The Planets In Order

In our Solar System, there are eight planets. The planets in order from the Sun based on their distance are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

The planets of our Solar System are listed based on their distance from the Sun. There are, of course, the dwarf planets Ceres, Pluto, Haumea, Makemake, and Eris; however, they are in a different class.

Among the dwarf planets, Pluto was listed as a planet the longest. This all changed in 2006 when the Astronomical Union – IAU – finally decided on the definition of a planet.

According to the definition, a planet is a celestial body that is in orbit around the Sun, has enough mass to assume hydrostatic equilibrium – resulting in a round shape, and has cleared the neighborhood around its orbit.

Many still consider Pluto as a planet to this day. Though we must sadly disconsider Pluto, here are some quick facts about each planet of the Solar System.


Mercury is the closest planet to the Sun. It is only 58 million km / 36 million mi or 0.39 AU away. Though it is the closest, it isn’t the hottest planet in the Solar System; Venus holds that titled.

Mercury is, however, the smallest planet out of the eight. It is slightly larger than our Moon but smaller than Ganymede – one of Jupiter’s moons. Mercury itself doesn’t have any moons.

Being a terrestrial planet, Mercury has a high density, and it is primarily composed out of rock and iron ore. Its surface is heavily cratered, very similar to Earth’s Moon. 

Mercury orbits the Sun once every 87.97 Earth days, while one Mercurian day is equivalent to 59 Earth days. Surface temperatures range from – 173 to 427 degrees Celsius. The small planet has a diameter of 4.879 km / 3.032 mi.


The second closest planet to the Sun. Venus is on average at a distance of 108 million km / 67 million mi or 0.72 AU away from the Sun. It is the hottest planet of the Solar system since its atmosphere keeps the temperatures almost consistently the same.

The temperatures are around 462 degrees Celsius – about four and a half times the amount of heat needed to evaporate water. Its diameter has been measured to be at 12.104 km / 7.521 mi.

Venus has 90% the Earth’s surface area, and it orbits the Sun once every 225 days. One day on Venus is equivalent to 243 Earth days; thus, a day on Venus is longer than a year.

Its atmosphere is very thick, composed mainly out of carbon dioxide, nitrogen, and clouds of sulfuric acid. It doesn’t have any moons, and the planet, like Uranus, spins backward – retrograde rotation. It is a terrestrial planet, often considered Earth’s sister.


The third closest planet to the Sun. Earth is at an average distance of 150 million km / 93 million mi or 1 AU away from the Sun. It only has one moon and several other smaller satellites.

Earth is the biggest terrestrial planet having a diameter of 12.760 km / 7.926 mi. Surface temperatures on Earth are around 14 degrees Celsius.

Around 70% of Earth’s surface is covered in water, while the atmosphere is made out of 78% nitrogen, 21% oxygen, and 1% other gases.


The fourth terrestrial planet and closest celestial body to the Sun. Mars is 228 million km / 142 million mi or 1.52 AU distance away from the Sun.

Also known as the Red Planet due to its reddish hue primarily because of its iron oxide on its surface, Mars is very similar to Earth. It has two moons, Phobos and Deimos.

Like Earth, it has volcanoes, valleys, deserts, and polar ice caps.  The rotational period and tilt are also very similar to Earth with one day lasting 24 hours and 37 minutes, while a year is equivalent to 687 Earth days.

The atmosphere is thin, while the surface temperatures are, on average, around -63 degrees Celsius. Mars has a diameter of 6.787 km / 4.217 mi. More than 40 spacecraft have been launched to Mars.


The fifth and most massive planet of the Solar System. Jupiter is 778 million km / 484 million mi or 5.2 AU away from the Sun. It is 317 times more massive than Earth and 2.5 times larger than all the other planets combined.

Jupiter is a gas giant; it is primarily composed of hydrogen, helium, and other gases. Its atmosphere is the most intense in the Solar System.

Probably second only to Uranus in terms of wind speeds which can reach up to 100 m/s or even more. Jupiter has a diameter of 142.984 km / 88.846 mi.

One year on Jupiter is the equivalent of 12 Earth years, while a day lasts only 9.8 hours. Temperatures are around -148 degrees Celsius. Jupiter has 79 moons while possibly more awaiting confirmation; it is only second to Saturn in terms of satellites.


The sixth planet from the Sun, and also a gas giant. Saturn is 1.4 billion km / 886 million mi or 9.5 AU distance away from the Sun. Seven ring systems surround it.

The gas giant has been recently crowned as the king of the moons since it has 82 confirmed satellites. Its atmosphere is made up of hydrogen, helium, and other gases.

Saturn’s diameter has been estimated to be at around 120.500 km / 74.900 mi. A year on Saturn is the equivalent of 30 Earth years, while a day lasts 10.7 hours.

The average temperatures on Saturn are around -178 degrees Celsius. Saturn is probably the most recognizable planet of the Solar System.


The seventh planet from the Sun, the ice giant Uranus. Uranus is 2.9 billion km / 1.8 billion mi or 19.19 AU away from the Sun. It is classified as an ice giant due to the presence of ammonia, methane, water, and hydrocarbons in ice form.

The presence of methane causes its bluish hue. It also has a ring system though it is very faint. It is the coldest planet of the Solar System with temperatures at around -224 degrees Celsius.

Uranus is the only planet that rotates on its side. Like Venus, it also rotates in the opposite direction. This planet has a long orbital duration, 84 years. A day on Uranus, on the other hand, is the shortest, lasting only 17 hours.

Currently, 27 moons have been confirmed to orbit around Uranus. The diameter has been estimated at 51.118 km / 31.763 mi. It is the third-largest planet in the Solar System.


The farthest planet, Neptune. It lies at around 4.5 billion km / 2.8 billion mi or 30.07 AU away from the Sun. Like Uranus, it is also an ice giant.

It has a series of faint planetary rings, around 14 confirmed moons, and it has the fastest wind speeds of any planet, reaching speeds of 2.160 km / 1.314 mi per hour.

One day on Neptune lasts 16 hours, while a year is equivalent to 165 Earth years, the longest of any planet. Neptune is the fourth-largest planet having a diameter of around 49.244 km / 30.598 mi.

It is primarily composed out of layers of gases, around 29% helium and 80% hydrogen, with traces of other elements. Its bluish color is believed to be caused by the presence of methane. It is the first planet discovered through mathematical calculations and predictions.

Did you know?

  • Since Pluto has a very elliptical orbit, it can sometimes get closer to the Sun and Earth than Neptune.
  • The most cratered planet of the solar system is Mercury.
  • Some believe that Saturn and Jupiter came close once and thus provoked the Great Flood on Earth.
  • Every 15 years, the rings of Saturn briefly disappear from view due to their angle.
  • Saturn produces the eeriest radio emissions in the solar system.
  • Mars is the second most populated planet when it comes to robots.


  1. Universetoday
  2. Space
  3. Wikipedia

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