You may have heard that there are nine planets. In fact, as of November 2026, our solar system has eight planets. They circle the Sun, which is at the center of the solar system. The Sun holds 99.8 percent of all the mass in it. Pluto was once counted as a planet. As of November 2026, it is called a dwarf planet.

Mercury, Venus, Earth and Mars are the four rocky inner planets. Mercury is the smallest planet. It is the closest to the Sun. It goes around the Sun in just 88 Earth days. That is faster than any other planet. It has ice at its poles. The ice is hidden inside craters that never see sunlight.

You may have heard that Mercury is the hottest planet. After all, it is closest to the Sun. In fact, Venus is the hottest. It is the second planet from the Sun. Its surface is hot enough to melt lead. Venus also spins very slowly. One Venus day, about 243 Earth days, is longer than a Venus year.

Earth is the third planet from the Sun. About 71 percent of Earth is covered by water. You may have heard that we have seasons because Earth moves closer to the Sun in summer. In fact, Earth's axis is tilted by about 23 degrees from the plane of its orbit. That tilt gives us seasons.

Mars looks red because iron in its rocks and dust has rusted. It once had liquid water on its surface. It has the largest volcano in the solar system. The volcano is called Olympus Mons. It also has the biggest canyon in the solar system. The canyon is called Valles Marineris. A day on Mars lasts about 24.6 hours. That is very close to a day on Earth.

Jupiter is the largest planet in our solar system. It is more than twice as massive as all the other planets combined. You may have heard that you could land on Jupiter. In fact, it is a gas giant. It does not have a true solid surface. Its Great Red Spot is a giant storm. The storm is bigger than Earth.

Saturn is a planet with a spectacular set of rings around it. You may have heard that the rings are one big flat record. In fact, they are made of millions of separate pieces. Most are small. They range from tiny dust-sized icy grains to chunks as big as a house. Saturn is also the only planet less dense than water. It would float in a bathtub big enough to hold it.

Words to know

• craters: bowl-shaped holes
• tilted: leaning over
• dense: packed tightly
• massive: very heavy
• canyon: deep land cut

The short version

As of November 2026, our solar system has eight planets that circle the Sun. Also as of November 2026, Pluto, once counted as a planet, is now called a dwarf planet. The Sun is at the center, and Jupiter is the largest planet.

Quick facts

• As of November 2026, our solar system has eight planets that circle the Sun.
• Venus is the hottest planet, and its surface is hot enough to melt lead.
• Jupiter is more than twice as massive as all the other planets combined.
• Mars has the largest volcano in the solar system, Olympus Mons.
• Saturn is the only planet less dense than water, so it would float in a big enough bathtub.