What is the correct sequence of the planets in our Solar System?

In the past six decades, humanity has significantly advanced its exploration of the Solar System. Starting with the initial missions in the late 1950s, we've sent a range of spacecraft, including probes, orbiters, and landers—such as NASA's Perseverance Rover, which successfully landed on Mars in February 2021. But can you list all eight planets in the correct order? (There are only eight now, not nine—Pluto was reclassified in 2006.) Can you arrange them in their proper sequence?

If you're a bit unsure, we’ll break down various ways to remember the planet order and share some useful tips to help you memorize it in the future. Let’s start by considering their distance from the Sun.

A typical way to arrange the planets is by their distance from the sun. When we follow this approach, the planets appear in this specific sequence:

Planets Ordered by Their Proximity to the Sun

AU, or astronomical unit, represents the average distance between Earth and the sun (which is why Earth is 1 AU away). This is a standard unit for astronomers to measure vast distances in space. To put things in perspective, Mercury, the closest planet, sits at 35.98 million miles from the sun, whereas Neptune, the farthest, is 2.79 billion miles away. Earth’s distance from the sun is 92.96 million miles.

Techniques to Memorize the Planetary Sequence

There are various useful phrases that can help you recall the planetary order. These are typically mnemonic devices that use the initial letter of each planet's name to form a memorable phrase.

Below are some of the most well-known (and often humorous) ones:

In these phrases, "M" represents "Mercury," "V" stands for "Venus," and so on. Alternatively, you can try memorizing them with a series of rhyming lines:

Amazing Mercury is closest to the Sun,
Hot, hot Venus is the second one,
Earth comes third: it’s not too hot,
Freezing Mars awaits an astronaut,
Jupiter is bigger than all the rest,
Sixth comes Saturn, it's rings look best,
Uranus sideways falls
And along with Neptune,
They are big gas balls.

If you have a musical ear, there are some songs that could help with memorizing the planetary order. Two well-known examples are Mr. R's Planet Song and The Planet Song from Kids Learning Tube.

Alternative Ways to Order the Planets

Although many people prefer to organize the planets by their distance from the sun, there are other fascinating methods of arranging them that you might find interesting.

For instance, if you rank the planets by their size (radius) from largest to smallest, the list would look like this:

Planets Ordered by Size

If you order the planets by mass, from the heaviest to the lightest, it looks like this: Jupiter (1.8986 x 10 kilograms), Saturn (5.6846 x 10 kg), Neptune (10.243 x 10 kg), Uranus (8.6810 x 10 kg), Earth (5.9736 x 10 kg), Venus (4.8685 x 10 kg), Mars (6.4185 x 10 kg), and Mercury (3.3022 x 10 kg). Interestingly, Neptune weighs more than Uranus, even though Uranus is bigger. Scientists can't directly weigh planets, so they determine mass by observing how long nearby objects take to orbit and how far away they are from the planet. The greater the planet's mass, the stronger its pull on nearby objects.

Planets With the Most Moons

Another interesting way to compare the planets is by the number of moons they have. Let’s start with the planet that has the greatest number:

(Please note that these numbers include provisional moons which are still under review by astronomers.)

To sum up, there are various ways to arrange and rearrange the planets based on different characteristics. Just remember, there are a total of eight – that's the main takeaway. (Sorry, Pluto!)