However, the observation of gravitational waves at LIGO gave it new momentum, and in 2018 he resumed his research. Since then, scientists have documented dozens of such events if they could be traced in detail, they would reveal new insights into the universe and its history.ĭual began working on methods to measure the gravitational constant in 1991, but at one point had put his work on hold. They were the result of two orbiting black holes that had merged at a distance of about 1.3 billion light years from Earth. Such waves were detected for the first time in 2015 at the LIGO observatories in the US. Science has still not fully understood this natural force or the experiments that relate to it.įor example, a better understanding of gravity would allow us to better interpret gravitational wave signals. That’s why he hopes that he and his team can use the experiment to help crack the gravity conundrum. “In dynamic measurements, unlike static ones, it doesn’t matter that it’s impossible to isolate the gravitational effect of other bodies,” he says. The extremely small movements of the rods are detected with high precision by four laser devices.įor Dual, the advantage of the new method is that it measures gravity dynamically via the moving beams. The team can view the measurement data in real time whenever they choose.įor the experiment, an orange rod vibrates, which causes a blue rod to move due to gravitational forces. The researchers run the experiment remotely from Zurich, which minimizes disruptions from personnel present on site. Still, Dual confirms that “we’re on the right track.” We’re already in the process of taking measurements with a slightly modified experimental setup so that we can determine the constant G with even greater precision.” Initial results are available but haven’t yet been published. However, Dual acknowledges that the new value is subject to a great deal of uncertainty: “To obtain a reliable value, we still need to reduce this uncertainty by a considerable amount. The value the researchers arrived at using this method is 2.2% higher than the current official value given by the Committee on Data for Science and Technology. Using laser devices, the team measured the motion of the two beams, and the measurement of this dynamic effect allowed them to infer the magnitude of the gravitational constant. After the researchers set one vibrating, gravitational coupling caused the second beam to also exhibit minimal movement (in the picometer range-i.e., one trillionth of a meter). The experimental setup consists of two beams suspended in vacuum chambers. To rule out sources of interference as far as possible, Dual’s team set up their measuring equipment in what used to be the Furggels fortress, located near Pfäfers above Bad Ragaz, Switzerland. He and his colleagues conducted a new experiment to redetermine the gravitational constant and have now presented their work in Nature Physics. “The only option for resolving this situation is to measure the gravitational constant with as many different methods as possible,” explains Jürg Dual, a professor in the mechanical and process engineering department at ETH Zurich. One reason gravity is extremely difficult to quantify is that it is a very weak force and cannot be isolated: when you measure the gravity between two bodies, you also measure the effect of all other bodies in the world. It is still less precise than the values of all the other fundamental natural constants-for example, the speed of light in a vacuum. Over the centuries, scientists have conducted numerous experiments to determine the value of G, but the scientific community isn’t satisfied with the current figure. The constant cannot be derived mathematically it has to be determined through experiment. It is part of Isaac Newton’s law of universal gravitation, which he first formulated more than 300 years ago. The gravitational constant G determines the strength of gravity-the force that makes apples fall to the ground or pulls the Earth in its orbit around the sun. Researchers have redetermined the gravitational constant G using a new measurement technique.Īlthough there is still a large degree of uncertainty regarding this value, the new method offers great potential for testing one of the most fundamental laws of nature.
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