In 2016, astronomers announced there was a new planet in the outer solar system. Planet Nine, supposedly larger than Neptune and located far beyond the orbits of the planets known so far, is a particular mystery since no one has yet observed it. Scientists have merely tracked its supposed orbit by watching the gravitational pull the planet exerts on the asteroids and space debris near it.
But this isn’t the first time scientists have predicted planets before spotting them. It’s not even the first time they’ve done it because of hard-to-explain orbits. And they’ve usually been wrong.
