Venus is the second planet from the Sun and Earth’s closest planetary neighbor in distance and size. This verified profile outlines its orbital characteristics, measurable physical attributes, and atmospheric conditions that define Venus as a terrestrial planet with extreme surface climate. The following sections clarify composition, rotation, surface properties, and observational history using current planetary science. These facts on Venus explain how the planet behaves today and how scientists have inferred its properties over time.
Key planetary facts on Venus
Venus functions as a rocky world with a dense atmosphere that generates high surface pressure and temperatures. Its slow retrograde rotation and nearly circular orbit distinguish it from most terrestrial planets. Reliable data come from Earth-based radar imaging, orbital spacecraft, and entry probes. These sources provide consistent measurements used in this evergreen summary of facts on Venus, focusing on observables rather than models. The table below separates commonly cited attributes from verified values and the evidence behind them.
Verified measurements and observational basis
| Attribute | Verified Detail | Source Type |
|---|---|---|
| Orbital period (sidereal) | 224.701 days | Spacecraft radar and telescopic tracking |
| Rotational period (sidereal) | 243.025 days | Radio tracking and atmospheric tracing |
| Rotation direction | Retrograde (east to west) | Observed motion of surface features |
| Mean distance from Sun | 108.2 million km (0.723 AU) | Orbit determination from radar and angles |
| Mean radius | 6,051.8 km | Spacecraft altimetry and shape modeling |
| Mass | 4.867 × 10^24 kg | Gravitational tracking by orbiters |
| Surface gravity | 8.87 m/s² | Derived from mass and radius |
| Surface pressure | 92 bar (roughly 9.2 MPa) | Direct measurement from lander probes |
| Mean surface temperature | 737 K (462°C / 864°F) | Infrared observations and lander sensors |
Orbit and motion characteristics
Venus follows a near-circular orbit that keeps it within roughly 0.72 AU of the Sun, completing one revolution in about 224.7 days. Its orbit is well-determined using radar ranging to its surface features and tracking of spacecraft. The planet exhibits an apparent retrograde motion in the sky when observed from Earth, an effect of the combination of orbital mechanics and planetary rotation. Solar day length on Venus extends to approximately 116.75 Earth days due to the interplay between its sidereal rotation and orbital period. Together, these motions define repeated configurations such as greatest elongations and inferior conjunctions, which remain predictable over centuries.
Physical structure and composition
Venus is a terrestrial planet with a size and mass close to Earth’s, yet its surface environment is radically different. Its bulk composition likely resembles a mixture of silicate rocks and metals, with a differentiated interior that may include a solid inner core, a liquid outer core, and a mantle. Seismic data are limited, but gravity and shape measurements help constrain interior models. The crust appears relatively uniform and lacks the mobile plates seen on Earth. Heat flow estimates suggest ongoing, but not intense, internal activity compared to Earth.
Atmosphere and climate profile
The atmosphere of Venus is the defining feature of the planet, consisting mainly of carbon dioxide with a thick cloud layer of sulfuric acid droplets. This combination produces an extreme greenhouse effect, raising surface temperatures to hot enough to melt lead. Winds in the upper atmosphere are fast, but near the surface they are light and slow due to high density. Observations indicate persistent cloud patterns, complex chemistry, and traces of gases such as sulfur dioxide and water vapor, measured by spectrometers on orbiters and descent probes.
Surface geology and observable features
Venus has a solid surface shaped by volcanism, tectonic deformation, and impact cratering. Spacecraft radar and altimetry have mapped vast lava plains, coronae, and mountain belts. Shield volcanoes and large volcanic rises suggest long-lived, widespread effusive eruptions, though no active eruption has been uniquely confirmed as of the latest available data. Impact crater statistics indicate a relatively young surface in geological terms, with most regions dating within the last few hundred million years. The surface pressure and temperature make direct sampling difficult, so much of our understanding comes from orbiters and short-lived landers.
Exploration history and measurement methods
Our knowledge of Venus comes primarily from dedicated missions by space agencies worldwide. Early flyby and orbital missions provided the first global maps, while later landers delivered direct atmospheric and surface measurements. Current observations rely on a combination of Earth-based radar, orbital spectrometers, and long-term tracking of spacecraft positions. Cross-checking data from different methods increases confidence in the numbers often cited as facts on Venus. Continued monitoring supports refinement of orbital parameters and helps track subtle changes in atmosphere and rotation.
Comparative context within the solar system
Venus is often compared to Earth because of their similar sizes and masses, yet their climates and surface conditions diverge sharply. Unlike Earth, Venus lacks a significant magnetic field and has a slow retrograde rotation. Its surface pressure is roughly equivalent to the deep ocean on Earth, and its temperature exceeds that of Mercury even though Mercury orbits closer to the Sun. These contrasts highlight the importance of atmospheric evolution in shaping planetary outcomes over time. Understanding Venus informs models of climate extremes and planetary habitability beyond our world.