Astronomy Picture of the Day . Mercury on the Horizon . ... 20.03.2000 . ... Because Mercury orbits so close to the Sun, it is never seen far from the Sun, and so is only visible near sunrise or sunset . If trailing the Sun, Mercury will be visible for several minutes before it follows the Sun behind the Earth. If leading the Sun, Mercury will be visible for only several minutes before the Sun rises and hides it with increasing glare. ... Publications with keywords: Mercury - horizon . ...