One of the outer planets, Saturn, has a density of only 0.

土星是外行星之一，它的密度只有0。

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Also, because of their relative locations, the four Jovian planets are known as the outer planets, while the terrestrial planets are known as the inner planets.

同样，由于它们的相对位置，四颗类木行星被称为外行星，而类地行星被称为内行星。

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The outer planets are giant worlds with thick outer layers of gas.

外行星是具有气体外层的巨大行星。

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Some scientists have called Jupiter the protector of the inner planets and our own Earth -- from objects from the outer solar system.

VOA: special.2009.08.25

In fact, there's a property of gravitational fields anywhere, even in outer space, but there is some residual field between all the planets and all the stars in the universe, that the force on a body is proportional to the mass of the body.

实际上,这是任何地方的引力场都具备的属性,甚至是在外太空,在所有的行星和恒星之间,存在着某种剩余场,在这个场里作用在物体上的力,和物体的质量之间存在比例关系

耶鲁公开课 - 基础物理课程节选

Probes have shown us stunning images of the rings of Saturn and the outer planets of our solar system.

CNN: Bush: 'It is time for America to take the next steps' in space

The probes' initial goal was to survey the outer planets Jupiter, Saturn, Uranus and Neptune - a task they completed in 1989.

BBC: Voyager Solar System 'exit' debated

Without it such a galaxy's outer parts would spin more slowly than the inner ones (just as the outer planets of the solar system move around the sun more slowly than the earth does).

ECONOMIST: The galactic gourmand