It is hypothesized that the planets and the solar system were formed from a huge cloud of gases and dust particles left over when a massive star exploded as a supernova. The galaxy that holds all of our planets is called the Milky Way Galaxy. The planets that are found in the Milky Way are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto was once a planet but is now considered a dwarf planet along with many other dwarf planets. Ceres is a dwarf planet that is also located in the asteroid belt, between Mars and Jupiter. Mercury, Venus, Earth, and Mars are called inner planets because they are the closest planets to the Sun and can feel the Sun’s heat. Jupiter, Saturn, Uranus, and Neptune are called outer planets because they are the planets farthest away from the sun and are icy cold. In the middle of the solar system is the Sun.
All of the planets orbit around the sun. Mercury is the closest planet to the Sun, but not the hottest. It has the shortest year and longest day. Mercury is the smallest planet in our solar system. Venus is the hottest planet of the solar system. It is the slowest rotating planet but doesn’t have the longest day. Venus is the closest planet to Earth, in distance and in size. Earth is the largest of all the inner planets and the densest planet of the solar system. It has, proportionally, the biggest moon of any planet. It is the only planet known to support life in our galaxy so far. Mars is the last and coldest of the inner planets. It is half the diameter of Earth and has two tiny moons. Mars is the second most explored planet in the solar system.
Ceres is the first dwarf planet. It is the largest object in the asteroid belt and was considered to be a planet for 50 years. Ceres is the first dwarf planet to be visited by a spacecraft. Jupiter is the largest planet in the Solar System. It has 79 moons which is the most moons any planet has. Jupiter’s largest moon, Ganymede, is bigger than Mercury. It has the shortest day of any planet. Saturn is the second largest planet in the solar system. Its rings are made of billions of pieces of ice, dust, and rocks that vary in shapes and sizes. Uranus was the first planet to be discovered. It spins on its side rather than up and down. Neptune is the eighth and final planet of the solar system. It has the longest year of any planet. Pluto is the largest dwarf planet. Its orbit is synchronized with Neptune’s and sometimes comes closer to the Sun than Neptune in its orbit.
