Our Sun is a star.
What is a Star?Believe it or not, stars differ significantly in size. But all stars are relatively massive celestial bodies made up mostly of hydrogen and helium and produce light and heat from nuclear reactions going on deep inside. The nearest star to Earth is the Sun.
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Scientists estimate that there are about 200 billion stars in our Milky Way galaxy. Scientists also estimate that there may be billions of other galaxies!! So the total number of stars in space is literally astronomical!!!!
Stars come 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! The hottest stars are blue, and can be as hot as 200,000,000° Fahrenheit at their core!
Our Sun is a Medium-Sized Star!?
Our Sun is a medium-sized star with a surface temperature of about 10,000° Fahrenheit. It is categorized as a G-type yellow-dwarf main sequence star. Thankfully, it is predicted that our Sun will remain in the main sequence phase for a few billion more years.
Nuclear Fusion
The Sun shines because it is able to convert energy from gravity into light. How does it do this? Imagine being at the center of the Sun. A HUGE amount of mass is above you, squeezing down on you from all sides. This is what happens to the hydrogen gas in the core of the Sun. It gets squeeze together so tightly that hydrogen atoms combine to form helium atoms. This is called nuclear fusion.
As a result of nuclear fusion, the Sun emits about 386,000,000,000,000,000,000,000,000 watts of energy every moment. Most of that energy goes off into space, but about 174,000,000,000,000,000, or 174 quadrillion watts actually strikes the Earth. To help put that into perspective, the total amount of energy that all humanity uses in a year is approximately 410 quintillion watts.
As a result of nuclear fusion, the Sun emits about 386,000,000,000,000,000,000,000,000 watts of energy every moment. Most of that energy goes off into space, but about 174,000,000,000,000,000, or 174 quadrillion watts actually strikes the Earth. To help put that into perspective, the total amount of energy that all humanity uses in a year is approximately 410 quintillion watts.
Star Constellations
A constellation is a recognized pattern of stars in the night sky.
- In ancient times, people looked up at the stars and picked out patterns that they saw. They often associated these patterns with pictures from their own stories that they told. Most of the constellations that we use today come from the ancient Romans, and they depict many of the people and animals from their myths.
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Topic Tips
- Our Sun is a medium sized star that provides Earth light and heat as a result of nuclear fusion reactions.
- Our Sun is only one of billions of other stars located in our Milky Way Galaxy. Our Universe is made up of billions of other galaxies.