the following quotes come from this link:
http://paranormal.about.com/library/.../aa021102a.htm
"Even mainstream astronomers have long speculated that there may be an unknown planet - a Planet X - somewhere out beyond the orbit of Pluto that would account for the anomalies they were detecting in the orbits of Neptune and Uranus. Some unseen body seems to be tugging at them. The finding was reported in the June 19, 1982 edition of the New York Times:
Something out there beyond the furthest reaches of the known solar system is tugging at Uranus and Neptune. A gravitational force keeps perturbing the two giant planets, causing irregularities in their orbits. The force suggests a presence far away and unseen, a large object, the long-sought Planet X. Astronomers are so certain of this planet's existence that they have already named it "Planet X - the 10th Planet."
The anomalous body was first spotted in 1983 by IRAS (Infrared Astronomical Satellite), according to news stories. The Washington Post reported: "A heavenly body possibly as large as the giant planet Jupiter and possibly so close to Earth that it would be part of this solar system has been found in the direction of the constellation Orion by an orbiting telescope aboard the U.S. infrared astronomical satellite. So mysterious is the object that astronomers do not know if it is a planet, a giant comet, a nearby 'protostar' that never got hot enough to become a star, a distant galaxy so young that it is still in the process of forming its first stars or a galaxy so shrouded in dust that none of the light cast by its stars ever gets through." "
""A Mystery Revolves Around the Sun," an article posted by MSNBC on October 7, 1999 said: "Two teams of researchers have proposed the existence of an unseen planet or a failed star circling the sun at a distance of more than 2 trillion miles, far beyond the orbits of the nine known planets... Planetary scientist at Britain's Open University, speculates that the object could be a planet larger than Jupiter." And in December, 2000, SpaceDaily reported on "Another Candidate For 'Planet X' Spotted."
Another article and photo appeared in Discovery News: "Large Object Discovered Orbiting Sun." The article, published in July, 2001, says, "The discovery of a large reddish chunk of something orbiting in Pluto's neighborhood has re-ignited the idea that there may be more than nine planets in the solar system." Naming it 2001 KX76. the discoverers estimate that it is smaller than our Moon and might have an elongated orbit, but they gave no indication that it was heading this way."
so it appears that evidence pertaining to nibiru has appeared in the main stream media but that was some time ago. since then i have not seen anything more recent except on alternative sites. the article about IRAS discovery reported in the Washington Post was quickly taken down and never heard of again. fortunately some people captured the article and you can google it to find it
