Virgin Galactic's passenger spaceplane, which is designed to take tourists to the edge of space, flew its first rocket-powered test flight Monday, breaking the sound barrier at high altitude.

SpaceShipTwo ignited its engine after being released by WhiteKnightTwo, a plane that carried it to 47,000 feet (14,000 meters) above California's Mojave desert, British billionaire Richard Branson's firm said in a statement.

The U.N.'s climate chief called for urgency Monday as she opened a new round of global talks amid warnings that Earth-warming carbon dioxide levels were approaching a symbolic threshold never seen in human history.

Data from the Mauna Loa Observatory in Hawaii have shown the concentration of CO2 in the atmosphere to be at 399.72 parts per million (ppm), Christiana Figueres told climate negotiators in Bonn.

Conservationists accused Australia of failing to protect the Great Barrier Reef from massive industrial development as they launched a multi-million dollar campaign to drum up awareness.

The move follows UNESCO demanding decisive action to protect the world's largest coral reef from a gas and mining boom and increasing coastal development, or risk the embarrassment of seeing it put on its danger list.

Russian astronauts will take an unlit Olympic torch on a space walk ahead of the country's hosting of the 2014 Winter Olympics in Sochi, the deputy head of the Russian space agency said on Sunday.

"It will not be a copy but exactly the same as the torch at the Olympics," deputy head of Russia's space agency Roscosmos, Vitaly Davydov, told the Interfax news agency.

Several dozen Humboldt penguins sun themselves along the coast of an islet in central Chile where the majestic birds coming here to nest once numbered in the thousands.

Humboldt penguins -- which nest only in parts of Chile and Peru -- over the years have become decimated by human encroachment, rat infestations and unforgiving weather currents carried by unusually warm El Nino ocean temperatures, naturalists said.

China is rapidly assuming a global leadership role on climate change alongside the United States, a new study said Monday, but it warned greenhouse gas emissions worldwide continue to rise strongly.

The report by the independent Australian-based Climate Commission, "The Critical Decade: International Action on Climate Change" presents an overview of action in the last nine months.

India will receive normal monsoon rains this year, the government said on Friday, boosting prospects of a stronger performance this year by Asia's third-largest economy.

The pounding rains that sweep across the continent from June to September are dubbed the "economic lifeline" of India, which is one of the world's leading producers of rice, sugar, wheat and cotton.

Poaching on an "industrial" scale has slashed the elephant population in the countries of central Africa by nearly two-thirds, a group of international non-governmental organisations (NGOs) said on Friday.

"A recent study shows that the population of forest elephants has dropped by almost two-thirds or 62 percent in the past 10 years, victims of large-scale ivory poaching," the group of eight NGOs said in a statement.

An unmanned cargo vehicle on Friday successfully docked with the International Space Station, in a delicate manoeuvre after its navigation antenna failed to properly deploy following launch, Russian mission control and NASA said.

Russian cosmonauts Roman Romanenko and Pavel Vinogradov first oversaw a so-called partial "soft docking" of the Progress craft at 1225 GMT, careful to make sure the unopened antenna did not cause any damage.

Some 7,000 light years away, Einstein's theory of general relativity has stood up to its most intense test yet, scientists said on Thursday.

The project involved observing a massive, fast-spinning star called a pulsar, and its companion white dwarf -- a smaller but very dense star that is dying, having lost most of its outer layers -- doing a dizzying orbital dance.