Size of the Solar System





How big is the Earth?

If you drove once around the Earth you would have gone 25,000 miles. That would mean 40 to 50 days of driving to just go around once.

What is the distance from the Earth to the Sun?

93 million miles. A 747 jet flies at about 600 miles in one hour. If we could take a 747 jet to the Sun, it would take 17 years to fly from the Earth to the Sun.

As we move farther away from the Earth, distances get so large so fast that astronomers have to use the fastest speed possible - the speed of light (186,000 miles every second). Light can go around the Earth 7 and 1/2 times in one second. It takes light 1 and 1/2 seconds to go from the Earth to the Moon, 240,000 miles. It takes 8 minutes for the light of the Sun to reach us. It takes 5 light-hours (meaning the distance light travels in 5 hours) for light to get out to Pluto from the Earth.

When we leave our solar system, distances get very large. The nearest star, named Proxima Centauri, is over 4 light-years away. Or, for example, if the Sun were a large grapefruit in Washington D.C., Proxima Centauri would be a cherry in California. On this same scale, the Earth would be smaller than the top of a pin, and only 50 feet from the grapefruit sun.

The center of our galaxy is about 27,000 light years from us. Our sister galaxy, called M31, is two million light years away! It is part of the 'local group' of galaxies. The Magellenic Clouds, which are seen only from the Southern Hemisphere, are the closest galaxies of the local group.

Although we think our planet is very large, when we compare it to other objects in our solar system, it is really quite small. We could fit 1000 Earths inside Jupiter. And we could fit 1000 Jupiters inside the Sun. It would take one million Earths to fill the Sun, and our Sun is only about a medium-sized star.

When we look up at stars at night, we are seeing light that left the star a long time ago. The light from Proxima Centauri, the nearest star, takes 4 years to get here. When we look at the fuzzy circle of a distant galaxy, we are seeing light that left that galaxy at least 2 million years ago.

In Silver City, New Mexico, a side-walk solar system is being made. The entire solar system fits on a little over 1 mile of side-walk. Everything is scaled, so the Sun is only 1 and 1/2 feet across, and Pluto is the size of a pin head.

