The Solar System

In the Solar System Channel, you can explore the planets and celestial objects around our own sun. Learn about topics such as Mars, Jupiter and the Moon.


Uranus is the seventh planet from the sun, and is named for the ancient Greek deity of the Heavens, the earliest supreme god. It is the third largest planet in the solar system, and is three times as large as Earth.

Venus is the second planet from the sun, and is about the same size as Earth. It is a terrestrial planet, meaning it has a solid surface. But the harsh conditions on Venus make it very inhospitable. Two spacecraft, Pioneer Venus 1 and Magellan, were able to penetrate the thick atmosphere of this planet.

Saturn is the sixth planet from the sun and the second largest planet in the solar system. It is named for the Roman god of agriculture, one of the most important gods in the Roman world. Saturn is made mostly of hydrogen and helium, and its poles appear to be flattened because of its speedy rotation on its axis...

Saturn is the sixth planet from the sun and the second largest planet in the solar system. It is named for the Roman god of agriculture, one of the most important gods in the Roman world.

Mars, which is the fourth planet from the sun and the third smallest in size, got its name because of its rusty red color. People associated the planet's blood-red color with war, so they named it Mars, after the Roman god of war.

Since the 1960s, we've been captivated by our planetary neighbor. How different is the planet next door, and what have we learned about it so far, compliments of the Phoenix Mars Lander and other spacecraft?

The sun warms our planet every day, provides the light by which we see and is necessary for life on Earth. But what is it exactly, and what will happen when it burns itself out?

Why does the moon look so much bigger when it is near the horizon than when it is high up in the sky? This question has been pondered for hundreds if not thousands of years, and is commonly referred to as the moon illusion.

Where I live it is pretty common to see "shooting stars" -- streaks of light in the sky at night. How big is a shooting star? Do they land on earth or do they burn up? Do they land on the ground as meteorites?

The Chandler wobble is the change in the spin of the earth on its axis. Think of the wobble you see in a toy top when it first starts spinning or slows down. Its "poles" do not spin in a perfectly straight line.

If I was on the moon and the earth was black (no lights were on) and a flashlight was turned on facing the moon, would I see the light? If I couldn't, would there be any way to detect any residual matter that came from the light on Earth or does light die after a certain distance?

If "nature abhors a vacuum," then why doesn't the vacuum of space suck away all of the Earth's atmosphere?

Can the curvature of the Earth only be seen from outer space? If you didn't know that the Earth is a sphere, there are three common observations you could use to convince yourself that it is.