Adventures of the Agronauts

The Sun is a ball of gas made mostly of two gasses: hydrogen and helium. The Sun is always working to change hydrogen to helium. The Sun makes the light that we see and the heat that we feel.

The Sun is one of many stars in our galaxy. Other stars in the sky are much further away from us than the Sun. Their long distance away from us is the reason they look like tiny points of light in the night sky.

We measure the distance of stars from Earth in light years. A light year is the distance that light travels in one year. Since light travels at a speed of 186,000 miles/second (300,000 kilometers/second), a star that is one light year away is actually 5.8 trillion miles (9.5 trillion kilometers) from us! The Sun is only 8 light minutes away. The closest star to us other than the Sun is Alpha Centauri, and it is 4 light years away. The most distant stars we can still see without a telescope are about 1000 light years away!

All the stars we see at night from Earth are also stars in our Milky Way Galaxy. There are over 100 billion stars in our Galaxy, but on an average dark night we can only see about 1000 to 1500 of them! Stars produce light and heat by changing hydrogen into helium, just like the Sun (remember, the Sun is a star, too!)