Dark Jupiter May Haunt Edge of Solar System

Lisa Grossman - A century of comet data suggests a dark, Jupiter-sized object is lurking at the solar system’s outer edge and hurling chunks of ice and dust toward Earth.

“We’ve accumulated 10 years’ more data, double the comets we viewed to test this hypothesis,” said planetary scientist John Matese of the University of Louisiana. “Only now should we be able to falsify or verify that you could have a Jupiter-mass object out there.”

In 1999, Matese and colleague Daniel Whitmire suggested the sun has a hidden companion that boots icy bodies from the Oort Cloud, a spherical haze of comets at the solar system’s fringes, into the inner solar system where we can see them.

In a new analysis of observations dating back to 1898, Matese and Whitmire confirm their original idea: About 20 percent of the comets visible from Earth were sent by a dark, distant planet.

This idea was a reaction to an earlier notion that a dim brown-dwarf or red-dwarf star, ominously dubbed Nemesis, has pummeled the Earth with deadly comet showers every 30 million years or so. Later research suggested that mass extinctions on Earth don’t line up with the Nemesis predictions, so many astronomers now think that object doesn’t exist.

“But we began to ask, what kind of an object could you hope to infer from the present data that we are seeing?” Matese said. “What could possibly tickle [comets'] orbits and make them come very close to the sun so we could see them?”

Rather than a malevolent death star, a smaller and more benign companion called Tyche (Nemesis’ good sister in Greek mythology) could send comets streaming from the Oort Cloud toward Earth.

... After examining the orbits of more than 100 comets in the Minor Planet Center database, the researchers concluded that 80 percent of comets born in the Oort Cloud were pushed out by the galaxy’s gravity. The remaining 20 percent, however, needed a nudge from a distant object about 1.4 times the mass of Jupiter. ...

via Dark Jupiter May Haunt Edge of Solar System | Wired Science | Wired.com.