The biggest moon in the solar system is Ganymede. It is one of the 16 Moons of Jupiter, which is 5276 km across and bigger than Pluto.
Uranus is a blue-green world of freezing chemical slush, shrouded in clouds of methane gas and tilted on its side. In 1986, Voyager discovered that Uranus had 17 moons in all.
Between 12 to 15 billion years ago, it is believed that the Universe began with an incredible Big Bang, an unimaginably enormous explosion of energy. This explosion sent matter flying through space. From this matter, the galaxies were formed. Galaxies are whirling masses of stars. One of those billion stars is our Sun.
Venus is constantly battered by Sulphuric acid rain and the pressure of the air is at least 90 times more than that of the Earth's. Its vast plain has 167 extremely high volcanoes on the surface, some over 8,000 m high.
Comets are celestial objects which consist of a nucleus of ice and dust, orbiting the Sun like planets. Halley's Comet is the one which comes close to Earth roughly every 77 years. In 1986, several spacecrafts flew close to the comet which is expected again in the year 2062.
The Milky Way is shaped like a pinwheel but it does not rotate as one large disk. The Sun takes 220 million years to complete a trip around the centre of the Milky Way.
Black holes are the heavenly bodies in which the force of gravity is so strong that it does not allow anything to escape, not even light. That's why it cannot be seen with the most powerful telescopes.
At least nine other stars including '51 Pegasi7 are now known to have planets, like the Sun has.
As per the latest estimate, there are around 6000 artificial satellites orbiting the Earth. Of these, about 3000 have lived out their useful life, are not operational and are part of the space debris.
Moon has the highest mountain of 8,000 m near the Korolev basin at the far side. The lowest temperature on the Moon falls to-163°C at nights. A full moon is 9 times brighter than a half moon.
