Frame of reference in which a specified particle is at rest
In special relativity, the rest frame of a particle is the frame of reference (a coordinate system attached to physical markers) in which the particle is at rest.
The rest frame of compound objects (such as a fluid, or a solid made of many vibrating atoms) is taken to be the frame of reference in which the average momentum of the particles which make up the substance is zero (the particles may individually have momentum, but collectively have no net momentum). The rest frame of a container of gas, for example, would be the rest frame of the container itself, in which the gas molecules are not at rest, but are no more likely to be traveling in one direction than another. The rest frame of a river would be the frame of an unpowered boat, in which the mean velocity of the water is zero. This frame is also called the center-of-mass frame, or center-of-momentum frame.
The center-of-momentum frame is notable for being the reference frame in which the total energy (total relativistic energy) of a particle or compound object, is also the invariant mass (times the scale-factor speed of light squared). It is also the reference frame in which the object or system has minimum total energy.
In both special relativity and general relativity it is essential to specify the rest frame of any time measurements, as the time that an event occurred is dependent on the rest frame of the observer. For this reason the timings of astronomical events such as supernovae are usually recorded in terms of when the light from the event reached Earth, as the "real time" that the event occurred depends on the rest frame chosen. For example, in the rest frame of a neutrino particle travelling from the Crab Nebula supernova to Earth, the supernova occurred in the 11th Century AD only a short while before the light reached Earth, but in Earth's rest frame the event occurred about 6300 years earlier.
the restframe of a particle is the frame of reference (a coordinate system attached to physical markers) in which the particle is at rest. The rest frame...
center-of-momentum frame exists for the system, then the invariant mass of a system is equal to its total mass in that "restframe". In other reference...
Proper length or rest length is the length of an object in the object's restframe. The measurement of lengths is more complicated in the theory of relativity...
stationary in an inertial frame. Analyzed in Stella's restframe, she is motionless for the entire trip. When she is coasting her restframe is inertial, and Terence's...
In astronomy, the local standard of rest or LSR is a reference frame which follows the mean motion of material in the Milky Way in the neighborhood of...
its proper length, which is the length as measured in the object's own restframe. It is also known as Lorentz contraction or Lorentz–FitzGerald contraction...
{rel} A}} ), is the velocity vector of an object or observer B in the restframe of another object or observer A. The relative speed v B ∣ A = ‖ v → B...
the moving clock as ticking more slowly than a clock at rest in the observer's own reference frame. In addition, a clock that is close to a massive body...
further illustrated by the Minkowski diagram below. The diagram is in the restframe of the garage. The vertical light-blue band shows the garage in spacetime...
peculiar velocity refers to the velocity of an object relative to a restframe — usually a frame in which the average velocity of some objects is zero. In galactic...
appear isotropic in the restframe (in this case, the jet) appear pushed towards the direction of motion in the observer's frame (in this case, Earth)....
innovation of 1908. While a frame at rest in a Minkowski diagram has orthogonal spacetime axes, a frame moving relative to the restframe in a Minkowski diagram...
as seen in the frame in which the clock is moving (S′), is longer than the time (Δt) between these ticks as measured in the restframe of the clock (S)...
kinetic energy Er is the rotational energy or angular kinetic energy in the restframe Thus the kinetic energy of a tennis ball in flight is the kinetic energy...
{\displaystyle \tau } is the proper time as measured by a clock in the restframe of the particle and the Minkowski metric is given by η μ ν = η μ ν = (...
mass" is usually preferred over rest energy. The measurable inertia and the warping of spacetime by a body in a given frame of reference is determined by...
relativity states that the speed of light is invariant for all observers in any frame of reference; that is, it is always the same. Time dilation is a direct...
becomes observational frame of reference (or observational reference frame), which implies that the observer is at rest in the frame, although not necessarily...
ultraviolet, X-ray and even gamma rays. Most quasars are brightest in their rest-frame ultraviolet wavelength of 121.6 nm Lyman-alpha emission line of hydrogen...
straight wire that carries an electrical current. In the frame of reference where the laboratory is at rest, the wire is motionless and electrically neutral:...
six-parameter family of linear transformations from a coordinate frame in spacetime to another frame that moves at a constant velocity relative to the former...
of a typical object in the system, measured in the frame of reference where the object is at rest, and c {\displaystyle c} is the speed of light. The...
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