Indira Gandhi Planetarium, Lucknow Veer Bahadur Singh Planetarium, Gorakhpur        Aryabhatt Planetarium, Rampur

Solar System

Our solar system is nearly five billion years old. It is made up of eight planets, a handful of so called draft planets, and more than 170 moons, as well as dust, gas and thousands of asteroids and comets all orbiting around a central SUN. Everything in the solar system revolves around and is influenced by the sun, including four inner planets, an asteroid belt, four outer planets, comets, asteroids and dwarf planets. The solar system formed 4.6 billion years ago out of a cloud, which condensed into a disk, and materials conglomerated to form the sun, planets and other solar bodies. See Gallery

Sun is a huge, bright sphere of mostly ionized gases, about 4.5 billion years old and is the closest star to Earth, at a distance of about 150 million kms. The next closest star, Proxima Centauri, is nearly 2,68,000 times farther away. The Sun is some 3,33,400 times more massive than Earth and contains 99.86% of the mass of the entire Solar System. The temperature of the Sun’s surface is approximately 6000 ℃. More Details

This is the closest planet to the Sun. It revolves around the Sun in a widely elliptical orbit that takes it as close as 47 million kms and as far as 70 million kms from the Sun. Mercury completes a trip around Sun every 88 days, speeding through space nearly 50 km/sec, faster than any other planet. It is amazing that, because of its closeness with the sun, temperature on its surface reaches up to 4680 ℃ but in night it can drop to a frigid -1830 ℃. Its mean distance from the Sun is 57.9 million kms. Its mass is 0.06 % that of Earth and diameter is 4879 kms. More Details

Venus is the brightest object in the sky, after the Sun and the Moon. Although, being the second planet from the Sun,it is the hottest with a surface temperature of over 4700 ℃. It rotates on its axis once every 243 earth days, while it orbits the Sun every 225 days. Its day is longer than a year. At first glance, if the Earth has a twin it would be Venus. The diameter of Venus is 12100 kms and its mass is 0.82 times of Earth mass. Its mean distance from the Sun is 108.2 million kms. More Details

Our home planet, is the only planet in the Solar System known to harbor life, life that is incredibly diverse. Its means distance from the Sun is 150 million kms. This distance is also known as one Astronomical Unit (AU). It rotates on its axis in 23 hours 56 minutes. This period is known as one day (or day and night). It orbits the Sun in 365.26 days. Its mass is 5.9742 ×〖10〗^24 kgs kgs and diameter is 12756 kms. More Details

The red planet, Mars, has inspired wide flights of imagination over the centuries, as well as intense scientific interest. Mars is the nearest planet to the Earth after Venus and it is the only planet to have a day time temperature close to ours. Scientists believe that 3.5 billion years ago, Mars experienced the largest known floods in the Solar System. Yet the central question about Mars remain: Where is the water? More Details

Jupiter is the most massive planet in our Solar System, and in composition it resembles a small star. In fact, if Jupiter had been between 50 and 100 times more massive, it would have become a star rather than a planet. Its diameter is 1,42,984 kms. At a mean distance of 778.4 million kms from Sun, it completes one revolution around Sun in 11.86 Earth years and one rotation in 9 hours and 55 minutes. Its mass is 318 times of Earth’s mass. More Details

Saturn is the sixth planet from the Sun and is the second largest in the solar system with an equatorial diameter of 119,300 kms. Saturn is visibly flattened at the poles, a result of the very fast rotation of the planet on its axis. Its day is 10 hours, 39 minutes long, and it takes 29.5 Earth years to revolve around the Sun. More Details

Uranus is the seventh planet from the Sun and is the third largest in the solar system. It has an equatorial diameter of 51,800 kms (32,190 miles) and orbits the Sun once every 84.01 Earth years. It has a mean distance from the Sun of 2.87 billion kms(1.78 billion miles). It rotates about its axis once every 17 hours 14 minutes. Uranus has at least 22 moons. More Details

Neptune is the outermost planet of the solar system. It has an equatorial diameter of 49,500 kms (30,760 miles). If Neptune were hollow, it could contain nearly 60 Earths. Neptune orbits the Sun every 165 Earth years. It has eight moons. A day on Neptune is 16 hours and 6.7 minutes. More Details