Venus
Venus is the second planet from the Sun and Earth's closest planetary neighbor. Often called Earth's twin because of their similar size and mass, Venus is in reality a hellish world with crushing atmospheric pressure and temperatures hot enough to melt lead. It is the brightest natural object in the night sky after the Moon.
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- Diameter
- 12,104 km
- Mass
- 0.815 Earths
- Distance from Sun
- 0.723 AU
- Surface gravity
- 8.87 m/s²
- Average temperature
- 464°C
- Known moons
- 0
- Orbital period
- 224.7 Earth days
- Rotation period
- 243.0 Earth days (retrograde)
- Ring system
- No
Source: NASA Planetary Fact Sheets (nssdc.gsfc.nasa.gov)
Atmosphere
Dense carbon dioxide (96.5%) with nitrogen (3.5%). Surface pressure 92 times Earth's. Sulfuric acid clouds.
In Depth
Venus is sometimes called Earth's evil twin. While similar in size, mass, and composition, Venus took a radically different evolutionary path. Its thick atmosphere of carbon dioxide traps solar energy in a runaway greenhouse effect, heating the surface to 464°C — hotter than Mercury despite being nearly twice as far from the Sun. The atmospheric pressure at the surface is 92 times that of Earth, equivalent to being 900 meters underwater. Dense clouds of sulfuric acid completely obscure the surface from view, reflecting so much sunlight that Venus appears as the brightest planet in our sky. Venus rotates backward (retrograde) and incredibly slowly: one Venus day lasts 243 Earth days, longer than its 225-day year. The surface is dominated by vast volcanic plains, two continent-sized highland regions (Ishtar Terra and Aphrodite Terra), and over 1,600 major volcanoes. Radar mapping by the Magellan spacecraft revealed a young surface with relatively few impact craters, suggesting global volcanic resurfacing events within the last 500 million years.
Notable Features
- 01
Runaway greenhouse effect making it the hottest planet at 464°C
- 02
Retrograde rotation — Venus spins backward compared to most planets
- 03
Maxwell Montes — the highest mountain on Venus at 11 km above the mean surface
- 04
Over 1,600 major volcanoes, more than any other planet
Exploration & Missions
Venus has been visited by more than 40 spacecraft. The Soviet Venera program achieved remarkable firsts: Venera 7 (1970) was the first spacecraft to land on another planet, and Venera 13 (1982) returned the first color photos from Venus's surface, surviving just 127 minutes. NASA's Magellan orbiter (1990-1994) mapped 98% of the surface using radar. The ESA's Venus Express (2006-2014) studied the atmosphere in detail. NASA's VERITAS and DAVINCI missions, along with ESA's EnVision, are planned for the late 2020s-2030s to investigate whether Venus was once habitable.
Fun Facts
Venus spins so slowly that its day is longer than its year — 243 Earth days to rotate versus 225 days to orbit the Sun.
The surface of Venus is hot enough to melt lead, tin, and zinc.
Venus has no magnetic field, which means the solar wind interacts directly with its upper atmosphere.
Ancient civilizations thought Venus was two separate objects — the 'Morning Star' and the 'Evening Star.'
Frequently Asked Questions
Why does Venus rotate backward?▾
Scientists aren't entirely sure. Leading theories suggest either a massive ancient collision flipped the planet, or tidal interactions between its thick atmosphere and the Sun gradually reversed its rotation over billions of years. Venus and Uranus are the only planets with retrograde rotation.
Could humans ever live on Venus?▾
The surface is inhospitable with temperatures of 464°C and crushing pressure. However, at about 50 km altitude, conditions are surprisingly Earth-like: temperatures around 25-75°C and pressure close to sea level. NASA has studied concepts for floating habitats in Venus's upper atmosphere.
Was Venus once like Earth?▾
Possibly. Climate models suggest Venus may have had liquid water oceans and moderate temperatures for up to 2 billion years. As the Sun brightened, water evaporated, hydrogen escaped to space, and carbon dioxide built up, triggering the runaway greenhouse effect we see today.
Learn More
The 8 Planets in Order: An Interactive Guide for Students — an in-depth article covering all 8 planets, with size comparisons and learning activities.
Data source: NASA Planetary Fact Sheets
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