Welcome to the World of Stars !!!
Stars!!! Don't they fascinate you? A lightning ball, A fireball, or simply a ball of gases that are burning continuously giving out a tremendous amount of heat and light.
From our very simplest rhyme "twinkle twinkle little star" to the massive black hole theories we have used the term star. The ultimate source of energy in this blue planet (Earth), "our sun” is also a star.
So, let’s talk technically, what is a star? Stars are huge celestial bodies made mostly of hydrogen and helium that produce light and heat from the churning nuclear forces inside their cores.
How big these stars can be? Contradictory to our very popular rhyme "twinkle twinkle little star”, a star is so huge that our Earth looks very tiny infront of it. Stars vary in size from 59,000 km (radii) to 1,188,000,000km (radii) based on current known observations. So, why they look so tiny while gazing from the Earth? The answer to this is quite simple. Stars are very far from us. Even the nearest star to us, the sun, is 149,600,000 km far from us. This distance can go up to 13.4 billion light-years till current known values. Hence larger the distance from us smaller it seems to be. The next question that attracts us is how these huge balls of fire are made?
Stars are born within the clouds of dust and scattered throughout most galaxies. Such huge clouds are called nebula. The most famous of these is Orion Nebula, which is clearly visible through our eyes without any special equipment. These clouds start to shrink under their own gravity. As the cloud gets smaller, it breaks into clumps. Each clump eventually becomes so hot and dense that nuclear reactions begin. When the temperature reaches 10 million degrees Celsius, the clump becomes a new star.
Stars are fueled by the nuclear fission of hydrogen to form helium deep in their interiors. The outflow of energy from its center part helps it to maintain pressure to help it from not collapsing under its own weight and also the main source of energy by which it shines.
Well, how hot are these heavenly bodies? Stars vary in colors from red, orange, yellow, white, bluish-white, and blue. The color depends on how hot the star is. A red star is the coolest, but still is about 5,000° Fahrenheit! Our sun is yellowish-white and the surface is about 10,000° Fahrenheit. The hottest stars are blue, and can be as hot as 200,000,000° Fahrenheit at their core.
So, now we can conclude why the sun is said to be the ultimate source of energy on Earth. As it is also a star, huge star.