The Mariana Trench

The Mariana Trench

Author: BBC Radio 4 February 19, 2026 Duration: 58:04

Misha Glenny and guests discuss one of the wonders of the natural world. In 1875 in the western Pacific, the crew of HMS Challenger discovered the Mariana Trench which turned out to be deeper than Everest is high, by two kilometres. Trenches like Mariana form when one tectonic plate slips under another and heads down and there are around fifty of them globally. While at one time some thought it was too dark and deep for life there and others wildly imagined monsters, the truth has turned out to be much more surprising.

With

Heather Stewart, Director of Kelpie Geoscience and Associate Professor at the University of Western Australia

Jon Copley Professor of Ocean Exploration and Science Communication at the University of Southampton

And

Alan Jamieson Director of the Deep Sea Research Centre at the University of Western Australia

Producer: Simon Tillotson

Reading list:

Susan Casey, The Underworld: Journeys to the Depths of the Ocean (Doubleday, 2023)

Jon Copley, Deep Sea: 10 Things You Should Know (Orion Books, 2023)

Hali Felt, Soundings: The Story of the Remarkable Woman Who Mapped the Ocean Floor (Henry Holt & Co, 2012)

M.E. Gerringer, ‘Pseudoliparis swirei: A newly-discovered hadal liparid (Scorpaeniformes: Liparidae) from the Mariana Trench’ (Zootaxa 4358 (1), 161-177, 2017)

A.J. Jamieson, The Hadal Zone: Life in the Deepest Oceans (Cambridge University Press, 2015)

A.J. Jamieson et al., ‘A global assessment of fishes at lower abyssal and upper hadal depths (5000 to 8000 m)’ (Deep-Sea Research Part 1. 178: 103642, 2021)

A.J. Jamieson et al., ‘Fear and loathing of the deep ocean: Why don’t people care about the deep sea?’ (ICES Journal of Marine Science. 78: 797-809, 2020)

A.J. Jamieson et al., ‘Microplastic and synthetic fibers ingested by deep-sea amphipods in six of the deepest marine environments on Earth’ (Royal Society Open Science, 6, 180667, 2019)

A.J. Jamieson et al., ‘Bioaccumulation of persistent organic pollutants in the deepest ocean fauna’ (Nature Ecology and Evolution. 1, 0051, 2017)

V.L. Vescovo et al., ‘Safety and conservation at the deepest place on Earth: A call for prohibiting the deliberate discarding of nondegradable umbilicals from deep-sea exploration vehicles’ (Marine Policy. 128, 104463, 2021)

J.N.J. Weston et al., ‘New species of Eurythenes from hadal depths of the Mariana Trench, Pacific Ocean (Crustacea: Amphipoda)’ (Zootaxa. 4748(1): 163-181, 2020)

In Our Time is a BBC Studios Production

Spanning history, religion, culture, science and philosophy, In Our Time from BBC Radio 4 is essential listening for the intellectually curious. In each episode, host Misha Glenny and expert guests explore the characters, events and discoveries that have shaped our world.


For anyone with a restless mind, the weekly In Our Time podcast from BBC Radio 4 offers a deep and engaging conversation across the vast terrain of human thought and experience. Host Misha Glenny guides a panel of distinguished academics, not in lecture format, but through a lively, accessible discussion where ideas genuinely collide and unfold. You might find yourself immersed in the complex legacy of a figure like Napoleon one week, and the next be untangling the scientific principles of photosynthesis or the philosophical arguments of the Enlightenment. The scope is deliberately broad, covering history, religion, culture, science, and philosophy, because understanding one often requires context from another. What you hear is the genuine process of exploration-the questions, the debates, and the connections made in real time by leading experts. It’s the kind of podcast that doesn’t just recount the Sack of Rome or the intricacies of Russian court politics, but examines why these moments mattered and how their echoes are still felt. The result is a consistently stimulating hour that treats listeners as curious equals, offering the intellectual satisfaction of following a great conversation to its illuminating conclusion.
Author: Language: English Episodes: 100

In Our Time
Podcast Episodes
Hormones [not-audio_url] [/not-audio_url]

Duration: 50:13
Melvyn Bragg and guests discuss some of the chemical signals coursing through our bodies throughout our lives, produced in separate areas and spreading via the bloodstream. We call these 'hormones' and we produce more th…
The Hanseatic League [not-audio_url] [/not-audio_url]

Duration: 49:01
Melvyn Bragg and guests discuss the Hanseatic League or Hansa which dominated North European trade in the medieval period. With a trading network that stretched from Iceland to Novgorod via London and Bruges, these Germa…
Panpsychism [not-audio_url] [/not-audio_url]

Duration: 53:59
Melvyn Bragg and guests discuss the idea that some kind of consciousness is present not just in our human brains but throughout the universe, right down to cells or even electrons. This is panpsychism and its proponents…
Nefertiti [not-audio_url] [/not-audio_url]

Duration: 49:50
Melvyn Bragg and guests discuss the woman who inspired one of the best known artefacts from ancient Egypt. The Bust of Nefertiti is multicoloured and symmetrical, about 49cm/18" high and, despite the missing left eye, st…
Condorcet [not-audio_url] [/not-audio_url]

Duration: 50:31
Melvyn Bragg and guests discuss Nicolas de Condorcet (1743-94), known as the Last of the Philosophes, the intellectuals in the French Enlightenment who sought to apply their learning to solving the problems of their worl…
Twelfth Night, or What You Will [not-audio_url] [/not-audio_url]

Duration: 53:53
Melvyn Bragg and guests discuss one of Shakespeare’s great comedies, which plays in the space between marriage, love and desire. By convention a wedding means a happy ending and here there are three, but neither Orsino n…
Vincent van Gogh [not-audio_url] [/not-audio_url]

Duration: 56:02
Melvyn Bragg and guests discuss the Dutch artist famous for starry nights and sunflowers, self portraits and simple chairs. These are images known the world over, and Vincent van Gogh (1853-1890) painted them and around…
Tiberius [not-audio_url] [/not-audio_url]

Duration: 53:10
Melvyn Bragg and guests discuss the Roman emperor Tiberius. When he was born in 42BC, there was little prospect of him ever becoming Emperor of Rome. Firstly, Rome was still a Republic and there had not yet been any Empe…
Karl Barth [not-audio_url] [/not-audio_url]

Duration: 55:22
Melvyn Bragg and guests discuss one of the most influential theologians of the twentieth century. Karl Barth (1886 - 1968) rejected the liberal theology of his time which, he argued, used the Bible and religion to help h…
Edgar Allan Poe [not-audio_url] [/not-audio_url]

Duration: 58:44
Melvyn Bragg and guests discuss Poe (1809-1849), the American author who is famous for his Gothic tales of horror, madness and the dark interiors of the mind, such as The Fall of the House of Usher and The Tell-Tale Hear…