In the scientific community there is no confusion at all. First, Tyche is a name given to a hypothetical planet in the Oort cloud by two researchers John Matese and Daniel Whitmire both at the University of Louisiana at Lafayette. By studying the distribution of comet orbits they postulate that a planet exists in the Oort cloud at a distance of around 15,000 AU (15,000 times the Sun-Earth distance). They also look at two surveys that have been done IRAS and 2MASS. Since these surveys did not reveal any large object that puts a limit on the size of Tyche and that is between 1 and 4 times the mass of Jupiter. The eccentricity may be as high as 0.5 but even then, that orbit puts Tyche nowhere near Pluto let alone Earth. Matese and Whitmire go on to say that based on the sensitivity of the WISE instrument a planet as they describe should be visible in the WISE data. However, the WISE data is a large dataset and it will take a couple of years to search through all of the data to know if an object was found. Finally, even though Matese and Whitmire use NASA data they do not speak for NASA. Their paper can be read online:

[link to arxiv.org]

To dispel a recurrent myth regarding IRAS. In 1983 the Washington Post did print an article claiming the discovery of a tenth planet. The Washington Post article took a statement way out of context. The actual statement was that IRAS discovered 9 objects that were at the time unidentified and they could be anything from a distant planet to a galaxy because they didn’t have enough information. What the Washington Post did not later report is that these 9 objects were quickly identified but a follow-up story was never written. These are the papers describing the discovery and identification:

Unidentified point sources in the IRAS minisurvey, Houck et al. Astrophysical Journal, vol. 278, March 1, 1984, p. L63-L66

Unidentified IRAS sources - Ultrahigh-luminosity galaxies, Houck et al., Astrophysical Journal, vol. 290, March 1, 1985, p. L5-L8.

Optical counterparts of unidentified IRAS point sources Infrared luminous galaxies, Aaronson and Olszewski, Nature, vol. 309, May 31, 1984, p. 414-417.

This is a statement made by those involved with IRAS at the time stating that a tenth planet was not discovered:

[link to web.ipac.caltech.edu]

The second thing is Nibiru. The term Nibiru does appear in Sumerian texts and at times refers to the planet Jupiter but also means crossing or gateway. The Sumerian texts also refer to Nibiru as a deity or a star. What Sitchin did was to create a myth about a planet in a 3600 year orbit. Some say it will collide with Earth in 2012 and some say later. The main point is that there just is no observational evidence supporting a planet is a 3600 year orbit. Such an object would have been picked up in the IRAS and 2MASS surveys as well as many ground based surveys that have occured. Also, such an object would affect the motions of the planets. Since no anomalous motions of the planets are seen there is no evidence to support the existence of Nibiru.

[link to en.wikipedia.org]
[link to www.sitchiniswrong.com]
[link to www.sitchiniswrong.com]

Planet X is another term often used. Planet X is the name given to a planet that supposedly influences the obits of Uranus and Neptune to explain some anomalies in their orbits. However, when Voyager 2 passed by Neptune in 1993 a corrected mass of Neptune was determined and the “anomalies” of the orbits of Uranus and Neptune disappear when the corrected mass of Neptune is used. So the need for Planet X has gone away.

[link to articles.adsabs.harvard.edu]

Nemesis is another, even more distant object, on the order of 100,000 AU, considered to be a dwarf star or brown dwarf. Nemesis was a name given to a proposed star to explain the source of comets from the Oort cloud and a possible periodicity in extinction events:
Davis, Hut, and Muller, Extinction of species by periodic comet showers, Nature, vol 308, 19 April 1984, p715

However, Adrian Melott and Richard Bambach discuss the possibility of a star in the outer Oort cloud, such as Nemesis, causing the 27 million year periodic extinctions on Earth by sending comets into the inner solar system. They find that based on the closest approach of other nearby stars such an Oort cloud star could not maintain an orbit well enough to cause the 27 million year events. In short no Nemesis.

[link to lanl.arxiv.org]


David Morrison does work for NASA and has written on the non-existence of Nibiru:

[link to www.nasa.gov]

[link to www.csicop.org]

[link to news.discovery.com]

The “confusion” comes because people are relying on popular media, blogs, personal web sites, and books that are not scientifically reviewed until after printing. The scientific literature contains no confusion.