A hidden black hole reveals itself, and Kazakhstan's tiger comes home

It gave itself away the only way a quiet black hole can, by shredding a star that wandered too close and throwing off a brief, brilliant flare, caught by the Zwicky Transient Facility's twin telescopes at Palomar Observatory during their every-two-days sweep of the northern sky. An AI system sifted through the hundreds of thousands of transients the survey records each night to flag the one worth a second look. Astronomers had long suspected wandering black holes exist, flung to galactic outskirts by mergers and collisions, but a quiet one is invisible until it eats something. "This discovery will have a huge impact," said co-author Suvi Gezari. "It means that we're going to find many more examples of wandering black holes."

Looking at arthropods, insects, spiders, crabs, centipedes, the team found sperm cells in many species linking into coordinated groups, using a membrane-bound material that binds them the way a rowing crew moves in sync. The behavior evolved independently, and disappeared independently, many separate times across hundreds of millions of years. "Fertilization is often viewed as a competition among individual sperm, but in many species we see cells working together in ways that can influence reproductive success," says Syracuse biologist Steve Dorus.

After two months, the group taking the supplement lost 2.6 kilograms on average, about 3 percent of body weight, while the placebo group gained half a kilogram. Blood tests explained why: the supplement more than doubled participants' GLP-1, the same appetite-suppressing gut hormone that drugs like semaglutide are built to mimic. The placebo group also reported more nausea and bloating than the people taking dead bacteria for breakfast.

Half also took a nightly syrup made from 1,100 milligrams of dried basil leaf extract; the rest took a placebo. The basil group saw larger drops in both mood and worry symptoms. Compounds in basil, including linalool and eugenol, are thought to act on the same brain pathways that calm stress responses, something animal studies had hinted at but never confirmed this directly in people with depression.

Andrew Glover and colleagues at Imperial College London, working with REACH Malaria, Université Cheikh Anta Diop, and the Global Fund, built a model using real household survey data to identify where more frequent net drops, or nets treated with two different insecticides to fight resistance, would prevent the most cases per dollar.

Reaching this moment took a decade: the reserve was established in 2018 for exactly this purpose, and officials have since reforested the area and rebuilt the food web a tiger needs, Bukhara deer starting in 2020, then saiga antelope and the kulan, a wild ass. Hope was joined by a male named Amur and two cubs from Russia's Khabarovsk Reserve; all four adjusted to the reserve's sights and smells in large enclosures before Hope, fitted with a GPS collar, was cleared to go it alone. The male stays captive a while longer while experts confirm he can hunt on his own, and the cubs will grow up semi-wild until they're old enough, around 18 months, to be tested and released.

With support from India's National Dairy Development Board, all 368 cattle-owning households got a biogas plant, a simple system turning cattle dung and water into cooking gas plus a nutrient-rich slurry. Families stopped burning wood and buying LPG cylinders. Then the village's women organized the country's first all-women manual cooperative to process and sell that leftover slurry as organic fertilizer, earning each household an extra 3,000 to 5,000 rupees a month.

The physics is called Kelvin-Helmholtz instability, and it happens when two fluids moving at different speeds slide past each other and twist into vortices. "The vortex formation on the Sun has long been a central question in solar physics. For the first time, we have identified both their origin and their driving mechanism," said lead author David Kuridze of the National Solar Observatory. The team pointed the telescope at a magnetically active patch beside a large sunspot to catch it happening.