Understand that the Sun is an ordinary star, how far away it is and what it is made of, and why it is the Sun that holds the whole system together.
The star we see every day
What the Sun is
The Sun is a star. A perfectly ordinary one: medium-sized, yellowish-white. It is simply about 270,000 times closer to us than any other star, so it shines brightly instead of looking like a tiny dot.
The Sun is a ball of hot gas, mostly hydrogen and helium. It has no solid surface you could stand on: the deeper you go, the denser and hotter it gets, until the “nuclear furnace” begins at the very center.
How big is the Sun? More than a million planets the size of Earth would fit inside it. By mass, the Sun holds about 99.8% of all the matter in the solar system — everything else (planets, moons, asteroids, comets) is a measly 0.2%, mere small change.
That is why the Sun's gravity holds the planets in their orbits. Remove the Sun, and the planets would fly off like stones from a released sling.
Light from the Sun takes about 8 minutes to reach Earth. This means we always see the Sun as it was 8 minutes ago.
Lesson notes
What the Sun is
The Sun is a star. A perfectly ordinary one: medium-sized, yellowish-white. It is simply about 270,000 times closer to us than any other star, so it shines brightly instead of looking like a tiny dot.
The Sun is a ball of hot gas, mostly hydrogen and helium. It has no solid surface you could stand on: the deeper you go, the denser and hotter it gets, until the “nuclear furnace” begins at the very center.
How big is the Sun? More than a million planets the size of Earth would fit inside it. By mass, the Sun holds about 99.8% of all the matter in the solar system — everything else (planets, moons, asteroids, comets) is a measly 0.2%, mere small change.
That is why the Sun's gravity holds the planets in their orbits. Remove the Sun, and the planets would fly off like stones from a released sling.
Light from the Sun takes about 8 minutes to reach Earth. This means we always see the Sun as it was 8 minutes ago.