What is the order of the planets in the solar system?

Over the past 60 years, humans have started to seriously explore our solar system. From the first launches in the late 1950s until today, we’ve sent probes, orbiters, landers, and even rovers (like NASA’s Perseverance Rover that landed on Mars in February 2021) on every planet in our solar system. But can you name these eight planets? (Yes, there are only eight – not nine. Pluto was “demoted” in 2006.) And can you put them in the correct order?

In case you’re a little rusty, we’re going to break down some common methods of ordering planets as well as some tips to help you remember them in the future. Let’s start with the distance from the sun.

The order of the planets by distance

The most common way to order planets is by their distance from the sun. Using this method, the planets are listed in the following order:

  • Mercury – 0.39 AU from the sun
  • Venus – 0.72 AU
  • Earth – 1.00 AU
  • March – 1.52 AU
  • Jupiter – 5.20 AU
  • Saturn – 9.54 AU
  • Uranus – 19.20 AU
  • Neptune – 30.06 AU

AU stands for astronomical units – this is the equivalent of the average distance of Earth from the sun (which is why Earth is 1 AU from the sun). It is a common way for astronomers to measure distances in the solar system which explains the large scale of these distances. To put it another way, Mercury, which is the closest, is 35.98 million kilometers from the sun, while Neptune, the furthest away, is 2.79. billion miles from the sun. Earth is 92.96 million kilometers from the sun.

How to remember the order of the planets

There are many expressions useful for remembering the order of the planets. They are usually mnemonics that use the first letter of the name of each planet to find a phrase that is easier to remember.

Here are some of the most common (and stupidest):

  • My very excellent mother just served us noodles (or nachos)
  • My very simple method just speeds up the names
  • My dearest Malamute jumped up north

In each case, “M” stands for “Mercury”, “V” for “Venus”, and so on. You can also try to remember it with a few rhyming verses:

The incredible Mercury is closest to the Sun,
Hot, hot Venus is the second,
Earth comes third: it’s not too hot,
The freezing of Mars awaits an astronaut,
Jupiter is bigger than all the others,
Sixth comes Saturn, its rings are the most beautiful,
Uranus falls sideways
And with Neptune,
They are big balls of gas.

Finally, if you have a fondness for music, there are a few songs that can help you remember them. Two popular are Mr. R’s Planet Song and The song of the planet by Kids Learning Tube.

You can order the planets in other ways

While most people want to know the order of the planets by distance, there are other ways to order the planets that you might be interested in.

For example, if you classify the planets by size (radius) from the biggest to the smallest, then the list would be:

  • Jupiter (43,441 miles / 69,911 kilometers)
  • Saturn (36,184 miles / 58,232 km)
  • Uranus (15,759 miles (25,362 km)
  • Neptune (15,299 miles / 24,622 km)
  • Earth (3,959 miles / 6,371 km)
  • Venus (3,761 miles / 6,052 km)
  • March (2,460 miles / 3,390 km)
  • Mercury (1,516 miles / 2,440 km)

Or you can order the planets by weight (mass). Then the list from the most massive to the least massive would be: Jupiter (1.8986 x 1027 kilograms), Saturn (5.6846 x 1026 kg), Neptune (10.243 x 1025 kg), Uranus (8.6810 x 1025 kg), Earth (5.9736 x 1024 kg), Venus (4.8685 x 1024 kg), Mars (6.4185 x 1023 kg) and Mercury (3.3022 x 1023 kg). Interestingly, Neptune has more mass than Uranus, even though Uranus is bigger! Scientists can’t scale a planet, so to determine the mass, they look at how long it takes for nearby objects to orbit the planet and how far from the planet these objects are. The heavier the planet, the more it shoots nearby objects.

Finally, a fun way to order the planets is to the number of moons they have. Let’s start with the planet that has the most:

  • Saturn (82)
  • Jupiter (79)
  • Uranus (27)
  • Neptune (14)
  • March (2)
  • Earth (1)
  • Venus and Mercury (both zero)

(Note that these figures include provisional moons which are still confirmed by astronomers.)

In short, there are a number of ways to order and rearrange planets based on different facts about them; as long as you remember that there are eight in total, that’s what matters. (Sorry Pluto!)

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Arline J. Mercier

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