Venus is the second planet from the Sun. It is a rocky planet with the densest atmosphere of all the rocky bodies in the Solar System, and the only one with a mass and size that is close to that of its orbital neighbour Earth. Orbiting inferiorly (inside of Earth's orbit), it appears in Earth's sky always close to the Sun, as either a "morning star" or an "evening star". Proximity to the Sun: Venus is the second planet from the Sun, orbiting at an average distance of about 67 million miles (108 million kilometers). It is the closest planet to Earth and often referred to as our "sister planet" because of its similar size and composition. Similar Size to Earth: Venus is often called Earth's twin because it's very similar in terms of size and mass. It has a diameter of approximately 7,520 miles (12,104 kilometers), making it only about 400 miles (644 kilometers) smaller than Earth. Extreme Surface Temperature: Despite its similarities to Earth, Venus has a hostile environment. Its surface temperature is the hottest in the solar system, reaching up to 900 degrees Fahrenheit (475 degrees Celsius). This extreme heat is due to a runaway greenhouse effect, caused by the thick atmosphere trapping heat. Atmosphere Composition: Venus has a thick atmosphere primarily composed of carbon dioxide (about 96.5%), with trace amounts of nitrogen and sulfur dioxide. The atmosphere is so dense that it exerts a pressure about 92 times greater than that of Earth's at sea level. No Water on the Surface: Venus is often referred to as Earth's "evil twin" due to its harsh conditions. It lacks liquid water on its surface, as the high temperatures would cause it to evaporate. Any water that may have existed in the past likely boiled away. Retrograde Rotation: Venus has a unique rotational pattern compared to most planets. It rotates on its axis very slowly and in the opposite direction to most other planets, a phenomenon known as "retrograde rotation." A day on Venus (one rotation) is longer than its year, taking about 243 Earth days, while its year is around 225 Earth days. Extreme Volcanism: Venus is home to numerous volcanoes, some of which are among the largest in the solar system. The planet's surface is marked by vast volcanic plains, impact craters, and highland regions. The most famous volcano on Venus is Maxwell Montes, which is the highest peak on the planet. Thick Cloud Cover: Venus is shrouded in thick clouds of sulfuric acid, making it nearly impossible to observe its surface from space using visible light. These clouds reflect sunlight, giving Venus its bright appearance and making it one of the brightest objects in the night sky. Lack of a Magnetic Field: Unlike Earth, Venus lacks a significant global magnetic field. This has left the planet's atmosphere vulnerable to being stripped away by solar wind, contributing to its current inhospitable conditions. Numerous Space Missions: Several spacecraft have been sent to study Venus, including NASA's Magellan, which mapped the planet's surface with radar, and the Soviet Union's Venera missions, which landed probes on the surface. In recent years, interest in Venus has been rekindled, with proposed missions aimed at studying its atmosphere and surface conditions in more detail.