The Planets of Our Solar System

The Top Facts You Probably Didn’t Know

We live in a vast and wonderful solar system with planets and moons that orbit our star, the sun. But, how much do you know about each of our planets? Many of us may have learned the order of planets from Mercury to Pluto (now a dwarf planet), but each one has a unique composition and is full of facts that differ strongly from the earth. Let’s take a look at each one. At the end, let us know how much you already knew!


This planet is small with a diameter of 3,032 miles. It is gradually shrinking at a nearly imperceptible rate of 9 miles per 4 billion years. As the planet appears to be gradually cooling, its volume is reducing. Mercury does not have a strong atmosphere and it is susceptible to violent impacts from passing meteors, causing its surface to be riddled with craters. Temperatures on the planet can range from a staggering 800 degrees Fahrenheit down to -269 degrees Fahrenheit. Its lack of a strong atmosphere does not allow it to capture heat from the sun, so its nightly temperature drops drastically. Mercury does not have any moons because of its size and low gravitational pull.


Venus rotates on its axis slower than any of the other planets in the solar system. It takes 243 earth days to rotate one time. It is also full of carbon dioxide within its atmosphere, making it an expert at trapping heat, making it hotter than its neighbor Mercury. Temperatures on Venus are 863.6 degrees Fahrenheit! It spins in the opposite direction of the other planets. Each planet except for Venus spins counterclockwise on its axis. Venus also orbits the sun in the opposite direction of the planets. This is likely due to a collision that occurred an unknown number of millennia ago that essentially flipped the planet upside down. Venus is abnormally bright, being the second brightest planet or moon in the sky, after earth’s moon. This is due to the reflective nature of its sulphuric acid clouds. Because it is easier to see in the sky compared to the other planets, it makes sense that it is the first planet to be tracked across the sky. Many say this began in the second millennium BCE.


We live on its surface all of our lives and may think we know quite a bit about our planet. But, did you know scientists believe at one point in history that the earth may have looked purple instead of blue? This is because it is theorized that microbes relied on retinal instead of chlorophyll for survival. Retinal reflects back violet and red light. There is an estimated 60 tons of cosmic dust that falls into the earth from meteorites, comets, and other celestial bodies. This contributes to the sodium and iron in our atmosphere. There is a theory that Earth once had two moons that collided and left us with the current moon we see in the sky. Other planets aren’t the only places where temperatures can be extreme. On the East Antarctic Plateau, it can drop to -133.6 degrees Fahrenheit. Earth is not perfectly round. It is a bit more narrow at the poles and bulged at the equator. The largest living organism on earth is a fungus. You can find the honey fungus spanning almost two and a half miles in the state of Oregon.


A year on Mars is 687 Earth days because its orbit is further from the sun. It has two moons that are likely asteroids that were captured by Mars’ gravitational pull. They are named Deimos and Phobos. Mars’ axis tilts similarly to Earth’s axis tilt, giving it seasons. Its atmosphere is not dense and cannot trap heat from the sun. It averages -212 degrees Fahrenheit during its cold season and a pleasant 68 degrees Fahrenheit during its warmest season. Mars has its own volcano, Olympus Mons, which is dormant but is the largest volcano and the highest peak of any other in the solar system. It is approximately three times taller than Mount Everest. Mars has another distinguishing feature on its surface. It has a crater that covers 40% of it. It also has the largest canyon of any of the planets in the solar system that is 4 miles deep and extends for thousands of miles.


This planet has more moons than any other in the solar system. It is the largest planet in the solar system and is also the one that spins the fastest. It takes approximately 10 hours for Jupiter to complete a full spin on its axis. The planet has a strong magnetic field (about 14x stronger than Earth’s) and a vast amount of radiation around it. Jupiter has rings that can be divided into three layers. Winds near Jupiter’s center are estimated to be 400 miles an hour. Jupiter is sometimes credited with shielding Earth from passing objects by pulling them into itself with its strong magnetic field. Its mass is 318 times greater than Earth.


It is sometimes called “The Jewel of the Solar System” with its visible rings and large size, second only to Jupiter. The planet is made up of gases, mostly, and its rings are made up of rocks, ice, and dust. Wind speeds at Saturn’s equator can reach 1,118 miles per hour. A year on Saturn is about the same as 29 years on Earth but a day on Saturn is 10 hours and 14 minutes. At its widest, Saturn could fit Earth across itself 9 times. Saturn is the least dense planet in the solar system. It is said that when Galileo looked up to Saturn with an early version of the telescope in 1610, he thought its rings were two moons stuck to the sides of the planet.


This is the third largest planet and is made of gas and ice. As such, it is the coldest planet in the solar system with temperatures reaching -360 degrees Fahrenheit. Uranus is spinning on its side, like a bowling ball rolling toward the pins. Because of its unusual orientation to the sun, a summer on Uranus lasts 42 Earth years, as does a winter season, putting a year on Uranus to be the equivalent of 84 Earth years. Uranus has 13 rings, all made of dark particles that are extremely small. Winds on the planet can reach 560 miles per hour. The human eye can see Uranus in the night sky on Earth because the planet just meets the brightness scale needed for the human eye to see it.


It is made of water, methane, and ammonia around a core of rock. It has 5 primary rings and 4 arcs of rings that are clusters of dust and space debris. It has 14 moons. Because of Pluto’s strongly elliptical orbit, Neptune is occasionally the furthest planet from the Sun. Of the other gaseous planets in the solar system (Uranus, Saturn, Jupiter), Neptune is the smallest. It is said to have a similar gravitational pull as that on Earth at only 17% stronger, the closest gravitational pull to Earth of any other planet in the solar system. Its winds reach 1,304 miles per hours.


This dwarf planet (as of 2006) has been beloved by generations as part of the planets of the solar system. Pluto was discovered in 1930 and was named at the suggestion of a girl who was 11 years old. Pluto has a diameter of 1,473 miles, making it smaller than Earth’s moon which has a diameter of 2,160 miles. Pluto is part of the Kuiper Belt that orbits the Sun just outside of Neptune’s orbit. Pluto has five moons. It is one-third water and two-thirds rock. It has mountain ranges and craters on its surface.

The Future of Space Exploration

As we dive deeper into space through advancements like the James Webb telescope, we will continue to uncover details of other planets that will enhance our understanding of our solar system’s place in the vast expanses of space.