What atmospheric phenomenon causes flickering objects near the horizon to display brief flashes of red and blue?

Answer

Dispersion, where different wavelengths of light are refracted by slightly different amounts.

When the atmosphere severely distorts light near the horizon, it acts like a prism, separating white light into colors because blue light bends more than red light as it passes through the turbulent air.

What atmospheric phenomenon causes flickering objects near the horizon to display brief flashes of red and blue?
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