The following is in response to a number of questions we have received regarding a possible "Planet X"
Many thanks for writing and for your question regarding Planet X, which is sometimes called Nibiru as well.
You must understand that there has been a lot of speculation based on some entirely mathematical proposals which have only a minimum amount of data to fuel it.
It all began after the planet Neptune was discovered. As astronomers watched Neptune in its orbit, it was found to have a deviation from its predicted orbit that could be explained if another planet existed further out in the solar system. A search was undertaken, and Pluto was found in 1930. The problem was that Pluto was not as massive as calculation had indicated, but Pluto's orbit was different to the other planets and so far out that it took a while to work out just what was going on and how much more mass might be needed out there to correct the anomaly with Neptune's orbit.
As it turned out, Pluto has 5 satellites, which makes it a bit more massive than originally thought. In addition, we have recently found that the Kuiper Belt of objects, of which Pluto is a part. Some of these are almost as large as Pluto, and over 1000 have been discovered. The Belt extends out to a very considerable distance beyond Pluto and it is suspected that over 100,000 objects exist that are 65 miles across or more. In fact, all the comets originate from that region. As yet, our investigation is not complete. However, these bodies contribute quite a bit of mass to the outer solar system beyond Neptune.
But there is a further thread to this story. As spacecraft got out to Neptune and investigated it more thoroughly, it was found to be less massive than originally thought. This fact makes all the difference. It eliminates the need for a big massive object out beyond Pluto. So the whole reason for the search has been removed since spacecraft went out there. Planet X or Nibiru is not needed to account for the data.
It is true that the Kuiper Belt may hold something of which we are unaware, but there is now only speculation fueling the information about objects in that region. There have been the theories of Planet X and Nibiru which have captured the imagination of some, but those theories now have no data basis on which to operate.
Note also, that if some object the size of Pluto or larger were to enter the solar system even as far out as Neptune, our modern instruments would undoubtedly pick it up as it came towards the sun. Its entry into the inner solar system would therefore not come as a surprise as it takes some time (years) for an object to come in to the sun from those depths. In that time, every astronomer would be talking about it and there would be no hiding it. There could be no conspiracy. Look at what happens with much smaller fragments from out there we call comets. We see them coming a few years before they go around the sun, usually in tight orbits.
Finally, we note something that the Bible says specifically. In Revelation 8 there are some astronomical-type judgments, including two in which a large asteroid or comet (or both) impact the earth causing serious damage. It is stated that in one case, the waters turn to blood as a result. This would happen if the object that hit was an iron-rich asteroid accompanied by a considerable amount of dust and debris. The iron-rich dust and debris would act as nuclei for rain drops to form around and the rain would be heavily stained with iron compounds and be blood red. In all places where these pieces fell, any water would be similarly stained.
In the other case, we are told that the waters become poison and kill off all who drink of it. Comets have a high percentage of cyanides of various types as part of their composition. Indeed one comet was erupting hydrogen cyanide gas when examined by space probes. If a comet nucleus like this hit the earth, or partly fragmented before hitting, then the Biblical results would seem to follow.
Associated with these larger pieces ("a mountain burning like a lamp") will be a huge amount of other dust and debris which will give rise to a fiery display of meteors. Indeed, the dust cloud associated with this debris could block out light from the sun, moon and stars. The Bible predicts these things will occur.
The point is that these bodies are small compared with what is postulated for Planet X or Nibiru, so they will be much more difficult to detect. They could easily escape attention until it was too late to do anything about it. That is the Biblical scenario. So you do not need a Planet X to do what the Bible says is going to happen.
The only other point to add is that the Catalina Sky Survey instruments at Mt. Lemmon in Arizona are dedicated to discovering earth crossing asteroids and similar fragments. They have caught up with a large number of them, but occasionally are still taken by surprise as an object comes from the direction of the sun. So our system of early warning is not foolproof for small "mountain-sized" objects up to several miles across. These are quite capable of doing enormous damage; you do not need a rogue planet to do all that!
That is the best information that I can possibly give you. I hope that is a help.
Barry Setterfield, August 2015