how big is the sun in mercury's sky
Extraterrestrial skies On average, the visible diameter of the Sun on Mercury is 2.5 times as large as it appears from Earth, and its total brightness is more than 6 times as great. Because of the planet's eccentric orbit, the Sun's apparent size in the sky would vary from 2.2 times that from Earth at aphelion (with total brightness 4.8 times as great), to 3.2 times at perihelion (with total brightness 10.2 times as great).