# Physicists have performed the most accurate measurement of the force of gravity  The force of gravity may seem strong if you on foot is falling a bowling ball, but in reality it is the weakest of the fundamental interactions. Compare it with electromagnetism: attraction across the Earth’s gravity will not prevent you stick a magnet on the fridge. This weakness greatly complicates the measurement of gravity.

A group of scientists from China reported that they were able to perform the most accurate measurement of the force of gravity or Newton’s universal gravitational constant G. G describes the gravitational attraction between two objects based on their masses and the distance between them. Numerically it is equal to the magnitude of the force of gravity acting on a point body of unit mass from another of the same body, located it on a single distance. A new dimension will be important for most precise atomic clocks, and to explore the Universe, Earth, and other Sciences that are somehow tied to gravity.

The value measured by the team “have a minimum of uncertainty at the moment”, it said in a paper published in Nature.

## The most accurate measurement of the gravitational constant

Given the small value of G, determine its exact value is incredibly difficult, and coordinated by the International Committee on data for science and technology (CODATA) value is much less accurate than the values of other numerical variables which are used by scientists. Today, scientists use the amount 0,0000000000667408. But the computation of G in this range would be akin to drawing with a fat brush, while constant in the other experiments “drawn” using thinner brushes.

In the new study, the researchers conducted two independent calculate G using a pair of pendulums in a vacuum, one for each test. Each pendulum is swinging between a pair of massive objects, which can be adjusted.

Pendulums to measure the force of gravity in two ways. First, they measure the difference between how fast the pendulum is swinging in the “middle”, or a parallel position in comparison with the “far” or horizontal position. They also measured the changes in the swinging of a pendulum, depending on the gravity of the test mass.

Obviously, such experiments require ultrasensitive detectors and well controlled installations for the precise determination of G. in addition, the laboratory is a special room in the cave, to account for the possible effects of temperature change.

Scientists were able to make two measurement methods taking into account the time rocking and angular acceleration, respectively, and they accounted for 6,674184 and 6,674484 hundred billionth (10-11). For an accurate measurement, but for unknown reasons, still went together. Maybe it’s the string used for the pendulum.

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