Our sun is a rather small, yellow star that you would hardly notice among all the other stars in the Milky Way.

Although the planets are different sizes and different distances away, they have concentric orbits, traveling around the sun in the same direction and on the same flat plane.

How many of the planets can you name without looking?

How can you tell this is an old picture?

If you answered. "Because Pluto is no longer considered a planet." you are right.

According to the new definition, a planet is an object that orbits the sun and is large enough to have become round due to the force of its own gravity. In addition, a planet has to dominate the neighborhood around its orbit.

Pluto has been demoted because it does not dominate its neighborhood. Charon, its large "moon," is about half the size of Pluto, while all the true planets are far larger than their moons.

In addition, bodies that dominate their neighborhoods, "sweep up" asteroids, comets, and other debris, clearing a path along their orbits. By contrast, Pluto's orbit is somewhat cluttered.

Image credits for this page:
Solar system: Aerospaceweb.org

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M Y P L A C E I N T H E U N I V E R S E

With modern telescopes, we can clearly see the other planets in our Solar System. These planets orbit the sun along with us. (You know they are very far apart, but this picture squeezes them together in order to show all of them.) Most of the planets are too cold to support life, because they are far away from the sun. Others are too close to the sun, and much too hot. Earth is just right, and life on earth is abundant.