PopSci's 2nd Annual Brilliant 10

MICHAEL MANGA

Geophysics: UC Berkeley


He models billion-year and minutes-long processes to grasp earth's workings.



Michael Manga wants to understand planetary evolution, but he doesn't have a few million years to sit around and observe. So he and his UC Berkeley colleagues have built a few Earths of their own. Ranging from cooler-size tanks of oil to 350-gallon vats of corn syrup, Manga's model planets may not look quite right, but they do reveal geological processes. In one recent experiment, he and colleague Mark Jellinek simulated the life cycle of Earth's hot spots—places where searing plumes of rock melt as they approach the Earth's surface, spurring volcanic eruptions. Manga and Jellinek filled a small tank with a form of motor oil, then piped into the bottom of the tank a thin layer of soybean oil, which is denser. When they heated the mix from below, the soybean oil formed veins that rose to the surface, then dispersed. Manga and Jellinek had successfully compressed a
billion-year phenomenon into an hour.



Manga is so prolific, says former adviser Rick O'Connell, a Harvard professor of earth science, that he's advancing not one area of geology but a dozen. Recently, Manga and grad student Helge Gonnermann disproved a long-held notion that when hot melted rock, or magma, rises quickly and breaks into pieces, it causes an explosive volcanic eruption. Manga and Gonnermann found the opposite is often true: Magma that breaks up as it shoots to the surface can prevent explosive eruptions. When magma rises fast, the surrounding pressure drops, allowing gas trapped in the magma to expand—much like carbon dioxide bubbles in a just-opened can of soda—and break up the
magma. Manga and Gonnermann found that sometimes the gas escapes from between the magma fragments and dissipates: Explosion avoided. This model has been confirmed by recent volcanic events, such as the eruption of Mount St. Helens.



Manga has his eye on Mars and Venus, and hopes future missions to those planets will unlock some of Earth's mysteries—such as why Earth is the only local planet that has moving tectonic plates. He also plans to log more hours with the corn syrup. At 35, he certainly has the time.



—Gregory Mone