For the past two decades, the U.S. space agency has been practically obsessed with Mars. It has hardly missed an opportunity about every two years to fling robotic spacecraft at the red planet.

This summer, the most high-tech rover ever, Curiosity, will land near the Martian equator in search of the chemical building blocks of life. The more scientists study Mars, the closer they get to answering whether microbial life once existed there, a clue to the ultimate question: Are we alone?

Farm workers swing their sickles through red branches, bundling them up before laying them out in the sunshine to dry.

The annual harvest at Groenkol Rooibos tea estate, in South Africa's Western Cape helps quench the world's growing thirst for "red bush" tea, but farmers fear that climate change could destroy the delicate eco-system that their crop depends on.

An explosion caused by a fire left one navy personnel wounded and two others missing at a Brazilian base in Antarctica early Saturday and forced dozens of researchers to evacuate, authorities said.

The Brazilian Navy said the fire broke out in a room housing energy generators of the Comandante Ferraz Antarctic Base, a research station located in Admiralty Bay, King George Island, near the tip of the Antarctic Peninsula.

The World Bank on Friday said the world's oceans were at risk and called for a coalition of governments, NGOs and other groups to protect them, aiming to raise $1.5 billion in five years.

"The world’s oceans are in danger," from over-fishing, marine degradation and loss of habitat, World Bank president Robert Zoellick said. "Send out the S-O-S: We need to Save Our Seas."

Stargazers of the world are getting a treat this weekend.

On Saturday and again Sunday, Venus, Jupiter and Earth's moon converge for a brilliant night show.

The collapse of the Mayan civilization was likely due to a relatively mild drought, much like the drier conditions expected in the coming years due to climate change, scientists said Thursday.

Scholars have long believed that a major drought caused severe dry conditions that killed off the ancient culture known for its mastery of language, math and astronomy.

More than 50 million years ago, the Earth was a hotter place than it is today and horses the size of pet cats roamed the forests of North America, U.S. scientists said on Thursday.

These earliest known horses, known as Sifrhippus, actually grew smaller over tens of thousands of years in order to adapt to the higher temperatures of a period when methane emissions spiked, possibly due to major volcanic eruptions.

A new species of lizard with striking iridescent rainbow skin, a long tail and very short legs has been discovered in the rainforest in northeast Cambodia, conservationists announced.

Scientists named the skink Lygosoma veunsaiensis to honor theVeun Sai-Siem Pang Conservation Area in Rattanakiri province where it was found, Conservation International (CI) said in a statement.

Australian researchers Thursday revealed they had filmed a pod of extremely rare Shepherd's beaked whales for the first time ever.

The Australian Antarctic Division team was tracking blue whales off the coast of Victoria state last month when they spotted the reclusive mammals, which are so rarely seen that no population estimates of the species exist.

Theories that men will eventually become extinct because the Y chromosome which determines maleness is shrinking are quite wrong, according to a gene study published on Wednesday.

The men-are-doomed scenario leapt to prominence nearly a decade ago when scientists found that the male chromosome had dramatically shriveled.