Recycling of household waste has tripled in Europe over the past decade but some countries are dragging their feet for meeting a target set for 2020, the European Environment Agency (EAA) said in a report issued on Tuesday.

From 2001 to 2010, recycling of materials and composting of organic waste in the 27 nations of the European Union (EU) rose from 13 percent of the total to 39 percent.

The Mars rover Curiosity is sidelined again, further delaying the restart of science experiments, after recovering from a computer problem.

The latest complication occurred over the weekend when the six-wheel rover entered safe mode after experiencing a software file error.

Greener cars that use alternative fuels could help the United States slash its greenhouse gas emissions from everyday driving a full 80 percent by 2050, according to a scientific study out Monday.

That could lead to a more than 13 percent cut in overall U.S. pollution into the atmosphere, with consumer-driven cars and small trucks currently responsible for 17 percent of the nation's greenhouse gas emissions, said the study.

Photos and mementoes that were snatched up and blown hundreds of miles during tornados in the south of the United States two years ago are giving researchers new insight on how debris is carried by the storms and how it could threaten the public.

A new study has documented how one photo traveled nearly 220 miles (355 kilometers) over Alabama and Tennessee, said John Knox, an associate professor of geography at the University of Georgia who led the research. That is among the longest-documented trajectories of tornado debris.

Solid gold can be deposited in Earth's crust "almost instantaneously" during earthquakes, said a study published in the journal Nature Geoscience on Sunday.

The gold is formed when a tremor splits open a fluid-filled cavity in the Earth's crust, causing a sudden drop in pressure, according to a team of Australian researchers.

Scientists said Sunday they had discovered an unexpectedly large and active community of single-cell organisms living on the Pacific sea floor at the deepest site on Earth.

The "surprisingly active" community of microbes exists about 11 kilometers (seven miles) below sea level in the Mariana Trench, one of the world's most inaccessible places, some 200 miles southwest of the Pacific island of Guam.

Oil-rich Abu Dhabi on Sunday officially opened the world's largest concentrated solar power plant, which cost $600 million to build and will provide electricity to 20,000 homes.

The 100-megawatt Shams 1 is "the world's largest concentrated solar power plant in operation" said Sultan al-Jaber, the head of Abu Dhabi's Masdar, which oversees the emirate's plan to generate seven percent of its energy needs by 2020 from renewable sources.

The fossilized remains of a giant pelican-like bird dating back some 35 million years have been uncovered in Peru's Ica desert, paleontologists said Friday.

Klaus Honninger, who heads the team that made the find, said the bird resembled a giant pelican that stood more than two meters (6.6 feet) tall dating from the Oligocene epoch.

Diverse underground ecosystems buried deep beneath the Earth's crust may offer clues to the origins of life on Earth, several recent studies have revealed.

Whether it is tiny worms found wriggling in the depths of a South African mine or micro-organisms discovered six kilometers (3.7 miles) under the surface in China, subterranean life forms are found everywhere.

Three astronauts returned safely to Earth from the International Space Station early Saturday, aboard a Russian capsule which landed on the freezing Kazakhstan steppe, mission control said.

"There is landing!" flashed a Russian mission control center message transmitted by NASA. Rescue teams rushed to recover the capsule carrying NASA U.S. astronaut Kevin Ford and Russian cosmonauts Oleg Novitskiy and Evgeny Tarelkin.