If you want an idea of the conditions on Mars, journey to Antarctica. Take a close look at the work of an astrobiologist studying Antarctica's valleys, the "most Mars-like places on Earth."

The mineral zircon serves as a tiny time capsule, recording geologic events—it's especially useful because the oldest discovered grains (4.2 billion to 4.3 billion years old) are not much younger than the Earth itself.

From acting on the Broadway stage to acting on her concerns about habitat destruction in Madagascar, Penelope Bodry-Sanders has had a wide-ranging and active career.

In the early 1900s, some astronomers believed that the color contrasts on Mars' surface were great oceans. Today we know they are huge dust storms. Track how our knowledge of Mars has changed with this seventh-grader.

When this ninth-grader from New York uncovered fossils in the state's Finger Lakes region, it was the first time they'd seen light in 400 million years. Learn what information they yielded after all those years.

An earthquake prediction when she was young peaked the interest of this eighth-grader from Michigan. While the earthquake never occurred, her fascination continues to this day.

Did you know that Long Island was once part of a chain of volcanoes? Or that it was part of the tropics—and faced south? Step back in time with this seventh-grader for a look at the forces that shaped this giant sandbar.

Why did museum scientists travel to the Sahara to retrieve a boulder? This stromatolite was built by microbes, the only life that existed on Earth until about a billion years ago.

At the bottom of the ocean, how do scientists find their way around? This marine geologist's work includes helping to create accurate, high-resolution maps of the sea floor.

Beneath the glacier-clad summit of Mt. Rainier lies an active volcano, which has more than once produced enough molten rock to bury an area the size of Tacoma and Seattle combined almost 10 feet under.