A stray comet from another star is swinging past Earth. Discovered over the summer, the comet known as 3I/Atlas will pass within 167 million miles of our planet on Friday. That’s as close as it will get on its grand tour of the solar system. NASA continues to aim its space telescopes at the visiting ice ball. But it’s fading as it races back toward interstellar space, never to return. It’s the third known interstellar object to pass our way. Scientists believe it may have come from a star system much older than our own, making it a tantalizing target.