A decade-long study of Greenland's glaciers suggests they may not be melting as quickly as thought, leading to a slower sea-level rise than worst-case predictions, said a study on Thursday.

How fast glaciers melt depends in large part on how fast they move, and the research in the journal Science shows the glaciers may lead to a sea level rise of 0.8 meters (2.6 feet) by 2100, not two meters (6.5 feet) as some have estimated previously.

The first attempt by a private company to send a cargo-loaded spacecraft to the International Space Station was delayed again on Wednesday and a new launch date remains uncertain, SpaceX said.

The planned May 7 launch has been postponed while engineers work out software issues, said SpaceX spokeswoman Kirstin Grantham.

Scanning the horizon on his solar-powered catamaran, Swiss electrical engineer Raphael Domjan counts down the hours to the completion of his record-breaking world tour.

"The idea was not to perform a feat but an eco-adventure with the aim of passing on the message that change is possible," Domjan told Agence France Presse-TV as his boat furrowed through choppy waves from Italy's Elba Island to Corsica in France.

Sheep-sized relatives of modern-day wombats lived in Australian treetops 15 million years ago, a paleontologist said Thursday as she was honored for her discovery.

Karen Black, from the University of New South Wales, said her team discovered the world's largest tree-climbing marsupial among fossils found at the Riversleigh World Heritage Site in Queensland state.

Scientists have witnessed the rare spectacle of a supermassive black hole devouring a star that had ventured too close -- an event that occurs about once in 10,000 years, they reported on Wednesday.

Matter-sucking black holes normally lurk dormant and undetected at the center of galaxies, but can occasionally be tracked by the scraps left over from their stellar fests.

Large, plant-eating dinosaurs were already in decline by the time a space rock smashed into Earth 65 million years ago and ended the reptiles' long reign, a study published on Tuesday says.

The findings by scientists in the United States and Germany do not dispute the mass extinction that so dramatically ended the Cretaceous era.

Oetzi, the 5,300-year-old "Iceman" mummy of the Alps, lived for some time after being shot in the back by an arrow, scientists said on Tuesday after using forensic technology to analyze his preserved blood.

Contrary to a leading theory, Oetzi did not expire immediately from his wounds, they reported in the Journal of the Royal Society Interface, published by Britain's academy of sciences.

Earthquake monitors, sound wave detectors and sensors on planes that pick up airborne traces of atomic material are all ways that global scientists will know within minutes if North Korea conducts a nuclear test.

The ability of global scientists to detect such events has improved since the hermit state's last two nuclear tests in 2006 and 2009. Scientists today, for example, have a larger network of worldwide seismology stations and more sensitive instruments, experts say.

Twenty Greenpeace activists chained themselves to an icebreaker in Helsinki's harbor on Wednesday in a bid to block Anglo-Dutch oil giant Shell's plans to drill for oil in the Arctic.

The activists want "to try to prevent the ship from leaving for Alaska by peaceful means," Greenpeace Nordic spokesman Juha Aromaa told Agence France Presse.

Scientists have long accepted that gas from farm animals is a major factor in climate change, but how do you stop cattle and sheep from doing what comes naturally?

That's the question consuming researchers in New Zealand who hope that by measuring every belch and bleat of their sheepish subjects they can come up with a solution.