If you are wondering what is the order of the planets from the Sun in our Solar System, you are in the right place to finally discover it! Here you will learn all the 8 "official" Solar System planets in order from the Sun (according to the International Astronomical Union - IAU) with pictures, sizes, and physical characteristics (AKA interesting facts tables!). Let's get started!
🪐 Planets in Order
There are eight official planets in our Solar System that orbits the Sun, and their order in distance from the Sun is as below:
If you want to easily remember the Solar system planets order, learn a popular mnemonic that is often taught in school: "My Very Educated Mother Just Served Us Noodles." The first letter of every word is the first letter of the proper planet - in order!
Mercury is the first planet in order from the Sun in our Solar System. It amazes human beings from the very beginning with its retrograde movements, and more recently with phases and discovered similarities to the Moon. Mercury is the planet closest (first) to the Sun and the smallest member of our Solar System family. Its diameter is 4,878 kilometers / 3,031 miles, and its mass is only 5.5% of the Earth's mass. As a result, the gravitational force on Mercury is not enough strong to maintain the atmosphere on the planet. Mercury's surface, covered with countless craters, is therefore exposed to intense solar radiation.
Mercury Interesting Facts
Hard, solid data! If you like straight to the point sources of information, here you have almost all the most important facts about the planet Mercury:
|Distance from Sun||36 million miles / 58 million km / 0.39 AU|
|Radius||1,516 miles / 2,439 km|
|Diameter||3,032 miles / 4,878 km|
|Mass||3.285 × 1023 kg (0.055 M⊕ / 5.5% Earths)|
|Length of Year (Orbit)||88 Earth days|
|Length of Day||59 Earth days|
|Temperatures||-290°F to 800°F / -180°C to 430°C|
|Moons||No - zero (0)|
What Color is Mercury?
Generally speaking, Mercury's color is dark gray, very similar to the Moon.
However, it's hard to determine what does it even mean - "true". It's because the eyes of every human being perceive colors in a little different way. It may not even exist something like the true color - it's only how we, as people, perceive it in the current situation like phase, time, or place of observation.
Who Discovered Mercury?
The official discoverer of the planet is Galileo Galilei, who was first to observe it through a telescope in the 17th century.
However, this planet is visible to the naked, unarmed eye, and was therefore already known and observed by ancient civilizations, many centuries ago. That is why the real discoverer is impossible to determine - he/she probably did not even have a name, like we know today!
The exact date of the discovery of Mercury is unknown - the first historical mention comes from Sumerians, and it was about 3000 BC.
Retrograde is the movement of a celestial body that appears to be rotating or moving in the opposite direction to most bodies in a given orbital system. In the Solar System, the reverse motion has the opposite direction to the Earth's motion around the Sun, which, seen from the North Pole of the Sun, is counterclockwise.
Below you will find the nearest Mercury retrograde dates.
- February 16 – March 9, 2020
- June 17 – July 12, 2020
- October 13 – November 3, 2020
- January 30 – February 20, 2021
- May 29 – June 22, 2021
- September 27 – October 18, 2021
- January 14 – February 3, 2022
- May 10 – June 2, 2022
- September 9 – October 2, 2022
- December 29, 2022 – January 18, 2023
Mercury Size - The Smallest Planet
Mercury has a diameter of 3,031 miles / 4,878 km - less than half the diameter of the Earth - and it's the smallest planet in the Solar System (only dwarf planets like Pluto, Haumea, Makemake or Eris are smaller). Because of its little size, it is difficult to see it in the sky through binoculars or a telescope - but the easiest time to do this anyway is just before the sunrise or just after the sunset.
Atmosphere and Temperatures on Mercury - Hot or
Surprisingly, being the closest planet to the Sun, Mercury is not the hottest one - it's only the second in terms of surface temperatures, right after Venus. Why's that? It's because Mercury does not have an atmosphere - there is nothing to retain the heat coming from the Sun, like Venus has (thick, yet still!).
Mercury is the second densest planet in the Solar System - just after Earth.
Does Mercury Have Phases?
Yes, it has. Any planet that emits less light than the star it orbits can have phases depending on the viewer's position. Both the planets that are within the Earth's orbit - Mercury and Venus - have phases, but because they orbit the Sun closer than the Earth does, it's hard to see them.
The planet has no moons. The only other Solar System planet that has no moons also is Venus.
Mercury Planet vs Moon
A lot of people compare this planet to our Moon, so let's check out what are the facts - are they really similar?
- Look. They are both just huge rocks with a lot of craters on the surface.
- No atmosphere.
- No liquid water on the surface.
|Object type||A planet||A moon|
|Mass||3.29 × 1023 kg||7.35 × 1022 kg|
|Radius||2439 km||1737 km|
|Surface gravity||3.7 m/s2||1.62 m/s2|
|Density||5.43 g/cm3||3.34 g/cm3|
|Distance from Sun (average)||58 million km||150 million km|
|Day (Earth time)||58d 15h 30m||27 days and change|
Venus, the "younger sister" of the Earth, is a little smaller than our planet - its diameter is 12104 kilometers and is the second planet in order from the Sun. The geological structure of this planet most probably resembles Earth's. The dense layer of clouds made us know little about this planet until the 1960s. It was not until December 1962 that the first measurements on Venus were transmitted to Earth by the Mariner 2 spacecraft.
Venus Interesting Facts
|Distance from Sun||67 million miles / 108 million km / 0.72 AU|
|Diameter||7,521 miles / 12,104 km|
|Mass||4.867 × 1024 kg (0.815 Earth mass)|
|Length of Year (Orbit)||225 Earth days|
|Length of Day||243 Earth days|
|Surface temperature||887°F / 475°C|
|Moons||no - zero (0)|
The Earth, our home, is the third planet from the Sun.
Earth Interesting Facts
|Distance from Sun||93 million miles / 150 million km / 1 AU|
|Diameter||7,918 miles / 12,742 km|
|Mass||5.972 × 1024 kg|
|Length of Year (Orbit)||365 days|
|Length of Day||23 hours and 56 minutes|
|Moons||1 - the Moon|
The Moon - How far away is the Moon from Earth?
That's a good astronomy question! Without further ado - if you want to know how far away is the Moon from the Earth, then here I provide the answer: the average distance (because of the elliptical orbit it is not constant - the momentary distance of the Earth-Moon changes by about 50,000 kilometers during the month) from the center of the Earth to the center of the Moon is exactly 384,400 km / 238,854 miles. But how can you imagine it? How can you get some sense of feeling of how the distance actually looks like? Keep reading!
Moon-Earth Distance at Correct Scale
If we chose 380,000 kilometers (slightly below the true-average one) as the distance, this is how it would like:
It looks much closer to me when I'm gazing at the Moon from my backyard!
All the Other Solar System Planets Would fit Between the Earth and the Moon
What? Are you serious?!
Yes, I totally am! It's hard to believe (especially considering the sizes of the Solar System planets like Jupiter or Saturn), but it's a mere fact - and it's easy to calculate it.
Let's check the diameters of all the other planets of the Solar System (we don't take the Pluto dwarf planet into the calculation, as it's not considered as a fully-fledged Solar System planet anymore):
If we sum them up, the result is 380,009 km, which is less than 384,400 km, which is the average distance from Earth to the Moon! We even have around 4,391 kilometers to spare for some additional celestial bodies.
The average distance is 238,854 miles / 384,400 kilometers.
Mars, the fourth planet in order from the Sun, is adjacent to the Earth on the outer side. Mars is a planet considered to be the most similar to the Earth and not only in terms of appearance: there is water there, its axis of rotation is similar to the Earth's, and a day on Mars lasts only 41 minutes longer than on the Earth. Mars is the best-researched planet of the Solar System (except Earth, of course!).
Mars Interesting Facts
|Distance from Sun||142 million miles / 228 million km / 1.52 AU|
|Diameter||4,212 miles / 6,779 km|
|Mass||6.39 × 1023 kg (0.107 Earths)|
|Length of Year (Orbit)||687 Earth days|
|Length of Day||24 hours 37 minutes|
|Surface temperature||Average -67°F/ -55°C, ranges -225°F to +70°F / -153°C to +20 °C|
|Moons||Two (2) - Phobos and Deimos|
Jupiter, the fifth planet from the Sun, is the largest planet in the Solar System. Interestingly, it is also the planet with the shortest day. Jupiter consists mainly of gas - only a small part of it is made of rocks and metals - so it does not have a constant surface.
Jupiter Interesting Facts
|Distance from Sun||484 million miles / 778 million km / 5.2 AU|
|Diameter||86,880 miles / 139,820 km|
|Mass||1.9 × 1027 kg (318 Earths)|
|Length of Year (Orbit)||11.9 Earth years|
|Length of Day||9.8 Earth hours|
|Surface temperature||Average -234°F / -148°C|
|Moons||97 total - some of the most known are Io, Europa, Ganymede, and Callisto|
Saturn, the sixth planet from the Sun, is the second-largest planet in the Solar System after Jupiter. It consists mainly of hydrogen and helium (with a small addition of ammonia and methane), so it also belongs to the group of gas giants. Saturn is almost twice as far from the Sun as Jupiter, so its atmosphere does not heat up so heavily.
Saturn Interesting Facts
|Distance from Sun||886 million miles / 1.4 billion km / 9.5 AU|
|Diameter||72,365 miles / 116,460 km|
|Mass||5.68 × 1026 kg (95.1 Earths)|
|Length of Year (Orbit)||29.5 Earth years|
|Length of Day||10.7 Earth hours|
|Surface temperature||Average -288°F / -178°C|
|Moons||Over 80 - Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Iapetus, Hyperion, and more|
Uranus, the seventh planet from the Sun, was initially taken as a comet. It's the coldest planet in the Solar System.
Uranus Interesting Facts
|Distance from Sun||1.8 billion miles / 2.9 billion km / 19.19 AU|
|Diameter||31,518 miles / 50,724 km|
|Mass||8.681 × 1025 kg (14.54 Earths)|
|Length of Year (Orbit)||84 Earth years|
|Length of Day||18 Earth hours|
|Surface temperature||Average -357°F / -216°C|
|Moons||27 known - Puck, Miranda, Ariel, Umbriel, Titania, Oberon, and more|
Neptune is the eighth and last planet from the Sun in the Solar System. For now, we can only speculate about its internal structure. Before the departure of Voyager 2 in August 1989, two moons of Neptune and several ring structures were known to science - today we know about eight moons and five rings.
Neptune Interesting Facts
|Distance from Sun||2.8 billion miles / 4.5 billion km / 30.07 AU|
|Diameter||30,599 miles / 49,244 km|
|Mass||1.0243 x 1026 kg (17 Earths)|
|Length of Year (Orbit)||165 Earth years|
|Length of Day||16 Earth hours|
|Surface temperature||Average -353°F / -214°C|
|Moons||14 known - Naiad, Thalassa, Despina, Galatea, Larissa, Hippocamp, Proteus, and more|
Is Pluto a Planet? and Why It Is No Longer Anymore?
Pluto was discovered by the American astronomer Clyde Tombaugh in 1930 and then qualified as a fully-fledged Solar System planet and maintained this status until 2006. It was in this year that the International Astronomical Union (IAU) introduced the concept of a dwarf planet and classified the planet in this category. Therefore, the answer to the question "is Pluto a planet?" is no, not anymore (but who knows what the future holds?).
Pluto Interesting Facts
|Official Name||(134340) Pluto|
|Object Type||Dwarf planet|
|Distance from Sun||39.5 AU|
|Diameter||1,477 miles / 2,377 km|
|Mass||1.303 × 1022 kg (0.0022 M⊕ / 0.22% Earths)|
|Length of Year (Orbit)||247.94 Earth years / 90,560 Earth days|
|Known Moons||5 (Charon, Nix, Hydra, Kerberos, Styx)|
How Is a Dwarf Planet Different From an "Ordinary" Planet?
A dwarf planet is a celestial body that has not cleared its orbit and has not become gravitationally dominant in its area, which is why it shares its orbital space with other celestial bodies of a similar size (however scientists, astronomers, and astrophysicists are still debating this definition).
Moons of Pluto
The planet has 5 natural satellites:
- Charon (I) - Pluto's largest moon. It was first observed by James Christy in 1978. It is so large in relation to Pluto (there is not the slightest comparison to the Earth-Moon system) that the Pluto-Charon system can be considered a double dwarf planet.
- Nix (II) - discovered in 2005.
- Hydra (III) - similarly to Nix, discovered in 2005. Both of these moons (Nix and Hydra) were first sighted by the Hubble Telescope. They don't have a "regular" round shape - they look more like elongated, irregular pieces of rock.
- Kerberos (IV) - discovered in 2011, also by the Hubble Telescope.
- Styx (V) - 2012, again thanks to the Hubble Telescope.
Other Dwarf Planets in the Solar System
At the time of writing this, the International Astronomical Union (IAU) officially recognizes 5 celestial bodies as dwarf planets in the Solar System:
Of this group, only Ceres orbits in the asteroid belt between the orbits of Mars and Jupiter. The remaining objects orbit beyond Neptune's orbit and are therefore also referred to as plutoids.
No, it is no longer a fully-fledged Solar System planet anymore. However, it was until 2006, when the IAU (International Astronomical Union) introduced the concept of a dwarf planet and classified the planet in this category, similarly to planets Ceres, Haumea, Makemake, and Eris.
Hi, I'm Paweł! I'm an astrophotographer, full-time astrophotography blogger, passionate stargazer, and amateur astronomer. Here on Astro Photons, I share my astrophotography, space, and astronomy knowledge to help beginners to make their first steps into the hobbies.