How Does the Sun Switch Places With the Moon?

The Moon

• Earth's moon is the fifth largest moon in the solar system. It orbits (or circles) the Earth in a nearly circular loop, taking approximately 27 days to complete one orbit, known as a lunar month. You can see the moon in the sky as it passes in its orbit around the Earth and see it set below the horizon as it becomes visible elsewhere on the globe.

The Sun

• As the moon orbits the Earth, the Earth simultaneously orbits the sun and spins on its axis. The spinning of the Earth results in the appearance of a rising and setting sun, which causes the Earth to have day and night. In fact, the sun is stationary; it is the Earth's position relative to the sun that causes the sun to appear to move.

The Sun and Moon From Earth

• The sun and moon do not actually "switch places" and are often observed at the same time in the sky. The moon is noticed more at night, however, because it is better contrasted against the dark sky. Additionally, due to the phases of the moon (crescent, full, etc., caused by the varying positions of the sun, Earth and moon) the moon may be extremely difficult to see in the day if it is not full. Sometimes there is no moon visible in the sky at all, even though it is risen. This is known as a "new moon," and occurs when the Earth blocks the sun's light from reaching the surface of the moon.

The Sun and Moon From Space

• If viewed from space, the sun and moon do not appear to switch places. From space, Earth can be seen slowly circling the Sun, which is located at the center of our solar system. At the same time as the Earth moving around the Sun, the moon could be seen to circle the Earth. The Earth carries the Moon in its orbit on its journey around the Sun. During this cycle, the moon can be observed both between the Earth and the sun---a new moon---and on the other side of the Earth than the sun---a full moon. During new moon phases, the sun and moon appear in the sky simultaneously from our vantage point on Earth. During the full moon phases, they appear to "switch places." From space, however, they can both be seen at all times.

Fun Facts

• It takes Earth 365 days, 6 hours, 9 minutes and 9.54 seconds to circle the sun, known as an sidereal year. This is 6 hours, 9 minutes and 9.54 seconds longer than a calendar makes allowance for. To correct for this, every four years a leap year is observed; this year lasts 366 days. In its orbit around the Sun the Earth travels a total distance of 584 million miles. To cover this distance in 365 days, Earth travels at 66,700 miles an hour, or 18.5 miles a second. Don't say you never go anywhere.