Astronomy Picture of the Day

Discover the cosmos! Each day we feature a different image or photograph of our fascinating universe, along with a brief explanation written by a professional astronomer.

September 3, 1995

Earth's Moon, A Familiar Face
Credit: Clementine, BMDO, NRL, LLNL

Explanation: The above mosaic of the Earth's Moon was compiled from photos taken by the spacecraft Clementine in 1994. This image represents the side of the Moon familiar to Earth dwellers. The Moon revolves around the Earth about once every 28 days. Since its rate of rotation about its axis is also once in 28 days, it always keeps the same face toward the Earth. As the Moon travels around its orbit, the Earth based view of the half of the Moon that faces the Sun changes causing the regular monthly progression of Lunar phases. Humans first crashed a spacecraft into the Moon in 1959, but the first humans to reach the Moon landed in 1969. There are now golf balls on the Moon.

Tomorrow's picture: Ganymede: Moonquake World

We are proud to acknowledge that an external review by Point Communications has rated Astronomy Picture of the Day in the top 5 percent of all World Wide Web sites.