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
The Battle of Clontarf [not-audio_url] [/not-audio_url]

Duration: 51:40
Melvyn Bragg and guests discuss one of the best known events and figures in Irish history. In 1014 Brian Boru, High King of Ireland, defeated the Hiberno-Norse forces of Sigtrygg Silkbeard and allies near their Dublin st…
The Gracchi [not-audio_url] [/not-audio_url]

Duration: 49:09
Melvyn Bragg and guests discuss the brothers Tiberius and Gaius Gracchus whose names are entwined with the end of Rome's Republic and the rise of the Roman Emperors. As tribunes, they brought popular reforms to the Roman…
Maurice Merleau-Ponty [not-audio_url] [/not-audio_url]

Duration: 59:02
Melvyn Bragg and guests discuss the French philosopher Maurice Merleau-Ponty (1908-1961), who was part of the movement known as phenomenology. While less well-known than his contemporaries Jean-Paul Sartre and Simone de…
Thomas Middleton [not-audio_url] [/not-audio_url]

Duration: 56:29
Melvyn Bragg and guests discuss one of the most energetic, varied and innovative playwrights of his time. Thomas Middleton (1580-1627) worked across the London stages both alone and with others from Dekker and Rowley to…
Cyrus the Great [not-audio_url] [/not-audio_url]

Duration: 50:59
Melvyn Bragg and guests explore the history and reputation of the Persian ruler Cyrus the Great. Cyrus the Second of Persia as he was known then was born in the sixth century BCE in Persis which is now in Iran. He was th…
Pollination [not-audio_url] [/not-audio_url]

Duration: 50:10
Since plants have to mate and produce offspring while rooted to the spot, they have to be pollinated – by wind, water, or animals – most commonly insects. They use a surprising array of tricks to attract pollinators: str…
Kali [not-audio_url] [/not-audio_url]

Duration: 57:41
Melvyn Bragg and guests discuss the Hindu goddess Kali, often depicted as dark blue, fierce, defiant, revelling in her power, and holding in her four or more arms a curved sword and a severed head with a cup underneath t…
Oliver Goldsmith [not-audio_url] [/not-audio_url]

Duration: 54:23
Melvyn Bragg and guests discuss the renowned and versatile Irish writer Oliver Goldsmith (1728 - 1774). There is a memorial to him in Westminster Abbey’s Poet’s Corner written by Dr Johnson, celebrating Goldsmith's life…
Catherine of Aragon [not-audio_url] [/not-audio_url]

Duration: 52:38
Melvyn Bragg and guests discuss Catherine of Aragon (1485-1536), the youngest child of the newly dominant Spanish rulers Ferdinand and Isabella. When she was 3, her parents contracted her to marry Arthur, Prince of Wales…
Sir John Soane [not-audio_url] [/not-audio_url]

Duration: 53:25
Melvyn Bragg and guests discuss the architect Sir John Soane (1753 -1837), the son of a bricklayer. He rose up the ranks of his profession as an architect to see many of his designs realised to great acclaim, particularl…