Extreme heat in Australia forced the government's weather bureau to upgrade its temperature scale Tuesday, with new colors on the climate map to reflect new highs forecast next week.

Central Australia was shown with a purple area on the latest Bureau of Meteorology forecast map issued for next Monday, a new color code suggesting temperatures will soar above 50 degrees Celsius (122 Fahrenheit).

It's a six-month expedition in almost constant darkness, in the coldest place on the planet, with no chance of rescue if things go wrong. British explorer Sir Ranulph Fiennes calls it one of the last remaining polar challenges: crossing Antarctica during the region's winter.

Against the backdrop of Cape Town's majestic Table Mountain, Fiennes, 68, and his five-member team left the South African port city on Monday aboard a South African polar vessel, the SA Agulhas, for what they have dubbed "The Coldest Journey."

A new estimate released Monday suggests that the Milky Way galaxy is home to at least 17 billion planets similar in size to Earth.

It doesn't mean all are potentially habitable, but the sheer number is a welcome starting point in the search for worlds like our own.

Adventurer Sir Ranulph Fiennes said Sunday his bid for the world's first Antarctic winter crossing, with no option of rescue, would be a trip into the unknown despite his multiple record expeditions.

Known as the world's greatest living explorer, Fiennes will depart Monday for the coldest place on Earth.

Scientists and broadcasters said Monday they have captured footage of an elusive giant squid up to eight meters (26 feet) long that roams the depths of the Pacific Ocean.

Japan's National Science Museum succeeded in filming the deep-sea creature in its natural habitat for the first time, working with Japanese public broadcaster NHK and the U.S. Discovery Channel.

Scientific experts have greenlighted the restart of two Belgian nuclear power plants despite signs of micro-cracks in reactor vessels, the daily Le Soir said Saturday.

No independent confirmation was immediately available from Belgium's nuclear safety authority, AFCN.

Spaceport America officials are urging legislators to limit potential lawsuits from wealthy outer space tourists who take off from New Mexico, saying such a bill is crucial to the future of the project.

Legal experts, however, say there is no way to know whether the so-called informed consent laws will offer any protection to spacecraft operators and suppliers in the event something goes wrong.

The world's largest and most powerful atom smasher goes into a 2-year hibernation in March, as engineers carry out a revamp to help it reach maximum energy levels that could lead to more stunning discoveries following the detection of the so-called "God particle."

With the reopening of its $10 billion proton collider in early 2015, the stage will be set for observing more rare phenomena — and unlocking more mysteries, said James Gillies, chief spokesman for the European particle physics laboratory known as CERN.

The sight of two dolphins twisting playfully in the murky waters of the Mekong river elicits barely-stifled squeals of delight from a boatload of eco-tourists.

But a short distance upstream, river guard Pech Sokhan sighs as he holds up two large, tangled gill nets recently pulled from the river -- evidence old habits die hard despite a ban on the practice that ensnares many dolphins.

Australia's southern island of Tasmania has experienced its hottest day since records began, with the capital Hobart sweltering at 41.8 Celsius (107.2 Fahrenheit) on Friday.

The Bureau of Meteorology said the temperature in Tasmania, where records have been kept since the early 1880s, beat the previous high of 40.8 Celsius set in January 1976.