Decades-Long Quest Reveals Details of the Proton’s Inner Antimatter

Physicists have glimpsed an imbalance in the types of antimatter that swim in the sea of quarks and gluons that make up the proton. A shoestring experiment 20 years in the making, called SeaQuest, has found that there are more down antiquarks than up antiquarks in the proton sea: on average, 1.4 down antiquarks for every up antiquark. The asymmetry could help to decide which of the competing theoretical models of the proton will come out on top.

Life-size kangaroo is Australia’s oldest discovered art

A kangaroo painted in red ochre in a rock shelter in remote northwestern Australia is at least 17,100 years old — the oldest rock art yet dated on the continent. It’s difficult to determine the age of Australian rock art because the region’s ancient artists didn’t tend to use organic materials that can be radiocarbon dated. In this case, researchers analysed fossilised mud-wasp nests laying over and under the art. Alongside the kangaroo, the richly decorated cave includes images interpreted as a boomerang, a reclining human figure and a 3-metre-long snake.

No sign of Planet Nine

The hypothesis that there is a giant planet at the fringes of the Solar System has been dealt a blow by an analysis of distant, icy objects. The findings cast doubt on the evidence that the six trans-Neptunian objects (including Pluto) are under the gravitational pull of a huge planet. The research doesn’t rule out the possibility of a ninth planet orbiting the Sun, and astronomers need more data to put the debate to rest.

Million-year-old mammoth genomes shatter record for oldest ancient DNA

Mammoth teeth preserved in eastern Siberian permafrost have produced the oldest DNA on record. The DNA was extracted from tooth specimens that are up to 1.6 million years old. The DNA identifies a new kind of mammoth that gave rise to a later North American species. The research pushes the technology close to its limits. Once an organism dies, its chromosomes shatter into pieces that get shorter over time. Eventually, the DNA strands become so small that — even if they can be extracted — they lose their information content. The mammoth teeth were preserved in the constant cold of permafrost, which slows DNA fragmentation.

Three quantum devices linked in a network

Physicists have taken a major step towards a future quantum version of the Internet by linking three quantum devices in a network. Although the network doesn’t yet have the performance needed for practical applications, it demonstrates a key technique that will enable a quantum Internet to connect nodes over long distances. A quantum Internet would enable ultrasecure communications and unlock scientific applications, such as new types of sensors for gravitational waves.

Evidence of Unknown Human Species Found in DNA of Melanesians

Scientists found traces of a previously unknown, long-extinct human species hidden in the DNA of today's Melanesians. The two ancient hominid species whose DNA traces scientists expected to find were the Neanderthals and Denisovians. But the results of the study showed something else.

Researchers rethink life in a cold climate after Antarctic find

Sponges and other animals have been discovered on a boulder under 900 metres of ice and 500 metres of water in Antarctica. The creatures were spotted by chance by an underwater camera, after researchers drilled through the Filchner-Ronne ice shelf to obtain a sediment core from the sea bed. No sunlight reaches the animals, and they are thought to live on food carried hundreds of kilometres from the nearest light.

Stonehenge Built From An Earlier Stone Circle?

Stonehenge might have been built from an earlier stone circle: Waun Mawn in west Wales. Stonehenge’s majestic bluestone pillars had already been traced to their source. The stones were excavated from quarries in Wales as early as 3400 BC, about 500 years before Stonehenge was built. Now, researchers have used carbon dating and other techniques to suggest that similar stones that once stood in Waun Mawn were removed at just about the time the first construction at Stonehenge began. The findings further develop a picture of an interconnected society centered on the Irish Sea that flourished in the fourth century BC.