2 天之前 · 地球是目前太阳系中以太阳为中心由內向外的第三顆行星，与太阳平均距离149,597,870公里（1天文單位），是目前宇宙中已知唯一存在生命的天体 [3] 。 地球质量约为5.97×10 24 公斤，半径约6,371公里，平均密度5.5g/cm 3 ，是太阳系行星中最高的。 地球同时进行自转和公转运动，分别产生了昼夜及四季的 ...

2 天之前 · Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of bodies beyond the orbit of Neptune.It is the ninth-largest and tenth-most-massive known object to directly orbit the Sun.It is the largest known trans-Neptunian object by volume by a small margin, but is less massive than Eris.Like other Kuiper belt objects, Pluto is made primarily of …

2 天之前 · Essentially, because Mercury is closest to the Sun, when taking an average over time, Mercury is most often the closest planet to the Earth, [121] [122] and—in that measure—it is the closest planet to each of the other planets in the Solar System.

2 天之前 · It is the largest planet in the Solar System, with a diameter of 142,984 km (88,846 mi) at its equator, giving it a volume 1,321 times that of the Earth. [ 2 ] [ 43 ] Its average density, 1.326 g/cm 3 , [ e ] is lower than those of the four terrestrial planets .

3 天之前 · The Moon is by size and mass the fifth largest natural satellite of the Solar System, categorizable as one of its planetary-mass moons, making it a satellite planet under the geophysical definitions of the term. [17] It is smaller than Mercury and considerably larger than the largest dwarf planet of the Solar System, Pluto.

5 天之前 · Of the eight major planets, Venus and Neptune have the most circular orbits around the Sun, with eccentricities of 0.007 and 0.009, respectively. Mercury, the closest planet, has the highest eccentricity, with 0.21; the dwarf planet Pluto, with 0.25, is even more eccentric.

2025年2月13日 · Earth, third planet from the Sun and the fifth largest planet in the solar system in terms of size and mass. Its single most outstanding feature is that its near-surface environments are the only places in the universe known to harbour life.

2025年2月12日 · Earth – our home planet – is the third planet from the Sun, and the fifth largest planet.

2025年2月8日 · Planet, broadly, any relatively large natural body that revolves in an orbit around the Sun or around some other star and that is not radiating energy from internal nuclear fusion reactions. There are eight planets orbiting the Sun in the solar system.

2025年1月28日 · It’s a chunk of ice, rock, and hydrocarbons that drifts 4.67 billion miles (7.5 billion km) from Earth at its orbit’s farthest point. It's the tiny former planet that stirred up controversy when it was reclassified as both a dwarf planet and a member of the collection of icy cosmic objects we call the Kuiper Belt.