Robert Owen (email@example.com)
Wed, 29 Sep 1999 14:27:26 -0400
Larry Klaes wrote:
> >From the BBC News Online, 28 September 1999
> Old spacecraft makes surprise discovery
> By BBC News Online Science Editor Dr David Whitehouse
> Scientists have discovered a new object orbiting the Sun after a
> spaceprobe was mysteriously knocked off course.
> Researchers have yet to identify the object, but they are confident
> it exists because of the way it appears to have deflected the tiny
> Pioneer 10 craft, which is hurtling out towards the stars.
> If the observations are confirmed by other astronomers, it will be
> only the second time in history that a Solar System object has been
> discovered by its gravitational effect alone.
> The first was the planet Neptune which was discovered in 1846. Its
> position was predicted because of its gravitational tug on the planet
> Uranus, which appeared to be behaving oddly following its discovery
> 59 years earlier.
> The new body, found by a team at Queen Mary and Westfield College in
> London, UK, and the Jet Propulsion Laboratory in California, is
> probably a so-called Kuiper Belt object.
> The astronomers looked at Pioneer 10's tracking data obtained with
> the Nasa Deep Space Network, an array of large radio telescopes
> designed to communicate with far-off space probes.
> Rocky swarm
> On 8 December, 1992, when Pioneer was 8.4 billion km (5.2 billion
> miles) away, they saw that it had been deflected from its course for
> about 25 days.
> The scientists have been looking for such an effect for years and are
> currently analysing the data using several different methods to
> confirm their findings.
> In a few weeks time, they are expected to be able to place an upper
> limit on the mass of the object and make predictions about its
> position. Early indications suggest it may be an object that is being
> ejected from our Solar System after encountering a major planet.
> "We are quite excited that we have found one of these events. It is a
> very neat signal," Dr Giacomo Giampieri of Queen Mary and Westfield
> College told BBC News Online.
> If confirmed, it would be one of over 100 known icy and rocky objects
> that circle the Sun at vast distances, mostly beyond the most distant
> planet Pluto.
> They are small in planetary terms, just a few hundred kilometres at
> most, but astronomers believe there are millions of them swarming
> around the Sun in a vast belt. The first one was detected in 1992.
> Starbound probe
> The Pioneer 10 spacecraft was launched in March 1972 and has lived up
> to its name.
> It was the first spacecraft to travel through the asteroid belt, the
> ring of rocky debris that orbits the Sun between Mars and Jupiter.
> Before it successfully traversed this region of space, scientists did
> not know if a spacecraft could get through unharmed.
> It was also the first craft to reach a gas-giant planet, Jupiter,
> after which it left the solar system becoming the first craft to
> effectively leave the Sun's planetary system, even though it has not
> yet passed into interstellar space.
> It is currently 11 billion km (6.8 billion miles) away and still
> transmitting even though Nasa ceased monitoring its signals in 1997
> after it had spent 25 years in space.
> Earlier this year, scientists were puzzled by what was described as a
> mysterious force acting on the probe. It led to speculation that
> there was something wrong in our understanding of the force of
> Eventually the effect was tracked down to the probe itself, which was
> unexpectedly pushing itself in one particular direction. Pioneer 10
> will reach the stars of the constellation of Taurus in about two
> million years.
> Copyright 1999, BBC
Robert M. Owen
The Orion Institute
57 W. Morgan Street
Brevard, NC 28712-3659 USA
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