Latest Theories of gravitation Stories
While airplane and rocket experiments have proved that gravity makes clocks tick more slowly â€“ a central prediction of Albert Einstein's general theory of relativity â€“ a new experiment in an atom interferometer measures this slowdown 10,000 times more accurately than before, and finds it to be exactly what Einstein predicted.
Does an exciting but controversial new model of quantum gravity reproduce Einstein's theory of general relativity?
Quantum mechanics and Einstein's theory of general relativity are both extremely accurate theories of how the universe works, but all attempts to combine the two into a unified theory have ended in failure.
When the world's most powerful particle accelerator starts up later this year, exotic new particles may offer a glimpse of the existence and shapes of extra dimensions.
There is no attractive gravitational force between matter. Gravitation is based on a repelling force. Gravitation arises from particle pressure towards matter.
Two Canadian researchers at the Perimeter Institute for Theoretical Physics suggest that the motion of galaxies in a distant cluster is more easily explained by a Modified Gravity (MOG) theory than by the presence of dark matter.
In the folklore of physics, no story is better known than the tale of Galileo dropping balls from the Leaning Tower of Pisa and proving that gravity accelerates all objects equally regardless of their masses or composition. But was Galileo correct?
Measuring an anomaly in the gravitational force would be evidence for new subatomic particles, or an indication that the universe has more than four dimensions.
For almost 100 years, scientists have been searching for direct evidence of the existence of gravity waves â€“ faint ripples in the fabric of spacetime predicted in Albert Einsteinâ€™s theory of General Relativity.
Thirty-five years after Moon-walking astronauts placed special reflectors on the lunar surface, scientists have used these devices to test Albert Einstein's general theory of relativity to unprecedented accuracy. The findings may help to explain physical laws of the universe and benefit future space missions.
Classical and Quantum Gravity is a peer-reviewed journal published by IOP Science. As of May 2012, the editor-in-chief is Clifford M Will (Washington University, St. Louis). The journal covers all aspects of gravitational physics and the theory of space-time. It scope includes: Classical general relativity, Applications of relativity, Experimental gravitation, Cosmology and the early universe, Quantum gravity, Supergravity, superstrings and supersymmetry, and Mathematical physics relevant...
String Theory -- A string theory is a physical model whose fundamental building blocks are extended objects (strings, membranes and higher-dimensional objects) rather than points. String theories are able to avoid problems, such as infinite energy density, associated with the presence of mathematical points in a physical theory. The term 'string theory' properly refers to both the 26 dimensional bosonic string theories and to the 10 dimensional superstring theories discovered by...