"General relativity is a theory of gravitation developed by Albert Einstein between 1907 and 1915."
An introduction to the concept of gravity and its effect on space and time according to General Relativity.
Newtonian Gravity: The classical theory of gravity that describes the interactions between two massive bodies.
Galilean Relativity: The idea that the laws of physics are the same in all inertial frames of reference.
Special Relativity: A theory that describes the relationship between space and time in the absence of gravity. It involves concepts such as time dilation and length contraction.
Lorentz Transformations: The mathematical transformations that relate the measurements of space and time between different frames of reference in special relativity.
Minkowski Space: The space-time geometry used in special relativity that allows for the representation of events in a four-dimensional spacetime.
General Relativity: A theory that includes gravity as a curvature of spacetime. It involves concepts such as the equivalence principle and the geodesic equation.
Einstein Field Equations: The equations used to describe the curvature of spacetime in general relativity.
Black Holes: Regions of spacetime where the gravitational pull is so strong that nothing, not even light, can escape.
Gravitational Waves: Ripples in the fabric of spacetime that are produced by the acceleration of massive objects.
Cosmic Inflation: An early period of rapid expansion in the universe thought to have been caused by a repulsive gravitational force.
Dark Energy: A hypothetical form of energy that is thought to be responsible for the accelerating expansion of the universe.
Time Travel: The concept of moving through time, which is affected by gravitational fields and the speed at which an object is traveling.
Singularity: A point in space or time where the laws of physics break down and can no longer be applied.
Wormholes: Hypothetical tunnels that connect two different points in space-time, which are allowed by the equations of general relativity.
Energy-momentum Tensor: A mathematical object used in general relativity to describe the distribution of mass, energy, and momentum throughout space-time.
General Relativity: A theory of gravitation that was developed by Albert Einstein in the early 20th century. It uses the concept of spacetime, and states that massive objects warp this fabric of spacetime, causing other objects to move in a certain way around them. General relativity has been confirmed through many experiments and observations.
Newtonian Gravity: A concept of gravity developed by Sir Isaac Newton in the 17th century. It explains how all objects with mass are attracted to each other, and how the strength of this attraction increases with the mass of the objects and decreases with the distance between them. Newtonian gravity is still used today in most cases because it is simpler to apply than general relativity.
Quantum Gravity: A theoretical concept that attempts to reconcile general relativity and quantum mechanics. It suggests that gravity is caused by particles called gravitons, and involves very small scales, and currently there is no experimentally confirmed theory of quantum gravity.
Modified Newtonian Dynamics (MOND): A controversial theory that proposes modifying Newton's laws of gravity in order to explain some observed phenomena without the need for dark matter. MOND proposes that the gravitational force changes at very low accelerations, rather than continuing to follow Newton's laws.
Einstein-Cartan Gravity: A theory that combines general relativity with the concept of spinning particles called fermions. It suggests that the presence of these particles causes a curvature in spacetime, which then affects the motion of other particles.
String Theory Gravity: A theoretical framework that combines gravity with quantum mechanics by assuming that the fundamental building blocks of the universe are not particles, but rather extended one-dimensional objects called strings. This theory is still in early stages of development and there are no confirmed experiments on it till now.
Conformal Gravity: A theory that modifies general relativity by introducing a new scalar field that affects the curvature of spacetime. It also proposes a fundamental new symmetry that allows for more elaborate modifications of general relativity.
Rosen's bimetric gravity: A formulation of general relativity in which two metrics coexist. It reformulates General Relativity to eliminate the cosmological constant by introducing a second metric that couples to the first, somewhat reminiscent of Supergravity.
"The theory of general relativity says that the observed gravitational effect between masses results from their warping of spacetime."
"By the beginning of the 20th century, Newton's law of universal gravitation had been accepted for more than two hundred years as a valid description of the gravitational force between masses."
"In Newton's model, gravity is the result of an attractive force between massive objects."
"Experiments and observations show that Einstein's description of gravitation accounts for several effects that are unexplained by Newton's law, such as minute anomalies in the orbits of Mercury and other planets."
"General relativity also predicts novel effects of gravity, such as gravitational waves, gravitational lensing, and an effect of gravity on time known as gravitational time dilation."
"Many of these predictions have been confirmed by experiment or observation, most recently gravitational waves."
"General relativity has developed into an essential tool in modern astrophysics."
"It provides the foundation for the current understanding of black holes, regions of space where the gravitational effect is strong enough that even light cannot escape."
"Their strong gravity is thought to be responsible for the intense radiation emitted by certain types of astronomical objects (such as active galactic nuclei or microquasars)."
"General relativity is also part of the framework of the standard Big Bang model of cosmology."
"Although general relativity is not the only relativistic theory of gravity..."
"...it is the simplest one that is consistent with the experimental data."
"The most fundamental of which is how general relativity can be reconciled with the laws of quantum physics to produce a complete and self-consistent theory of quantum gravity."