For all their similarities, Mars possesses unique geophysical traits — traits that early on set Mars on a developmental path distinct from Earth's.

Mercury is the most unusual of the four planets closest to the Sun. It’s also the most neglected. Until MESSENGER, it was the only one of the four that hadn’t been comprehensively imaged.

Discover how scientists are now marrying traditional fieldwork with cutting-edge computer modeling to produce the first animated, theoretical picture of the Basin and Range Province's geological evolution.

In 2004, news of Asteroid MN4 hit the blogosphere: "So, in summary, there's a 1-in-233 chance of the worst disaster in recorded history happening on April 13, 2029, and a 232-in-233 chance of nothing happening." Take a closer, scientific look.

Given the potential for asteroids to literally and figuratively impact life on Earth in a profound way, asteroids have been quite sought after since the first and largest one, Ceres, was discovered in 1801. Learn more.

Meteorite specialist Dr. Denton Ebel talks asteroids bigger than Everest, glass mini-marbles raining from the sky, and dinosaur toast.

In 1669, the fastest and largest lava flow documented for Mount Etna on the island of Sicily killed most of Catania's 20,000 residents and destroyed much of the city. Why are scientists now watching Etna more than any other volcano in Europe? Find out.

During a July 2004 project to drill an ice core from the top of Peru's Andes Mountain, the lead researcher took a detour… and made a discovery with profound implications. Learn more.

By analyzing the relics glaciers hold — compacted snow and trapped air from ancient atmospheres, ash from long-quiet volcanoes, dust, insects, and pollen — scientists can reconstruct hundreds of thousands of years of Earth’s climate.

In the past two million years alone, Earth has experienced around 20 ice ages — cycles of advance and retreat of large continental ice sheets. When is the next one due? And will global warming change that due date?