The Mariana Trench

The Mariana Trench

From In Our Time by BBC Radio 4

February 19, 2026 · 58 min

About this episode

Misha Glenny and guests discuss the Mariana Trench and its significance in ocean exploration.

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…

People in this episode

Host: Misha Glenny

Guests: Heather Stewart, Jon Copley, Alan Jamieson

Topics covered

  • Mariana Trench
  • ocean exploration
  • tectonic plates
  • deep sea life
  • geoscience

Keywords

  • Mariana Trench
  • HMS Challenger
  • deep sea
  • tectonic plates
  • ocean life
  • geoscience
  • exploration

Mentioned in this episode

Organizations: Kelpie Geoscience, University of Southampton, Deep Sea Research Centre, University of Western Australia

Books & works: The Underworld: Journeys to the Depths of the Ocean, Deep Sea: 10 Things You Should Know, Soundings: The Story of the Remarkable Woman Who Mapped the Ocean Floor, Pseudoliparis swirei: A newly-discovered hadal liparid, The Hadal Zone: Life in the Deepest Oceans, A global assessment of fishes at lower abyssal and upper hadal depths

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