Venus

Lore & Background

Venus orbits closer to the Sun than Earth, and the two planets approach each other in synodic periods of 1.6 years, making Venus the closest planet to Earth. It has no moons and a very slow retrograde rotation, resulting in a Venusian day of 116.75 Earth days, about half its solar year of 224.7 Earth days. Its weak magnetosphere is induced by the solar wind interacting with the atmosphere, lacking an internal dynamo. Internally, Venus has a core, mantle, and crust, with internal heat escaping through active volcanism rather than plate tectonics. The surface is covered by about 80% smooth volcanic plains, with two highland 'continents': Ishtar Terra in the north and Aphrodite Terra in the south. The southern continent is called Aphrodite Terra, after the Greek mythological goddess of love, and is the larger of the two highland regions at roughly the size of South America. Unique volcanic features include flat-topped 'farra', radial fracture systems called 'novae', spider-web-like 'arachnoids', and circular 'coronae'. The surface is relatively young, at 300–600 million years old, with few impact craters. Venus may have had liquid surface water early in its history before a runaway greenhouse effect evaporated it, though analysis of gas decomposition suggests it has likely been inhospitable for its entire history.

Reader's Guide

Venus has been observed throughout human history and acquired particular importance in many cultures. From Earth, it appears brighter than any other natural point of light, visible as either the brightest 'morning star' or 'evening star', and was given the Old English poetic name Ēarendel, meaning 'ray of light'. With telescopes, the phases of Venus became discernible and, by 1613, were presented as decisive evidence disproving the geocentric model and supporting the heliocentric model.

Venus was first visited in 1961 by Venera 1, achieving the first interplanetary spaceflight. The first data were returned by Mariner 2 in 1962, and the first interplanetary impactor, Venera 4, reached Venus in 1967, followed by the lander Venera 7 in 1970. The first images were captured by Mariner 10 during its 1974 gravity assist en route to Mercury. In interplanetary spaceflight, Venus is frequently used as a waypoint for gravity assists, offering economical routes for spacecraft. As of 2025, Solar Orbiter is on its way to fly by Venus in 2026, and the next mission planned is the Venus Life Finder, scheduled for 2026. Atmospheric conditions at cloud layer altitudes are the most similar to Earth in the Solar System and have been identified as possibly favourable for life, with potential biomarkers found in 2020, spurring new research and missions.

Did You Know?

• Venus has a retrograde rotation, meaning it spins in the opposite direction to most planets.
• The surface pressure on Venus is 92 times greater than Earth's at sea level, turning the lowest atmosphere into a supercritical fluid.
• Venus has no moons and is the closest planet to Earth.
• The planet is expected to be destroyed when the Sun becomes a red giant in about seven or eight billion years.