30 Interesting Facts About the Solar System

1. The sun is the center of the solar system. All the other objects of the solar system orbit around it either directly or indirectly.
2. Out of the total eight planets of the solar system, the initial 4 (Mercury, Venus, Earth, and Mars) are composed of rock and metal and are called "rocky planets." The next 2 (Jupiter and Saturn) are known as "gas giants", as they are mainly composed of helium and hydrogen. The last  two planets (Uranus and Neptune) are called "ice giants" (composed of water, methane, and ammonia).
3. The four gas giant planets (Jupiter, Saturn, Uranus, and Neptune) have ring systems. Saturn has the largest and most noticeable ring system. Other planets have smaller and fainter rings, which were discovered in the 1970s. (Source)
4. The most distant region of the solar system is known as the Oort Cloud. It contains billions or trillions of objects, especially comets. (Source)
5. The solar system formed around 4.5 billion years ago from the solar nebula, a cloud of gas and dust. The explosion of a nearby exploding star (supernova) caused the disintegration of the nebula.
6. Apart from planets, the solar system also contains dwarf planets, moons, asteroids, and comets.
7. Smaller-sized planets in the solar system are known as dwarf planets. So far, IAU (International Astronomical Union) has recognized five dwarf planets: Pluto, Eris, Ceres, Makemake, and Haumea. The estimated numbers of dwarf planets in the solar system are 200. In contrast to full-fledged planets, dwarf planets have low gravity that cannot attract or repel smaller bodies in their orbit. (Source)
8. After its discovery in 1930, Pluto was labeled as the 9^th planet in the solar system. Later in 2006, it was reclassified as a ‘dwarf planet’ due to its smaller size. (Source)
9. Scientists believe there is a 9^th planet in the solar system, which is ten times more massive than earth. (Source) 
10. Complex organic compounds, necessary for life, are present on Earth and in other parts of the universe. These compounds have been discovered in Uranus, Neptune, meteorites, and asteroids. (Source)
11. Along with the earth, ice is also present in other parts of the universe, including planets, comets, and moons. Ice is there in the rings of Saturn and other giant planets. (Source)
12. All the planets in the solar system orbit the sun anticlockwise. However, a few exoplanets move in a different direction. (Source)

    

    All the planets and many other objects of solar system orbit anitclockwise

    
    
13. Most of the objects in the solar system move anticlockwise around the sun. Only a handful of celestial bodies orbit in a different direction. Two of these are “Drac” (Dracula) and “Niku” (rebellious), discovered in 2008 and 2016, respectively. (Source)
14. Apart from the sun and the solar system, there are more than 3,200 stars with planets in the Milky Way Galaxy. (Source)
15. Moon is a natural satellite that orbits around a planet. Jupiter has 67 known moons, while Saturn (62), Uranus (27), Neptune (14), and Mars (2) also have multiple moons. Earth has one moon, while Mercury and Venus are without a moon.
    
16. Saturn’s moon Titan is larger than the planet Mercury and the second-largest known moon in the solar system after Jupiter’s moon Ganymede. Along with earth, Titan is the only place in the solar system having lakes, rivers, and seas on its surface. It is also the only known moon in the solar system with an earth-like atmosphere. (Source)
17. Mercury is the closest planet that orbits around the sun, but Venus has a higher temperature than Mercury despite being relatively away from the sun. The reason behind this higher temperature of Venus is the presence of greenhouse gases in its atmosphere, which retains most of the heat of the sun. Mercury is airless, like the moon. (Source)
18. Mercury is the smallest planet (0.055 Earth masses), while Jupiter is the largest planet (318 Earth masses) in the solar system.
19. The sun and the solar system complete one revolution around the center of the Milky Way galaxy in around 250 million years. It is known as the galactic year of the Solar System.
20. The solar system is located about 25,000 light-years away from the center of the Milky Way Galaxy. 
21. The most common ice in the solar system is water ice, present in all planet systems except Venus. Carbon dioxide ice is present in most of the universe, with the highest deposits on mars. Titan (Saturn’s moon) has the most complex ice system that contains several types of ices. (Source)
22. More than 3,700 known comets in the solar system orbit the sun. They are composed of gases, dust, and rocks from the leftover of the solar system. Frozen comets are the size of a small town, while the heated ones are larger than a few planets. (Source)
23. The closest star system (Alpha Centauri) to the solar system is 4.37 light-years away from the solar system.
24. Between Mars and Jupiter, an Asteroid Belt contains numerous asteroids and other smaller objects.

    

    Asteroid belt between Mars and Jupiter

25. Beyond Neptune, a Kuiper Belt also contains many small bodies. However, it is several times wider and more massive than Asteroid Belt.
26. The upper atmosphere of Uranus is covered with clouds of hydrogen sulfide gas. They give the smell of rotten eggs and farts. (Source)
27. More than 200 moons have been discovered in the solar system. Apart from planets, a few dwarf planets and asteroids also have moons. (Source)
28. Sedna is the most distant observable object in the solar system. The diameter of the solar system related to Sedna is 287.46 billion km or 1,921.56 AU. (Source)
29. Olympus Mons on Mars is famous as the highest mountain in the solar system, with an altitude of 21.9 km. However, the highest mountain could be the mountain peak of a crater on asteroid Vesta with an estimated height of 22.5 km. (Source)
30. There are various types of spacecraft. The purpose of these spacecraft is to observe, orbit, or land on planets, moons, and other objects of the solar system to gain information. (Source)