Astronomy

On a clear night, only a few hundred stars can be seen without the use of any astronomical instruments. The Milky Way Galaxy consists of at least 200 billion stars. Stars are huge balls of hot gases. The sun is a star, but it is not the largest star; it is only the nearest star. A star has three recognizable stages: its birth; the years in which it exists; and its death. Its formation and its life expectancy have captured the curiosity of astronomers for centuries. Astronomers from the past have devoted their entire lives to the studying of the formation of stars. Gases make up 99 percent of the materials in the galaxy. These gases in space gather together to form clouds of gas, known as nebulae. Millions of years later, "the temperature of the cloud climbs until it becomes hot enough to radiate light. It is then no longer a gas cloud; it is a star"[1] (Asimov 182). New stars are formed when nuclear reactions occur in these concentrated clouds of gas. Stars are made of 60 different elements, all of which are found on Earth.

Elements such as hydrogen, helium, iron, and calcium. The average star's atmosphere consists of

87% hydrogen, 10% helium, and 3% of other elements. Each star has its own motion, but it is not obvious. Although the sun appears to be huge, many stars are bigger than it. Our sun's diameter is

864,000 miles. Betelgeuse, a red supergiant, has a diameter 500 times bigger than the sun: 500 million miles. Betelgeuse, though, is not the biggest star.

Epsilon Aurigae is close to one billion miles in diameter and VV Cephei has a diameter of two billion miles, known as the super-supergiants.

There are also stars that are small. One of the smallest is the Whale and it has a diameter of

1,600 kilometres. Small stars are known as white dwarfs. Stars also have different temperatures.

Temperatures ranging from 2,100C to 50,000C.

The temperature of the stars is indicated by the colour of the stars. The blue colour stars are the hottest and usually the brightest stars, the yellow stars are medium hot, and the red stars are coolest and the most dim. Over time, there have been many questions concerning the supply of gas clouds in our galaxy. Some people concluded that there will be only enough to fuel the creation of stars for another 200 million years. Due to this immature hypothesis, astronomers investigated and came to the conclusion that there will be materials enough for the creation of new stars for at least another 10 billion years. Other questions asked were: will there be new stars being born after 10