In our Solar System, astronomers regularly divide the planets right into two teams — the inside planets and the external planets. The within planets space closer come the Sun and also are smaller and rockier. The external planets are further away, larger and also made up largely of gas.

You are watching: Compare and contrast the inner and outer planets.

The inner planets (in order of distance from the sun, closest come furthest) are Mercury, Venus, Earth and Mars. After an asteroid belt comes the outer planets, Jupiter, Saturn, Uranus and Neptune. The amazing thing is, in some other planetary equipment discovered, the gas giants are actually quite close to the sun.

This renders predicting just how our Solar System created an interesting exercise for astronomers. Typical wisdom is the the young sun blew the gases into the outer fringes of the Solar System and also that is why there space such huge gas giants there. However, some extrasolar systems have “hot Jupiters” the orbit close to their Sun.

The within Planets:

The four inner planets are referred to as terrestrial planets since their surfaces space solid (and, together the surname implies, somewhat similar to planet — back the term deserve to be misleading since each of the 4 has vastly various environments). They’re made up mostly of hefty metals such as iron and nickel, and have one of two people no moons or few moons. Below are brief descriptions of every of this planets based upon this information from NASA.

Mercury: Mercury is the smallest world in our Solar device and likewise the closest. The rotates gradually (59 planet days) relative to the moment it takes come rotate around the sun (88 days). The planet has no moons, however has a tenuous environment (exosphere) comprise oxygen, sodium, hydrogen, helium and also potassium. The NASA MESSENGER (MErcury Surface, an are ENvironment, GEochemistry, and also Ranging) spacecraft is currently orbiting the planet.

The terrestrial planets of ours Solar mechanism at roughly relative sizes. From left, Mercury, Venus, Earth and Mars. Credit: Lunar and Planetary Institute

Venus: Venus was once considered a twin earth to Earth, until astronomers found its surface ar is in ~ a lead-melting temperature that 900 degrees Fahrenheit (480 levels Celsius). The earth is likewise a slow rotator, v a 243-day lengthy Venusian day and an orbit approximately the sunlight at 225 days. Its setting is thick and also contains carbon dioxide and nitrogen. The planet has no rings or moons and is at this time being checked out by the European room Agency’s Venus to express spacecraft.

Earth: Earth is the only planet with life together we understand it, however astronomers have uncovered some virtually Earth-sized planets exterior of ours solar mechanism in what can be habitable areas of their corresponding stars. It consists of an atmosphere of nitrogen and oxygen, and also has one moon and no rings. Plenty of spacecraft one our world to provide telecommunications, weather information and other services.

Mars: Mars is a planet under extreme study since it shows indicators of liquid water flow on its surface in the ancient past. Today, however, its atmosphere is a wispy mix of carbon dioxide, nitrogen and argon. It has actually two tiny moons (Phobos and Deimos) and also no rings. A Mars day is slightly much longer than 24 earth hours and it take away the planet around 687 planet days come circle the Sun. There’s a small fleet that orbiters and rovers in ~ Mars appropriate now, including the big NASA Curiosity rover that landed in 2012.

The outer planets of ours Solar device at roughly relative sizes. From left, Jupiter, Saturn, Uranus and also Neptune. Credit: Lunar and also Planetary Institute

The external Planets:

The outer planets (sometimes dubbed Jovian planets or gas giants) are huge planets swaddled in gas. Castle all have rings and every one of plenty that moons each. In spite of their size, only two of them space visible without telescopes: Jupiter and also Saturn. Uranus and Neptune were the first planets discovered since antiquity, and showed astronomers the solar system was enlarge than previously thought. Below are short descriptions of every of this planets based ~ above this details from NASA.

Jupiter: Jupiter is the largest planet in our Solar System and also spins an extremely rapidly (10 planet hours) family member to that orbit that the sun (12 earth years). That is thick setting is mostly consisted of of hydrogen and also helium, perhaps bordering a terrestrial main point that is around Earth’s size. The planet has dozens the moons, some faint rings and a an excellent Red spot — a raging storm happening because that the previous 400 years at the very least (since us were maybe to view it with telescopes). NASA’s Juno spacecraft is en route and also will visit there in 2016.

Saturn: Saturn is ideal known because that its significant ring system — seven recognized rings v well-defined divisions and also gaps between them. Exactly how the rings obtained there is one subject under investigation. It additionally has dozens the moons. Its atmosphere is mostly hydrogen and also helium, and it additionally rotates quickly (10.7 earth hours) family member to the time to circle the sun (29 planet years). Saturn is currently being saw by the Cassini spacecraft, which will fly closer come the planet’s rings in the comes years.

Near-infrared views of Uranus reveal its otherwise faint ring system, highlighting the extent to which the is tilted. Credit: Lawrence Sromovsky, (Univ. Wisconsin-Madison), Keck Observatory.

Uranus: Uranus was an initial discovered by william Herschel in 1781. The planet’s day takes around 17 planet hours and one orbit about the sun takes 84 earth years. That is mass consists of water, methane, ammonia, hydrogen and also helium neighboring a rocky core. It has dozens that moons and also a faint ring system. There space no spacecraft slated to visit Uranus right now; the critical visitor was Voyager 2 in 1986.

Neptune: Neptune is a far-off planet that consists of water, ammmonia, methane, hydrogen and also helium and a feasible Earth-sized core. The has much more than a dozen moons and six rings. The only spacecraft to ever before visit it was NASA’s Voyager 2 in 1989.

See more: Columbian Exchange Positive And Negative Effects, Positive And Negative Sides Of Columbian Exchange

To learn an ext about the planets and missions, inspect out these links:

Solar mechanism Exploration: Planets (NASA)NASA Photojournal (NASA)Missions (NASA)Space scientific research (European space Agency)USGS Astrogeology (U.S. Geology Survey)The Solar System and also Its Planets (European room Agency)

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CategoriesAstronomy, guide to room TagsEarth, within planets, Jupiter, Mars, Mercury, Neptune, outer planets, Saturn, Uranus, Venus

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