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ONE of the more strident proponents of the idea that a fifth force exists
in nature has capitulated. Frank Stacey, a physicist from the University
of Queensland, now says that a ‘subtle error’ occurred in the calculations
that led him and others to propose the existence of an extra force beyond
the four known forces of gravity, electromagnetism, and the strong and weak
forces of atomic nuclei.

The fifth force, if it had existed, would have challenged Newton’s law
of gravity and the theory of general relativity.

According to Stacey’s interpretation of experiments conducted down two
mineshafts in Queensland, this force reduced the strength of gravity by
about one per cent at short distances, compared with the forces between
planets.

But last week Stacey said that the lie of the land locally would affect
gravity locally. This ‘topographic bias’ had been added to the data when
determining the constant in Newton’s law.

The bias was caused by the way surface surveys were done by mining companies
– they followed valleys and avoided hills. The surface surveys, with their
built-in bias, were used as part of the calculations to suggest a fifth
force. The bias also affected calculations made in other parts of the world,
Stacey explained.