NASA said this week that it was working fine before it went behind the red planet. When it appeared again, there was only silence.

Astronomers have long been concerned about reflections from satellites showing up in images taken by telescopes and other scientific instruments.

The multiverse pops out of quite a few theories in physics, and has been proposed as a solution to certain vexing problems. But it’s also been argued that the very idea of a multiverse is just bad ...

The five-part series premieres Wednesday, September 17, at 9pm ET/8C on PBS, and will also be available for streaming at pbs.org/nova, NOVA on YouTube, and the PBS ...