Venus, the second planet from the Sun, is often called Earth's "sister planet" due to their similar size and mass. However, a closer look reveals a world of extremes and unique characteristics that set it apart.
Orbital and Rotational Oddities
Venus holds several records for unusual movements in the Solar System.
- Retrograde Rotation: Venus rotates clockwise on its axis, which is the opposite direction of most other planets (including Earth), which rotate counter-clockwise. This is known as retrograde rotation.
- Slowest Rotation: Venus has the slowest rotation period of any major planet, taking 243 Earth days to complete one rotation. This is longer than its 225-day orbital period around the Sun, meaning a day on Venus is longer than a year on Venus.
- The Sun Rises in the West: Due to its retrograde rotation, on Venus, the Sun would appear to rise in the west and set in the east.
Extreme Atmospheric Conditions
The atmosphere of Venus creates an environment that is hostile to life as we know it.
Heat and Pressure
The planet's dense atmosphere causes an extreme greenhouse effect, making it the hottest planet in the Solar System, despite not being the closest to the Sun.
|
Characteristic |
Measurement |
Comparison |
|---|---|---|
|
Average Surface Temperature |
462 °C (864 °F) |
Hotter than Mercury |
|
Atmospheric Pressure |
92 times that of Earth |
Equivalent to being 900 meters (3,000 feet) underwater on Earth |
|
Primary Atmospheric Gas |
Carbon Dioxide (96%) |
Contributes to the runaway greenhouse effect |
Clouds and Precipitation
The clouds of Venus are not made of water vapor but are composed of sulfuric acid, which is extremely corrosive.
- Sulfuric Acid Rain: Acid rain falls from the upper atmosphere, but the intense heat below causes it to evaporate before it ever reaches the surface, in a process called "virga."
- High-Speed Winds: While the surface winds are slow, the winds in the cloud layer can reach speeds up to 360 km/h (224 mph), a phenomenon known as "super-rotation."
Surface Features
What lies beneath the thick, toxic atmosphere is a largely flat and volcanic landscape.
- Volcanic Activity: Venus is covered in thousands of volcanoes and lava flows. Scientists believe it has more volcanoes than any other planet in the Solar System, though most are dormant.
- Impact Craters: Unlike the Moon or Mercury, Venus has very few small impact craters. The extremely dense atmosphere burns up or breaks apart most incoming space objects before they can reach the surface.
- Tesserae: These are heavily deformed regions that are thought to be remnants of the planet's older crust, exhibiting complex geological features.