What is known about the planet Nibiru and is it true that it is dangerous to the Earth?

what is that?
According to mythological sources, the planet Nibiru (it's the planet X and the planet Marduk) is a planet that wanders through space, but once in 3600 years it returns to the Sun. There is even a theory that this planet also belongs to the solar system, but for some unknown reason its supposed orbit is very far removed.

Mythological sources ?! Are you seriously? And what does science say?
So, there is as yet no exact scientific evidence to support its existence. However, there are some experts who claim that the existence of the planet Nibiru was confirmed by NASA. Other "experts" in space even accuse the organization of knowing very much about planet X and hushing up information. The very same NASA still keeps silent about this.

Why is Nibiru dangerous to the Earth?
Dimensions Nibiru allegedly four times more than our planet. And its gravity is so strong that it can lead to powerful catastrophes, up to the change of the poles of the Earth, which in turn will cause hurricanes, typhoons, floods, etc. There is even a theory that dinosaurs also died out as a result of the planet passing near the Earth Nibiru.

And how often does this planet pass next to our Earth?
According to myths, it is rather rare - once in 3600 years. Around the Sun, this cosmic body rotates in a very elongated orbit at a speed of 102 km / s. Once in 3600 years, Nibiru appears between the planets Mars and Jupiter. Ufologists also argue that when approaching the Earth the Annunaki descended to Earth, communicated with earthlings. That is why ancient people sometimes have drawings of amazing cosmic bodies. However, considering that at this time there were disasters on our planet, probably, the communication was not too joyful.