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This foolish idea of shooting at the moon is an example of the absurd lengths to which vicious specialisation will carry scientists. A.W. Bickerton, physicist, NZ, 1926

2. THE PIONEER ANOMALY Previous | Next

Two spacecraft are flouting the laws of physics

BY RIGHTS, the Pioneer 10 and 11 space probes should no longer be of interest to anyone. Launched in the 1970s, they are now far beyond the edge of our solar system, drifting silently out into the void. The last contact we had with Pioneer 10 was on January 10, 2003, when a weak signal made it back to Earth. It is now nearly 8 billion miles away, past the orbits of Neptune and Pluto, and we will not hear from it again because it no longer has any power left with which to send out a signal.

However, the Pioneer probes are of interest. That is because they are drifting off course in a very intriguing way. In every year of travel, the probes veer 8000 miles further away from their intended trajectory. It is not much when you consider that they cover 219 million miles a year; the drift is around 10 billion times weaker than the Earth’s pull on your feet. Nonetheless, it is there, and decades of analysis have failed to find a straightforward reason, such as a heat leak from the probes. So it is possible that these errant spaceprobes are telling us something extraordinary. Maybe Newton’s law of gravitation, the law that describes how their trajectories should be playing out, is in need of an overhaul. Or is there is a new and strange force waiting to be discovered?

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Location:Cincinnati, Ohio

#1 - Posted: 13/08/2008 18:48


The radiative and particulate loss of mass by the Sun,



M(sun)/M(sun) = -9.13X10-14 per year

or more causes the orbits of the planets to expand at the same rate, their periods to lengthen at twice this rate."



The probes were launched over 30 years ago.  By the numbers above, that means as much as

3 X 10^-12 solar masses have been lost since the probes were launched.   If the probes travel 219000000 miles per year the loss of mass should cause an anomaly of about

219000000 X 9 X 10^-14   or 1.8 X 10^4 miles or .0002 miles.   Obviously this ain't the answer but it shows we're looking for is a pretty big effect relative to one of the physical effects we know. 


I suppose somebody has worked this out using general realtivity but I haven't seen it.  If anyone has, I'd appreciatea a link.

8000/219000000 = 4X10^-5, several orders of magnitude short of what is needed. 

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