The waning gibbous moon stands out against the dark backdrop of space in this April 26, 2024, image from the International Space Station. Waning gibbous is one of eight moon phases, occurring after the full moon. The Sun always illuminates half of the Moon while the other half remains dark, but how much we can see of that illuminated half changes as the Moon travels through its orbit. As the Moon begins its journey back toward the Sun, the lighted side appears to shrink, but the Moon’s orbit is simply carrying it out of view from our perspective.
See NASA’s interactive map for observing the Moon—from Earth—every day of the year.
Image Credit: NASA