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Physicists search for new physics in primordial quantum fluctuations

(PhysOrg.com) -- Inflation, the brief period that occurred less than a second after the Big Bang, is nearly as difficult to fathom as the Big Bang itself. Physicists calculate that inflation lasted for just ...

Physics / Quantum Physics

created Mar 26, 2012 | popularity 4.6 / 5 (25) | comments 99 | with audio podcast feature

Why we've got the cosmological constant all wrong

(PhysOrg.com) -- Some scientists call the cosmological constant the "worst prediction of physics." And when today’s theories give an estimated value that is about 120 orders of magnitude larger than the ...

Physics / General Physics

created Mar 05, 2012 | popularity 4.5 / 5 (41) | comments 152 | with audio podcast feature

Repulsive gravity as an alternative to dark energy (Part 2: In the quantum vacuum)

(PhysOrg.com) -- During the past few years, CERN physicist Dragan Hajdukovic has been investigating what he thinks may be a widely overlooked part of the cosmos: the quantum vacuum. He suggests that the quantum vacuum has ...

Physics / General Physics

created Feb 01, 2012 | popularity 4.7 / 5 (77) | comments 143 | with audio podcast report

Repulsive gravity as an alternative to dark energy (Part 1: In voids)

(PhysOrg.com) -- When scientists discovered in 1998 that the Universe is expanding at an accelerating rate, the possibility that dark energy could explain the observation was intriguing. But because there ...

Physics / General Physics

created Jan 31, 2012 | popularity 4.6 / 5 (49) | comments 125 | with audio podcast report

Decoding cosmological data could shed light on neutrinos, modified gravity

(PhysOrg.com) -- Today’s most powerful telescopes collect huge amounts of data from the most distant locations of the universe – yet much of the information is simply discarded because it involves ...

Physics / General Physics

created Jan 17, 2012 | popularity 4.8 / 5 (13) | comments 104 | with audio podcast feature

Physicists propose test for loop quantum gravity

(PhysOrg.com) -- As a quantum theory of gravity, loop quantum gravity could potentially solve one of the biggest problems in physics: reconciling general relativity and quantum mechanics. But like all tentative ...

Physics / Quantum Physics

created Jan 03, 2012 | popularity 4.3 / 5 (34) | comments 106 | with audio podcast feature

Four reasons why the quantum vacuum may explain dark matter

(PhysOrg.com) -- Earlier this year, PhysOrg reported on a new idea that suggested that gravitational charges in the quantum vacuum could provide an alternative to dark matter. The idea rests on the hypothesis that particles ...

Physics / General Physics

created Nov 28, 2011 | popularity 5 / 5 (67) | comments 124 | with audio podcast report

Water waves exhibit negative gravity near a periodic array of buoys

(PhysOrg.com) -- Ocean waves can be incredibly strong and very difficult to block completely. When a wave moving across the ocean interacts with a buoy, the wave can be slightly dampened, but will still pass ...

Physics / Condensed Matter

created May 09, 2011 | popularity 3.8 / 5 (21) | comments 17 | with audio podcast feature

Antimatter gravity could explain Universe's expansion

(PhysOrg.com) -- In 1998, scientists discovered that the Universe is expanding at an accelerating rate. Currently, the most widely accepted explanation for this observation is the presence of an unidentified ...

Physics / General Physics

created Apr 13, 2011 | popularity 4.8 / 5 (44) | comments 266 | with audio podcast feature

Physicists investigate fate of five-dimensional black strings

(PhysOrg.com) -- While black holes in four-dimensional space-time are stable and can persist for a long time, their higher-dimensional analogues are usually unstable. One such theoretical analogue is a five-dimensional ...

Physics / General Physics

created Sep 10, 2010 | popularity 4.5 / 5 (36) | comments 14 | with audio podcast feature

Time travel theory avoids grandfather paradox

(PhysOrg.com) -- The possibility of going back in time only to kill your ancestors and prevent your own birth has posed a serious problem for potential time travelers, not even considering the technical details ...

Physics / Quantum Physics

created Jul 21, 2010 | popularity 4.1 / 5 (55) | comments 96 | with audio podcast report

Revised theory of gravity doesn't predict a Big Bang

(PhysOrg.com) -- The Big Bang theory has formed the basis of our understanding of the universe's origins since it was first proposed in 1927 by Georges Lemaitre. And for good reason: the theory is supported ...

Physics / General Physics

created Jul 12, 2010 | popularity 4.7 / 5 (77) | comments 213 | with audio podcast feature

Proposed test of weak equivalence principle could be most accurate yet

(PhysOrg.com) -- The weak equivalence principle (WEP) - which states that all bodies fall at the same rate in a gravitational field, regardless of structure or composition - is one of the key postulates of ...

Physics / General Physics

created May 03, 2010 | popularity 4.8 / 5 (18) | comments 18 feature

Einstein equations indicate possibility of black hole formation at the LHC

(PhysOrg.com) -- One of the concerns that has been voiced about the Large Hadron Collider (LHC), is that it could result in the formation of black holes that could destroy the world. While most scientists ...

Physics / General Physics

created Apr 06, 2010 | popularity 4 / 5 (63) | comments 364 | with audio podcast feature

Proposed Spacetime Structure Could Provide Hints for Quantum Gravity Theory

(PhysOrg.com) -- Spacetime, which consists of three dimensions of space and one time dimension, is such a large, abstract concept that scientists have a very difficult time understanding and defining it. Moreover, ...

Physics / Quantum Physics

created Dec 16, 2009 | popularity 4.6 / 5 (58) | comments 16 feature

Gravitation

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.

For more information about Gravitation, read the full article at Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.