General relativity has readers feeling upside down

It’s all relativeIn “Earth is young at heart” (SN: 6/25/16, p. 5), Emily Conover reported that Earth’s core is more than two years younger than the planet’s surface, according to new calculations. Thanks to the effect of gravity on the passage of time, a clock placed at Earth’s core will tick fractions of a second […]

Lack of nutrients stalled rebound of marine life post-Permian extinction

Out-of-reach nutrients could help explain why life on Earth took so long to bounce back from the worst extinction of all time. Analyzing the chemical changes that followed the Permian extinction 252 million years ago, geologists propose that hot sea surface temperatures led to conditions that trapped nitrogen far below the ocean’s sunlit, life-filled layers. […]

Black hole app lets you blow up stars

If you have an appetite for cosmic destruction, there’s an app for that. NOVA Black Holes, a free iPad game developed by the PBS series NOVA, lets you hurl a star at other celestial objects while navigating an increasingly complex minefield of stars, planets and black holes. Each level presents a new target and a […]

Activity trackers fall short in weight-loss trial

Carefully counting steps, stairs and sprints might backfire for some people. At the end of a two-year weight-loss trial, people who used activity monitors had lost less weight than people without the device. The results, described in the Sept. 20 JAMA, are the exact opposite of what researchers expected to find. Going into the study, […]

New era of human embryo gene editing begins

A Swedish scientist is gene editing healthy human embryos, and he is probably not alone, researchers say. Chinese researchers have twice reported editing genes in human embryos that are unable to develop into a baby (SN Online: 4/6/16; SN Online: 4/23/15). But developmental biologist Fredrik Lanner of the Karolinska Institute in Stockholm is the first […]

Rosetta spacecraft lands on comet, ends mission

Rosetta is no more. The comet orbiter touched down on the surface of comet 67P/Churyumov–Gerasimenko at 7:19 a.m. Eastern and immediately shut down, bringing to an end a nearly 26-month mission in orbit around the comet. “I hereby declare mission operations ended,” said Rosetta mission manager Patrick Martin. The landing site has been dubbed Sais, […]

Hot and spicy pain signals get blocked in naked mole-rats

Like Marvel’s surly superhero Luke Cage, naked mole-rats are seemingly indestructible, hairless creatures that are impervious to certain kinds of pain. This last power has puzzled researchers, because like other mammals, mole-rats have functional versions of a protein called TRPV1, which responds to painfully hot stimuli. It turns out that a different protein, TrkA, is […]