But it's certainly not Nibiru, and it doesn't mean any of the internet conspiracists claiming that planet is about to wipe us out are correct. Instead, it's just an interesting – entirely physical and explained, if mysterious and uncertain – planet.
Nibiru has been blamed for a variety of things – strange events on Earth, days of darkness where the sun won't rise, and even the potential destruction of Earth. One man has said, repeatedly, that the planet is going to cause the apocalypse on Earth – changing the date when that doesn't become true.
Of course, any planet that Nasa discovered almost certainly won't have any of the attributes that believers in Nibiru ascribe to it. It won't be heading to Earth to destroy us all – at least not any time soon – and it doesn't have any mystical powers.
But those talking about Nibiru are right about one thing: there might in fact a planet on the edge of our solar system, and scientists really aren't sure whether it exists or not. Scientists say that it's now more likely that it does exist than it doesn't.
"There are now five different lines of observational evidence pointing to the existence of Planet Nine," said Konstantin Batygin, a planetary astrophysicist at Caltech in Pasadena, California, whose team could be about to find the planet. "If you were to remove this explanation and imagine Planet Nine does not exist, then you generate more problems than you solve. All of a sudden, you have five different puzzles, and you must come up with five different theories to explain them," he said in a new Nasa statement.
Professor Batygin alongside astronomer Mike Brown claim to have found a range of different, indirect pieces of evidence for the planet. It seems to be tilting our universe, for instance, in a way that makes scientists think there must be something out on the edge disrupting things.
Now astronomers are looking deep into the sky using advanced telescopes to try and see the planet itself. Doing so is difficult, given it is so distant, hidden and dark – but they are now using the Subaru Telescope at Mauna Kea Observatory in Hawaii, described as the "best tool" for the job, to try and spot them.
When they do that, they'll be more likely to find out where it was. And, unlike the myths Planet X or Nibiru, its origin won't be the inside of someone's head.
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