Relativistic mechanics in the context of "Relativistic quantum chemistry"

This list includes well-known general theories in science and pre-scientific natural history and natural philosophy that have since been superseded by other scientific theories. Many discarded explanations were once supported by a scientific consensus, but replaced after more empirical information became available that identified flaws and prompted new theories which better explain the available data. Pre-modern explanations originated before the scientific method, with varying degrees of empirical support.

Some scientific theories are discarded in their entirety, such as the replacement of the phlogiston theory by energy and thermodynamics. Some theories known to be incomplete or in some ways incorrect are still used. For example, Newtonian classical mechanics is accurate enough for practical calculations at everyday distances and velocities, and it is still taught in schools. The more complicated relativistic mechanics must be used for long distances and velocities nearing the speed of light, and quantum mechanics for very small distances and objects.

In physics, classical mechanics is a theory that describes the effect of forces on the motion of macroscopic objects and bulk matter, without considering quantum effects, and often without incorporating relativistic effects either.

It is used in describing the motion of objects such as projectiles, parts of machinery, spacecraft, planets, stars, galaxies, deformable solids, fluids, macromolecules and other objects. The development of classical mechanics involved substantial change in the methods and philosophy of physics. The qualifier classical distinguishes this type of mechanics from new methods developed after the revolutions in physics of the early 20th century which revealed limitations in classical mechanics. Some modern sources include relativistic mechanics in classical mechanics, as representing the subject matter in its most developed and accurate form.

In physics, length scale is a particular length or distance determined with the precision of at most a few orders of magnitude. The concept of length scale is particularly important because physical phenomena of different length scales are said to decouple, i.e. they can be separated and studied independently. In other words, the decoupling of different length scales makes it possible to have a self-consistent theory that only describes the relevant length scales for a given problem. Scientific reductionism says that the physical laws on the shortest length scales can be used to derive the effective description at larger length scales. The idea that one can derive descriptions of physics at different length scales from one another can be quantified with the renormalization group.

In quantum mechanics the length scale of a given phenomenon is related to its de Broglie wavelengthℓ = ħ/p, where ħ is the reduced Planck constant and p is the momentum that is being probed. In relativistic mechanics time and length scales are related by the speed of light. In relativistic quantum mechanics or relativistic quantum field theory, length scales are related to momentum, time and energy scales through the Planck constant and the speed of light. Often in high energy physics natural units are used where length, time, energy and momentum scales are described in the same units (usually with units of energy such as GeV).

In relativistic physics, Lorentz symmetry or Lorentz invariance, named after the Dutch physicist Hendrik Lorentz, is an equivalence of observation or observational symmetry due to special relativity implying that the laws of physics stay the same for all observers that are moving with respect to one another within an inertial frame. It has also been described as "the feature of nature that says experimental results are independent of the orientation or the boost velocity of the laboratory through space".

Lorentz covariance, a related concept, is a property of the underlying spacetime manifold. Lorentz covariance has two distinct, but closely related meanings: