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.

July 20, 1995
See Explanation. Clicking on the picture will download the highest resolution version available.
The Grand Canyon of Mars
Picture Credit: NASA,Viking Project,USGS

Explanation: The Mariner Valley, also known as the Valles Marineris canyon system, appears in this mosaic of images from NASA's Viking spacecraft as a huge gouge across the red planet. This "Grand Canyon" of Mars is about 2500 miles long and up to 4 miles deep. By comparison, the Earth's Grand Canyon is less than 500 miles long and 1 mile deep.

For more information about Mars see Calvin J. Hamilton's Mars Page.

The exploration of Mars is chronicled by the Center For Mars Exploration.

We keep an archive of Astronomy Pictures of the Day.
Astronomy Picture of the Day is brought to you by Robert Nemiroff and Jerry Bonnell . Original material on this page is copyrighted to Robert J. Nemiroff and Jerry T. Bonnell.