A 'captured' alien planet may be hiding at the solar system — and it's not 'Planet X'

What if our solar system secretly contains a world that doesn’t belong here? Scientists suggest there could be a ‘captured’ alien planet—an outsider star system world that the Sun’s gravity pulled in long ago. And here’s the twist: it wouldn’t be Planet X or Nibiru. Could this hidden planet really exist, and how would we even find it? Learn more about your ad choices. Visit megaphone.fm/adchoices