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A cumulonimbus cloud emitting green is a sign that it is a severe thunderstorm, [21] capable of heavy rain, hail, strong winds and possible tornadoes. The exact cause of green thunderstorms is still unknown, but it could be due to the combination of reddened sunlight passing through very optically thick clouds.
Green flash occurs because the atmosphere causes the light from the Sun to separate, or refract, into different frequencies. Green flashes are enhanced by mirages, which increase refraction. A green flash is more likely to be seen in stable, clear air, when more of the light from the setting sun reaches the observer without being scattered.
In a technique known as blue field entoptoscopy, the effect is used to estimate the blood flow in the retinal capillaries.The patient is alternatingly shown blue light and a computer generated picture of moving dots; by adjusting the speed and density of these dots, the patient tries to match the computer generated picture to the perceived entoptic dots.
A fireball, astronomers explain, is simply a very bright meteor – brighter than magnitude -4, roughly equivalent to the brilliance of Venus in the morning or evening sky. A bolide is a specific ...
It is also known as a lagas in the sky which comes from the Cornish language term for the sun dog lagas awel meaning 'weather's eye' (lagas, 'eye' and awel, 'weather/wind'). This is in turn related to the Anglo-Cornish term cock's eye for a halo round the Sun or the Moon, also a portent of bad weather. [16]
The main shapes seen are "spots" (or "dots"), "stars" (or "supernovas"), "streaks" (or "stripes"), "blobs" (or "clouds") and "comets". These shapes were seen at varying frequencies across astronauts. On the Moon flights, astronauts reported seeing the "spots" and "stars" 66% of the time, "streaks" 25% of the time, and "clouds" 8% of the time ...
Airglow over Auvergne, France Yellow, green and red bands of airglow along Earth's limb as seen from space. Airglow (also called nightglow ) is a faint emission of light by a planetary atmosphere . In the case of Earth's atmosphere , this optical phenomenon causes the night sky never to be completely dark, even after the effects of starlight ...
Perceiving visual static, flickering, or graininess on monochrome colors, in the sky, or in darkness can be a normal phenomenon associated with neural noise, amplified in the absence of bright visual stimuli. This effect is known as the Ganzfeld Effect. In conditions of low illumination, especially in dimly lit environments, this phenomenon is ...