Watching X-rays flung out into the universe by the supermassive black hole at the center of a galaxy 800 million light-years away, Stanford University astrophysicist Dan Wilkins noticed an intriguing pattern. He observed a series of bright flares of X-rays—exciting, but not unprecedented—and then, the telescopes recorded something unexpected: additional flashes of X-rays that were smaller, later and of different “colors” than the bright flares.

According to theory, these luminous echoes were consistent with X-rays reflected from behind the black hole—but even a basic understanding of black holes tells us that is a strange place for light to come from.

“Any light that goes into that black hole doesn’t come out, so we shouldn’t be able to see anythin...

Many times we eat, not because we are hungry, but because of social pressures or because the food is so appetizing, that, even though we are full, we just want another bite.

Overeating, whether it is guided by hunger or pleasure, typically leads to obesity, which affects about 42% of the adults in the U.S., according to the Centers for Disease Control and Prevention. Looking to contribute to the development of effective treatments for obesity, an international team led by researchers at Baylor College of Medicine investigated in an animal model how the brain regulates feeding triggered by hunger or other factors.

Led by Dr...

In the late 1970s, M. Stanley Whittingham was the first to describe the concept of rechargeable lithium-ion batteries, an achievement for which he would share the 2019 Nobel Prize in Chemistry. Yet even he couldn’t have anticipated the complex materials science challenges that would arise as these batteries came to power the world’s portable electronics.

One persistent technical problem is that every time a new lithium-ion battery is installed in a device, up to about one-fifth of its energy capacity is lost before the device can...

Astronomers have developed the most realistic model to date of planet formation in binary star systems.

The researchers, from the University of Cambridge and the Max Planck Institute for Extra-terrestrial Physics, have shown how exoplanets in binary star systems—such as the ‘Tatooine’ planets spotted by NASA’s Kepler Space Telescope—came into being without being destroyed in their chaotic birth environment.

They studied a type of binary system where the smaller companion star orbits the larger parent star approximately once every 100 years—our nearest neighbour, Alpha Centauri, is an example of such a system.

“A system like this would be the equivalent of a second Sun where Uranus is, which would have made our own solar system look very different,” said co-author Dr...