![]() ![]() Design of compound achromatic lenses, in which chromatic aberration is largely cancelled, uses a quantification of a glass's dispersion given by its Abbe number V, where lower Abbe numbers correspond to greater dispersion over the visible spectrum. In optics, one important and familiar consequence of dispersion is the change in the angle of refraction of different colors of light, as seen in the spectrum produced by a dispersive prism and in chromatic aberration of lenses. Within optics, dispersion is a property of telecommunication signals along transmission lines (such as microwaves in coaxial cable) or the pulses of light in optical fiber. In optics and in wave propagation in general, dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency sometimes the term chromatic dispersion is used for specificity to optics in particular.Ī medium having this common property may be termed a dispersive medium (plural dispersive media).Īlthough the term is used in the field of optics to describe light and other electromagnetic waves, dispersion in the same sense can apply to any sort of wave motion such as acoustic dispersion in the case of sound and seismic waves, and in gravity waves (ocean waves). A compact fluorescent lamp seen through an Amici prism And last year, an Italian locksmith captured the first ever shot of a supernova's first light.Dependence of phase velocity on frequency In a dispersive prism, material dispersion (a wavelength-dependent refractive index) causes different colors to refract at different angles, splitting white light into a spectrum. In 2013, dashcams proved to be crucial to understanding a small asteroid that struck Russia. STEVEs are far from the only important scientific finds that have been made on commercial devices. ![]() “As commercial cameras become more sensitive and increased excitement about the aurora spreads via social media, citizen scientists can act as a ‘mobile sensor network,’ and we are grateful to them for giving us data to analyze,” says Toshi Nishimura, a space physicist at Boston University and lead author of the new study, in the release. Learning about them has been an effort showcasing the strength of amateur-professional scientific alliances. Scientists completely missed STEVEs until amateurs brought the odd lights to their attention. “The precipitating electrons that cause the green picket fence are thus aurora, though this occurs outside the auroral zone, so it’s indeed unique.” What's the distinction? “Aurora is defined by particle precipitation, electrons and protons actually falling into our atmosphere, whereas the STEVE atmospheric glow comes from heating without particle precipitation,” says Bea Gallardo-Lacourt, a space physicist at the University of Calgary and coauthor of the new study, in the release.
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