For those still holding out hope that antimatter levitates rather than falls in a gravitational field, like normal matter, the results of a new experiment are a dose of cold reality.
General Physics
Sep 27, 2023
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1881
Yale researchers may have solved a longstanding puzzle as to why certain metallic meteorites show traces of a magnetic field—a finding that may shed light on the formation of magnetic dynamos at the core of planets.
Astronomy
Aug 1, 2023
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2845
Earth is rapidly warming and scientists are developing a variety of approaches to reduce the effects of climate change. István Szapudi, an astronomer at the University of Hawaiʻi Institute for Astronomy, has proposed a ...
Planetary Sciences
Jul 31, 2023
23
186
Gravitational astronomy is a relatively new discipline that has opened many doors for astronomers to understand how the huge and violent end of the scale works. It has been used to map out merging black holes and other extreme ...
Astronomy
Jul 3, 2023
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99
Looking to the not-too-distant future when the European Service Module will propel European astronauts in the Orion spacecraft to the Gateway and on to the surface of the moon, scientists and engineers are eagerly exploring ...
Space Exploration
Jun 30, 2023
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12
A joint research group led by Prof. Sheng Dong and Prof. Lu Zhengtian from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS), investigated the coupling effect between neutron ...
Quantum Physics
Jun 16, 2023
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857
Despite the enormous densities, the early universe didn't collapse into a black hole because, simply put, there was nothing to collapse into.
Astronomy
Jun 12, 2023
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91
According to Einstein's general theory of relativity, time and space are fused together in a quantity known as spacetime. The theory suggests that massive objects, like a galaxy or galaxy clusters, can cause spacetime to ...
Astronomy
Jun 12, 2023
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140
Currently about halfway through the Euclid simulations campaign, the key focus in the Main Control Room is the Launch and Early Orbit Phase (LEOP) and spacecraft commissioning.
Space Exploration
Jun 6, 2023
0
13
Our familiar, warm, yellow sun is a relative rarity in the Milky Way. By far the most common stars are considerably smaller and cooler, sporting just half the mass of our sun at most. Billions of planets orbit these common ...
Planetary Sciences
May 29, 2023
7
811
Newton's law of universal gravitation is a general physical law derived from empirical observations by what Isaac Newton called induction. It describes the gravitational attraction between bodies with mass. It is a part of classical mechanics and was first formulated in Newton's work Philosophiae Naturalis Principia Mathematica ("the Principia"), first published on 5 July 1687. In modern language it states the following:
Every point mass attracts every other point mass by a force pointing along the line intersecting both points. The force is directly proportional to the product of the two masses and inversely proportional to the square of the distance between the point masses:
Assuming SI units, F is measured in newtons (N), m1 and m2 in kilograms (kg), r in meters (m), and the constant G is approximately equal to 6.673×10−11 N m2 kg−2. The value of the constant G was first accurately determined from the results of the Cavendish experiment conducted by the British scientist Henry Cavendish in 1798, although Cavendish did not himself calculate a numerical value for G). This experiment was also the first test of Newton's theory of gravitation between masses in the laboratory. It took place 111 years after the publication of Newton's Principia and 71 years after Newton's death, so none of Newton's calculations could use the value of G; instead he could only calculate a force relative to another force.
Newton's law of gravitation resembles Coulomb's law of electrical forces, which is used to calculate the magnitude of electrical force between two charged bodies. Both are inverse-square laws, in which force is inversely proportional to the square of the distance between the bodies. Coulomb's Law has the product of two charges in place of the product of the masses, and the electrostatic constant in place of the gravitational constant.
Newton's law has since been superseded by Einstein's theory of general relativity, but it continues to be used as an excellent approximation of the effects of gravity. Relativity is only required when there is a need for extreme precision, or when dealing with gravitation for very massive objects.
This text uses material from Wikipedia, licensed under CC BY-SA
