The relationship between mass and energy as described by Einstein's famous equation, E=mc².
Speed of Light: The maximum speed at which energy, matter, and information can travel in the universe.
Mass-Energy Equivalence: The concept that mass is a form of energy and can, therefore, be converted into energy and vice versa.
Space-time: The concept of treating space and time as a unified fabric, where distance and time are relative to the observer's frame of reference.
Lorentz Transformations: Mathematical equations that describe how space and time are perceived by observers in relative motion.
Time Dilation: The phenomenon where the time interval between two events is longer for an observer in relative motion compared to a stationary observer.
Length Contraction: The phenomenon where the length of an object appears shorter to an observer in relative motion compared to a stationary observer.
Relativistic Doppler Effect: The shift in frequency and wavelength of electromagnetic radiation due to the relative motion between the source and observer.
Twin Paradox: A thought experiment in which one twin travels at a significant fraction of the speed of light relative to the other twin, causing a difference in their aging.
General Relativity: The theory of gravity that describes the curvature of space-time due to the presence of massive objects and how objects move in that curved space.
Black Holes: An object with such a strong gravitational field that nothing, including light, can escape from it.
Wormholes: A hypothetical shortcut through space-time that connects two distant points.
Gravitational Waves: The ripples in the fabric of space-time caused by the acceleration of massive objects.
Quantum Gravity: The quest to unify Einstein's theory of general relativity with quantum mechanics, the theory of the very small.
Energy-Momentum Conservation: The principle that energy and momentum are always conserved in interactions between objects, as well as how it relates to mass-energy equivalence.
Einstein's Field Equations: The set of equations that describe the relationship between the curvature of space-time and the distribution of matter and energy.
Dark Matter and Dark Energy: The mysterious substances that are thought to make up the majority of the universe's mass and energy.
Black Hole Information Paradox: The problem of reconciling quantum mechanics and general relativity in the presence of black holes.
Cosmology: The study of the origin, structure, evolution, and ultimate fate of the universe, including the implications of relativity for the evolution of the universe.
Gravitational Lensing: The bending of light by the gravity of massive objects and its use in astrophysics and cosmology.
Unification of Forces: Attempts to unify the fundamental forces of nature, including gravity, electromagnetism, and the strong and weak nuclear forces.
Mass-energy equivalence: This equation relates mass and energy, and states that the mass of an object is equivalent to a certain amount of energy, given by E=mc².
Kinetic energy: The energy of an object due to its motion, given by E=(1/2)mv².
Radiant energy: Energy carried by electromagnetic waves, such as light.
Rest energy: The energy an object possesses simply due to its mass, given by E=mc².
Gravitational potential energy: The energy an object possesses due to its position in a gravitational field, given by E=Gm₁m₂/r.
Binding energy: The energy required to separate two objects that are bound together, such as the energy that holds the nucleus of an atom together.
Dark energy: A type of energy that is thought to drive the acceleration of the expansion of the universe.
Dark matter energy: A hypothetical form of energy associated with dark matter, which is thought to make up a large portion of the universe's mass.
Vacuum energy: The energy associated with the vacuum of space, which is thought to play a role in the expansion of the universe.
Stress-energy tensor: A mathematical description of the energy and momentum of matter and fields in spacetime.