The planet Venus is named after the ancient Roman goddess of love and beauty . It is the brightest planet in the sky when viewed from Earth. Venus is about the same size as Earth. However, unlike Earth, it is not able to sustain life because it has a poisonous atmosphere  and high temperatures.

Venus is the second planet from the sun. Its distance from the Sun averages about 108 million kilometres (67 million miles). Venus is one of the inner planets, along with Mercury, Earth and Mars. These four planets are all rocky, solid and relatively dense.Its diameter is about 12,100 kilometres (7,500 miles). Scientists believe that Venus might have layers similar to those of Earth: an inner core made of metal, a thick middle layer of rock and a crust.

The surface of Venus was greatly shaped by lava from erupting volcanoes. Most of the surface consists of gently rolling plains, though there are also several lowland areas. In addition, Ishtar Terra and Aphrodite Terra are two highlands as big as continents. Maxwell Montes is the highest region on Venus.

Venus’s atmosphere is made up mainly of carbon dioxide. The planet is covered by thick clouds that reflect the sunlight, making Venus very bright in Earth’s night sky. The clouds are composed mostly of sulphuric acid. They allow only a small amount of sunlight to reach the planet’s surface. Because of this, the days on Venus are dim and overcast.

Although much of the sunlight is reflected, the heat energy from the Sun does reach the surface. The large amounts of carbon dioxide and the heavy cloud cover trap this energy at the surface, making the planet very hot. The temperature on Venus is about 464°C (867°F) near the planet’s surface. Venus is even hotter than Mercury, the planet closest to the Sun. As a result, the surface of Venus is hot enough to melt lead. Rocks may even glow faintly red from their own heat.Like all planets, Venus has two types of motion, known as orbit and spin. Unlike the other planets in the solar system (except Uranus), Venus spins on its axis in a clockwise direction. This means that a person on Venus would see the Sun rise in the west and set in the east – the opposite of the situation on Earth. In addition, Venus spins on its axis very slowly. It takes 243 Earth days to complete one rotation. At the same time, Venus orbits the Sun in about 225 Earth days.

The same side of Venus is always facing Earth when the two planets pass in orbit. Most of the planets travel around the Sun in an elliptical, or oval, orbit. Venus’s orbit is almost a perfect circle. (For more information on orbit and spin, see planets.)

Because of Venus’s brightness in the night sky, it has been observed since ancient times. The Italian scientist Galileo made the first observations of Venus through a telescope in the early 1600s.The greatest advances in the study of Venus have been made with unmanned spacecraft. More than 20 missions have visited the planet. The United States National Aeronautics and Space Administration (NASA) launched the Mariner 2 spacecraft in 1962. It became the first spacecraft to fly near another planet when it passed by Venus. In 1967, Mariner 5 flew even closer to Venus. It passed within only about 4,000 kilometres (2,500 miles) of the planet.