On September 29th 2011 NASA conducted a science briefing discussing the new wide field infrared mapping capabilities for NEAR EARTH of the NEOWISE space telescope. In this video, NEOWISE Principal Investigator, Amy Meinzer answers a call in questions about the program's ability to locate the mysterious Planet X.
Her response turns out to be somewhat supportive of Nibiru Hunders, stating, "We have actually been able to find 100 of these new objects near earth called Brown dwarfs", Amy goes on to say, "and, so... that is very similar to what people are looking for.
Amy Mainzer did not say: Planet X doesn't exists, she says ‘Planet X isn't coming to get us’".
Some alternative News media sites and Plant X hunters are taking that statement as a sort of information slip up, when Amy says, "if there were something out there, it would be large and have a circular orbit." Granted, the quote is somewhat mysterious in nature, especially coming from the NEOWISE Principal Investigator.
It is possible that her nomenclature slip had to do with the fact that the tenth planet now called Eris (Dwarf planet), was originally called Xena and was commonly referred to as planet X. This is not to be associated with the Nibiru or planet X of collision supposition.
NEOWISE Space Infrared Survey: NEOWISE is the term used to describe the near-Earth object observing capability of the Wide-field Infrared Survey Explorer (WISE) telescope. WISE uses a 40 cm aperture telescope to observe the entire sky 1.5 times in its 9-month design lifetime. The cryogens used to cool the telescope are expected to run out in November 2010. The infrared wavelength regions are centered at 3.4, 4.6, 12, and 22 microns. The WISE spacecraft is in a nearly polar orbit with the telescope always directed 90 degrees from the sun's direction. NEOWISE is an enhancement to the WISE data pipeline that allows new moving objects to be followed up by ground-based telescopes operating in the visible region. These follow-up observations ensure that a NEO's orbit will be secure and the object will not become lost. Because dark asteroids re-radiate strongly in the infrared, NEOWISE observations can often provide better estimates for NEO diameters than can optical telescopes. That is, optical telescopes observe reflected sunlight so they cannot easily tell the difference between a small bright object and large dark object.
Principal Investigators: Ned Wright (UCLA) for WISE & Amy Mainzer (JPL) for NEOWISE
Look here for additional information on WISE and NEOWISE: