Special relativity is a theory proposed by Albert Einstein that describes the relationship between space and time for objects moving at constant, high velocities relative to each other.

The two main postulates are: 1) The laws of physics are the same in all inertial (non-accelerating) frames of reference. 2) The speed of light in a vacuum is constant, regardless of the motion of the light source or observer.

Relativity refers to the idea that the laws of physics are the same for all non-accelerating observers, and that the rate at which time passes and spatial distances appear depends on the relative motion of the observer.

Time dilation is the phenomenon where time appears to move slower for an observer who is in motion relative to another observer. Clocks moving at higher speeds relative to an observer appear to tick more slowly.

Length contraction is the phenomenon where objects appear shortened along the direction of their relative motion to a stationary observer. The contraction increases as the relative velocity increases.

Space and time are interwoven into a single continuum known as spacetime according to special relativity. Events that appear simultaneous for one observer may occur at different times for another observer in motion relative to the first.

General relativity is Einstein's theory that describes gravity, not as a force, but as a consequence of the curvature of spacetime caused by the presence of mass and energy.

The equivalence principle states that the effects of gravity are indistinguishable from the effects of acceleration for an observer in small enough regions of spacetime.

A black hole is a region of spacetime where the gravitational pull is so strong that nothing, not even light, can escape from it. It is caused by an extremely compact mass that results in severe spacetime curvature.

General relativity explains gravity as the result of the curvature of spacetime caused by the presence of mass and energy. Objects follow the curved geometry of spacetime, which we experience as the force of gravity.

Some consequences include gravitational lensing, gravitational waves, the prediction of black holes, the expansion of the universe, and other effects that diverge from Newton's theory of gravity.

The detection of gravitational waves from merging black holes and neutron stars, as well as observations of black holes at the center of galaxies, have provided strong evidence for general relativity.

Relativity shows that space and time are not absolute and independent, but are interwoven into a 4-dimensional spacetime that bends and warps in the presence of mass and energy. Our notions of absolute space and time are challenged.

Applications include GPS navigation, understanding cosmological phenomena like black holes and the big bang, time dilation corrections for spacecraft, and potential future technologies like warp drives.

The speed of light is the maximum possible speed, and acts as the conversion factor between measurements of space and time intervals for different observers. Relativity shows that nothing can exceed this cosmic speed limit.

Einstein developed relativity by reconceptualizing space, time, energy, and gravity through thought experiments and by carefully examining the contradictions in classical physics that arose for objects moving at high velocities.

The equation E=mc^2 shows that energy (E) and mass (m) are related and interchangeable, where c is the speed of light. It implies that mass and energy are different forms of the same fundamental entity.

In general relativity, gravity is understood as the curvature of spacetime caused by mass and energy. Light follows the curved geometry, explaining effects like gravitational lensing around massive objects.

A gravitational wave is a ripple in the curvature of spacetime that propagates outward from accelerating massive objects, such as orbiting black holes or neutron stars. It carries energy away from the source.

At the event horizon of a black hole, an observer would experience extreme tidal forces and spaghettification as different parts of their body experience very different gravitational accelerations from the extreme curvature.

General relativity provides the theoretical framework for the Big Bang model. It predicts that a universe containing matter should expand or contract based on its overall density and curvature of spacetime.

A gravitational singularity is a point in spacetime where quantities like curvature and density become infinite, as mathematical descriptions break down. Singularities exist at the centers of black holes.

Whereas Newton viewed gravity as a force acting between masses, general relativity describes it as a manifestation of spacetime curvature caused by mass and energy. It matches Newton's laws in low gravity, but differs significantly in extreme conditions.

Gravitational time dilation is the phenomenon where time passes slower in regions with stronger gravitational fields compared to regions with weaker gravitational fields, due to differences in spacetime curvature.

The principle of general covariance states that the laws of physics must take the same form in all coordinate systems, accelerated or not. The laws must be generally covariant under coordinate transformations.

Spacetime curvature refers to the warping of the geometry of the combined space and time dimensions caused by the presence of mass and energy. This curvature is what we experience as gravity.

In relativity, space and time are merged into a single 4-dimensional continuum called spacetime. The geometry of this unified spacetime is warped by the presence of mass and energy, resulting in gravitational effects.

The twin paradox is a thought experiment involving a twin who goes on a high-speed trip while the other remains on Earth. Due to time dilation, the traveling twin ages less, appearing younger when reunited with the stationary twin.

In general relativity, planets follow curved paths through spacetime determined by the curvature around the sun's mass. This predicts minor deviations from Newton's elliptical orbits that have been observed.

No, special relativity alone cannot explain gravity or its effects. It deals only with frames of reference in uniform motion and the constant speed of light. General relativity is needed to incorporate gravity's influence.

Reference frames are crucial in relativity, as the laws of physics must take the same form for all inertial (non-accelerating) observers, while observations of space and time differ between relatively moving frames.

The Schwarzschild radius is the boundary of the event horizon of a non-rotating black hole. Within this radius, spacetime is so extremely curved that nothing, not even light, can escape the gravitational pull.

Newton's laws could not fully account for the motion of Mercury's perihelion. General relativity accurately predicts this by incorporating the curvature of spacetime around the sun's mass.

General relativity's equations allow for theoretical wormhole solutions that would act as shortcuts through spacetime. However, their existence remains speculative and may require exotic forms of matter to stabilize them.

In general relativity, spacetime geometry is represented by a 4-dimensional manifold described by the metric tensor, which is curved in the presence of mass and energy according to Einstein's field equations.

The cosmological constant is a term Einstein introduced in his field equations to allow for a static universe. It can be interpreted as a form of energy inherent to spacetime itself, related to the expansion of the universe.

Einstein's field equations mathematically relate the curvature of spacetime (on the left side) to the distribution of energy, momentum, and pressure throughout spacetime (on the right side).

The strength of gravitational lensing, where light is bent by massive objects, depends on the mass distribution of the deflector and the alignment between the source, lens, and observer.

General relativity revolutionized our understanding by describing gravity not as a force, but as a manifestation of curved spacetime caused by the presence of mass and energy, unifying gravity with the geometry of space and time.

Gravitational waves do not involve electromagnetic radiation. They are ripples in the curvature of spacetime itself propagating as gravitational radiation at the speed of light.

The frame-dragging effect, predicted by general relativity, is the twisting of spacetime geometry around a rotating massive object, caused by the object's angular momentum.

Relativity shows that mass and energy are interchangeable via the famous equation E=mc^2, where increased energy corresponds to increased mass. This relationship is a core principle of relativity.

Predictions that have been experimentally verified include the deflection of starlight by the sun's gravity, the precession of Mercury's orbit, gravitational redshift, gravitational lensing, gravitational waves, and the existence of black holes.

In general relativity, gravitational fields are not separate forces, but are instead manifestations of the curvature of spacetime itself caused by the presence of mass and energy.

At relativistic speeds close to the speed of light, an observer would perceive distances in the direction of motion to be contracted or shortened compared to distances measured perpendicular to the motion.

E=mc^2 shows that energy and mass are equivalent and interchangeable according to relativity. An increase in energy corresponds to an increase in mass, and vice versa.

Black holes contain singularities where general relativity's equations break down, challenging our understanding. Theories like string theory attempt to resolve these issues by describing gravity at the quantum scale.

General relativity does not incorporate quantum mechanics and fails to describe phenomena at the smallest scales. It also cannot account for the accelerating expansion of the universe without introducing a cosmological constant.