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Fifteen volunteers spent 40 days in cave with no natural light or clocks. Most want to go back, here’s why… © Human Adaptation Institute

Podcast: What happens to you after 40 days with no natural light?

Published: 10th May, 2021 at 08:00
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Fifteen volunteers spent 40 days in a cave with no natural light or clocks. Most of them want to go back.

Around two months ago, a group of 15 people – scientists, explorers and medics – travelled deep into a cave in the south of France. The expedition descended to a point so deep that natural light could not reach them, and there the team stayed for 40 days and 40 nights without clocks, phones or anyway of telling the time.


The project’s goal was to understand what happens to our brains and bodies when we’re deprived of an external measure of time and they hoped to discover how a group of people could adapt to such an extreme situation.

Just two weeks ago, that team emerged from the cave, and Christian Clot, the expedition’s leader and the designer of the DEEP TIME mission, joins editor Daniel Bennett on this week's episode of the Science Focus Podcast to talk about what the experiment discovered, how the expedition changed him and what ultimately happened when the team returned to the surface.

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Daniel BennettEditor, BBC Science Focus

Daniel Bennett is the Editor of BBC Science Focus. He is an award-winning journalist who’s been reporting on science and technology for over a decade, writing about the science of serials killers, sandwiches, supernovae and almost everything in between.


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