Well, Nibiru is a hypothetical planet.
No, it is not a hypothetical Planet. If the source of your information is not the Journal of Ancient Near Eastern Texts, American Journal of Semitic Languages, Journal of Near Eastern Studies, Journal of Cuneiform Texts
or the Journal of the Royal Asiatic Society
, then whatever your reading about Nibiru is corrupted, false and erroneous.
Just as the Trans-Uranian planets are. If it is in the list, it HAS to have a proposed effect on us, just as the other hypothetical planets do.
Nothing hypothetical can have a real effect. You can make up whatever names you want. It's showmanship, not astrology.
Some people just have
to be different.
If Nibiru is a planet, then most of what is said about it must be inaccurate. I've seen a few lists of attributes for it. One list stated that its mass is more than 20 times that of Earth, yet its gravity is less than twice that of Earth. The first thing I thought after reading that list is, "Wow, they must think that planet is made of cotton candy!"
Like I said, if information isn't a direct quote from one of the professional peer-reviewed journals I mentioned then the information isn't valid.
Unfortunately, I only have my laptop with me, but as I recall, the Planet is described in several texts dating from circa 3400 BCE and then again circa 1500 BCE. The description of the Planet as it rises in relation to the other Planets mentioned in the texts shows that it does not have a circular orbit like the Planets, rather it has an highly-elliptical orbit much like a comet.
It is also inclined to the Plane of the Ecliptic and by quite a lot, more than Pluto (which is inclined by about 15° +/- depending on where Pluto is in its orbit). It first appears in the southern skies, so if you were in the Southern Hemisphere or close to the Equator, you'd see it long before people in the Northern Hemisphere would. Its orbital motion is clock-wise, that it is if you were on Nibiru the Sun would rise in the west, not the east. The Sun rises in the east because Earth (and the rest of the Planets) move counter-clockwise around the Sun. The texts also imply that the Planet's speed increases, which would be logical since something in an highly elliptical orbit would have its orbital speed increase due to the acceleration of gravity as it approaches the Sun (just like a comet's speed increases).
That's all that is factually known. Anything else is pure speculation. It's described as having an orange-red glow about it. A terrestrial planet with a larger mass would have an higher concentration (density) of Noble Gases in the outer atmosphere. Earth has Argon, Neon, Krypton and few others but in very low concentration. In theory as the Planet approached the Sun the solar radiation (photons) would excite the valence electrons in the Noble Gases and could cause it to glow like that in the same way a neon-light works. Again, I don't know that for a fact, I'm just trying to use science to logically explain something. It's mass could be 3 to 4 times that of Earth, but 20 times is a little ridiculous.
Because of its highly elliptical orbit, it would be near impossible to find until it was right on top of our Solar System. The only way you could find it is assuming you know almost exactly where to look, you'd have to point your observatory telescope in that direction and photograph the night sky every night for about 6 to 12 years (or longer) in hopes that it passed in front of a star/galaxy and blocked the light of that star/galaxy as it passed.