Glossaire beginning with S
- Shooting star
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Meteorite with a mass of gram entering the Earth's atmosphere and producing light because of its heating. Shooting stars come generally from comets whose orbit, along which big dust grains are scattered, is crossed by the Earth. Synonymous: meteor fall.
- Solar wind
- Gas ejected by the corona of the Sun, which bathes all the Solar system.
- Spectral band
- An ensemble of often unresolved lines that produce an absorption or emission covering an extended range of wavelengths. The bands are characteristic of molecules.
- Spectral line
- Reinforcement or decrease in intensity in the spectrum of an object occurring at a specific wavelength; it is called an emission line if there is a reinforcement and an absorption line if there is a decrease. The wavelength of a line is characteristic of the atom, ion or molecule that produces it.
- Spectroscopy
- Technique of decomposing light into its different wavelengths by a grating or a prism. By extension, decomposition of any electromagnetic wave (ultraviolet, infrared or radio). The instrument used for spectroscopy is called spectroscope if it is not recording, or spectrograph in the reverse case.