Our Solar mechanism is an immense and amazing place. Between its eight planets, 176 moons, 5 dwarf planets (possibly hundreds more), 659,212 known asteroids, and 3,296 known comets, it has wonders to sate the most demanding the curiosities. Our Solar system is made up of various regions, which space delineated based on their street from the Sun, but additionally the species of planets and bodies that can be uncovered within them.

You are watching: What do inner planets have in common

In the within Solar System, we uncover the “Inner Planets” – Mercury, Venus, Earth, and also Mars – which room so named due to the fact that they orbit closest come the Sun. In addition to your proximity, this planets have actually a number of an essential differences that collection them except planets somewhere else in the Solar System.

For starters, the inner planets space rocky and also terrestrial, composed mainly of silicates and metals, vice versa, the outer planets room gas giants. The inside planets are also much an ext closely spaced 보다 their outer Solar device counterparts. In fact, the radius of the entire region is much less than the distance in between the orbits of Jupiter and also Saturn.

The positions and names that planets and also dwarf planets in the solar system.Credit: Planets2008/Wikimedia Commons

This an ar is also within the “frost line,” i m sorry is a small less 보다 5 AU (about 700 million km) indigenous the Sun. This line represents the boundary in a device where conditions are warm sufficient that hydrogen compound such together water, ammonia, and also methane space able to take liquid form. Past the frost line, this compounds condense right into ice grains.Some scientists describe the frost line together the “Goldilocks Zone” — where problems for life may be “just right.”

Generally, inside planets are smaller and also denser 보다 their counterparts, and have few to no moons or ring circling them. The external planets, meanwhile, frequently have dozens that satellites and also rings composed of particles of ice and rock.

The terrestrial within planets are composed greatly of refractory minerals, such together the silicates, which form their crusts and also mantles, and also metals such as iron and nickel which form their cores. 3 of the four inner planets (Venus, Earth and Mars) have atmospheres comprehensive enough to generate weather. All of them have affect craters and also tectonic surface functions as well, such as rift valleys and volcanoes.


Of the inner planets, Mercury is the closest come our Sun and also the the smallest of the terrestrial planets. This little planet looks very much prefer the Earth’s Moon and is even a comparable grayish color, and also it even has countless deep craters and also is spanned by a thin layer the tiny bit silicates.

Its magnetic ar is only about 1 percent that of Earth’s, and also it’s very thin atmosphere method that that is hot during the job (up to 430°C) and also freezing in ~ night (as low as -187 °C) since the environment can neither keep warm in or out. It has no moons the its own and is made up mostly the iron and nickel. Mercury is one of the densest planets in the Solar System.

The within planets to scale. Native left to right: Earth, Mars, Venus, and Mercury. Credit: Wikimedia Commons/Lsmpascal


Venus, which is about the exact same size together Earth, has a thick toxic atmosphere that catch heat, making it the hottest earth in the Solar System. This environment is written of 96% carbon dioxide, together with nitrogen and also a couple of other gases. Dense clouds within Venus’ environment are created of sulphuric acid and other corrosive compounds, with really litter water.

Only 2 spacecraft have ever before penetrated Venus’s special atmosphere, yet it’s not just fabricated objects that have trouble acquiring through. There space fewer crater effects on Venus than various other planets since all yet the biggest meteors don’t survive the thick air without disintegrating. Lot of Venus’ surface is marked with volcanoes and also deep canyons — the greatest of i m sorry is end 6400 kilometres (4,000 mi) long.

Venus is often dubbed the “morning star” because, through the exception of Earth’s moon, it’s the brightest object we see in the sky. Like Mercury, Venus has no moon the its own.


Earth is the third inner planet and also the one we recognize best. Of the four terrestrial planets, planet is the largest, and also the just one that right now has fluid water, i beg your pardon is necessary for life together we understand it. Earth’s environment protects the world from dangerous radiation and also helps keep an useful sunlight and warmth in, which is additionally essential because that life to survive.

Illustration that the inside Planets and also their orbits about the Sun picture credit: NASA

Like the various other terrestrial planets, planet has a rocky surface with mountains and canyons, and also a hefty metal core. Earth atmosphere includes water vapor, which help to moderate daily temperatures. Choose Mercury, the planet has an inner magnetic field. And also our Moon, the just one us have, is made up of a mixture of assorted rocks and minerals.


Mars is the fourth and final inner planet, and also known as the “Red Planet” as result of the rust of iron-rich materials that type the planet’s surface. Mars additionally has some of the most exciting terrain attributes of any type of of the terrestrial planets. These incorporate the biggest mountain in the Solar system – Olympus Mons – which rises some 21,229 m (69,649 ft) over the surface, and also a gigantic canyon dubbed Valles Marineris. Valles Marineris is 4000 kilometres (2500 mi) long and also reaches depth of as much as 7 kilometres (4 mi)!

For comparison, the cool Canyon in Arizona is around 800 kilometres (500 mi) long and also 1.6 km (1 mi) deep. In fact, the extent of Valles Marineris is as lengthy as the joined States and also it spans about 20 percent (1/5) of the whole distance approximately Mars. Lot of the surface ar is very old and filled v craters, yet there are geologically newer locations of the world as well.

A top-down image of the orbits of Earth and Mars. Credit: NASA

At the Martian poles room polar ice caps that shrink in size during the Martian spring and summer. Mars is less thick than Earth and also has a smaller magnetic field, i beg your pardon is indicative that a heavy core, rather than a liquid one.

Mars’ thin environment has led some astronomers to think that the surface water that as soon as existed there could have in reality taken liquid form, however has since evaporated right into space. The planet has two little moons referred to as Phobos and also Deimos.

Beyond Mars are the four outer planets: Jupiter, Saturn, Uranus, and Neptune.

We have actually written countless interesting articles about the inner planets below at universe Today. Here’s The Solar mechanism Guide and The Inner and Outer Planets in our Solar System.

For an ext information, check out this write-up from NASA ~ above the planets that the Solar System and also this short article from Solstation about the inside planets.

Astronomy Cast also has illustration on every one of the inside planets consisting of this one about Mercury.

See more: Time Difference Between California And Georgia, California Time To Atlanta Time Conversion

Share this:

Like this:

Like Loading...
CategoriesAstronomy, overview to space TagsEarth, inner planets, Mars, Mercury, Solar System, Venus

Post navigation

Join our 836 patrons! check out no ads on this site, view our videos early, special bonus material, and much more. Sign up with us in ~ patreon.com/sdrta.net