The physics of fluids explains how crowds of marathon runners move

Marathoners queuing up for a big race tend to go with the flow, surging toward the start line like a fluid. Using footage of runners moving in groups toward the start of the Chicago Marathon, researchers developed a theory that treats the crowd like a liquid to explain its movement. The theory correctly predicted the ... Read more

Treating cystic fibrosis patients before birth could safeguard organs

A drug that treats a rare form of cystic fibrosis may have even better results if given before birth, a study in ferrets suggests. The drug, known by the generic name ivacaftor, can restore the function of a faulty version of the CFTR protein, called CFTRG551D. The normal CFTR protein controls the flow of charged ... Read more

How scientists took the first picture of a black hole

Black holes are extremely camera shy. Supermassive black holes, ensconced in the centers of galaxies, make themselves visible by spewing bright jets of charged particles or by flinging away or ripping up nearby stars. Up close, these behemoths are surrounded by glowing accretion disks of infalling material. But because a black hole’s extreme gravity prevents ... Read more

Here’s how polar bears might get traction on snow

Tiny “fingers” can help polar bears get a grip. Like the rubbery nubs on the bottom of baby socks, microstructures on the bears’ paw pads offer some extra friction, scientists report November 1 in the Journal of the Royal Society Interface. The pad protrusions may keep polar bears from slipping on snow, says Ali Dhinojwala, ... Read more

Common, cheap ingredients can break down some ‘forever chemicals’

There’s a new way to rip apart harmful “forever chemicals,” scientists say. Perfluoroalkyl and polyfluoroalkyl substances, also known as PFAS, are found in nonstick pans, water-repellent fabrics and food packaging and they are pervasive throughout the environment. They’re nicknamed forever chemicals for their ability to stick around and not break down. In part, that’s because ... Read more

Why mosquitoes are especially good at smelling you

Some mosquitoes have a near-foolproof thirst for human blood. Previous attempts to prevent the insects from tracking people down by blocking part of mosquitoes’ ability to smell have failed. A new study hints it’s because the bloodsuckers have built-in workarounds to ensure they can always smell us. For most animals, individual nerve cells in the ... Read more

Oort cloud comets may spin themselves to death

Comets from the solar system’s deep freezer often don’t survive their first encounter with the sun. Now one scientist thinks he knows why: Solar warmth makes some of the cosmic snowballs spin so fast, they fall apart. This suggestion could help solve a decades-old mystery about what destroys many “long-period” comets, astronomer David Jewitt reports ... Read more