Earth's Twin? Discovering Venus Up Close

Venus is often called Earth's twin—but this sibling resemblance is only skin deep. While Venus is similar in size and mass to Earth, it’s also one of the most inhospitable planets in the solar system. With crushing pressure, scorching temperatures, and clouds of sulfuric acid, Venus challenges our understanding of planetary evolution.

In this article, we’ll explore the fascinating features of Venus, its similarities and stark differences from Earth, and what we’ve learned from past and present missions.

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Basic Facts About Venus

• Orbital Position: 2nd planet from the Sun
• Average Distance from the Sun: ~108 million km (67 million miles)
• Diameter: 12,104 km (about 95% of Earth’s)
• Mass: ~81.5% of Earth's
• Day Length: 243 Earth days (retrograde rotation)
• Year Length: 225 Earth days

Venus rotates in the opposite direction to most other planets, including Earth. A day on Venus is actually longer than its year. Its thick atmosphere causes extreme greenhouse effects, making it the hottest planet in the solar system.

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Why Is Venus Called Earth’s Twin?

Venus and Earth have several key physical similarities:

• Size and Mass: Nearly the same diameter and surface gravity
• Composition: Rocky terrestrial planets
• Location: Both in the Sun’s habitable zone vicinity
• Internal Structure: Iron core, rocky mantle, and crust

Because of these shared traits, scientists initially believed Venus might harbor Earth-like conditions. However, space missions shattered that assumption.

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Venus’s Hostile Atmosphere

Venus’s atmosphere is what truly sets it apart from Earth:

• Composition: ~96.5% carbon dioxide, ~3.5% nitrogen
• Surface Pressure: ~92 times that of Earth’s (like being 900 meters underwater)
• Average Surface Temperature: ~465°C (869°F), hotter than Mercury
• Clouds: Composed of concentrated sulfuric acid droplets
• Wind Speeds: Up to 360 km/h (224 mph) in the upper atmosphere

The runaway greenhouse effect traps heat extremely efficiently. Sunlight enters the atmosphere but cannot escape, leading to sustained extreme temperatures globally—even at the poles and night side.

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Surface Features: A World Hidden Beneath Clouds

Venus’s dense cloud cover prevents visual observation of the surface from Earth, but radar mapping has revealed dramatic geological features:

• Volcanoes: Over 1,600 major ones, including Maat Mons and Sif Mons
• Tesserae: Highly deformed regions resembling wrinkled terrain
• Coronae: Circular structures caused by upwelling of magma
• Impact Craters: Few in number, indicating a relatively young surface (~300–500 million years old)

Unlike Earth, Venus shows little evidence of plate tectonics. Its crust may be too rigid and dry to allow plate movement, suggesting a different geologic evolution.

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Missions to Venus: A Brief History

Soviet Venera Program (1961–1984)

The first spacecraft to land on Venus. Venera 7 was the first to transmit data from the surface in 1970. Venera 13 sent the first color images in 1982.

NASA’s Magellan Mission (1989–1994)

Used radar to map 98% of Venus’s surface in high detail.

ESA’s Venus Express (2006–2014)

Studied Venus’s atmosphere and its interaction with solar wind.

JAXA’s Akatsuki (launched 2010)

Currently studying Venus’s weather patterns and cloud dynamics.

Upcoming Missions

• NASA’s VERITAS (launch planned late 2020s): Will map surface and investigate geology
• NASA’s DAVINCI+: Will descend into the atmosphere to study its chemistry
• ESA’s EnVision: Will explore surface activity and interior

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Why Study Venus?

Venus offers critical clues to understanding Earth's climate, planetary habitability, and why two similar planets can evolve so differently.

• Climate Models: Venus helps test atmospheric models under extreme conditions
• Runaway Greenhouse Effect: A real-world example of what could happen on Earth
• Exoplanet Analogues: Many exoplanets may resemble Venus more than Earth

Studying Venus could also help us better prepare for long-duration missions to other worlds.

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Is There Life on Venus?

For decades, Venus was considered too harsh for any form of life. However, a 2020 study suggested the possible presence of phosphine, a gas linked to biological processes, in its upper clouds. This sparked renewed interest, though later studies have cast doubt on the finding.

Still, the discovery reminded us that even in extreme environments, we may find unexpected chemistry—and perhaps life—in places we least expect.

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Conclusion

Though often labeled Earth’s twin, Venus is more like Earth’s tragic sibling—a planet that started similarly but took a drastically different path. Understanding why Venus turned into a scorching wasteland while Earth became habitable offers profound insight into the delicate balance of planetary environments.

With new missions on the horizon, Venus may soon reveal long-held secrets buried beneath its thick veil of clouds.

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