Africa's savannahs and the lions that roam there are disappearing at an alarming rate as ballooning human populations deprive the big cats of their natural habitat, a study released Tuesday showed.

About 75 percent of the continent's savannahs and two-thirds of the lion population have vanished over the past 50 years, according to researchers at Duke University in North Carolina.

NASA plans to send a new rover to Mars in 2020 as it prepares for a manned mission to the Red Planet, the U.S. space agency said Tuesday.

The announcement came a day after NASA released the results of the first soil tested by the Curiosity rover, which found traces of some of the compounds like water and oxygen that are necessary for life.

Australian researchers are working on a new breed of pineapple -- one that is not only sweet and juicy but which has the added tropical taste of coconut.

In what is thought to be a world first, the Department of Agriculture in Queensland state is in the final stages of developing the new variety of the fruit, to be known as the AusFestival pineapple.

Salmon that is genetically modified to grow twice as fast as normal could soon show up on dinner plates — if the company that makes the fish can stay afloat.

After weathering concerns about the safety and environment impact of the salmon, Aquabounty in 2010 was to poised to become the world's first company to sell fish whose DNA has been altered to speed up growth. But the a government agency has not approved the fish, and Aquabounty is running out of money.

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.