meteorites

Travels in Geology: Chesapeake Bay, from impact craters to executive orders

The lower part of the Chesapeake Bay offers more than crab cakes and boating. Today, the bay is central to one of country’s largest environmental campaigns. But an excursion around the Virginian coasts provides an amazing peek into the mid-Atlantic region’s rich geological, environmental and cultural history, spanning impact events, glaciation, early colonial settlements and modern struggles with pollution and rising sea level.

06 Oct 2009

Do impacts trigger extinctions? Impact theory still controversial

The revolution started with a bang in 1980. For some, this revolution became a religion, even an orthodoxy. The true believers became proselytes and began to see signs supporting their viewpoint everywhere. But each time the proselytes claimed to have found yet another example in support of their “religion,” naysayers and doubters emerged. Two sides formed, each loudly castigating and questioning their opponents.

This back-and-forth ideological debate describes both the historical and still-ongoing struggle over a purported cause of mass extinctions: the meteor impact theory.

23 Jun 2010

Ancient meteorites reveal early magnetic fields

Even before the birth of the planets, our solar system was hardly a lonely place. Small rocky bodies, called planetesimals, filled the inner solar system, eventually colliding together to form the planets. Now a new look at a group of ancient meteorites shows that at least some planetesimals generated their own magnetic fields — a feat many scientists thought extremely difficult for such small astronomical bodies. The work also has scientists rethinking how planets formed.

21 Jan 2009

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