Venus

Venus is the second planet from the Sun and a terrestrial planet comparable in size to Earth. It has a mean radius of about 6,051 km, giving it a gravity of 8.87 m/s², but its mass is only about 81.5% that of Earth. Venus completes an orbit in roughly 225 Earth days and, because its days are longer than its year, its rotation period takes about 243 Earth days, spinning in the opposite direction of most planets.

The planet's atmosphere is dense, mainly composed of carbon dioxide with clouds of sulfuric acid. Surface pressure is about 92 times Earth's, while temperatures routinely exceed 740 K (about 470°C), making it the hottest planet in the Solar System. The greenhouse effect is intense, and the thick cloud deck hides the surface from optical observation.

Geologically, Venus possesses extensive volcanic plains, large shield volcanoes, and a few large rift valleys. Spectral imaging from spacecraft has revealed evidence of recent volcanic activity and a dynamic surface altered by tectonic processes. The planet's high pressure and temperature make it hazardous for exploration equipment.

Since the 1960s, numerous probes have studied Venus, including Soviet Venera landers that suffered brief, albeit valuable, touchdown experiences, NASA’s Magellan radar map, and the Japanese Akatsuki orbiter, which captures atmospheric motion. Future missions aim to retrieve samples and probe the atmosphere’s chemistry further.

The planet is named after the Roman goddess of love and beauty, reflecting early observations of its bright, constant visibility. In modern times, it has served as a benchmark for atmospheric science, climate modeling, and planetary geology.