A new view of dinosaurs, a clearer view of lunar origins
Dinosaurs have undergone any number of scientific makeovers in the last few decades. When I was young, they were depicted as lumbering, over-sized lizards, “cold-blooded” and drab. That simplistic image was eventually replaced with a more vibrant one. The velociraptor à la Jurassic Park was agile, quick, birdlike — and quite possibly festooned in feathers. Bright colors (though maybe not Barney purple) and rich social lives have also been proposed.
Scientists’ latest look at dinosaurs offers up another revision. As Meghan Rosen describes in “Dinosaurs had middling metabolisms,” the new work compares dinosaur growth rates, estimated from fossils, with growth rates from modern animals for insights into dino metabolism. Energetically, dinosaurs were neither fowl nor lizard, but something in between, the researchers conclude. Like today’s sea-faring tuna and great white sharks, dinos share some traits with both ectotherms (what people mean when they say “cold-blooded”) and endotherms “warm-blooded”).
In science, revisionism can be a good thing. Finding ways to test assumptions and accepted truths can lead to insight and discovery. As Tina Hesman Saey reports in “Human-ape split gets an earlier date,” for example, the latest DNA studies of chimpanzees are forcing a rethink of just how long ago chimps and humans shared a common ancestor. And despite popular thinking that the Internet can be harnessed to power good causes, one of the first long-term scientific studies of giving in a major online movement reveals far more “slacktivism” than activism, Bruce Bower writes in our feature story “Token Gestures.” At the same time, other new experiments suggest ways to motivate the public to action.
Of course, science also confirms what we think we know. Take the origin of the moon. The best theory holds it formed after a planet-sized object collided with a young Earth. The resulting explosion created the moon, which would have been chemically distinct from Earth. But chemical analyses of lunar and terrestrial rocks revealed no differences. Now, a more precise comparison of the rocks has found distinctions that support the leading theory, Rosen reports in “Rocks’ chemistry reveals details of moon’s origins.”
Testing, revising, substantiating: That’s just what science is supposed to do.