Mercury-Closest To the Sun Almost twice the size of Pluto and 4879 kilometres in diameter, Mercury is the closest planet to the Sun at a distance of only 57.9 million kilometres. It is only five percent of the Earth’s size and takes 58.65 days to revolve once on its axis which means that it has a day which is equal to 180 Earth days. Like Venus, Mercury does not have any...

Venus the Hottest Planet   Next, to Mercury, Venus is the hottest and the brightest planet in the Sun’s family. Venus has a diameter of 12,104 kilometres and is located 108 million kilometres from the Sun. It has a surface gravity of 0.90 as compared to Earth. Venus rotates on its axis in a clockwise direction in 243.16 days thus having a four year day. It travels at a speed of...

Mars the ‘Red Planet’ Mars, the fourth planet has a diameter of 6,794 kilometres and it orbits at a distance of 228 million kilometres from the Sun. The surface gravity on Mars is 0.38 of the Earth’s gravity and the planet is about one tenth the size of the Earth. Mars moves at a speed of 24 kilometres per second and takes about 780 days to complete one revolution around the...

Saturn and its Rings Saturn is the sixth planet, in order of revolution, in the family of the Sun. It has a diameter of 1,20,536 kilometres and is located in orbit about 1427 million kilometres away from the Sun. Saturn is about 95 times larger and has a surface gravity of 1.16 as compared to Earth. Moving at a speed of 9.6 kilometres per second it takes about 30 years to...

The Movement of Planets around the Sun All planets in the Sun’s family were probably formed from the same spinning cloud of material from which the Sun was created. This could probably explain the reason why they move in the same direction while rotating on their axis’. This movement is necessary, if the planets did not move at just the right speed depending upon their distance from the Sun, they would...

The Sun and its Family   The Sun, as we see it, is a huge ball of very hot gas measuring about 1,380,000 kilometres in diameter. Dark spots can often be seen on the Sun’s surface, these are known as Sun spots and they come and go frequently. These spots stand out as dark patches since they are cooler as compared to the hot area by which they are surrounded. Huge...

Galaxies and Stars It is said that a very powerful explosion took place billions of years ago which resulted in the formation of the galaxies. Galaxies contain dust, gas and thousands of millions of stars. These galaxies are gradually moving away from each other since the Universe is constantly expanding. On a clear night we can see thousands of stars in the skies. Most of the stars we see belong to...

The Earthquakes and its measurement  The tremors produced by an earthquake can be measured by using sophisticated instruments called ‘ Seismographs’ it shows earth tremors as wriggles in hire traced on a turning drum. A tremor vibrates the weight that holds the tracer. The seismograph then gives a number with a decimal point to rate the earthquake. The intensity of the earthquake is measured on the Richter Scale, an established scale...