Venus
Venus is the second planet from the Sun and the hottest in the Solar System: a runaway greenhouse beneath a dense carbon-dioxide atmosphere and sulphuric-acid clouds, with a surface pressure 92× Earth's.
Key facts
Science
Physical
- Mass
- 4.87 × 10²⁴ kg · 0.815 M⊕
- Radius
- 6,052 km · 95% of Earth's radius
- Density
- 5,243 kg/m³ · 5.2× water
- Computed from mass and radius
- Surface gravity
- 8.87 m/s² · 90% of Earth's gravity
- Computed from mass and radius
- Escape velocity
- 10.4 km/s · 93% of Earth's escape velocity
- Computed from mass and radius
- Axial tilt
- 2.64 °
Orbital
- Distance from the Sun
- 0.725 AU
- Computed from the position at the selected time
- Semi-major axis
- 0.723 AU
- Computed from the cached state vector
- Eccentricity
- 0.006754
- Computed from the cached state vector
- Inclination
- 24.44 °
- Computed from the cached state vector
- Orbital period
- 224.7 days
- Computed from the cached state vector
- Perihelion
- 0.718 AU
- Computed from the orbital elements
- Aphelion
- 0.728 AU
- Computed from the orbital elements
- Mean orbital velocity
- 35 km/s
- Computed from the orbital elements
Rotation
- Rotation period
- 243.0 days
- Direction
- Retrograde
Atmosphere
- Composition
- 96.5% CO₂, 3.5% N₂
- Surface pressure
- 92 bar
- Scale height
- 15.9 km
Temperature
- Minimum
- 735 K (462 °C)
- Mean
- 737 K (464 °C)
- Maximum
- 740 K (467 °C)
Composition
- Bulk composition
- Iron core, silicate mantle; volcanic basaltic plains
Radiation & temperature
- Insolation
- 1.91 S⊕ · 1.91× the sunlight Earth receives
- Computed from the distance to the Sun (inverse-square; Earth's sunlight = 1), before any atmosphere.
- Bond albedo
- 0.76 · reflects 76% of incoming sunlight
- Equilibrium temperature
- 229 K (-44 °C)
- Computed from albedo + distance from the Sun (airless black body)
- Measured mean temperature
- 737 K (464 °C)
- Greenhouse warming
- +508 K
- Measured temperature minus the airless equilibrium — the greenhouse effect
Discovery & history
- First known
- Known since antiquity
- Name
- The Roman goddess of love and beauty — fitting for the brightest planet.
As the brightest natural object in the sky after the Sun and Moon, Venus has been known since prehistory and features in the records of nearly every ancient civilisation. Galileo's 1610 observation of its phases was powerful evidence that the planets orbit the Sun. Its hellish surface, hidden beneath sulphuric-acid clouds, was finally mapped by radar from the Magellan orbiter in the 1990s.
The first spacecraft launched toward another planet — silent by the time it passed Venus at about 100,000 km.
First successful flyby of another planet; found Venus searingly hot with no magnetic field.
A Venus probe named Zond to hide its failure; silent since May, it passed Venus at about 100,000–110,000 km.
The first human-made object to reach the surface of another planet, though contact had been lost two weeks before.
The first data from inside another planet's atmosphere — 93 minutes of readings showing it is 90–95% carbon dioxide.
Cameraless flyby that probed Venus's crushing CO₂ atmosphere by radio occultation and confirmed the planet has essentially no magnetic field.
First soft landing on another planet; transmitted 23 minutes from the surface of Venus.
The first landing on the day side — 63 minutes on the surface and the first measurements of its soil.
Used Venus's gravity to reach Mercury — the first interplanetary gravity assist — imaging its clouds in UV.
Returned the first photograph ever taken from the surface of another planet, surviving 53 minutes.
Photographed flat, pancake-like rocks near Beta Regio and measured 465 °C and 92 atmospheres.
First long-duration Venus orbiter; radar-mapped 93% of the surface through the clouds over 14 years (1978–92).
Sent four probes into the atmosphere at once; the Day Probe kept transmitting for 67 minutes after reaching the surface.
Returned the first colour images and a soil analysis from Venus, surviving 127 minutes in the heat.
Took colour panoramas and drilled a sample resembling the basalts of Earth's ocean floors.
With Venera 16, mapped the north of Venus by radar from orbit at 1–2 km resolution.
Delivered a lander and the first balloon to float in another planet's atmosphere, then flew on to Halley's Comet.
Its lander analysed the rock in Aphrodite Terra, and its balloon drifted 11,100 km through the clouds.
Radar-mapped 98% of the surface of Venus through its permanent clouds (1990–94).
Studied the atmosphere for eight years, from the south-polar vortex to signs of active volcanism.
The first spacecraft to use a solar sail as its main propulsion in deep space passed Venus 80,800 km away.
Images
Images from open archives · credit shown per image