Varuna points way to 10th solar planet

Geschrieben von Mr. Burns am 02. Juli 2001 08:11:57:

PARIS: A large asteroid, named Varuna after the lord of
the cosmos in Hindu mythology, has been spotted in the
outer fringes of the Solar System, a discovery which
suggests the Sun may have more than nine planets,
astronomers say.

Varuna was detected last November by Arizona-based
astronomers in the Spacewatch Project, a scheme aimed
at scouring the asteroid belts to look, in part, for rogue
rocks that could be a potential threat to Earth.

The spherical object is 900 km in diameter, which makes
it only a tad smaller than Charon, the tiny moon that
orbits Pluto, the most distant of the Sun's nine known
planets.

The discovery, by a team led by David Jewitt of the
Institute of Astronomy in Honolulu, is reported last week
in Nature, the British science weekly. Until 1992, Pluto
and Charon were the only known objects in the Kuiper
Belt, an ancient ring of icy bodies believed to be have
been formed from the outer reaches of material that
swirled around the infant Sun billions of years ago.

Since then, more than 400 other Kuiper Belt objects
have been discovered by powerful telescopes. But
astronomers suspect the belt could hold hundreds of
thousands of rocks 100 km across, and possibly billions
of others 10 kms across. The biggest handicap to
identifying them has been the poor reflectivity of these
objects.

They are so far from the Sun that solar rays are terribly
weak, and many of the objects themselves are dark,
which means that they reflect very little light to enable
astronomers to identify and measure them.

In Varuna's case, the asteroid was easy to spot because
it shone brightly, thanks to its reflective surface. In a
commentary, US-based astronomers Stephen Tegler and
William Romanishin said they were excited by the
discovery of Varuna.

It could vindicate the US astronomer Clyde Tombaugh,
who in 1930 found "Planet X," the long-suspected ninth
planet of the Solar System, and named it Pluto, but
continued his search of Kuiper Belt in the belief that other
planets were still to be discovered, they said.

"Their work raises the possibility that Pluto is not the only
Planet X, but perhaps one of several," said Tegler and
Romanishin. "We can now imagine that bodies even
larger and more distant than Pluto will be found."

Other discoveries could come with the launch of a
space-based telescope in 2002 to measure the infrared
emissions of distant objects, something that is difficult to
accurately achieve from the Earth because of the filtering
effect of our planet's atmosphere, they said.(AFP)

Timesofindia

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