Hundreds of circles, squares, and other geometric shapes once hidden by forest hint at a previously unknown ancient society that flourished in the Amazon, a new study says.

By "pushing Hubble to the limit," astronomers have created the deepest view yet of the universe, revealing tiny, blue galaxies that are now the earliest known.

Many Chinese tourist attractions are secretly operating as fronts for illegal tiger farming, butchering captive tigers for the multibillion-dollar black market in wildlife parts, conservationists say.

NASA's new Kepler space telescope has already spotted five new planets, each hotter than molten lava and one as dense as Styrofoam.

Built to rove for 90 days, Spirit has lasted six years on Mars. But now it's stuck and may lose power by May. Even standing still, though, Spirit can do a surprising amount of science, NASA says. Video.

Global warming, or climate change, is a subject that shows no sign of cooling down. Here's the lowdown on why it's happening, what's causing it, and how it might change the planet. Includes photo gallery.

On New Year's Day a mysterious disk eclipsed a bright star—and won't let up for 18 months. Now scientists hope to test an idea that might solve the centuries-old puzzle behind the phenomenon.

A planet-forming disk has its temperature taken, a satellite spies on Fiji's mangrove forests, bright blemishes hint at increased action on the sun, and more in our selection of the week's best space pictures.

Undersea carbon dioxide reservoirs could store massive amounts of the potent greenhouse gas near eastern U.S. cities—but may also pose an earthquake risk, a new study says.

Today animated apples are tumbling on Google—a birthday tribute to Isaac Newton, father of gravitational theory and so much more. Find out why he still matters.

An unusually long cooling of the Pacific Ocean lowered temperatures across North America—but it's not proof that global warming has slowed down, scientists say.

Millions of doses of the H1N1/09 vaccine contain a substance called squalene, which is extracted from the livers of rare deep-sea sharks caught in the wild, conservationists say.

Earth's north magnetic pole is racing toward Russia at almost 40 miles (64 kilometers) a year due to magnetic changes in the planet's core, new research says.

Dolphin "drive" hunts, a bloody tradition denounced in the recent documentary <i>The Cove,</i> continue in Japan and Denmark's Faroe Islands.

A new program in Japan is helping giant salamanders get past dams built to control flooding so the rare amphibians can lay their eggs upstream. Video.