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In astronomy and optics scattering is deflection of photons by either macroscopic surfaces such as an asteroid or by small particles as in the rings of Saturn. No atomic or molecular absorption or emission processes are involved. The sky is blue because molecules in the air preferentially scatter blue light.
Scattering, also called scatter, is the process by which small particles suspended in a medium of a different index of refraction diffuse a portion of the incident radiation in all directions. In scattering, no energy transformation results, only a change in the spatial distribution of the radiation.
Along with absorption, scattering is a major cause of the attenuation of radiation by the atmosphere. Scattering varies as a function of the ratio of the particle diameter to the wavelength of the radiation. When this ratio is less than about one-tenth, Rayleigh scattering occurs in which the scattering coefficient varies inversely as the fourth power of the wavelength. At larger values of the ratio of particle diameter to wavelength, the scattering varies in a complex fashion described by the Mie theoryThe Mie theory also called Lorenz-Mie theory is a complete mathematical-physical theory of the scattering of electromagnetic radiation by spherical particles, developed by Gustav Mie in 1908. Mie theory is named after German physicist Gustav Mie ( 1868 Ro; at a ratio of the order of 10, the laws of geometric optics begin to apply.
In particle physicsParticle physics is a branch of physics that studies the elementary constituents of matter and radiation, and the interactions between them. It is also called high energy physics because many elementary particles do not occur under normal circumstances in, scattering refers to deflection of subatomic particleIn physics, a subatomic particle is a particle smaller than an atom. These include atomic constituents such as electrons, protons, and neutrons (protons and neutrons are actually composite particles, made up of quarks), as well as particles produced by ras, a process central to many experiments. In scattering experiments, a target of some material is bombarded with a beam of particles (typically electronThe electron (also called negatron commonly represented as e&minus is a subatomic particle. In an atom the electrons surround the nucleus of protons and neutrons in an electron configuration. Electrons have the smallest electrical charge and when they movs, protonFor alternative meanings see proton (disambiguation). Proton Classification Subatomic particle Fermion Hadron Baryon Nucleon Proton Properties Mass: 938 MeV/ c2 Electric Charge: 1. 6 × 10−19 C Spin: 1/2 In physics, the proton is a subatomic particles, or neutronNeutron Classification Subatomic particle Fermion Hadron Baryon Nucleon Neutron Properties Mass: 940 MeV/ c 2 Electric Charge: 0 C Spin: 1/2 In physics, the neutron is a subatomic particle with no net electric charge and a mass of 940 MeV/ c 2 ( kg; verys) and the number of particles emerging in various directions is measured. This distribution reveals information about the interaction that takes place between the target and the scattered particle.
A famous scattering experiment of alpha particleAlpha particles or alpha rays are a form of particle radiation which are highly ionizing and have low penetration. They consist of two protons and two neutrons bound together into a particle that is identical to a helium nucleus, and can be written as He2s off gold nuclei performed by Ernest Rutherford revealed the basic structure of the atom - a tiny nucleus surrounded by electrons. See Rutherford scattering. Scattering has also been done off of nucleons and quarks.
Mathematically, scientists describe scattering by an impact parameter (which describes how close the incident particle would come to the target if it moved in a straight line) and an angle of deflection (which describes the angle at which the particle emerges relative to its original direction). The distribution of deflection angles is described by a function known as the differential cross section, which (roughly) relates a direction in space in which some particles emerge to the amount of the incoming beam (in area) those particles came from.
The abstract mathematics of scattering is developed as scattering theory .