The biggest star in our universe is known as the sun. The sun has a diameter of about 870,000 miles, more than 100 times wider that the Earth. It has powerful gravity and so it attracts objects such as comets and other planets. The sun provides warmth, light, and makes our planet suitable for life. It is made of incandesent gas, aka helium. The sun is also made up of many other elements in small amounts.
From far away stars look pretty small. In reality, if you were to zoom in trillions of miles to look at them, you would see that they are huge bright bodies, simular to the sun. Stars are very far away. For example, even the closest star, Proxima Centauri, lies four light years away from Earth.
Constellations are stars that form patterns in the sky. Ancient Astronomers named them after characters from their myths and legends. With most constellations you would believe the stars are in close proximity. Actually, they are often quite far away from eachother. They just happen to be in the same dirrection in space. Even stars that appear to have the same brightness are probably very different.
When we study the spectra of stars we can find out their color compostition, teperature, size and speed of travel. Astronomers are also able to figure out the distance to stars and their mass using other techniques. There are dwarfs with only a hundreth the diameter of the sun and supergiants hundreds of times of the suns diameter. Red stars are either very faint or bright, while other stars tend to be brighter if they are bluer. Some stars do not shine steadily. They may change and brightness. They are called pulsating variables, they periodically change. They are mostly bright when they are small and hot, dimmist when they are large and cool. They are like this often by the end of their lives.
Stars are born in dark swathes of gas and dust that occupy interstellar space. They are very cold, consist of hidrogen gas, and are called giant molecular clouds. Here, gravity pulls the gas molecules together which results in denser clumps. Within them is even denser regions, called cores. From these cores that stars are born. It is gravity that makes a core colapse, compressing the material in the center. As this happens, in continues to get hotter. It begins to go as it transfered into a protostar. It finishes heating up and fires up, begining its life as a new star.
After creation, stars spend most of their life shinning steadily until they have used up all their hydrogen fuel. They begin to die, and go through a phase when they swell and brighten. The way a star really dies depends on its mass. Low mass stars puff off their outer layers and fade away. High mass stars die in an explosion called a supernova.
Overall stars are a very interesting part in our solar system. The sun is also very important and allows our planet to have life. Stars go through many different stages in their life, changing in size and brightness. They can live for 10 billion years. Stars are just a small part of our universe