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
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 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.