The lions that roam Africa's savannahs have lost as much as 75 percent of their habitat in the last 50 years as humans overtake their land and the lion population dwindles, said a study released Tuesday.

Researchers at Duke University, including prominent conservationist Stuart Pimm, warn that the number of lions across the continent have dropped to as few as 32,000, with populations in West Africa under incredible pressure.

The Mars rover Curiosity has offered a tantalizing taste of evidence that there was once life on the Red Planet, but scientists said Monday it is too soon to make much of the first soil analyses.

NASA's Sample Analysis at Mars (SAM) instruments have been sending back information as it hunts for compounds such as methane, as well as hydrogen, oxygen and nitrogen, that are the building blocks of life.

NASA's Voyager 1 spacecraft has encountered a "magnetic highway" at the edge of the solar system, a surprising discovery 35 years after its launch, the experts behind the pioneering craft said Monday.

Earlier this year a surge in a key indicator fueled hopes that the craft was nearing the so-called heliopause, which marks the boundary between our solar system and outer space.

U.N. climate negotiators bickered in Doha on Monday over cash and commitments needed to curb Earth-warming greenhouse gases, even as fresh alarm bells were rung about the perils the planet faces.

Halfway through 11-day talks, nearly 200 nations remained far apart on issues vital for unlocking a global deal on climate change, said delegates at the talks in Qatar's capital.

European scientists said on Monday they had found tantalizing clues to back theories that Venus -- Earth's cursed sister -- has active volcanoes.

Mapping of the desolate surface of Venus shows the second planet from the Sun to be studded with more than a thousand volcanoes.

The amount of heat-trapping pollution the world spewed rose again last year by 3 percent. So scientists say it's now unlikely that global warming can be limited to a couple of degrees, which is an international goal.

The overwhelming majority of the increase was from China, the world's biggest carbon dioxide polluter. Of the planet's top 10 polluters, the United States and Germany were the only countries that reduced their carbon dioxide emissions.

A New Zealand researcher Monday claimed to have solved the riddle of a mystery South Pacific island shown on Google Earth and world maps which does not exist, blaming a whaling ship from 1876.

The phantom landmass in the Coral Sea is shown as Sandy Island on Google Earth and Google maps and is supposedly midway between Australia and the French-governed New Caledonia.

A few hundred people marched in a peaceful demonstration Saturday for "climate justice" in Doha, where negotiators from nearly 200 countries are debating about how to slow global warming and help protect the most vulnerable countries from rising seas and other impacts of climate change.

Waving banners saying "Stop climate change" and "Arabs reduce emissions," the well-behaved crowd marched along the Qatari capital's Corniche, a waterfront walkway lined by gleaming skyscrapers.

Australia has unveiled a new radio telescope in the remote outback that will give the world a vastly improved view of the sun and much faster warnings on massive solar storms.

The Murchison Widefield Array (MWA) radio telescope will detect flares on the sun's surface that could damage communication satellites, electricity power grids and GPS navigation systems, director Steven Tingay said Saturday.

Astronomers are reporting a find that challenges traditional theories as to how rocky planets -- such as Earth -- are formed.

Besides Earth, our solar system has three other rocky planets: Mercury, Venus and Mars. They have a solid surface and core of heavy metals, and differ from planets that are large spinning bodies of gas, like Jupiter or Saturn.