What Do The Inner Planets Have In Common With The Outer Planets?


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Samuel Chiltern answered
To clarify, the inner planets are the four smaller, rocky planets that are closest to the sun. These are (in order of distance from the sun):

  • Mercury
  • Venus
  • Earth
  • Mars
The four outer planets are termed 'gas giants', because they are much larger and consist largely of gas. This creates a thick atmosphere, rather than a solid surface. The gas giants are known as (again in order of distance from the sun):

  • Jupiter
  • Saturn
  • Uranus
  • Neptune
What Do the Inner and Outer Planets Have in Common?
The inner and outer planets only share a few common features, most notably that they all orbit the sun and are roughly spherical in shape. It is thought that at least some of the outer planets have solid cores, just like the inner planets, although astronomers are still unsure about this.

What Do the Inner Planets Have in Common With Each Other?
The inner planets are referred to as 'terrestrial' planets, since they are composed largely of rock. Therefore, we would be able to walk upon their surfaces, theoretically at least.
The inner planets are much smaller than the outer planets, due to their greater density. This also causes them to rotate on their axes much more slowly than do the outer planets
What Do the Outer Planets Have in Common With Each Other?
The outer planets can be roughly subdivided into two groups: One containing Jupiter and Saturn, and the other containing Uranus and Neptune.

Jupiter and Saturn are thought to consist mainly of hydrogen and helium, and it's most likely that they both have cores of molten rock. Jupiter is by far the largest planet in the solar system, but Saturn is still much bigger than Uranus or Neptune.

Uranus and Neptune are sometimes referred to as 'ice giants' - which should give you some idea of their nature. Between 80-85% of each of these planets is composed of a hydrogen-rich atmosphere. The planets' cores are thought to be mainly comprised of ice, but the proportion of rock to ice is not known.

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