You ask, how can NASA not really know what they are researching and looking at is indeed the existence of maybe what could be known if found; the possibility of a tenth main planet that exists or has existed for decades right under the noses of NASA scientists.
Because this mysterious chunk of matter that is known as Tyche is 15,000 times further from the sun than our planet Earth is and this hidden ball of mystery lies in (if real) in what is known as the Oort cloud which is the outer shell of asteroids in our solar system, so it is not just a hop, skip, and jump and hop in your space scooter and shoot on over to Tyche distance from Earth. It takes time to gather all data and research information for any entity that far away for to be able to confirm what you may be looking at.
Scientist continue to research this mysterious planet to be able to really prove it does exist. The information gathered so far may prove to show that this planet may possibly be about four times the size of Jupiter. One of the main reason that scientist do think Tyche does exist is the change in the path of most comet when they enter the solar system.
Scientist are predicting when all the research is finished and if and when the research does point to the true existence of Tyche, this planet is predicted to be mostly made up of hydrogen and helium and will probably have much of the same characteristics as Jupiter does and there also may be the possibility that this planet has moon, all or most planet do so why not Tyche?
As the research goes on there are also other theories by scientists. Scientists are also looking at this from the other direction and saying that if this planet does exist it may not even be deemed a planet. The reason is scientists and astronomers theorize that Tyche could be a planet born in another star system and captured by ours.
The name Tyche comes from the name of a Greek goddess that "governed the destiny of a city, and if it is confirmed a planet the name Tyche " may also change. So, if NASA, astronomers, scientists and astrophysicists have missed the existence of this possible planet and especially a planet of this size, what else have we possibly missed that may be lurking out there in space in some crack or crevice of existence?
Tyche, Giant Hidden Planet, May Exist In Our Solar System,
(http://www.huffingtonpost.com/2011/02/14/tyche-hidden-planet_n_823028.html) Retrieved 2013.
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