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  2. Cherenkov radiation - Wikipedia

    en.wikipedia.org/wiki/Cherenkov_radiation

    Cherenkov radiation glowing in the core of the Advanced Test Reactor at Idaho National Laboratory. Cherenkov radiation (/ tʃ ə ˈ r ɛ ŋ k ɒ f / [1]) is electromagnetic radiation emitted when a charged particle (such as an electron) passes through a dielectric medium (such as distilled water) at a speed greater than the phase velocity (speed of propagation of a wavefront in a medium) of ...

  3. 1883 eruption of Krakatoa - Wikipedia

    en.wikipedia.org/wiki/1883_eruption_of_Krakatoa

    The ash caused "such vivid red sunsets that fire engines were called out in New York, Poughkeepsie, and New Haven to quench the apparent conflagration". [31] This eruption also produced a Bishop's Ring around the sun by day, and a volcanic purple light at twilight.

  4. Solar radio emission - Wikipedia

    en.wikipedia.org/wiki/Solar_radio_emission

    Solar radio emission refers to radio waves that are naturally produced by the Sun, primarily from the lower and upper layers of the atmosphere called the chromosphere and corona, respectively. The Sun produces radio emissions through four known mechanisms, each of which operates primarily by converting the energy of moving electrons into ...

  5. Atmospheric diffraction - Wikipedia

    en.wikipedia.org/wiki/Atmospheric_diffraction

    The ionosphere is a layer of partially ionized gases high above the majority of the Earth's atmosphere; these gases are ionized by cosmic rays originating on the sun. When radio waves travel into this zone, which commences about 80 kilometers above the earth, they experience diffraction in a manner similar to the visible light phenomenon described above. [1]

  6. January 1938 geomagnetic storm - Wikipedia

    en.wikipedia.org/wiki/January_1938_geomagnetic_storm

    The early stages appeared as a red glow in the northwest and later in the northeast, with a low broad green arc in between. The area of the luminous sky increased, and by 20:30 the green color with areas of red extended well south of Orion. Up to 23:00, there seemed to be three periods of brilliant display: the first, and perhaps the best, at ...

  7. Crepuscular rays - Wikipedia

    en.wikipedia.org/wiki/Crepuscular_rays

    Crepuscular rays usually appear orange because the path through the atmosphere at dawn and dusk passes through up to 40 times as much air as rays from a high Sun at noon. Particles in the air scatter short- wavelength light (blue and green) through Rayleigh scattering much more strongly than longer-wavelength yellow and red light.

  8. Bishop's Ring - Wikipedia

    en.wikipedia.org/wiki/Bishop's_Ring

    A Bishop's Ring is a diffuse brown or bluish halo observed around the sun. It is typically observed after large volcanic eruptions . The first recorded observation of a Bishop's Ring was by Rev. Sereno Edwards Bishop [ 1 ] of Honolulu , after the Krakatoa eruption of August 27, 1883.

  9. Halo (optical phenomenon) - Wikipedia

    en.wikipedia.org/wiki/Halo_(optical_phenomenon)

    Ice crystals (only four represented above) form the 22° halo, with red and blue light being refracted at slightly different angles Among the best-known halos is the 22° halo , often just called "halo", which appears as a large ring around the Sun or Moon with a radius of about 22° (roughly the width of an outstretched hand at arm's length).