Unique Characteristics of Venus, the Planet of Fire

Scientific Summary

This article presents the characteristics of Venus, the second planet in the Solar System, nicknamed the "Morning Star." It experiences the strongest greenhouse effect in the Solar System: its atmosphere, composed of 96% CO₂, traps heat, raising the surface temperature to 462°C, hotter than Mercury. Its retrograde rotation (the Sun rises in the west) is extremely slow: a day (243 Earth days) is longer than its year (225 Earth days). Its atmospheric pressure is 92 times that of Earth, equivalent to 1 km beneath the oceans. These characteristics make Venus a warning about the consequences of uncontrolled greenhouse effect.

What Are the Remarkable Characteristics of the Planet Venus?

Venus, the second planet in the Solar System, is an infernal world with extreme characteristics. It experiences the strongest greenhouse effect in the Solar System: its atmosphere, composed of 96% carbon dioxide, creates a thermal trap so effective that the surface temperature constantly reaches 462°C, hotter than Mercury despite its greater distance from the Sun. Thick layers of sulfuric acid clouds trap heat, making Venus a warning for planets whose climate balance is broken. Its retrograde rotation is unique: the Sun rises in the west and sets in the east, and its rotation is so slow that a Venusian day (243 Earth days) lasts longer than its year (225 Earth days). Finally, its atmospheric pressure is 92 times that of Earth, equivalent to the pressure at nearly one kilometer deep in the ocean, a pressure that has crushed all probes sent to its surface within hours. Venus, so similar to Earth in size and composition, has become a hell—understanding this evolution is a major challenge in planetary science.

The Most Remarkable Characteristics of Venus

N.B.: The official definition of a planet (since 2006) requires that it orbits the Sun, has a spherical shape due to its own gravity, and has "cleared" its orbit.

The Strongest Greenhouse Effect in the Solar System

Venus is the ultimate example of an uncontrolled greenhouse effect. Its atmosphere, composed of 96% carbon dioxide, creates a thermal trap so effective that the surface temperature constantly reaches 462°C, hot enough to melt lead. This infernal heat is greater than that of Mercury, which is closer to the Sun. Thick layers of sulfuric acid clouds trap heat, creating a true planetary oven. Scientists consider Venus a warning of what could happen to a planet whose climate balance is broken.

A Retrograde and Extremely Slow Rotation

Venus has the unique characteristic of rotating on its axis in the opposite direction to the other planets in the Solar System. On Venus, the Sun rises in the west and sets in the east. Additionally, its rotation is extremely slow: a single Venusian day lasts 243 Earth days, which is longer than its year (225 Earth days). Thus, a day on Venus lasts longer than a Venusian year. This extreme slowness could be the result of a giant collision in the past or intense tidal effects exerted by the Sun.

Crushing Atmospheric Pressure

If you could stand on the surface of Venus, you would be crushed by an atmospheric pressure 92 times greater than Earth's, equivalent to the pressure felt at nearly one kilometer deep in our oceans. This extremely dense atmosphere is primarily composed of carbon dioxide, with sulfuric acid clouds that reflect sunlight so well that Venus is the brightest object in the night sky after the Moon. This colossal pressure has destroyed all probes sent to its surface, which survived only a few hours before being crushed or melted.

Venus, often called the "Morning Star," is a fascinating world that may have had oceans in the distant past. Understanding how this planet, so similar to Earth in size and composition, could have become a hell is one of the great challenges of modern planetary science. Learn more.

Ongoing Volcanic Activity

Long considered a geologically frozen planet, Venus has revealed itself to be volcanically active. In 2023, researcher Robert Herrick (University of Alaska Fairbanks) compared two radar images of the Atla Regio region, taken months apart by the Magellan probe in 1991, and identified a change in the shape of a volcanic vent typical of an ongoing eruption. This discovery has since been supplemented by the identification of two other eruptions in the same Magellan archives, as well as the discovery in 2026 of a vast underground lava tunnel. Other evidence, such as heat variations detected by the Japanese Akatsuki probe in rift regions, supports the hypothesis of widespread volcanic activity, comparable in scale to that of Hawaii's volcanoes. This activity could explain why Venus's surface appears relatively young (less than 500 million years old), despite the lack of plate tectonics comparable to Earth's.

A Return of Space Missions to Venus

Since the Magellan flybys in the 1990s, no NASA probe had returned to study Venus in detail. This is about to change with two missions selected in 2021: DAVINCI, which will send a descent sphere through Venus's atmosphere to the surface to analyze its chemical composition, and VERITAS, a radar orbiter designed to map the surface with far greater precision than Magellan and to track thermal signatures of active volcanism. These American missions are joined by the European EnVision project and the Indian Shukrayaan mission. DAVINCI is currently scheduled for launch in late 2029, with its first Venus flyby in 2030 and its atmospheric sphere descending to the surface in late 2031. VERITAS, delayed by budgetary and personnel constraints at NASA, is not expected to enter orbit until the early 2030s.

References

FAQ: Everything You Need to Know About Venus's Characteristics

Why Is Venus Hotter Than Mercury?

Although Mercury is closer to the Sun, Venus is hotter due to its uncontrolled greenhouse effect. Its atmosphere, composed of 96% carbon dioxide, traps solar heat. The clouds of sulfuric acid reinforce this thermal trap, raising the surface temperature to 462°C, while Mercury, with no atmosphere, cannot retain heat and alternates between extreme temperatures.

Why Does the Sun Rise in the West on Venus?

Venus has a retrograde rotation: it rotates on its axis in the opposite direction to the other planets in the Solar System (except Uranus). As a result, the Sun rises in the west and sets in the east. This reversed rotation is likely due to a collision with a massive body in the past or tidal effects from the Sun.

Why Is a Day on Venus Longer Than a Year?

Venus rotates on its axis extremely slowly: its rotation period is 243 Earth days, while its orbit around the Sun takes only 225 Earth days. Thus, a Venusian day (rotation on its axis) is longer than a Venusian year (orbit around the Sun). On Venus, the Sun would rise less than once a year.

Why Is Venus's Atmospheric Pressure So High?

Venus's atmosphere is extremely dense and massive, primarily composed of carbon dioxide (96%) with clouds of sulfuric acid. Its total mass is much greater than Earth's atmosphere, creating a surface pressure of 92 bars (92 times that of Earth), equivalent to the pressure at nearly one kilometer deep in Earth's oceans.

Why Is Venus So Bright in the Night Sky?

Venus is the brightest object in the night sky after the Moon for several reasons:
• Its dense atmosphere and sulfuric acid clouds reflect about 70% of sunlight (high albedo).
• Its proximity to Earth and the Sun makes it very bright.
• Its size and rocky composition contribute to its visibility.
For these reasons, it is often called the "Morning Star" or "Evening/Morning Star."

Why Is Venus a Warning for Earth?

Venus is often considered a warning of the dangers of an uncontrolled greenhouse effect. Billions of years ago, Venus may have had oceans and a more temperate climate, similar to Earth's. But its CO₂-rich atmosphere triggered a runaway climate effect: heat vaporized the oceans, releasing more water vapor (a potent greenhouse gas), which reinforced the greenhouse effect until reaching the current infernal state. Understanding this evolution is crucial for modeling climate change on Earth.

How Many Probes Have Survived on Venus's Surface?

No probe has survived long on Venus's surface. The Soviet Venera program probes (Venera 7, 9, 10, 13, 14) are the only ones to have transmitted data from the surface. The longest operational time was about 2 hours for Venera 13 (1982), before being crushed by the colossal pressure (92 bars) and destroyed by the extreme heat (462°C). These conditions make direct exploration of Venus extremely difficult.

Is Venus Geologically Active Today?

Yes. After decades of Venus being considered geologically frozen, multiple pieces of evidence of active volcanism have been gathered since 2023 from a reanalysis of radar data from the Magellan probe (1990-1994): changes in the shape of volcanic vents, indicative of ongoing eruptions at the time of observation. A vast underground lava tunnel was also identified in 2026. This activity partly explains why Venus's surface appears relatively young, despite the lack of plate tectonics comparable to Earth's.

What Are the Next Missions to Venus?

After more than three decades without a dedicated mission, NASA is preparing two missions to Venus, selected in 2021: DAVINCI, scheduled for launch in late 2029 with its first Venus flyby in 2030 and its atmospheric sphere descending to the surface in late 2031, and VERITAS, a radar orbiter whose launch, delayed by budgetary constraints, is not expected before 2031. Europe is also preparing its own mission, EnVision, with orbital arrival expected around 2034.