How would a scientist estimate the time when a canyon formed? Various techniques and different interpretations of those techniques have yielded a wide range of estimated dates for the formation of Arizona's Grand Canyon. But results from a new technique are again challenging the canyon's previous date. Will science ever resolve the Grand Canyon dating game?

NASA's Image of the Day for January 25, "Blue Marble," is a composite of images taken by the Suomi NPP satellite that provides an exquisite view of the earth from space.¹ This is the latest in a series that began with the famous "Blue Marble" photo taken in 1972 by the Apollo 17 crew.

The Deccan Traps in India, and especially the Siberian Traps, have vast quantities of lava rock near the earth's surface. Many geologists have assumed that this formed over millions of years. However, recent studies testing that assumption have shown just the opposite—the magma moved rapidly from great depths.

On January 11, Google celebrated the 374th birthday of Nicolaus Steno by featuring a colorful doodle of rock layers on its homepage.¹