Comet Orbits Hint At New Planet, Scientist Says
1st Nov 1999
LONDON (Reuters) - An undiscovered planet as massive as Jupiter could be orbiting in the distant reaches of the solar system, a British astronomer reported Thursday.
Dr. John Murray, of the Open University, has not seen the large mysterious object but believes it exists because of peculiarities in the orbits of distant comets.
In a study published in the Monthly Notices of the Royal Astronomical Society, he argues that the existence of an unknown planet is a possible explanation.
"The hypothetical planet is within the distance range where numbers of small planets are predicted, but the presence of a large object orbiting so far from the Sun would be surprising,'' Murray wrote.
Dr Jacqueline Mitton, of the Royal Astronomical Society, said the existence of the massive object was inferred but had not been proven. "It's been called a planet for want of another term,'' she said in a telephone interview.
"Pluto, on the edge of our set of major planets, is about 40 times further away from the Sun than Earth. We're talking about an object which is 30,000 times farther away in what is called the Oort cloud of comets.''
Murray found oddities in the comet orbits which he believes could be explained by the existence of a large object or planet in the part of space where the comets are coming from.
Comets reaching the inner solar system include a group coming from directions in space that are strung out along an arc across the sky. Murray thinks this could mark the wake of a large body moving through space in the Oort cloud.
Other astronomers are skeptical because the existence of a large planet so far from the Sun cannot be explained by present theories on how the solar system was formed.
Murray speculates that the object, if it exists, could have been captured in its orbit after the solar system formed. Despite his belief that it is a planet, Murray is not ruling out other explanations for the clustering of the cometary orbits.
an emissary solution