Wild giraffe numbers have plummeted by 40 percent in the last three decades, and the species is now "vulnerable" to extinction, a top conservation body said Thursday.

The population of the world's tallest land mammal dropped to below 100,000 in 2015, mainly due to habitat loss and illegal hunting, the International Union for the Conservation of Nature (IUCN) reported.

Dark matter, the mysterious substance believed to comprise a quarter of our Universe, is spread out more smoothly than previously thought, said a study Wednesday that may challenge some tenets of physics.

Earth's days are getting longer but you're not likely to notice any time soon -- it would take about 3.3 million years to gain just one minute, according to a study published on Wednesday.

Authorities in Russia's Siberian region of Tuva on Monday were examining several pieces of the Progress cargo spaceship found after it crashed last week having failed to reach orbit.

Two pieces, including a large spherical object, were found by herders over the weekend, while another was discovered in the courtyard of a residential house on Monday, said the region's head Sholban Karaa-ool, warning people not to touch any metal debris.

Retired U.S. astronaut and the second man to walk on the moon, Buzz Aldrin, was recovering after his medical evacuation from Antarctica but is not yet able to return home, his manager Christina Korp said Sunday.

Virgin Galactic's new spaceship has made a successful first glide flight, a key step after a deadly crash of its predecessor two years ago, the spaceflight company said on Saturday.

The new SpaceShipTwo, dubbed VSS Unity, was hoisted aloft by carrier airplane WhiteKnightTwo VMS Eve from the Mojave Air & Space Port in California, the company said on Twitter.

An unmanned cargo ship traveling to the International Space Station burned up in the atmosphere shortly after launching Thursday, the Russian space agency said, raising concerns over space travel safety.

Struck by the legendary sniffing skills of man's best friend, scientists in the United States fitted a dog-inspired plastic nose to an explosives detector, and reported Thursday it worked much better.

Buzz Aldrin, the 86-year-old retired U.S. astronaut who was among the first men to walk on the Moon, has been evacuated from the South Pole for medical reasons, officials said Thursday.

Aldrin was visiting the South Pole as part of a tourist group, when his "condition deteriorated," said a statement from the operator, White Desert.

The periodic table got larger Wednesday after four new elements were officially named and added to the chart, including 'nihonium' -- the first ever to be discovered by Japanese scientists.

The new name for element 113, a highly radioactive element with an extremely short half-life, comes from Japan's name in Japanese -- 'nihon', literally 'the land of the rising sun'.