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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 other words, it is the opposite to a flashing light where the total duration of darkness is longer than the duration of light. It has the appearance of flashing off, rather than flashing on. Like a flashing light, it can be used for a single occulting light that exhibits only a single period of darkness or the periods of darkness can be ...
The green light typically changes to a solid green indication for a few seconds before changing to yellow and then red but the solid green phase may be omitted depending on the road authority that installed the traffic light. The intention of the flashing green is to let drivers know that the signal will only change to yellow for pedestrians ...
On other space missions, astronauts reported seeing other colors such as yellow and pale green, though rarely. [10] Others instead reported that the flashes were predominantly yellow, while others reported colors such as orange and red, in addition to the most common colors of white and blue. [9]
Instead, the normal green lamp flashes rapidly, indicating permission to go straight as well as make a left turn in front of opposing traffic, which is being held by a steady red lamp. (This "advance green", or flashing green can be somewhat startling and confusing to drivers not familiar with this system.
In New York City, a single flashing green light separated from the other red and blue flashing lights on an NYPD vehicle denotes it as a THV (Temporary Headquarters Vehicle) also known as a Mobile Command Post vehicle and also used on a 2-star Assistant Chiefs marked RMP (Radio Motor Patrol) vehicle to identify it as such.
**Military airport beacons flash alternately white and green, but are differentiated from civil beacons by two quick white flashes between the green flashes. In Class B, C, D, and E surface areas, operation of the airport beacon between sunrise and sunset often indicates that the ground visibility is less than 3 miles and/or the ceiling is less ...
An earthquake light also known as earthquake lightning or earthquake flash is a luminous optical phenomenon that appears in the sky at or near areas of tectonic stress, seismic activity, or volcanic eruptions. [1] There is no broad consensus as to the causes of the phenomenon (or phenomena) involved.