Due to these measurements, the Sun and the Moon have a similar size when viewed from Earth. When the moon passes in front of the sun, it blocks the light from reaching Earth. An annular solar eclipse is when the Moon and the Sun are in line, but either the moon is further from Earth or the Earth is closer to the Sun. In this situation, the apparent size of the Moon is smaller than that of the Sun, which then creates a bright ring surrounding the darkness of the Moon. A total eclipse is when the moon completely covers the sun. Note: The eclipse of February 26, 1979 was not exclusive to the U.S. and was also viewed from Canada and Greenland.