It's a fact that many of us have churned out during public engagement events that at least 50% of all stars are part of binary star systems. Some of them are simply stunning to look at; others present headaches with complex ...
Astronomy
23 hours ago
1
15
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
21
5938
A cornerstone but surprising prediction arising from Einstein's theory of general relativity is the existence of black holes, which astronomers later found to be widespread throughout the universe. Key characteristics of ...
Astronomy
Nov 30, 2023
0
79
An international team of researchers including Prof. Badri Krishnan at Radboud University has verified an important property of black holes known as the no-hair theorem using gravitational wave observations. Their research ...
General Physics
Nov 30, 2023
2
94
When galaxies collide, their supermassive black holes enter into a gravitational dance, gradually orbiting each other ever closer until eventually merging. We know they merge because we see the gravitational beasts that result, ...
Astronomy
Nov 27, 2023
1
55
In Einstein's famous theory of relativity the concepts of immutable space and time aren't just put aside, they're explicitly and emphatically rejected. Space and time are now woven into a coexisting fabric. That is to say, ...
General Physics
Nov 13, 2023
14
104
Astronomers are currently pushing the frontiers of astronomy. At this very moment, observatories like the James Webb Space Telescope (JWST) are visualizing the earliest stars and galaxies in the universe, which formed during ...
Astronomy
Nov 1, 2023
1
108
If you, like me, have used telescopes to gaze out at the wonders of the universe, then you too may have been a little captivated by the topic of gravitational lensing. Think about it: how cool is it that the very universe ...
Astronomy
Nov 1, 2023
0
27
Researchers from the University of Southampton, together with colleagues from the universities of Cambridge and Barcelona, have shown it's theoretically possible for black holes to exist in perfectly balanced pairs—held ...
General Physics
Oct 22, 2023
22
127
When two black holes collide, the impact is so big that we can detect it all way here on Earth. These objects are so immense that their collisions send ripples through spacetime itself. Scientists call these ripples gravitational ...
Astronomy
Oct 11, 2023
0
94
General relativity or the general theory of relativity is the geometric theory of gravitation published by Albert Einstein in 1916. It is the current description of gravitation in modern physics. It unifies special relativity and Newton's law of universal gravitation, and describes gravity as a geometric property of space and time, or spacetime. In particular, the curvature of spacetime is directly related to the four-momentum (mass-energy and linear momentum) of whatever matter and radiation are present. The relation is specified by the Einstein field equations, a system of partial differential equations.
Many predictions of general relativity differ significantly from those of classical physics, especially concerning the passage of time, the geometry of space, the motion of bodies in free fall, and the propagation of light. Examples of such differences include gravitational time dilation, the gravitational redshift of light, and the gravitational time delay. General relativity's predictions have been confirmed in all observations and experiments to date. Although general relativity is not the only relativistic theory of gravity, it is the simplest theory that is consistent with experimental data. However, unanswered questions remain, the most fundamental being how general relativity can be reconciled with the laws of quantum physics to produce a complete and self-consistent theory of quantum gravity.
Einstein's theory has important astrophysical implications. It points towards the existence of black holes—regions of space in which space and time are distorted in such a way that nothing, not even light, can escape—as an end-state for massive stars. There is evidence that such stellar black holes as well as more massive varieties of black hole are responsible for the intense radiation emitted by certain types of astronomical objects such as active galactic nuclei or microquasars. The bending of light by gravity can lead to the phenomenon of gravitational lensing, where multiple images of the same distant astronomical object are visible in the sky. General relativity also predicts the existence of gravitational waves, which have since been measured indirectly; a direct measurement is the aim of projects such as LIGO. In addition, general relativity is the basis of current cosmological models of a consistently expanding universe.
This text uses material from Wikipedia, licensed under CC BY-SA
