i did something that never occurred to the doomsayers: i sent an email to the two astronomers asking what happened back in '83. gerry neugebauer replied, and told me the real poop.
iras was designed to look in the far-infrared, well past what our eyes see. at the time, no one was really sure what it would find. to everyone's surprise, several bright point sources were found that did not correspond to anything seen on optical images taken of the same areas. in the press conference, the two scientists said that these objects could be almost anything, from a tenth planet in our solar system to distant galaxies.
guess which it turned out to be? sure enough, much deeper images were taken, and some of the objects were found to be dense gas clouds in our own galaxy, while others turned out to be very distant galaxies. in fact, these observations heralded the discovery of a new type of object: ultra-luminous infrared galaxies (ulirgs). these are galaxies in which there is a burst of stars being born. the cocoons of dust in which the stars are enshrouded generates copious infrared, which is what was detected by iras. they published these results in the prestigious astrophysical journal, and you can even read it yourself.
so iras did not see nibiru, planet x, or anything of the sort, despite the claims of the doomcriers. of course, they now claim that nasa is clamping down on the press for planet x. the original post article, they say, was hastily retracted due to pressure from the nasa thugs. of course, the doomcriers have absolutely no evidence of this (because, of course, this claim is wrong), but they continue to state it as if it is fact. it is nothing of the sort. they like to make claims like this for many reasons: it generates an "us vs. them" mentality, which is great for conspiracies, and it helps sell books and/or videos. but it's wrong at best and a lie at worst.
a good page with a lot of detail about the iras observations is written by tom chester, an astronomer on the original iras team that found the mystery sources. straight from the horse's mouth, if you will.
you can also read more about iras and planet x at the planet x and the pole shift website, which also has a copy of the original washington post article.