A volcano erupted Friday near the capital of Costa Rica, choking surrounding communities with smoke and ash.

In the capital San Jose, 30 kilometers (19 miles) from the Turrialba volcano, the air reeked of sulphur as dust and ash coated buildings and vehicles.

Monster tsunamis caused by meteor impacts swept across the northern plains of Mars more than three billion years ago, radically resculpting the edges of the Red Planet's ancient seas, according to a study published Thursday.

Australia's Great Barrier Reef could be beyond saving in five years without "now or never" funding to improve water quality as climate change ravages the World Heritage-listed site, scientists warned Thursday.

Australian scientists have found evidence of a huge asteroid they say slammed into Earth some 3.46 billion years ago -- making it the second oldest known to have hit the planet and larger than the one blamed for wiping out the dinosaurs.

Andrew Glikson, from the Australian National University's Planetary Institute, said that while the asteroid would have been massive, the exact location of where it hit was not known.

The Solar Impulse 2 plane touched down in Tulsa, in the south-central U.S. state of Oklahoma late Thursday, ending the latest stage of its record-breaking quest to circle the globe without consuming a drop of fuel.

The experimental solar-powered aircraft, aimed at promoting clean energy technologies, landed at 11:17 pm local time (0417 GMT) at Tulsa International Airport after taking off at 3:00 am (1000 GMT) from Phoenix, Arizona, live feed showed.

The Solar Impulse 2 plane took off from Phoenix, Arizona en route to Oklahoma on Thursday, resuming its record-breaking quest to circle the globe without consuming a drop of fuel.

Allowing the legal culling of wild wolves in order to discourage illegal poaching is counter-productive, researchers reported Wednesday in a study that challenges long-practiced conservation strategy.

During a 15-year period when wildlife management policies in two US states flipped half-a-dozen times, growth in wolf populations slowed systematically whenever culling was permitted, even after controlling for the number of animals legally killed, they found.

Astronomers celebrated Monday witnessing one of the highlights of the skywatchers' year, when the Sun, Mercury and Earth all lined up -- a phenomenon that happens just a dozen or so times per century.

Mercury was seen through telescopes as a black dot inching over the face of our star, providing a celestial spectacle lasting seven and a half hours.

Scientists unveiled Monday the gene in carrots that gives rise to carotenoids, a critical source of Vitamin A and the pigment that turns some fruits and vegetables bright orange or red.

The world's most powerful proton smasher is preparing for its biggest run yet which scientists hope will uncover new particles that could dramatically change our understanding of the Universe.