gegenschein

A faint, oval patch of light in the night sky at the antisolar point — the spot in the sky exactly opposite the sun. Caused by the same interplanetary dust that produces zodiacal light, but seen here by backscatter rather than forward scatter. The gegenschein is one of the faintest naked-eye phenomena in the sky, visible only under near-perfect dark conditions. Most people will never see it. It is the sun's ghost, projected onto the sky behind you.