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An absence of antigravity.

An absence of antigravity

Several research teams have failed to confirm the puzzling results of a recent experiment by two Japanese physicists, who reported that under certain circumstances a spinning gyroscope may partially counter the Earth's gravitational pull (SN: 1/6/90, p.15). James E. Faller and his colleagues at the Joint Institute for Laboratory Astrophysics in Boulder, Colo., repeated the Japanese experiment by looking for signs of weight loss in a spinning gyroscope consisting of a brass top about 2 inches in diameter sealed in a small plastic chamber. "We conclude that within our experimental sensitivity, which is approximately 35 times larger than needed to see the effect reported . . . , there is no weight change of the type . . . described," Faller and his team write in the Feb. 19 PHYSICAL REVIEW LETTERS. A French group reporting in the Feb. 22 NATURE has obtained similarly negative results.

Why the Japanese researchers detected such an effect in the first place remains a mystery. According to their paper in the Dec. 18 PHYSICAL REVIEW LETTERS, they went to considerable trouble to eliminate possible sources of error. However, they may have overlooked some subtle but important details, says mechanical engineer S.H. Salter of the University of Edinburgh in Scotland. The trick is to find a mechanism that could produce a small weight loss when the gyroscope is spinning clockwise (as seen from above) but not when it's spinning counterclockwise or standing still.

"It is possible to construct an argument to show that vibration in the gyro, compounded by nonlinearity in the weighing mechanisms . . ., could lead to misleading result," Salter comments in the Feb. 8 NATURE. Tiny differences in the tracks that house the ball bearings at the two ends of the spinning gyroscope could produce vibrations sufficiently large to affect the results. Moreover, laboratory balances like the one used to weigh the spinning gyroscopes aren't necessarily designed to handle vibrating loads accurately.
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Publication:Science News
Date:Feb 24, 1990
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