(Phys.org) —The universe may have existed forever, according to a new model that applies quantum correction terms to complement Einstein's theory of general relativity. The model may also account for dark matter and dark ...
(PhysOrg.com) -- Earth usually has more than one moon, according to a team of astronomers from the University of Helsinki, the Paris Observatory and the University of Hawaii at Manoa.
Space Exploration
Apr 4, 2012
19
0
A new theory of gravity might explain the curious motions of stars in galaxies. Emergent gravity, as the new theory is called, predicts the exact same deviation of motions that is usually explained by invoking dark matter. ...
General Physics
Nov 8, 2016
184
13980
Gravity is a fundamental force of physics, one which we Earthlings tend to take for granted. You can't really blame us. Having evolved over the course of billions of years in Earth's environment, we are used to living with ...
Space Exploration
Jan 1, 2016
0
56
A radical theory that consistently unifies gravity and quantum mechanics while preserving Einstein's classical concept of spacetime has been announced in two papers published simultaneously by UCL (University College London) ...
General Physics
Dec 4, 2023
30
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(Phys.org)—The possibility that other universes exist beyond our own universe is tantalizing, but seems nearly impossible to test. Now a group of physicists has suggested that the Large Hadron Collider (LHC), the largest ...
A team led by astronomer Margot Brouwer (Leiden Observatory, The Netherlands) has tested the new theory of theoretical physicist Erik Verlinde (University of Amsterdam) for the first time through the lensing effect of gravity. ...
Astronomy
Dec 16, 2016
180
17125
Symmetry has been one of the guiding principles in physicists' search for fundamental laws of nature. What does it mean that laws of nature have symmetry? It means that laws look the same before and after an operation, similar ...
General Physics
Jan 24, 2020
32
4638
(Phys.org) —The quintessential feature of a black hole is its "point of no return," or what is more technically called its event horizon. When anything—a star, a particle, or wayward human—crosses this horizon, the ...
A Harvard physicist has shown that wormholes can exist: tunnels in curved space-time, connecting two distant places, through which travel is possible.
General Physics
Apr 15, 2019
13
2079
Gravitation is a natural phenomenon by which objects with mass attract one another. In everyday life, gravitation is most commonly thought of as the agency which lends weight to objects with mass. Gravitation compels dispersed matter to coalesce, thus accounting for the existence of the Earth, the Sun, and most of the macroscopic objects in the universe. It is responsible for keeping the Earth and the other planets in their orbits around the Sun; for keeping the Moon in its orbit around the Earth; for the formation of tides; for convection, by which fluid flow occurs under the influence of a temperature gradient and gravity; for heating the interiors of forming stars and planets to very high temperatures; and for various other phenomena observed on Earth. Modern physics describes gravitation using the general theory of relativity, in which gravitation is a consequence of the curvature of spacetime which governs the motion of inertial objects. The simpler Newton's law of universal gravitation provides an accurate approximation for most calculations.
The terms gravitation and gravity are mostly interchangeable in everyday use, but a distinction is made in scientific circles. "Gravitation" is a general term describing the phenomenon by which bodies with mass are attracted to one another, while "gravity" refers specifically to the net force exerted by the Earth on objects in its vicinity as well as by other factors, such as the Earth's rotation.
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