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Stars - planetpedia

Diamonds of Sky

The stars that we see shining in the sky at night are sphere of very hot gas which give off a strong light. For a star to shine, it has to reach a temperature of around 10 million degrees Centigrade! The colour of a star depends on its size and its temperature.
The largest are also the hottest, and shine with a blue light. Some smaller stars shine with a white light, some yellow, others orange or pink.

The different ways in which stars shine depends upon on their distance from Earth. The closer the star, the more clearly we see it’s light. Smaller stars have an average diameter of a few thousand kilometres. The diameter of the largest stars can reach up to three billion kilometres.

How is a star born?

The life of a star begins at the heart of a nebula. Together, gas and dust form a nucleus which is always very dense and hot. When the temperature reaches about 10 million degrees, the nucleus ignites and the star begins to shine, burning hydrogen, which is one of its basic elements, for billions of years.

Life Cycle of Star

Proto Star Red Giant Nova and Supernova White Dwarf Way Neutron Star Pulsars Black Holes

Life Span

A star of great dimensions burns very quickly and in the end explodes. From this explosion there forms a supernova. Stars of medium dimensions like our Sun, once it exhausts the hydrogen, becomes bigger and brighter, changing into a ‘red giant’.
Gradually its nucleus shrinks again, slowly becoming cooler and heavier.

Cluster of stars

Scientists believe there are billions, billion stars throughout the universe. Approximately 3000 can be seen with the naked eye in each hemisphere of the Earth.

Nebulae

Nebulae are clouds of dust and gas in which there may be the origins of stars. Sometimes. they are the remains of the dying stars.
Some nebulae shine due to the presence of very hot stars. Some are dark and quite dense.

What How Why

What is a leap Year?

It takes the Earth 365 days and six hours to orbit around the Sun. The Six extra hours cannot be counted on the calander. So, to keep an accurate count, an extra day is added at the end of february every four years.

What How Why

What are the most precious stones?

When the magma cools, the material which it contains solidifies in the form of crystals. Precious stones are crystals with particular characteristics of colour, hardness and the way they can reflect the light. They are used in making jewellery.

What How Why

How is the height of a mountain measured?

To measure the height of mountain, the surface of the sea is taken as the point of reference. The height of the mountain is the distance between the top of the mountain and the surface of the sea.

What How Why

What is an electric current?

An electric current is a passage of electrons from one electrified body to another which is less charged. When too many electrons are generated, they can move.

What How Why

Why does iron go rusty?

Rust forms on the surface of iron objects when they are exposed to the air. It is the product of a chemical reaction called oxidization. The more the object is exposed to the air, the more rapidly rust spreads.

What How Why

How fast can a dog run?

A Greyhound can run at a speed of 64km per hour, a Weimaraner , once used for hunting wolves and wild boar, can reach speed of up to 56 km per hour in a chase. Many breeds of dog which were once bred for hunting are now more common as pets than hunting Dogs.