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Observing the Sky Solar System Satellites Navy Research Resources

Solar System: Inner Planets - Venus

The Brightest and Hottest

The second planet from the Sun, Venus is a terrestrial planet and is often called Earth’s sister planet. Although Venus and Earth are similar in size, mass, and composition, they have little else in common. For example, a thick, carbon dioxide and sulfuric acid atmosphere traps energy from the Sun to produce a greenhouse effect that makes Venus the hottest planet in the solar system, with temperatures over 450° C—much too hot for liquid water! Scientists believe that millions of years ago Venus may have had liquid water on its surface, and possibly an atmosphere like the Earth’s.

Photo of Venus
Courtesy of NASA JPL

Since Venus has 100 percent cloud cover, optical telescopes are unable to reveal information about the surface. Most of what we have learned about Venus’s surface comes from images and data gathered by various spacecraft and probes since the early 1960s. In the early 1990s, the Magellan spacecraft produced detailed maps of Venus's surface using imaging radar to penetrate the cloud cover. The radar data showed that much of the surface of Venus is covered by old lava flows. New data indicates that Venus still has active volcanoes.

Venus’s bright clouds reflect a tremendous amount of sunlight, making it the brightest object we can see in our sky, after the Sun and Moon. It has been known to sky watchers since prehistoric times, and has been worshipped by many cultures around the world. Venus is easily seen with the unaided eye, binoculars, or a telescope.

In 2004 look for Venus after sunset throughout May, and in the morning before sunrise from July through the end of the year.