Human terrarium, Biosphere 2, looking good at 20

In the 1990s, eight scientists agreed to spend two years sealed inside a 3-acre terrarium in Arizona's Sonoran Desert. Their mission was to see whether humans might someday be able to create self-sustaining colonies in outer space. Two decades later, scientists are still using the 7.2-million-square-foot Biosphere 2, only now the focus is figuring out how we'll survive on our own warming planet. Researchers say Biosphere 2 may be even more relevant today than when those first people passed through the airlocks on Sept. 26, 1991. Experience Biosphere 2 for yourself when you travel to the Grand Canyon with Discovery Student Adventures.

Yellowstone supervolcano's size exceeds expectations

Beneath Yellowstone National Park lurks a partially molten plume rising from the Earth's mantle, fueling the park's famous geysers and hot springs, and causing the crust above to bulge and recede in response to its forces. Now, researchers report that the source beneath the surface may be even more massive than previously thought. Using a new technique, they have created an image of the plume beneath Yellowstone showing the cyclone shape stretching at a 40-degree angle to the west at a depth of 200 miles for 400 miles east to west, as far as the new technique can reach. Witness extraordinary geologic features on a journey to Yellowstone with Discovery Student Adventures.

Stellar celebration: 50 years in space

Celebrations rang out in Russia and around the world to mark the 50th anniversary of humankind's first-ever space mission. On Tuesday, April 12, 1961, a Russian air force pilot named Yuri Gagarin became the first human to venture into space. Meantime, there was also reason for celestial celebration in the U.S. as we recognized the 30-year anniversary of the space shuttle program.

Arctic adventure: North Pole “discovered” 102 years ago

On April 6, 1909, explorers Robert E. Peary and Matthew A. Henson, along with a team of Inuit, became the first to reach the North Pole. The journey began with an entourage of 23 men, 133 dogs, and 19 sleds. But as the team traveled further north, they lightened their loads and reduced the size of the party. Only six men, including Peary and Henson, were left to step foot on the North Pole.