Mercury
Mercury is named after the Roman messenger God. Its surface is a lot like the moon's. It has a lot of craters. Scientists predict they have been formed by rocks that once crashed into the planet . Mercury is the smallest planet. Mercury has been so far visited from two spacecrafts . Mariner 10, and Messenger . Until 1962 people believed Mercury's day was as long as its year. Mercury is the closest planet to the sun . Its temperature is 90 to 700 k.
Venus
Venus is named after the Roman goddess of love. In the evening after sunset or morning after sunrise you can look into the sky and see Venus . It is sometimes called the evening or morning star. 243 Earth days is as long as one Venus day. That is a little longer then a Venus Year .Venus is also sometimes known as"'Earth's sister ".The first spacecraft to visit Venus was the Mariner 2 in year 1962. It was also visited by so far 20 other spacecrafts.
Earth
Earth is the only planet not named after a Roman god. It is also the only planet suitable for plants and animals to live. 75% of our earth is water. Most water is salt water. Earth is the fifth largest planet. It is also the third closest planet to the sun. One Earth day is 24 hours long . One Earth year is 365 Earth-days . Every four years there is one more day in a year. This is called a leap-year .
Mars
Mars is named after the Roman god of war. It has the highest volcano ever found that is the height of three Mt. Everests. This planet is very very rocky. Eight spacecrafts have so far visited Mars : the Mariner 4, Mars 2, Mars Pathfinder, Mars Expedition Rovers, and Phoenix. Three orbiters are now in operation: Mars Reconnaissance Orbiter, Mars Odyssey, and Mars Express.
Jupiter
Jupiter is named after the king of the Roman gods. It is the largest planet in the galaxy. No humans can possibly enter this planet [ and make it out alive ] because of the toxic gases surrounding the planet. Jupiter does not have a solid surface so it is not meant to be walked on. It was visited by : Pioneer 10, Pioneer 11, Voyager 1, Voyager 2, and Ulysses.
Saturn
Saturn is named after the Roman god of art and culture. It is the second biggest planet in the galaxy. Saturn has the most rings of all the planets in the galaxy. Saturn is also a gas giant, so like Jupiter it cannot be walked on. Saturn's biggest moon is Titon it has about three other moons. It has so far been visited by Pioneer 11 , and Voyager 1.
Uranus
Uranus is named after the Roman god of the heavens. Like Saturn and Jupiter it is a gas giant. It has 27 moons that are named. The surface is made of mostly rock and ice. It was visited so far by only one spacecraft the Voyager 2. Uranus is the third largest planet.
Neptune
Neptune is named after the Roman god of the sea. Like Uranus it has only been visited by Voyager 2. Like Saturn, Jupiter, and Uranus Neptune is a gas giant, so nobody can walk on it. Neptune is also the fourth largest planet in the solar system.
