Geologist Darby Dyar is working with the geological equivalent of space aliens-meteorites that fell to Earth from Mars. And at 4.5 billion years old, they are millions of years older than the earliest known earth rock. "Of the thirteen known Martian meteorites, pieces of Þve are here at Mount Holyoke," Dyar says.
How does she know they're from Mars? A glasslike layer reveals some rocks' extraterrestrial origin, as speeding through Earth's atmosphere melts, then cools, the rock's outer surface. And their Martian origin is conÞrmed by the composition of gases trapped inside the meteorites like air pockets in a loaf of bread.
Martian rocks contain many minerals common on Earth, which leads Dyar to conclude that "Earth and Mars formed by similar processes." Dyar studied moon rock samples for her doctoral dissertation, and her grand plan is to compare the geology of Earth and Mars rocks with asteroids and rocks from the Moon.
Holding a half-dollar-sized Martian meteorite in one palm, Dyar says, "From these little rocks, we're deducing how entire planets evolved." Two senior honors students, Maria Stefanis and Desiree Polyak, are over the moon about working with Dyar, one of the few scientists on the planet with access to chunks of Mars.
Photo by Fred LeBlanc |
