New Evidence For A Fifth Fundamental Force In The Universe
LOS ANGELES (AP) _ Physicists said Friday they have found new evidence supporting theories about the existence of a fifth fundamental force governing the workings of the universe, a force that slightly counteracts gravity.
The study by University of Washington physicist-astronomer Paul Boynton and his colleagues won’t settle debate over whether such a force exists, but ″certainly makes it somewhat more plausible,″ said Stanley Brown, an editor of the journal Physical Review Letters, which will publish the study Monday.
The American Institute of Physics said the study represented ″the most sensitive experiment conducted to date″ to determine whether a fifth force exists.
″Everybody working in the field perceives this as a major step forward,″ Purdue University physicist Ephraim Fischbach said during a telephone interview from West Lafayette, Ind. ″It’s extremely important, although nobody wants to claim this proves the fifth force.″
Last year, Fischbach published a widely reported analysis that proposed the existence of a fifth force in addition to the four forces already known to influence the behavior of matter.
The four are gravity, which attracts objects to each other; electromagnetism, which creates light, radio waves, microwaves and other forms of electromagnetic radiation; the strong force, which binds neutrons and protons together in the nucleus of an atom; and the weak force, which makes some atoms break down in radioactive decay.
If a fifth force exists, it would counteract gravity so a feather actually would hit the ground ever so slightly before a brick if wind resistance didn’t slow the feather.
″Our results are consistent with the existence of a fifth force. It’s good evidence, but not conclusive,″ Boynton said during a telephone interview from Seattle.
In an experiment supposedly conducted 400 years ago, Galileo found that when two objects of different weights were dropped from the Leaning Tower of Pisa, both hit the ground at the same time, contrary to the logical notion that heavier objects fall faster than lighter ones.
Boynton’s experiment involved a 3-inch-diameter metal ring suspended horizontally at the base of 400-foot granite cliff in the North Cascade mountains near Index, Wash.
One half, or semicircle, of the ring was made of aluminum, while the other half was made of beryllium. Both halves of the ring had the same mass, which is what gives an object weight when the object is pulled by gravity.
Because gravity exerts the same attraction on two objects of the same mass, both halves of the ring should have been pulled slightly toward the cliff if only gravity influenced the ring. Instead, Boynton found the aluminum half of the ring twisted slightly toward the cliff while the beryllium half rotated away from the cliff.
That suggests an unknown force was affecting the two halves of the ring in a different way based on the differing chemical composition of the two halves, so the force counteracted gravity’s pull on beryllium more strongly than it counteracted gravity’s pull on aluminum.
While gravity keeps planets in orbit around the sun, physicists believe the fifth force counteracts gravity only over about 10 to 1,000 yards.
Physicists who advocate the existence of a fifth force believe it may help them develop a long-sought ″unified theory″ to provide a simple explanation of how all the forces of nature influence matter.
Like previous studies, Boynton’s experiment suggests the strength of the fifth force is related to the chemical composition, or makeup, of an atom rather than its mass.
However, prior research indicated the strength of the fifth force’s anti- gravitational effect was related to a measure of composition called hypercharge, or the number of protons plus the number of neutrons in an atom. Boynton’s study and his review of earlier experiments suggests the fifth force is related to a measure of composition called isospin, which is the number of neutrons minus the number of protons.
As a result, Boynton’s research gives physicists ″more confidence there is an effect (fifth force) and more confusion about what the effect is,″ said Samuel Aronson, co-author of Fischbach’s study and associate chairman of physics at Brookhaven National Laboratory in Upton, N.Y.
Boynton’s co-authors were UW graduate student Anthony Szumilo, and physicists David Crosby and Philip Ekstrom, both of Northwest Marine Technology on Shaw Island, Wash.