The sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields. It has a diameter of about 1,392,684 km (865,374 mi), around 109 times that of Earth. The temperature at the surface of the Sun is about 10,000 Fahrenheit (5,600 Celsius). The core of the Sun has a temperature of close to 27,000,000 Fahrenheit (15,000,000 Celsius). The Sun formed about 4.57 billion years ago, and is expected to continue to radiate for another 5 billion years.
Mercury
Mercury’s orbit around the sun is 87.97 days
Mercury is the smallest (diameter of only 4,879 km) and closest to the Sun of the eight planets in the Solar System. Because it has almost no atmosphere to retain heat, Mercury's surface experiences the greatest temperature variation of all the planets. Mercury's surface is heavily cratered and similar in appearance to the Moon, indicating that it has been geologically inactive for billions of years. If you were to stand on the surface of planet Mercury, you would experience about 1/3rd the gravity you feel standing on Earth.
Venus
Venus’ orbit around the sun is 224.70 days
Aside from the Sun and the Moon, Venus is the brightest object in the sky. Venus reaches its maximum brightness shortly before sunrise or shortly after sunset, for which reason it has been referred to by ancient cultures as the Morning Star or Evening Star. Venus is a terrestrial planet and is sometimes called Earth's "sister planet" because of their similar size, gravity, and bulk composition. With a surface temperature of 735 K (462 °C; 863 °F), Venus is by far the hottest planet in the Solar System.
Earth
Earth’s orbit around the sun is 365.24 days
Earth formed approximately 4.54 billion years ago, and life appeared on its surface within its first billion years. The most remarkable thing about earth is the life that thrives all over our planet. Earth is also the only planet in our Solar System with tectonic plates. The plate tectonics help protect our planet from overheating like Venus. Liquid water is also an important element for life. Just over 70% of Earth’s surface area is water. Earth orbits the Sun at an average distance of about 150 million kilometers.
The Moon is Earth's only natural satellite. It began orbiting the Earth about 4.53 billion years ago. The Moon's gravitational interaction with Earth stimulates ocean tides, stabilizes the axial tilt, and gradually slows the planet's rotation. The Moon is in synchronous rotation with Earth. Because of this, the Moon always shows the same face to the Earth. We never saw the other side of the Moon until we sent up a probe to take pictures.
Mars
Mars’ orbit around the sun is 686.98 days
It is often described as the 'Red Planet' because the iron oxide prevalent on its surface gives it a reddish appearance. It’s about half the size of Earth, with a diameter of only 6,792 km. It has an even smaller mass, with just 10% the mass of the Earth. The planet has two small moons, Phobos and Deimos. Mars is the most studied planet in the Solar System after Earth, and can easily be seen from Earth with the naked eye, as can its reddish coloring.
Jupiter
Jupiter’s orbit around the sun is 11.86 years
Jupiter is the largest planet in the Solar System. It is 2.5 times more massive than all of the other planets combined or 317 times the mass of Earth. It rotates very quickly, completing a full rotation in just 10 hours. Jupiter has 63 bodies in orbit around it. Astronomers believe that one reason Earth is habitable is that the gravity of Jupiter does help protect us from some comets. Without Jupiter nearby, long-period comets would collide with our planet much more frequently. The best known feature of Jupiter is the Great Red Spot, The Great Red Spot is a persistent anticyclonic storm. The spot is large enough to contain two or three planets the size of Earth.
Saturn
Saturn’s orbit around the sun is 29,46 years
Saturn is the second largest planet in the Solar System, after Jupiter. Saturn has a prominent ring system that consists of nine continuous main rings and three discontinuous arcs, composed mostly of ice particles with a smaller amount of rocky debris and dust. Galileo Galilei was the first to observe the rings of Saturn in 1610 using his telescope, but was unable to identify them as such. In 1655, Christiaan Huygens became the first person to suggest that Saturn was surrounded by a ring. 62 known moons orbit the planet. This does not include the hundreds of 'moonlets' comprising the rings. Titan, Saturn's largest and the Solar System's second largest moon, is larger than the planet Mercury and is the only moon in the Solar System to retain a substantial atmosphere.
Uranus
Uranus’ orbit around the sun is 84,32 years
Uranus is similar in composition to Neptune, and both are of different chemical composition than the larger gas giants Jupiter and Saturn. For this reason, astronomers sometimes place them in a separate category called 'ice giants'. Like the other giant planets, Uranus has a ring system, a magnetosphere, and numerous moons. The wind speeds on Uranus can reach 250 meters per second (900 km/h, 560 mph). One unique feature of Uranus is that it rotates on its side. All of the planets are tilted on their axes to some degree, but Uranus has the most extreme axial tilt of 98°. This leads to the radical seasons that the planet experiences. Each pole gets around 42 years of continuous sunlight, followed by 42 years of darkness. Astronomers think that a large protoplanet smashed into Uranus billions of years ago. This collision set the planet tumbling. Eventually it settles into its current axial tilt. Uranus has 27 moons. Uranus cannot be seen with the naked eye and therefore was not found until after telescopes were created.
Neptune
Neptune orbit around the sun is 164,79 years
Since Pluto was demoted to a dwarf planet, Neptune is the eighth and farthest final planet in our Solar System. Neptune has a planetary ring system, though one much less substantial than that of SaturnNeptune's weather is characterized by extremely dynamic storm systems, with winds reaching speeds of almost 600 m/s (1340 mph). The large amounts of methane in the atmosphere of the planet are what cause its blue color. Neptune cannot be seen with the naked eye and was therefore not discovered until 1846.