An Etymological Dictionary of Astronomy and Astrophysics
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A process in which a molecule relaxes without emitting a → photon.

→ radiation; → -less; → relaxation.

Radiation produced when a free electron in a plasma is captured by an ionized atom.

→ recombination; → radiation.

All the constituents making up the Sun's emission: photons, electrons, protons, neutrinos, and atomic nuclei.

→ solar; → radiation.

The → radiation pressure of solar photons, which pushes a comet's dust outward to form a → dust tail.

→ solar; → radiation; → pressure.

That part of the → electromagnetic radiation with a → wavelength beyond 300 → microns.

→ submillimeter; → radiation.

The electromagnetic radiation emitted by high-energy particles that are moving in magnetic fields, as in a synchrotron particle accelerator. The acceleration of the moving charges causes the particles to emit radiation. Radio galaxies and supernova remnants are intense sources of synchrotron radiation. Characteristics of synchrotron radiation are its high degree of polarization and nonthermal spectrum.

→ synchrotron; → radiation.

The energy radiated from an object in the form of → electromagnetic waves as a result of its → temperature. Thermal radiation ranges in → wavelength from the longest → infrared radiation through the → visible light spectrum to the shortest → ultraviolet rays. In opposition, → non-thermal radiation is caused by energetic particles.

→ thermal; → radiation.