小小亦儿
星球 [词典] star; celestial body; heavenly body; [例句]早期的天文学家认为我们的星球是宇宙的中心。Early astronomers thought that our planet was the centre of the universe.
扬州灰豆子
n. 天体planet;heavenly body;celestial body orb 不知道您要表达什么意思，所以找了几个例句，结合您的语境看看那个最合适吧！例句：固定的星球 inerratic stars 星球上有智慧生命的发展 The development of conscious life on the planet. 人类尚需征服星球。 Man has yet to conquer the stars. 其它星球上可能存在的生命 the possibility of life on other worlds. 人类在这个星球上的早期阶段 the beginnings of human life on this planet. 在其他星球上有生命吗？ Is there life on other worlds? 科学家们还不能证实在其它星球上有生命存在。她断言离群索居对于创造性的工作是必不可少的。 Scientists cannot affirm the existence of life on other planets. She averred that solitude was necessary for creative work. 在天空中弧形运动的星 the stars that arc across the sky. 天灯(日、月、星) the lamps of heaven 用望远镜才能看到的星 telescopic(al) stars 推荐一个网站：类似的问题可以到上面找到满意的答案，呵呵
13820421534茜
star[英] [stɑ:(r)][美] [stɑr]n.明星; 星; 星级; 星状物;v.主演; （在文字等旁）标星号;[例句]The night was dark, the stars hidden behind cloud.夜很黑，星星都躲在云的后面。[复数]stars
小小乖肉球
Our solar system consists of the sun, nine planets (and their moons), an asteroid belt, and many comets and meteors. The sun is the center of our solar system; the planets, their moons, the asteroids, comets, and other rocks and gas all orbit the sun. The nine planets that orbit the sun are (in order from the sun): Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. A belt of asteroids (minor planets made of rock and metal) lies between Mars and Jupiter. These objects all orbit the sun in roughly circular orbits that lie in the same plane, the ecliptic (Pluto is an exception; it has an elliptical orbit tilted over 17° from the ecliptic). Easy ways to remember the order of the planets are the mnemonics: "My Very Excellent Mother Just Sent Us Nine Pizzas" and "My Very Easy Method Just Simplifies Us Naming Planets" The first letter of each of these words represents a planet - in the correct order. The largest planet is Jupiter. It is followed by Saturn, Uranus, Neptune, Earth, Venus, Mars, Mercury, and finally, tiny Pluto. Jupiter is so big that all the other planets could fit inside it. The Inner Planets vs. the Outer Planets The inner planets (those planets that orbit close to the sun) are quite different from the outer planets (those planets that orbit far from the sun). The inner planets are: Mercury, Venus, Earth, and Mars. They are relatively small, composed mostly of rock, and have few or no moons. The outer planets include: Jupiter, Saturn, Uranus, Neptune, and Pluto. They are mostly huge, mostly gaseous, ringed, and have many moons (again, the exception is Pluto, which is small, rocky, and has one large moon plus two tiny ones). Temperatures on the Planets Generally, the farther from the Sun, the cooler the planet. Differences occur when the greenhouse effect warms a planet (like Venus) surrounded by a thick atmosphere. The outer, gaseous planets are much less dense than the inner, rocky planets. The Earth is the densest planet. Saturn is the least dense planet; it would float on water. The Mass of the Planets Jupiter is by far the most massive planet; Saturn trails it. Uranus, Neptune, Earth, Venus, Mars, and Pluto are orders of magnitude less massive. Gravitational Forces on the Planets The planet with the strongest gravitational attraction at its surface is Jupiter. Although Saturn, Uranus, and Neptune are also very massive planets, their gravitational forces are about the same as Earth. This is because the gravitational force a planet exerts upon an object at the planet's surface is proportional to its mass and to the inverse of the planet's radius squared. A Day on Each of the Planets A day is the length of time that it takes a planet to rotate on its axis (360°). A day on Earth takes almost 24 hours. The planet with the longest day is Venus; a day on Venus takes 243 Earth days. (A day on Venus is longer than its year; a year on Venus takes only 224.7 Earth days). The planet with the shortest day is Jupiter; a day on Jupiter only takes 9.8 Earth hours! When you observe Jupiter from Earth, you can see some of its features change. The Average Orbital Speed of the Planets As the planets orbit the Sun, they travel at different speeds. Each planet speeds up when it is nearer the Sun and travels more slowly when it is far from the Sun (this is Kepler's Second Law of Planetary Motion). 链接的网址还有图片对照参考资料：
