What would likely happen to the appearance of the sky if Earth had a substantially thicker atmosphere than it currently does?

Answer

The sky would appear darker, perhaps even black, with the direct solar disk being the only visible light source.

A much thicker atmosphere means a longer path length for all light, causing even longer wavelengths like red to scatter significantly, thereby removing almost all light from the general sky area.

What would likely happen to the appearance of the sky if Earth had a substantially thicker atmosphere than it currently does?

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