Here are ten quotes to celebrate the birthday of Henry David Thoreau.
On Thursday, NASA officials announced that the agency has agreed to support a suite of seven instruments for the Mars 2020 mission, which is likely to cost about $1.9 billion.
A six-mile wide asteroid delivered the fatal blow to dinosaurs, who had already been struggling against a host of environmental threats. But what if the asteroid had missed Earth?
Climate change, changing sea levels, and volcanic activity severely undermined the environment for dinosaurs, even before a large impactor smashed into Earth, scientists say.
Biologists who tracked blue whales over 15 years say small adjustments to shipping lanes near San Francisco and Los Angeles could vastly improve the long-term survival of the species.
Renewed excavation of Wyoming's Natural Trap Cave promises to be a boon for scientists, armed with a capability for ancient DNA sequencing not available in 1984, the last time the cave was open to exploration.
Fossils unearthed in Siberia of a plant-eating dinosaur suggests that feathers were common among the ancient reptiles.
Some 70 million years ago, a trio of tyrannosaurs walked together across a mud flat in what is today Canada, leaving behind tracks that support the theory that these giant predators hunted in packs.
Antarctic fur seals, a conservation success story, now aren't getting enough to eat. A new study links the decline of the seals to a drop in the krill population, caused by warming oceans.
The development of aircraft over the past century has followed the same patterns as the evolution of flying birds, says an engineer who seeks to apply the laws of physics to evolution.
An exquisitely preserved fossil of a shrimplike predator from the Cambrian period has been unearthed in China.