We've talked a lot about life in the universe in this season — from where we might look, to what it might conceivably be, to the question of what even we mean by the word "life" anyway. And now, finally, it's time to grapple with the huge problem of what astronomers are actually looking for: the signals, the signs, the smoking gun of life on another planet. We're talking biosignatures, and Emily has some bad news: turns out, it's really hard to take a precise measurement of a conclusive biosignature of exolife ... mainly because, it's not clear any such conclusive biosignature even exists. But she has some good news, which is that we're getting a lot better at detecting atmospheres on exoplanets — so there's still hope!

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:

• What Wiki says about Biosignatures

• The Just Wonderful JWST

• The Eyeball Planet LHS 1140 b

• The paper on Detection of an atmosphere on LHS 1140 b

• A good summary of the paper

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