No, Nibiru is a made up bullshit planet and there’s no clear idea behind it - the things they say contradict each other and they don’t have enough astronomy to realize it. Planet X is a name for any planet that is postulated to exist in our solar system and has not been confirmed. X stands for unknown. The first such, when it was confirmed, was named Pluto. We have had many “planet X” candidates since then, but none have been confirmed. The conspiracy theorists treat them as if they are all the same planet. But they can’t tell the difference between planets even if their orbital distances differ vastly, and period, something with a period of 360 years to them seems the same as one with a period of 26 million years orbiting 1.5 light years away. They treat articles by astronomers about such ideas as if they all described the same planet. It’s just codswalop.

But there could be extra planets in our solar system. If so they have to orbit way beyond Neptune or we’d have seen them long ago. Making them “brown dwarfs” makes them even more conspicuous -a brown dwarf is a failed star that is hot by its internal heat - that doesn’t make it invisible. It’s as easy to see in visible light as any planet, if near a star or sun. But invisible in complete darkness in the depths of space light years from any star because it is visible only by reflected light, unlike a star that shines by its own light no matter where it is.

Also, if there are extra planets - they could in principle cross the orbit of Neptune - Pluto does. But they can’t also cross the orbit of Uranus, never mind Saturn and Jupiter as well. The problem is that they would have to be in a resonance with Neptune to keep missing the planet every time they cross its orbit, otherwise they are bound to hit it sooner or later, or fly so close as to be deflected away somewhere else. It’s 4.6 billion years since our Moon formed. Any planet that was in an orbit crossing those four gas giants would have been deflected from its orbit soon after it first entered it, within a million years. For instance if it was still in the orbit when the Moon formed, a time when the solar system was still in process of settling down, it would have gone well over 4.5 billion years ago.

It can’t be in an orbit within Neptune because we’d have known about it for centuries.

So, it’s just not possible to have an extra unknown planet in our solar system that passes by Earth.

That leaves rogue planets coming from interstellar space. But those are so rare that there is no real chance of that happening either.

So no, it can’t happen at all. For debunking of many of the conspiracy theories see my

• Nibiru Bullshit Tester - How to check if they know anything about astronomy
• Debunked: Nibiru is invisible because it is a brown dwarf or made of dark matter
• Debunked: Nibiru will hit Earth on [Insert Date here]
• Debunking: Planet 9 is Nibiru
• Debunked: Our Sun or Earth could be hit by a rogue planet, neutron star, black hole or star
• List of the articles in my Debunking Doomsday blog to date