- "The theory of relativity usually encompasses two interrelated physics theories by Albert Einstein: special relativity and general relativity."
The study of how physical laws and measurements of space and time are perceived differently by different observers.
Lorentz transformation: The mathematical equations used to transform space and time coordinates from one inertial frame of reference to another.
Time dilation: The phenomenon where time appears to pass slower for a moving observer than for a stationary observer.
Length contraction: The phenomenon where lengths appear to be shorter for a moving observer than for a stationary observer.
Mass-energy equivalence: The mathematical relationship between mass and energy as described in Einstein's famous equation, e=mc^2.
Relativistic momentum: The momentum of a particle as described within the context of special relativity.
Relativistic energy: The energy of a system as described within the context of special relativity.
Causality and time travel: The implications of relativity for the possibility of traveling back in time and causing paradoxes.
Relativistic electrodynamics: The behavior of electric and magnetic fields as described within the context of special relativity.
Four-vectors: A mathematical construct used to describe space and time in a unified way in special relativity.
Relativistic Doppler effect: The shift in frequency of a wave due to the relative motion between the source and observer.
Gravitational redshift: The shifts in frequency observed from two clocks in different gravitational potentials.
Twin paradox: A thought experiment that illustrates the difference in aging between a twin who remains stationary and one who travels at relativistic speeds.
Quantum field theory in curved spacetime: The behavior of quantum fields in gravitational fields according to the principles of special relativity.
Black holes: A phenomenon in which gravitational fields become so strong that nothing can escape, including light.
Cosmology: The study of the origin, structure, and evolution of the universe within the framework of special relativity.
Lorentz Transformations: This is the essential framework of special relativity, which comprises of mathematical transformations that enable consistent conversion of coordinates, time, and other physical quantities between reference frames in which an observer is at rest and one that is moving at a constant velocity.
Time Dilation: Time dilation is a type of special relativity that shows how time appears to pass slower for an object moving at high speed than for one at rest. This effect has been observed in particle accelerators.
Length Contraction: Length contraction is a similar phenomenon where the length of an object appears to shorten as it moves closer to the speed of light, as seen from an observer at rest.
Mass Increase: Special relativity also posits that as objects move closer to the speed of light, their mass increases. The concept is often used to explain why it becomes increasingly difficult to accelerate particles to relativistic speeds.
Twin Paradox: The twin paradox is a thought experiment in special relativity that shows how the passage of time differs depending on relative motion. One twin who remains on Earth ages more than the other twin who travels in a spaceship at relativistic speeds and returns to Earth.
Relativistic Doppler Effect: The Doppler effect is a phenomenon where sound waves or light waves appear to change frequency depending on relative motion. In special relativity, this effect is further enhanced due to the time dilation and length contraction.
Quantum Electrodynamics: Quantum electrodynamics is a branch of theoretical physics that incorporates both special relativity and quantum mechanics to describe the behavior of subatomic particles like electrons and photons.
Relativity of Simultaneity: The concept of a universal time is abandoned in special relativity as it posits that the concept of simultaneity depends on the reference frame of the observer.
Lorentz Invariance: Lorentz invariance is an essential feature of special relativity. It implies that the laws of physics remain unchanged under the Lorentz transformations.
Generalization to General Relativity: Special relativity is a critical foundation to the more comprehensive theory of general relativity, which includes gravity and non-inertial reference frames.
- "Special relativity was proposed and published in 1905 and general relativity in 1915, respectively."
- "Special relativity applies to all physical phenomena in the absence of gravity."
- "General relativity explains the law of gravitation and its relation to the forces of nature."
- "General relativity applies to the cosmological and astrophysical realm, including astronomy."
- "It superseded a 200-year-old theory of mechanics created primarily by Isaac Newton."
- "It introduced concepts including 4-dimensional spacetime as a unified entity of space and time, relativity of simultaneity, kinematic and gravitational time dilation, and length contraction."
- "With relativity, cosmology and astrophysics predicted extraordinary astronomical phenomena such as neutron stars, black holes, and gravitational waves."
- "The theory transformed theoretical physics and astronomy during the 20th century."
- "Relativity improved the science of elementary particles and their fundamental interactions."
- "With relativity, cosmology and astrophysics predicted extraordinary astronomical phenomena such as neutron stars, black holes, and gravitational waves."
- "It introduced 4-dimensional spacetime as a unified entity of space and time."
- "General relativity explains the law of gravitation and its relation to the forces of nature."
- "It introduced concepts including... kinematic and gravitational time dilation."
- "With relativity, cosmology and astrophysics predicted extraordinary astronomical phenomena such as neutron stars, black holes, and gravitational waves."
- "It introduced concepts including... 4-dimensional spacetime as a unified entity of space and time."
- "With relativity, cosmology and astrophysics predicted extraordinary astronomical phenomena such as neutron stars, black holes, and gravitational waves."
- "The theory transformed... astronomy during the 20th century."
- "It superseded a 200-year-old theory of mechanics created primarily by Isaac Newton."
- "Relativity improved the science of elementary particles and their fundamental interactions, along with ushering in the nuclear age."