Finaly — finally! — Chris and Emily get to the meat of the matter in this season on life in the universe. Very special guest Dr Kelly Redeker from the Department of Biology at the University of York breaks down the principles of life, both on Earth and on other worlds (or "slimy rocks" as Emily insists on calling them). Do you need a Frankenstein-esque spark? Is life inevitable? What about complex life? Intelligent life? And Emily asks Kelly the big question: will we find life outside our planet?

On the web: syzygy.fm

Help us make Syzygy even better! Tell your friends and give us a review, or show your support on Patreon: patreon.com/syzygypod

Syzygy is produced by Chris Stewart and co-hosted by Dr Emily Brunsden from the Department of Physics at the University of York.

Some of the things we talk about in this episode:

• Special guest Dr Kelly Redeger

• How to define life

• The origins of life

• Non-carbon-based life

In this season on life in the universe, it's time to look closer to home: what are the chances we will find evidence of life — present or past-tense — in the Solar System, our own back yard? Emily's fabulous colleague Dr Clément Moissard, plasma physicist at the University of York, joins us to discuss the search for life on Mars, on the icy moons of Jupiter and Saturn ... even on Pluto?! Surely not. It's a fascinating and fun conversation with plenty of surprises: Chris somehow missed the fact that we landed on Titan in 2005, Clément is super keen to visit mysterious Planet 9, and Emily just seems fixated on tasty space fish.

On the web: syzygy.fm

Help us make Syzygy even better! Tell your friends and give us a review, or show your support on Patreon: patreon.com/syzygypod

Syzygy is produced by Chris Stewart and co-hosted by Dr Emily Brunsden from the Department of Physics at the University of York.

Some of the things we talk about in this episode:

• Our special guest Dr Clément Moissard

• Latest evidence for life on Mars?

• Water on Europa

• Life on Enceladus?

• The Cassini-Huygens mission

• Cassini’s Grand Finale and images

• Wait … we landed on Titan?

• Sample return missions from Mars

• JUICE mission to Ganimede

• Zeppelins on Venus?!

• There’s water on Pluto?!

• Planet 9

Having established that the hunt for life in the galaxy ought to begin with an appropriate star, Emily turns our attention towards suitable planets. But what makes a hospitable home for life? It’s complicated, and it seems whatever way we look at it, we don’t have a lot of candidates to choose from. Emily discusses earth-like rocky planets, ocean worlds, and wonderfully-named Chthonian planets, before letting rip with some wild speculation. I mean, life could be anywhere, right?

On the web: syzygy.fm

Help us make Syzygy even better! Tell your friends and give us a review, or show your support on Patreon: patreon.com/syzygypod

Syzygy is produced by Chris Stewart and co-hosted by Dr Emily Brunsden from the Department of Physics at the University of York.

Some of the things we talk about in this episode:

• The first exoplanet, 51 Pegasi b

• The Habitable Zone

• Chthonian planets, Mini Neptunes & Super Earths

• The Habitable Worlds Catalog(ue)

• The Trappist-1 System

• Proxima Centauri b

• LHS 1140 b

• Hycean Worlds

• Dimethyl Sulphide discovery?

• Icy Ocean Planets

We're back with Season 3! For the next six episodes we're talking life in the universe, and so far we have N=1: we know there's life on Earth, but nowhere else as yet. Those are challenging statistics. In this episode Emily makes the case that to explore the possibility of life elsewhere in the cosmos, you need planets — and to have planets, you need stars. She then proceeds to whittle the number of potential life-bearing systems in our galaxy down to a scarily small number. But all is not lost, we still have five episodes to fill with hope and optimism.

On the web: syzygy.fm

Help us make Syzygy even better! Tell your friends and give us a review, or show your support on Patreon: patreon.com/syzygypod

Syzygy is produced by Chris Stewart and co-hosted by Dr Emily Brunsden from the Department of Physics at the University of York.

Some of the things we talk about in this episode:

• Types of stars

• Stellar magnetism

• Multiple star systems

• Stellar metallicity

• The Galactic Habitable Zone

According to one survey, around one-third of Australians think aliens not only exist, but have actually visited Earth. That's ... a bit fraction. In this final episode of season 2, we ask how we'd even find out if life exists around other stars. Emily introduces the Habitable Worlds Observatory, an incredible new space telescope that's just in the early design phase and not due for years yet, with lots of technical and scientific holes to plug. Whether we can find life on other planets, who knows ... but maybe we've just found season three of Syzygy!

On the web: syzygy.fm

Help us make Syzygy even better! Tell your friends and give us a review, or show your support on Patreon: patreon.com/syzygypod

Syzygy is produced by Chris Stewart and co-hosted by Dr Emily Brunsden from the Department of Physics at the University of York.

Some of the things we talk about in this episode:

• Habitable Worlds Observatory

• Square Kilometre Array

• SETI and Jill Tarter

• Jocelyn Bell Burnell and the first pulsar

• Roman Space Telescope

• Designs for the HWO

• Exoplanet biosignatures

Exo-planets, sure. Exo-moons and -comets? Fine. But exo ... telescopes?! Emily is going out on a limb in this episode, expanding the definition of telescope to include things that measure stuff in space, and we're here for it! Which means we really do have a few telescopes out there beyond the Solar System, in the shape of Voyagers 1 and 2, with a few more waiting in the wings.

On the web: syzygy.fm

Help us make Syzygy even better! Tell your friends and give us a review, or show your support on Patreon: patreon.com/syzygypod

Syzygy is produced by Chris Stewart and co-hosted by Dr Emily Brunsden from the Department of Physics at the University of York.

Some of the things we talk about in this episode:

• The Voyager Missions: Voyager 1 and Voyager 2

• Where are the Voyager spacecraft now?

• The Heliosphere, where the Solar System ends 

• The Voyager Golden Record

• NASA relieved to get a call from Voyager 1

• Syzygy Episode 42: Life, the Universe, and Everything

• Syzygy Episode 79: Voyager Hears a Hum

• Voyager 2 turns of last scientific instrument

• Uranus mystery finally solved!

• The Kuiper Belt and the Oort Cloud

• The Pioneer Program, esp. Pioneer 10 and Pioneer 11

• The Pioneer Plaque

• The New Horizons mission and the Pluto Heart image

• New Horizons visits Ultima Thule (Arrokoth)

We know, we know — we did exoplanets last time. But that was the current state-of-play and a 2024 exoplanets wrapped update. In this episode, Emily looks to the future! She does a deep dive into the promise of the just wonderful JWST, as it prods exoplanets in ways they’ve never been prodded before.

On the web: syzygy.fm

Help us make Syzygy even better! Tell your friends and give us a review, or show your support on Patreon: patreon.com/syzygypod

Syzygy is produced by Chris Stewart and co-hosted by Dr Emily Brunsden from the Department of Physics at the University of York.

Some of the things we talk about in this episode:

• The JWST mission

• The Transit method

• Exoplanet Phase Curves

• Exoplanet GJ1214b and the phase curve paper

• Transmission spectroscopy

• Exoplanet WASP 39b

• Direct imaging of exoplanets

• Exoplanet HIP65426b

• The JWST first release images

• The WASP 96-b “dodgy graph” (see Brundsen, 2025)

• Exoplanet WASP 43b’s day and night (and the Nature paper)

• The Trappist 1 system

It couldn't be a season of exo-stuff without taking a good hard look at the current state of exoplanets, the OG exo-thing. Emily sums up the state of exoplanet research in 2024 — her Exoplanets 2024 Wrapped, if you like — then lines up her top three exoplanets of the year, and considers what's coming up next in this exo-ploding field.

On the web: syzygy.fm

Help us make Syzygy even better! Tell your friends and give us a review, or show your support on Patreon: patreon.com/syzygypod

Syzygy is produced by Chris Stewart and co-hosted by Dr Emily Brunsden from the Department of Physics at the University of York.

Some of the things we talk about in this episode:

• Exoplanets found in 2024

• The Roche Limit

• Paper about Gliese 4256b and a nice article

• Comet Shoemaker Levy smashes into Jupiter!

• Brand-new IRAS 04125+2902: paper and article

• Retrograde hot Jupiter TIC 241249530 b: paper and article

Exoplanets, sure. Exo-moons too, apparently. But exo ... comets?! Yes indeed, they're a real thing, and we've known about them for ages! How do you spot something so tiny around another star, so far away? Emily has the insider knowledge, because it's something she's genuinely investigating in her job as an actual, real-life astronomer.

On the web: syzygy.fm

Help us make Syzygy even better! Tell your friends and give us a review, or show your support on Patreon: patreon.com/syzygypod

Syzygy is produced by Chris Stewart and co-hosted by Dr Emily Brunsden from the Department of Physics at the University of York.

Some of the things we talk about in this episode:

• Comets: dirty snowballs

• Exocomets

• Famous comets

• Shoemaker-Levy’s Jovian rendezvous

• Beta Pictoris, HyperMegaMall of astrophysics

• Exocomets around Beta Pic

• TESS, everyone’s favourite exo-hunter

Way, way back in the early epochs of Syzygy (ep 19 in Oct 2018 if you must know) we talked about the exciting prospect of spotting the first exomoon — a moon orbiting a planet orbiting a star that is not our own. It seemed reasonable to expect that six years later exomoons would be a thing we've discovered, and maybe even started a catalogue. But turns out, observing a minute signal on top of an already minute signal is hard. Emily outlines our best prospects for exomoon discovery.

On the web: syzygy.fm

Help us make Syzygy even better! Tell your friends and give us a review, or show your support on Patreon: patreon.com/syzygypod

Syzygy is produced by Chris Stewart and co-hosted by Dr Emily Brunsden from the Department of Physics at the University of York.

Some of the things we talk about in this episode:

• Syzygy ep 19: Moons, Exomoons & Moonmoons

• Does Kepler 1625b have an exomoon?

• Seems Unlikely …

• What about Kepler 167e?

• Volcanic exomoon around Wasp 49b?!