Double-slit experiment performed with molecules

For the first time, scientists have used individual molecules to act as the slits in the iconic double-slit experiment that demonstrates quantum objects behaving as both particles and waves. Researchers created an ultracold molecular beam in which helium atoms collide with deuterium molecules. They used lasers to coax each deuterium molecule into a superimposed state of two different orientations, at right angles. The helium atoms scatter off the superimposed deuterium on two different paths that interfere with each other, showing the quantum interference effect that is characteristic of the classic double-slit experiment. Because the set-up is tuneable, it could be a step towards achieving ‘quantum control’ — which would harness quantum features to manipulate chemical reactions.

Homo naledi infant skull discovery suggests they buried their dead

The first partial skull of a Homo naledi child has been found in the remote depths of the Rising Star cave in South Africa. The bone fragments and teeth belong to a child that died almost 250,000 years ago, when it was approximately 4–6 years old. Palæoanthropologists have named the child Leti after the Setswana word letimela, meaning ‘the lost one’. The remains were found on a ledge in a tiny 20-by-80 centimetre passage — suggesting, that the skull was placed there deliberately, as a form of funerary practice.

Mammoth tusk recovered from deep sea

Scientists at the Monterey Bay Aquarium Research Institute made a surprising discovery while using a remotely operated vehicle (ROV) to explore the waters off California. Not only was it a mammoth tusk, it might be from an animal that died during the Lower Palæolithic era, from which well-preserved specimens are rare. The finding suggests that the ocean floor could be an as-yet-untapped source of palæontological treasures.

First quantum computer to pack 100 qubits

IBM’s newest quantum-computing chip packs in 127 quantum bits (qubits), making it the first such device to reach 3 digits. But the achievement is only one step in an aggressive agenda boosted by billions of dollars in investments across the industry. IBM and other companies — including the technology behemoths Google and Honeywell, and a slew of well-funded start-ups — ultimately aim to make quantum computers capable of performing certain tasks that are out of reach of even the largest supercomputers that use classical technology.

NASA spacecraft will slam into asteroid in first planetary-defence test

NASA will slam a multimillion-dollar spacecraft into an asteroid to test whether it is possible to change a space rock’s trajectory. This is only a test — the asteroid, Dimorphos, is not a threat to Earth. If the mission launches successfully next week, the Double Asteroid Redirection Test (DART) spacecraft will hit Dimorphos at 6.6 kilometres per second late next year. The impact should shrink Dimorphos’s orbit so that it orbits its companion asteroid at least 73 seconds faster than before — a change that will be detectable from Earth. A tiny probe funded by the Italian Space Agency will be launched from DART and will fly past to photograph the aftermath.

Electronegativity’s role in determining bond strengths needs to be rethought

Textbook knowledge about how to determine the strengths of chemical bonds seems to be oversimplified. Chemical bonds are usually stronger between atoms that have a larger difference in their electronegativity — which is influenced by the number of protons in the nucleus and the organisation of the electrons. But in some cases, researchers have found that differences in the sizes of the atom, rather than their electronegativity, determine the bond strength. The stability and length of chemical bonds are key factors in molecules’ structure and reactivity, so understanding them is important for developing everything from pharmaceuticals to materials.

Genes Reveal How Some Rockfish Live up to 200 Years

Some Pacific Ocean rockfishes can live for more than 200 years. Their secret to longevity: slowly growing large in the frigid depths. Researchers have found that the longest-lived rockfishes, a group that includes several species that can live for more than 105 years, have genes that indirectly affect lifespan by influencing size and adaptability. They also have more copies of genes linked to DNA maintenance and resisting the inflammation that often comes with age.

Diamond delivers long-sought mineral from the deep Earth

Small black specks in a diamond mined decades ago in Botswana have turned out to be a vital ingredient of the deep Earth. This is the first time the mineral has been identified in nature, after decades of searching.

Earth’s first continents emerged from the ocean 700m years earlier than thought

Earth’s first continents emerged from the ocean between 3.3 billion and 3.2 billion years ago, before the existence of plate tectonics. An analysis of rock sediments from India places the rise of the first stable continents some 700 million years earlier than previously thought. The rocks might have been formed by lava piling up from continuous volcanic activity on Earth’s crust, and floating above the water like an iceberg.

Astrophysicists unveil glut of gravitational-wave detections

Gravitational-wave observatories have released their latest catalogue of cosmic collisions, including one featuring the lightest neutron star ever detected in this way, as well as two clashes involving surprisingly large black holes. The detections come from the LIGO and Virgo observatories in the United States and Italy, respectively, which made the landmark first detection of gravitational waves in 2015.

Sponge cells hint at origins of nervous system

Sponges are expert filter feeders, straining tens of thousands of litres of water through their bodies every day to collect their food. And they do this without a brain, or a single neuron, to their name. Now, researchers have sequenced the RNA in various individual cells from a freshwater sponge (Spongilla lacustris) and found that sponges use an intricate cell communication system to regulate their feeding and to potentially weed out invading bacteria. The findings could help to understand how animals’ nervous systems evolved.

Honeybees use social distancing when mites threaten hives

Honey bees (Apis mellifera) change the way they interact with one another when infested with the mite Varroa destructor, a pathogen that can cause colony collapse. Researchers in Italy studied video recordings of the inside of hives and found that, in mite-infested hives, older members of the colony performed dances to direct other bees to food sources at the periphery, keeping them away from the centre — where young bees, the queen and brood cells are located. The researchers also observed more grooming activity, which can help to reduce the spread of parasites, at the centre of the infested hives.