Astronomy Packet: 7
In our journey through the Solar System, we have not talked about one very important member, the King of the Solar System, our Sun.
What is the Sun?
It is important that we understand what the Sun is because it helps us to better understand our own place in the Universe. For thousands of years people thought that the Earth was at the center of the Universe. This idea was known as a geocentric Universe, geo meaning "Earth" and centric meaning "center." The Sun, they thought, was unique, the only one of its kind.
In modern times we have discovered that the Sun is not unique at all. It is just one star in a universe with trillions of other stars. The Sun is a normal star just like every other star in the sky.
Many of the stars in our sky have names, such as Antares and Betelgeuse. Similarly, the Sun also has a name. The name of our sun is Sol. Think about that for a moment. Why does that name sound familiar? Our planet sits in the Solar System, or the System around the star Sol. Would another star's planets be in a Solar System? No, each star's system is named after the star. If Antares has a system, its name would be The Antares System.
Is the Sun big?
Compared to everything else in the Solar System the Sun is huge. It is so big that if it were hollow you could fit one million Earths inside of it. The Sun contains 99.9% of all the mass in the Solar System.
However, while it is true that the Sun is bigger than anything else in our Solar System and also bigger than most of the stars in the Universe, compared to other stars the Sun is not large. It is a middle sized star.
Assignment # 1:
What is the Sun?