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Lecture | Global Questions Seminar

The Road to Planetary Defense: Cosmic Collisions, Nuclear Explosions, and the Environmental History of Asteroids and Comets

Thursday 11 May 2023
Global Questions Seminar 2022-2023
Pieterskerkhof 6
2311 SR Leiden


When astronomers measured the orbits of comets and discovered asteroids – then asteroids near Earth – some speculated that a collision with a little world could so alter our climate that human civilization would collapse. Motivated in part by the twentieth-century explosions of small asteroids in Earth’s atmosphere, a scattered group of largely unheralded scientists began to survey the skies for larger asteroids that might imperil human survival. Yet only in the last three decades did their efforts inspire well-funded programs to catalogue, map, and – very recently – transform asteroid and comet environments. As a result, the threat of Armageddon from the skies now seems far less menacing – and the promise of asteroid mining seems far more viable. What changed? This talk argues that the causes include a series of environmental transformations stretching all the way from Jupiter to Earth – and shows how environmental history can encompass the entire solar system.  

Dagomar Degroot

Dagomar Degroot is an associate professor of environmental history at Georgetown University. His first book, The Frigid Golden Age, was published by Cambridge University Press in 2018 and named by the Financial Times as one of the ten best history books of that year. His next book, Ripples in the Cosmic Ocean, is under contract with Harvard University Press and Viking. He publishes equally in historical and scientific journals, including Nature and the American Historical Review, and writes for a popular audience in, for example, the Washington Post, Aeon Magazine, and The Conversation. He maintains popular online resources on the history of climate change, including the podcast Climate History. He has shared the unique perspectives of the past with policymakers, corporate leaders, and journalists in many countries, from Wuhan to Washington, DC.

Global Questions Seminar

The motto of the Institute for History’s research programme is ‘Global Questions, Local Sources’. Across all areas and time periods, researchers of the Institute focus on important processes such as migration, colonialism, urbanization, and identity formation.

TheGlobal Questions Seminar’, for which we invite distinguished international colleagues to discuss the interplay between global and local issues from the past, brings all staff members of the Institute together.

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