# Our Solar System Planets

There are eight planets in our solar system including Earth. So far, no life as we know it exists on any planet other than our own.

## Mercury

- Size: Two-fifths the size of Earth in diameter; second smallest in the solar system
- Diameter: 3,032.4 miles (4,880 km)
- Surface: Covered by a dusty layer of minerals (silicates), the surface is made up of plains, cliffs, and craters
- Atmosphere: A thin mixture of helium (95%) and hydrogen
- Temperature: Mercury alternately bakes and freezes, depending on what side is lit by the Sun. The sunlit side can reach up to 950 degrees F (510 degrees C) and the dark side can drop as low as -346 degrees F (-210 degrees C)
- Rotation of its axis: 59 Earth days
- Rotation around the Sun: 88 Earth days
- Your weight: If you weigh 100 pounds on Earth, you would weigh 38 pounds on Mercury.
- Distance from Earth: 57 million miles, at the closest point in its orbit
- Mean Distance from Sun: 36 million miles (57.9 million km)
- Satellites: 0
- Rings: 0

## Venus

- Size: About 650 miles smaller in diameter than Earth
- Diameter: 7,519 miles (12,100 km)
- Surface: A rocky, dusty, waterless expanse of mountains, canyons, and plains, with a 200-mile river of hardened lava
- Atmosphere: Carbon dioxide (95%), nitrogen, sulfuric acid, and traces of other elements
- Temperature: Ranges from 55 degrees F (13 degrees C) to 396 degrees F (202 degrees C) at the surface
- Rotation of its axis: 243 Earth days
- Rotation around the Sun: 225 Earth days
- Your weight: If you weigh 100 pounds on Earth, you would weigh 88 pounds on Venus.
- Distance from Earth: At its closest, Venus is 26 million miles (41,840,000 km) away
- Mean Distance from Sun: 67.24 million miles (108.2 million km)
- Satellites: 0
- Rings: 0

## Earth

- Size: Four planets in our solar system are larger and four are smaller than Earth
- Diameter: 7,926.2 miles (12,756 km)
- Surface: Earth is made up of water (70%), air, and solid ground. It appears to be the only planet with water
- Atmosphere: Nitrogen (78%), oxygen (21%), other gases
- Temperature:
- Rotation of its axis: 23 hours, 56 minutes, 4 seconds
- Rotation around the Sun: 365.2 days
- Your weight:
- Distance from Earth:
- Mean Distance from Sun: 92.9 million miles (149.6 million km)
- Satellites: 1
- Rings: 0

## Mars

- Size: About one-half the size of Earth in diameter
- Diameter: 4,194 miles (6,794 km)
- Surface: Canyons, dunes, volcanoes, and polar caps of water ice and carbon dioxide ice
- Atmosphere: carbon dioxide (95%)
- Temperature: as low as -305 degrees F (-187 degrees C)
- Rotation of its axis: 24 Earth hours, 37 minutes, 23 seconds
- Rotation around the Sun: 687 Earth days
- Your weight: If you weigh 100 pounds on Earth, you would weigh 38 pounds on Mars.
- Distance from Earth: 35 million miles (56 million km) at the closest point in its orbit
- Mean Distance from Sun: 141.71 million miles (227.9 million km)
- Satellites: 2
- Rings: 0

## Jupiter

- Size: 11 times the diameter of Earth
- Diameter: 88,736 miles (142,800 km)
- Surface: A hot ball of gas and liquid
- Atmosphere: Whirling clouds of colored dust, hydrogen, helium, methane, water, and ammonia. The Great Red Spot is an intense windstorm larger than Earth.
- Temperature: -234 degrees F (-148 degrees C) average
- Rotation of its axis: 9 hours and 55 minutes
- Rotation around the Sun: 12 Earth years
- Your weight: If you weigh 100 pounds on Earth, you would weigh 265 pounds on Jupiter.
- Distance from Earth: At its closest, 370 million miles (591 million km)
- Mean Distance from Sun: 483.88 million miles (778.3 million km)
- Satellites: 63
- Rings: 4

## Saturn

- Size: About 10 times larger than Earth in diameter
- Diameter: 74,978 miles (120,660 km)
- Surface: Liquid and gas
- Atmosphere: Hydrogen and helium
- Temperature: -288 degrees F (-178 degrees C)
- Rotation of its axis: 10 hours, 40 min, 24 sec
- Rotation around the Sun: 29 1/2 Earth years
- Your weight: If you weigh 100 pounds on Earth, you would weigh 107 pounds on Saturn.
- Distance from Earth: 744 million miles at the closest point
- Mean Distance from Sun: 887.14 million miles (1,427 million km)
- Satellites: 31
- Rings: 1,000?

## Uranus

- Size: 4 times larger than Earth in diameter
- Diameter: 32,193 miles (51,810 km)
- Surface: Little is known
- Atmosphere: Hydrogen, helium, and methane
- Temperature: uniform temperature of -353 degrees F (-214 degrees C)
- Rotation of its axis: 17 hours
- Rotation around the Sun: 30,685 days or 84 Earth years
- Your weight: Not known
- Distance from Earth: At the closest point, 1,607,000,000 miles
- Mean Distance from Sun: 1,783.98 million miles (2,870 million km)
- Satellites: 27
- Rings: 11

## Neptune

- Size: Almost 4 times the size of Earth in diameter
- Diameter: 30,775 miles (49,528 km)
- Surface: A liquid layer covered with thick clouds and with constant, raging storms
- Atmosphere: Hydrogen, helium, methane, and ammonia
- Temperature: -353 degrees F (-214 degrees C)
- Rotation of its axis: 16 hours and 7 minutes
- Rotation around the Sun: 165 Earth years
- Your weight: Not known
- Distance from Earth: 2,680,000,000 miles at closest point
- Mean Distance from Sun: 2,796.46 million miles (4,497 million km)
- Satellites: 13
- Rings: 4

## Pluto

- Size: Less than one-fifth the size of Earth in diameter
- Diameter: 1,423 miles? (2,290 km?)
- Surface: A giant snowball of methane and water mixed with rock
- Atmosphere: Methane
- Temperature: between -369 degrees and -387 degrees F (-223 degrees and -233 degrees C)
- Rotation of its axis: 6 days, 9 hours, 18 minutes
- Rotation around the Sun: 248 Earth years
- Your weight: Not known
- Distance from Earth: At the closest point, 2.67 billion miles
- Mean Distance from Sun: 3,666 million miles (5,900 million km)
- Satellites: 1
- Rings: ?