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 23, 1995

A Venusian Tick
Credit: NASA, Magellan Project

Explanation: Data from the Magellan spacecraft has shown the Face of Venus to contain a host of volcanic features. This image shows an example of a fairly common type of venusian volcanic feature. Known as a "tick" it represents a volcano about 20 miles wide at the summit with ridges and valleys radiating down its sides lending it an insect like appearance.

Scientists are particularly interested in exploring the geology of Venus. Because of its similarity with the Earth in size, density, and overall location in the solar system, Venus may offer key insights into the workings of our own planet. Do the familiar processes of volcanism and plate tectonics occur on our sister planet as well as our own? The detailed radar mapping of the planet performed by the Magellan probe has gone a long way toward answering this question.

Tomorrow's picture: A Radar Image of Planet Earth

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.