In and around totality — the brief moments during a total solar eclipse when the moon fully hides the sun — the sudden shift from light to darkness can profoundly change color perception.Sitting in the grass of a Tennessee state park, Tracy Gregg felt the air grow cold as the late afternoon light she'd been bathing in suddenly faded. It was August 21, 2017, the date of a total solar eclipse that swept across much of the U.S., and she was directly in its path.
Human retinas have three types of color-sensing cones: red, green and blue. Combinations of these cones allow us to see all the colors of the rainbow in broad daylight. But in the mesopic period, signals from red cones are lost, whereas those for the shorter wavelengths sensed by green and blue cones persist. This is why greens and blues are so noticeably vibrant during twilight and a solar eclipse, Neitz says.
Dogs, however, probably miss out on any mind-blowing visual shifts because their retinas contain only two types of cones: blue and yellow. What dogs likely see instead, Mowat says, is a muddy and pale reddish brown, and they may not care much for the solar spectacle.