A total solar eclipse will occur at the Moon's ascending node of orbit between Thursday, December 16 and Friday, December 17, 2066, with a magnitude of 1.0416. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. A total solar eclipse occurs when the Moon's apparent diameter is larger than the Sun's, blocking all direct sunlight, turning day into darkness. Totality occurs in a narrow path across Earth's surface, with the partial solar eclipse visible over a surrounding region thousands of kilometres wide. Occurring about 18.5 hours before perigee, the Moon's apparent diameter will be larger.