Science

On a large table draped with hundreds of cables, a maze of mirrors and lenses bounces and guides a thin beam of laser light. It culminates at a silvery capsule, which holds 40,000 strontium atoms cooled to within a whisker of absolute zero. This delicate edifice is an optical clock, one of the world’s most accurate timepieces. Instruments like this aren’t exactly designed to be portable – which makes it more than a little surprising that the operators of one such device at the German national metrology institute packed it into a trailer and sent it hurtling down a motorway. It was the start of a perilous journey: a bad jolt could disrupt the beat of its precise ticks. But it was necessary. That was because, in 2022, scientists globally agreed that we should start work...

Atomic clocks record time using microwaves at a frequency matched to electron transitions in certain atoms. They are the basis upon which a second is defined. But there is a new kid on the block, the optical clock, which boasts even higher accuracy. Is it time to redefine the second? Optical clocks can reach accuracies at the level of 10-18 , “which is a number so accurate that if the clock started running at the big bang, by now it will have lost 1 second”, says Alexandra Tofful, an optical clock physicist at the National Physical Laboratory (NPL) in London, which oversees scientific measurement standards in the UK. Unlike atomic clocks, this new type of timekeeper probes electron transitions with light. “Because visible l...

Archaeologist Kristina Douglass studies how past human adaptation can inform solutions to today’s climate challenges. She and her team work in southwest Madagascar’s Velondriake Marine Protected Area, investigating how communities have adapted to environmental variability over thousands of years. They study archaeological sites, analyze remote sensing data and conduct oral histories to reveal the ways in which Indigenous communities have managed their landscapes and resources sustainably. “It’s like being in a library of human experience and looking for the perfect book to deal with a question that has just come up today,” says Douglass, who is a Columbia Climate School professor and a research scientist at the Lamont-Doherty Earth Observatory. “I really like to think of our wo...

Smartphones can be a distraction from other tasksPheelings media/Shutterstock Do you find yourself distracted at work, turning to your smartphone for a bit of mindless scrolling? One solution is to put your phone out of reach – but unfortunately, it seems this may not work. “People turn their phone upside down, hide it under a notebook, sometimes you see the slightly fatalistic ‘throw it over my shoulders behind me’,” says Maxi Heitmayer at the London School of Economics. He has previously studied phone use and found that people interact with their devices about every 5 minutes. To see if this distraction can be avoided, Heitmayer recorded 22 university students and office workers, aged between 22 and 31, working as usual on their laptops on a desk in a private ro...

Melting glaciers can have profound effects on nations all over the world—from mountain communities to small island states. At the U.N. headquarters in New York on Friday, March 21, U.N. General Assembly President Philémon Yang closed the proceedings of the inaugural World Glacier Day with a stark warning: “We cannot afford to wait, we must act before the ice disappears…before our glaciers all disappear.”  Alphabetically arranged flags outside the United Nations Headquarters in New York. Credit: Joseph Griffiths  The event was held in the Trusteeship Council Chamber, a space used from the 1940s through the 1990s to oversee the decolonization of territories under the administration of the U.N. The location was symbolic, since the chamber has long been associated with international coop...