Wednesday, June 24, 2009

PBS "Savage Planet": "Deadly Skies": Lightning, hail, and asteroids


PBS (Channel 13 in New York) has a new series called “Savage Planet”, with this home page. On Monday, June 22, WETA aired “Deadly Skies” (episode 3). The program focused on two major threats: cloud-to-ground lightning and hail in supercell thunderstorms, with a couple of storms in Sydney Australia (moving East to West) as examples, and meteor showers, particularly pieces of asteroids. It did not deal with tornadoes.

The program took the position that we map only a small fraction of the asteroids that could hit us. Once every few hundred thousand years, we take a hit (from a body over 1 km or so in diameter) that could wipe out civilization.

The show also takes the position that comets are even more dangerous than asteroids.
The last part of the show summarized the Shoemaker-Levy comet that hit Jupiter in 1994 (link). We wouldn’t be here if it weren’t for Jupiter, which protects Earth from most of the fragments that could hit it.

Attribution link for Wikimedia Commons NASA picture of the impact of Shoemaker-Levy on Jupiter, here.

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