A huge, five-million-year-old whale tooth has been discovered on an Australian beach, providing the first evidence of the now extinct killer sperm whale outside the Americas.

The 30-centimeter-long (12-inch) fossilized tooth, which is larger than that of a Tyrannosaurus rex, was found by a fossil enthusiast at Beaumaris Bay near Melbourne in February.

What happens when the site of the world's worst nuclear accident is left all but abandoned for nearly 30 years?

In the case of Chernobyl, it becomes a unique chance to see how wildlife recovers in what is a giant nature reserve, bereft of humans but tainted by radiation.

Igor Magala can still remember the metallic taste he got in his mouth as he drove up to the Chernobyl nuclear power station on the morning of April 26, 1986.

The night before, Magala -- the deputy construction boss at the plant -- had received a phone call telling him there had been an accident and summoning him in to help, but he had few other details.

The growth of genetically-modified crops has dipped for the first time following two decades of steady increases, according to a study released Wednesday.

Twenty years after the first genetically-modified plant was marketed, the worldwide acreage of GM crops reached 181.5 million hectares in 2014.      

China's top geneticists say the country should set its own standards and regulations on human genome research, state-run media reported Wednesday, as ethical debate erupted over a Chinese study on modified human embryos.

Researchers from Guangzhou Medical University said they used a gene-editing technique known as CRISPR to artificially induce a mutation in human cells and make them resistant to HIV, the virus that causes AIDS. 

SpaceX's unmanned Dragon cargo ship, carrying lettuce seeds, lab mice and an inflatable pop-up room, arrived Sunday at a crowded International Space Station where six spacecraft are now docked.

British astronaut Tim Peake reached out with the station's robotic arm and grappled the Dragon, carrying its nearly 7,000 pounds (3,175 kilograms) of gear, at 7:23 am (1123 GMT).

After four failed bids SpaceX finally stuck the landing Friday, powering the first stage of its Falcon 9 rocket onto an ocean platform where it touched down upright after launching cargo to space.

Images of the tall, narrow rocket gliding down serenely onto a platform that SpaceX calls a droneship sparked applause and screams of joy at SpaceX mission control in Hawthorne, California.

Winter is coming, and like many scientists posted in Antarctica, Bogdan Gavrylyuk is looking forward to going home.

It has been a year since the 43-year-old Ukrainian geophysicist started his latest posting, monitoring climatic phenomena on an island off western Antarctica.

Tigers are "functionally extinct" in Cambodia, conservationists conceded for the first time on Wednesday, as they launched a bold action plan to reintroduce the big cats to the kingdom's forests.

Cambodia's dry forests used to be home to scores of Indochinese tigers but the WWF said intensive poaching of both tigers and their prey had devastated the numbers of the big cats.

The skimmer is lowered from the rear of the icebreaker, its weight pushing massive pieces of ice under the water and forcing the spilt oil up to the surface, where the sticky black goo can be sucked up.

Luckily, this is just a test: as the world's superpowers eye the lucrative Arctic region with growing interest, unprecedented oil spill clean-up tests in icy Finnish conditions reveal just how hazardous and challenging an accident in the Arctic's pristine sea ice could be.