Where is the tenth planet located?
There have been various objects proposed as a new planet in the solar system over the last few thousand years. Ancient Greeks believed in the 'Counter Earth', and it was thought that the morning star 'Lucifer' and the evening star 'Venus' were two different planets. There have also been reports of a planet inside the orbit of Mercury called 'Vulcan' to account for perturbations in Mercury's orbit before the advent of Einstein's general relativity. Today the search continues beyond the orbit of Pluto, but with little success.
Here is a recent ABC news announcement in February 2000 that could suggest Planet-X or something like it may be out there after all.
Two teams of scientists - one in England, one at University of Louisiana at Lafayette - independently report this conclusion based on the highly elliptical orbits of so-called "long-period comets" that originate from an icy cloud of debris far, far beyond Pluto. A couple years ago, Whitmire, along fellow physicists John Matese and Patrick Whitman, noticed the farthest points of the comets' orbits didn't appear random but bunched together, tracing a path across the sky. First, they tried to explain the clumping from the gravitational pull from a main disk of stars in the Milky Way stars. But as he analyzed the orbits, the farthest points appeared to fall on a circular orbital path - exactly what you would expect if there was a planet out there.
As the planet - estimated to have a mass between one and 10 Jupiters - orbits, its gravitational wake disturbs the icy debris of the outer solar system, causing some of it to plunge toward the sun as comets, sort of like an elephant ambling through a china shop. The University of Louisiana research will be published in an upcoming issue of the journal Icarus. Murray's paper will appear in Oct. 11 issue of the Monthly Notices of the Royal Astronomical Society.
Both Murray and the University of Louisiana physicists put the planet in an orbit about 3 trillion miles - or half a light-year - from the sun. The nearest star is four light-years away. At that great distance, the 10th planet would be too dim to see by current telescopes, although there is some hope that if it exists, the next generation of space-based infrared telescopes might be able to pick it up. Murray hypothesizes the planet may have been wandering through the galaxy before being captured by the solar system's gravity. Whitmire suggests it is a "brown dwarf," or a failed star, a companion to the sun that was too small to light up.
Although suggestive, the findings are not conclusive. Too Early to Look for a Name "It's possibly suggestive," comments Brian Marsden, associate director for planetary sciences at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "I don't want to bet on it. We're certainly not going to name it."
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