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Yada, Yada, Yada!!! BBC 'reports' below. Didn't even say how much $$$ had been wasted on studying this. I'm sure the starving children of Africa would like to know. |
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15 May, 2001, 15:46 GMT 16:46 UK Mystery force tugs distant probes
The Pioneer craft
are heading towards the stars By BBC News
Online science editor Dr David Whitehouse An unexplained
force is pulling on distant spacecraft. Researchers have come to this
conclusion after a thorough analysis of the deep-space probes'
trajectories. It could be just
a tiny unnoticed effect in the spac craft themselves, but scientists warn
it could also be the first hint that modifications need to be made to our
understanding of the force of gravity. "It is
almost as if the probes are not behaving according to the known law of
gravity," said Dr John Anderson, of the American space agency's (Nasa)
Jet Propulsion Laboratory, and lead scientist on the study. He said:
"We've been working on this problem for several years, and we have
accounted for everything we could think of." Great detail
The unexplained
force appears to be acting on four deep-space probes scattered around the
Solar System. Pioneer 10 was
launched towards the outer planets in 1972. It is now well beyond Jupiter
but still in radio contact with Earth. By studying the
Doppler shift (the "stretching") of the radio signals from the
probe, scientists have been able to calculate how fast the craft is
travelling. Since 1980, its trajectory has been mapped in very great
detail. The puzzle is
that Pioneer 10 is slowing more quickly than it should. It was initially
suggested that this might be due to the force from a tiny gas leak or that
it was being pulled off course by the gravity of an unseen Solar System
object. Unseen body
The mystery
deepened further when an analysis of the trajectory being followed by its
sister spacecraft, Pioneer 11, launched in 1973, showed that it too was
being subjected to the same mysterious effect. But Pioneer 11 is
on the opposite side of the Solar System from Pioneer 10, about 22 billion
km (about 14 billion miles) away. This means the effect cannot be the
gravitational effect of some unseen body. Add to all this
hints that the same unexplained effect might have been acting on the
Galileo spacecraft on its journey to Jupiter, and the Ulysses spaceprobe
that is circling the Sun, and you have a Solar System-wide puzzle. In a report soon
to be published in a major astronomical journal, Dr Anderson and
colleagues have carried out an impressive study of the state of the
Pioneer spacecraft and all the tiny forces to which they could be
subjected. Planets
unaffected
"Our
analysis strongly suggests that it is difficult to understand how any of
these mechanisms can explain the magnitude of the observed behaviour of
the Pioneer anomaly," the team says. It has been
suggested that the spacecraft tracking data have shown a deviation in the
force of gravity that is apparent only across vast distances. It has also
been pointed out that the strength of the effect seems to be related to
two of the Universe's physical constants: the speed of light and the speed
of the expansion of the Universe. But others have
dismissed this as being too fanciful, arguing that if the Pioneer anomaly
was really indicative of a change in our understanding of gravity, then it
would be apparent in the orbits of the planets around the Sun - which it
is not. The effect is as
yet unexplained and with all four affected probes never to return to Earth
for analysis, it may well remain that way. |
