Roman Space Telescope will also find rogue black holes

In the past, we've reported about how the Roman Space Telescope is potentially going to be able to detect hundreds of thousands of exoplanets using a technique known as microlensing. Exoplanets won't be the only things it ...

How a ladybug warps space-time

Researchers at the University of Vienna and the Austrian Academy of Sciences, led by Markus Aspelmeyer have succeeded in measuring the gravitational field of a gold sphere, just 2 mm in diameter, using a highly sensitive ...

Factoring in gravitomagnetism could do away with dark matter

Observations of galactic rotation curves give one of the strongest lines of evidence pointing towards the existence of dark matter, a non-baryonic form of matter that makes up an estimated 85% of the matter in the observable ...

Researchers uncover key clues about the solar system's history

In a new paper published in the journal Nature Communications Earth and Environment, researchers at the University of Rochester were able to use magnetism to determine, for the first time, when carbonaceous chondrite asteroids—asteroids ...

Gaia: Most accurate data ever for nearly two billion stars

Today (3 December), an international team of astronomers announced the most detailed ever catalogue of the stars in a huge swathe of our Milky Way galaxy. The measurements of stellar positions, movement, brightness and colours are ...

Earth may have captured a stray 1960s-era rocket booster

Earth has captured a tiny object from its orbit around the sun and will keep it as a temporary satellite for a few months before it escapes back to a solar orbit. But the object is likely not an asteroid; it's probably the ...

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Newton's law of universal gravitation

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.

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