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Solar System Series

Venus

The solar system's most beautiful hell.

Author: Juan Carlos Euyoque Aguilera · October 7, 2026 · CC BY 4.0

Image of Venus (NASA/JPL, public domain)
NASA/JPL illustration, public domain. Not to scale.
12,104 km
Diameter
464 °C (737 K)
Mean temperature
243 days
Rotation
0.723 AU
Distance from the Sun

Venus shines as the most beautiful 'star' of the dawn, but beneath its sulfuric-acid clouds lies a 464 °C furnace, with the pressure of being 900 meters underwater.

Almost Earth's size and our most famous neighbor, Venus is a warning of what can happen to a rocky planet when its climate runs out of control.

Measured data [DATO]

DataValueStateSource
Diameter12,104 km[DATO] observedNASA Planetary Fact Sheet
Mass4.87×10²⁴ kg[DATO] observedNASA Venus Fact Sheet
Mean density5,243 kg/m³[DATO] observedNASA Venus Fact Sheet
Surface gravity8.9 m/s²[DATO] observedNASA Venus Fact Sheet
Escape velocity10.4 km/s[DATO] observedNASA Planetary Fact Sheet
Mean distance from the Sun108.2 million km (0.723 AU)[DATO] observedNASA Venus Fact Sheet
Orbital period224.7 days[DATO] observedNASA Planetary Fact Sheet
Rotation period−5,832.5 hours (243 days; retrograde)[DATO] observedNASA Venus Fact Sheet
Mean temperature464 °C (737 K)[DATO] observedNASA Venus Fact Sheet
Atmosphere96.5% CO₂, 3.5% N₂; surface pressure 92 bars, sulfuric-acid clouds[DATO] observedNASA Venus Fact Sheet
Notable featureRetrograde spin: its day (243 days) lasts longer than its year (224.7 days)[DATO] observedNASA Venus Fact Sheet
Known moons0 (LiveScience (solar system overview), April 2026)
No changes recorded. (Zoozve, its 'quasi-moon', orbits the Sun, not Venus.)		[DATO] observedLiveScience (solar system overview)

Truths [DATO]

  • [DATO] It is the hottest planet in the solar system: 464 °C on average, day and night, from a runaway CO₂ greenhouse effect.
  • [DATO] It spins backwards relative to the other planets, and so slowly that its day (243 days) is longer than its year (224.7 days).
  • [DATO] Its surface pressure is 92 bars — about 92 times Earth's at sea level — and its clouds are made of sulfuric acid.
  • [DATO] It has no global magnetic field and no moons (NASA Planetary Fact Sheet).

Marked myths [MITO]

[MITO] Venus is Earth's twin.

The resemblance ends at size, mass and density. At the surface: 464 °C, 92 bars of pressure, sulfuric-acid clouds. NASA itself qualifies the nickname: 'evil twin.'

Fuente: El apodo circula en medios y libros de texto; la corrección es de la NASA.

[MITO] Venus is the planet closest to Earth.

Venus makes the closest approach, but averaging positions over 10,000 years, Mercury spends more time near Earth (1.04 AU versus 1.14 AU). It is the difference between 'minimum distance' and 'mean distance.'

Fuente: Comentario de 2019 en Physics Today (Stockman, Monroe y Cordner), resumido por Space Daily.

Open questions [PREGUNTA]

  • [PREGUNTA] Did Venus have liquid-water oceans, or was it a hell from the start? (A 2024 Cambridge study argues it may never have been habitable.)
  • [PREGUNTA] What erased and resurfaced almost the entire planet hundreds of millions of years ago?
  • [PREGUNTA] What drives super-rotation — its atmosphere spinning 60 times faster than the planet?

The chain in brief

  1. [DATA] 1. Born almost Earth's twin: Nearly Earth's size — 12,104 km across and 4.87×10²⁴ kg: the same kind of rocky planet, our most famous neighbor.
  2. [DISPUTED] 2. The water is lost: The D/H signature of its atmosphere, some 150 times Earth's, shows it lost a large amount of water; whether it had oceans and how long they lasted is still disputed — the page itself leaves it as an open question.
  3. [DATA] 3. Runaway greenhouse: With no water to regulate it, CO₂ piled up: its atmosphere is 96.5% CO₂, and it is the hottest planet in the solar system, day and night, from a runaway greenhouse effect.
  4. [MODEL] 4. Today: the still oven: 92 bars of pressure and 464 °C (737 K) at the surface, sulfuric-acid clouds, a crust that does not recycle in plates — a stagnant lid — and no global magnetic field and no moons.
  5. [DISPUTED] 5. The resurfaced-skin question: Something erased and resurfaced almost the entire planet hundreds of millions of years ago; what it was remains open.