NASA's MAVEN spacecraft, which has orbited Mars since 2014, went quiet abruptly in early December. Efforts to reestablish a connection have been unsuccessful.

The Hubble Telescope appears as a tiny silhouette during a perfectly timed solar transit captured from Puerto Rico.

It wasn’t until she was diagnosed with ADHD at 22 that she learned she was experiencing a symptom sometimes called "time blindness." Russell Barkley, a retired clinical neuropsychologist at the University of Massachusetts, is often credited with linking time impairment with people with ADHD or autism. It relates to executive function that occurs in the frontal lobes of the brain, and it is a well-documented characteristic of many people with ADHD, said Stephanie Sarkis, a psychotherapist in Ta