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.

August 1, 1995
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Crossing The Ring Plane
Credit: NASA, Hubble Space Telescope

Explanation: "I do not know what to say in a case so surprising, so unlooked for and so novel." announced Galileo when Saturn's rings appeared to vanish in 1612. In fact, every 15 years Saturn's rings seem to almost disappear as viewed from the Earth. This happens just as the orbiting Earth crosses the plane of Saturn's rings. The edge on perspective temporarily robs astronomers of a spectacular sight, however, the ring plane crossing affords them the opportunity to measure the rings' thickness and search for undiscovered moons. In this image of Saturn, produced on May 22, 1995 by NASA's Hubble Space Telescope, two of Saturn's known moons are visible as star like objects to the left of the planet.

For more information about the ring plane crossing see the Saturn Ring Plane Crossing web page .

Tomorrow's picture: Jupiter's Rings

We keep a chronological archive and a subject sorted archive of Astronomy Pictures of the Day.
Astronomy Picture of the Day (TM) is created and copyrighted in 1995 by Robert Nemiroff and Jerry Bonnell who are solely responsible for its content.