The Solar System Planets-Smallest and Largest

The solar system consists of the Sun and eight planets, bound together by the Sun’s gravitational pull. The planets in the solar system are arranged in the following order, beginning with the sun and working outward: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. This article will look at some facts regarding the largest and smallest planets.

Which of the Solar System’s planets is the smallest?

Mercury is the solar system’s smallest planet. The planet’s average radius is 3031.67 miles. The dwarf planet is perfectly spherical in shape and possesses no flat poles.


Mercury’s surface temperature can reach 840 degrees Fahrenheit due to its proximity to the sun. However, because this planet lacks an atmosphere to trap heat, temperatures can drop to minus 275 degrees Fahrenheit at night. Therefore, it observes a temperature fluctuation of more than 1,100 degrees Fahrenheit, the biggest in the solar system.

Gravitational Field and Density

The planet is denser than other planets despite its size. With a density of 338.8 pounds per cubic foot, the planet has the second-highest density in the solar system. Furthermore, its gravitational force is 0.38 times that of Earth. Therefore, if you visit the planet, you will be thirty-eight per cent of your weight on Earth. 

The Orbit of Mercury

Mercury travels around the sun every 88 Earth days, at about 112,000 mph, which is faster than any other planet. Mercury’s oval-shaped orbit is very elliptical, taking it as close to the sun as 29 million miles and as distant as 43 million miles. 

Mercury’s Structure and Composition

The Composition and Size of Mercury Relative to Earth’s

The planet is classified as a terrestrial body. It is rich in metals and silicate minerals. Mercury appears to have a solid silicate crust and mantle that sits on top of a solid, iron sulphide outer core layer, a deeper liquid core layer, and a solid inner core. The planet has a relatively high iron concentration, which accounts for around 42 per cent of the planet’s volume.

Which is the largest planet in the solar system?

Jupiter is our solar system’s largest planet. It may fit as many as one-thousand Earths in the same space. Jupiter’s name comes from the ruler of Roman gods, and it is a massive gas planet, very different from the one we live on.

The Atmosphere of Jupiter

The Composition of Jupiter’s Atmosphere

The highly dense and somewhat dry atmosphere of Jupiter consists of a mixture of hydrogen, helium, as well as small amounts of methane and ammonia. In fact, the Sun contains the same blend of ingredients that make up Jupiter. Furthermore, diamond rain may fall from the sky, and a thick core of unknown composition may be hidden deep within the atmosphere. The clouds are most likely comprised of ammonia ice crystals, which change to ammonia droplets as they descend. Scientists predict the temperature of the cloud tops at around -280 degrees Fahrenheit. 


Jupiter, as a gas giant, has a lower mean density than any of the other terrestrial planets. It is, nevertheless, the second-densest of the gas giants, with a density of 1.326 g/cm3. 

The Orbit of Jupiter

As it is so massive, Jupiter does not technically orbit the sun. Instead, it pushes the centre of mass between it and the sun, commonly known as the barycenter, which is 1.07 solar radii from the star’s centre. Thus, both items revolve around the same centre of gravity.

Composition and Structure

Facts about Jupiter and its Structure

Strong east-west winds reaching more than 335 mph in Jupiter’s upper atmosphere form the beautiful light and dark bands that surround the planet. Furthermore, white clouds in the light zones are comprised of frozen ammonia crystals, whereas darker clouds made of various chemicals can be found in the dark belts. Blue clouds can be seen at the deepest observable depths. 

Moons of Jupiter

Jupiter has 79 known moons, most of which are named after the Roman gods and nymphs. Galileo Galilei discovered Jupiter’s four largest moons, Io, Ganymede, Europa, and Callisto, and they are frequently referred to as the Galilean moons.

Ganymede is our solar system’s biggest moon, larger than both Pluto and Mercury. It is also the only moon known to have its own magnetic field, which NASA’s Juno mission photographed in 2021 with a haunting sound. According to a 2014 study published in the journal Planetary and Space Science, the moon has at least one ocean between layers of ice.

The Rings of Jupiter (also called The Jovian ring system)

Jupiter’s Rings

The Jovian ring system is weak and mostly composed of dust. It is made up of four main parts: a thick inner torus of particles called the “halo ring,” a comparatively bright, extraordinarily thin “primary ring,” and two wide, thick, and faint outer “gossamer rings” named after the moons from which they are made: Amalthea and Thebe. The main and halo rings are made up of dust produced by high-velocity impacts from the moons Metis and Adrastea, as well as smaller, undetected bodies.

The New Horizons spacecraft’s high-resolution photos from February and March 2007 revealed a rich fine structure in the main ring.

Final Thoughts

Mercury, the smallest planet in our solar system, and Jupiter, the largest planet, provide many clues concerning the origin of our solar system, its geochemical variability, and the evolution of Earth. This article provides basic information about the smallest and largest planets in the solar system, as well as some interesting facts about them. 

To know about other planets visit Podium School.

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