's no secret that the Universe and the objects present within it, as we see them all today, have changed over time as the Universe has grown up over the past 13.8 billion years. Galaxies are larger, more massive, more evolved, and are richer in stars but fewer in number than they were back in the early stages of cosmic history. By looking farther and farther away, we can see the Universe as it was at earlier times, but we're going to be limited in many ways: by how deep our telescopes can see, by what wavelengths they're capable of seeing, and by what small fraction of the sky they're capable of observing.

That's why an observing program like COSMOS-Web, the largest, widest-field JWST observing program to date, is so important. It isn't just revealing galaxies as they are nearby (at late times), at a variety of intermediate distances (and earlier times), and at ultra-large distances (and the earliest times of all), but due to its wide-field nature, is revealing galaxy types of varying abundances: the common-type galaxies, galaxies that are representative of more uncommon varieties, and even significant numbers of rare galaxies. And it's this aspect of galaxy evolution that makes me so proud and lucky to welcome Dr. Olivia Cooper to the podcast.

Olivia is a recently-minted PhD who works as part of the COSMOS-Web team, specializing in galaxy evolution and using JWST data — along with data from other world-class observatories — to investigate how the galaxies in our Universe grew up, and what that can teach us about our own cosmic past. It truly is a banger of an episode that you'll want to listen to every minute of, so tune in and dive deep into the depths of the distant Universe on our latest adventure of the Starts With A Bang podcast!

(This image shows a tiny sliver of the COSMOS-Web survey, with galaxies at a variety of distances along with a portion of a rich cluster of galaxies, at right, of this image. Credit: ESA/Webb, NASA & CSA, G. Gozaliasl, A. Koekemoer, M. Franco, and the COSMOS-Web team)

Starts With A Bang 122 - Galaxy evolution and JWST

Seas of the Sun is a film about a bold science mission and the people who made it possible. Hosted by Space Rocks founder and producer and co-director on Seas of the Sun, this series was produced by Philip Wilding, and with music by Karlotta Skagfield.

Missions notes episode 2: The science of Cluster, with Science Operations Support scientist Matt Taylor and Lucile Turc of the University of Helsinki. We explore the world of heliophysics and Cluster’s contributions to this burgeoning field of study.

See the full film on 30 October 2025: https://www.youtube.com/europeanspaceagency

Learn more about the making of Seas of the Sun: http://www.spacerocksofficial.com

Starts With A Bang #108 - A Future Particle Collider

Ethan Siegel