The Ten-Mile-Wide Bullet


In 1980, Walter Alvarez, a geologist at the University of California, Berkeley, and his colleagues proposed that the dinosaurs had been exterminated by an asteroid that smashed into the Earth. I was fourteen at the time, and that mix of dinosaurs, asteroids, and apocalyptic explosions was impossible to resist. I can still see the pictures that appeared in magazines and books–paintings of crooked rocks crashing into Earth, sometimes seen from the heavens, sometimes from the point of view of an about-to-become-extinct dinosaur. Suddenly the history of life was more cinematic than any science fiction movie.By luck rather than foresight, I eventually became a science writer. I had the good fortune to start the job in the early 1990s, as the impact story was still unfolding. Until then, I knew Walter Alvarez only as a name on a page. Now I could call Alvarez and talk to him about new evidence other scientists were finding to support his impact hypothesis–evidence showing not only that the impact did come at the end of the Cretaceous period, but even revealing where it hit: a site called Chixculub, along the coast of the Yucatán Peninsula. “It ties everything together,” Alvarez told me with delight in 1991. I had the wonderful privilege of watching the story continue to develop–as a bull’s-eye ring a hundred miles across came to light under the Gulf of Mexico, as a piece of the asteroid itself was fished from the Pacific.

By 1997, the story had matured enough that Alvarez himself was ready to offer a firsthand account in T. rex and the Crater of Doom. It is an intimately readable look at how great science gets done. Scientists notice odd things that seem out of place, they contemplate ludicrous hypotheses, and then they doggedly test those hypotheses for years. T. rex and the Crater of Doom illustrates an important rule about science: some of the most revealing discoveries come not from deep within a single discipline, but at the borders between disciplines. The impact hypothesis would probably have come to nothing if not for the combined efforts of experts on everything from geochronology to pollen fossils to nuclear explosions.

That’s the beginning of my foreword to Princeton University Library’s new edition of Alvarez’s book. I’ve posted the entire introduction here.

0 thoughts on “The Ten-Mile-Wide Bullet

  1. Nice.

    I was at the first or second AAAS meeting after the first paper. There were quite a few symposia and such on what was looking like a very serious revision of thinking. Exciting as hell.

  2. Stephen Baxter’s novel “Evolution” has an entire chapter that depicts the event – it’s absolutely magnificent, I highly recommend it. I just wish I had read it sooner. 🙂

  3. Carl

    Could I just make free with your comments, in a totally on topic way, to plug our package of special material on impacts in Nature this week, which contains a lot of stuff about killer asteroids. The whole package can be found here and this story makes some specific points about the way the Alvarez paper influenced debates about impacts in general.

  4. Hi Carl,

    The science of Walter Alvarez and his colleagues in ‘T-Rex and the Crater of Doom’ may become intriguing science [fiction ?] when compared with the mythology [?] of Plato in ‘Timaeus and Critias’.

    ‘What if’ is a fun and an interesting exercise in thought experiment.

    1 – What if the capital city of Atlantis, described as a set of concentric circles is an impact crater, which is also described as a set of concentric circles?

    Chixculub may be too big if the current idea of the length of a stade is correct.

    2 – What if the lost metal oricalc [chalk ore] of Atlantis is equivalent to iridium [a platinum metal] found around impact craters?

    Maybe there is evidence of iridium mining around some impact crater?

    3 – There seem to be other ‘what ifs’ in Plato that may be explained by an impact or crater.

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