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Defending Earth from Asteroids: Live Stream Friday 10/25 at 11 am

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When the explosion of a truck-sized meteorite injured more than 1,000 people in Chelyabinsk, Russia, last February, it drew comparisons to another famously destructive cosmic event observed in Russia over a century ago.

Rare Impact

Visualize this: Once every 5 to 10 million years, a potentially hazardous asteroid (as imagined here) as big as the one that probably wiped out large dinosaurs 65 million years ago might impact Earth. 

David A. Hardy/Photo Researchers


In 1908, an enormous explosion shook an area in sparsely populated Siberia, near the Podkamennaya Tunguska River. Its force has been estimated to be nearly 1000 times greater than that of the 1945 atomic bomb at Hiroshima: the blast ripped out millions of trees across hundreds of square miles of remote forest, destroying hundreds of reindeer and scarring the landscape for decades to come.

The leading theory? A 220-million-pound space rock entered Earth’s atmosphere, consuming itself as it fell with an immensely powerful explosion. (Donald Yeomans, manager of the Near-Earth Object Office at NASA’s Jet Propulsion Laboratory, mentioned some of the more outlandish theories proposed about the Tunguska event in a January 2013 “Frontiers in Astrophysics” lecture at the Museum—listen to the podcast here.)

Had the blast occurred over a crowded city instead of the remote taiga forest, the devastation could have been catastrophic.

"Impacts like Tunguska and Chelyabinsk remind us that we live in a dynamic solar system," says Denton Ebel, a curator in the Department of Earth and Planetary Sciences at the Museum who specializes in meteorites. "But they also give us clues about what space rocks are like. Planetary protection requires deeper understanding of how asteroids and comets are put together."     

Luckily for Earth, impacts are rare (check out more online about the frequency of various impacts from the Museum’s recent exhibition Beyond Planet Earth: The Future of Space Exploration or at the Museum in the Arthur Ross Hall of Meteorites, curated by Dr. Ebel. )

But how should we be preparing to detect and deflect other potentially hazardous asteroids? (See the 2009 image below for orbits of known asteroids, including potentially hazardous near-Earth asteroids, whose orbits come within about 5 million miles [8 million kilometers] of Earth's.) 

Harzardous Asteroids

Paul Chodas


Find out by tuning in to a live stream on amnh.org/live this Friday, October 25, at 11 am, as Hayden Planetarium Director Neil deGrasse Tyson hosts a discussion with members of the Association of Space Explorers (ASE)—a group of astronauts and cosmonauts who recently recommended steps for planetary asteroid defense to the United Nations.

Watch the discussion live on Friday, October 25, at 11 am sharp on amnh.org/live.

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