Physics – a new way to measure gravity

Researchers at the Swiss Federal Institute of Technology (ETH) in Zurich have developed a new gravimetric experiment. According to the researchers, the method offers “great potential” to verify one of the most fundamental laws of nature, the gravitational constant G. It determines the gravitational force that makes an apple fall to the ground, the Earth revolves around the sun and prevents galaxies from flying apart. The constant that occurs in the law of gravitation discovered by Isaac Newton cannot be derived but must be determined empirically. However, its valid value does not satisfy experts. It is less accurate than the value of any other natural constant.

evasive power

Gravity is difficult to understand because it is weak and unprotected: if you measure the force of gravity between two objects, you always measure the effect of all the other objects in the world. The only way to solve this difficult situation is to “determine the gravitational constant using as many different methods as possible,” the researchers wrote in Nature Physics.

In order to rule out sources of interference as much as possible, the ETH team transferred their experience to an old military base in a castle deep in the Swiss Alps. The test setup consists of two suspended beams isolated from each other. The researchers made a vibration. Because of the so-called gravitational coupling, the second rod also began to vibrate slightly, as if by magic.

Measuring this dynamic effect allows conclusions to be drawn about the magnitude of the gravitational constant. The researchers set a value 2.2 percent higher than the current official figure recorded by the Commission on Data for Science and Technology.(sda)