Venus

Venus is the second planet from the Sun and one of the most extreme worlds in the Solar System. Often called Earth's twin because of its similar size and mass, Venus is actually a scorching planet hidden beneath thick clouds of sulfuric acid.

Although Venus is farther from the Sun than Mercury, it is the hottest planet in the Solar System.

An Extreme Greenhouse World

Venus is so hot because its atmosphere is made mostly of carbon dioxide, a gas that traps heat very effectively. This powerful greenhouse effect keeps heat from escaping into space and raises surface temperatures to about 870°F (465°C), hot enough to melt lead.

The planet's thick clouds reflect much of the sunlight that reaches Venus, but the dense carbon dioxide atmosphere below them retains enormous amounts of heat.

Atmosphere and Pressure

Venus has one of the densest atmospheres of any rocky planet. Atmospheric pressure at the surface is about 92 times greater than it is at sea level on Earth, roughly equal to the pressure found about 3,000 feet (900 meters) beneath Earth's oceans.

The thick cloud cover completely hides Venus's surface from ordinary visible-light observation. Scientists use radar and spacecraft instruments to study the landscape below.

The Surface of Venus

Radar mapping has revealed vast volcanic plains, lava flows, large shield volcanoes, highland regions, and impact craters. Venus does not show clear evidence of Earth-style plate tectonics, where large crustal plates continually move across the surface.

Instead, heat may build beneath Venus's crust over long periods. Some scientists think this can lead to episodes of widespread volcanic resurfacing, although the planet's volcanic history is still being investigated.

Key Facts About Venus

Diameter: About 7,521 miles (12,104 kilometers)
Mass: About 0.815 times Earth's mass
Average Distance from the Sun: About 67 million miles (0.72 AU)
Rotation Period: About 243 Earth days
Year Length: About 225 Earth days
Average Surface Temperature: About 870°F (465°C)

Retrograde Rotation

Venus rotates in the opposite direction from most planets, a motion called retrograde rotation. If you could stand on its surface, the Sun would appear to rise in the west and set in the east.

Venus takes longer to rotate once on its axis than it takes to complete one orbit around the Sun. However, because Venus rotates backward as it travels around the Sun, the time from one sunrise to the next is about 117 Earth days.

No Moons and No Strong Global Magnetic Field

Venus has no known moons and no strong global magnetic field like Earth's. Instead, its upper atmosphere interacts directly with the solar wind, creating an induced magnetic region around the planet.

Scientists are still studying how Venus has retained such a dense atmosphere while losing most of its water over time.

Earth’s Dangerous Twin

Venus and Earth are similar in size, mass, and overall composition, but they evolved into radically different worlds. Earth has oceans and life-supporting conditions, while Venus has a crushing atmosphere and surface temperatures hot enough to destroy most spacecraft in a short time.

By studying Venus, scientists can better understand how atmospheres, climate, volcanism, and planetary evolution can reshape worlds over billions of years.