The Solar System · 太阳系
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| Solar System/ˈsəʊlə ˈsɪstəm/ | 太阳系 | tài yáng xì |
| planets/ˈplænɪts/ | 行星 | xíng xīng |
| asteroids/ˈæstərɔɪdz/ | 小行星 | xiǎo xíng xīng |
| comets/ˈkɒmɪts/ | 彗星 | huì xīng |
| rocky/ˈrɒki/ | 岩石 | yán shí |
| gas giants/ɡæs ˈdʒaɪənts/ | 气态巨行星 | qì tài jù xíng xīng |
| satellites/ˈsætəlaɪts/ | 卫星 | wèi xīng |
| ellipses/ɪˈlɪpsɪz/ | 椭圆 | tuǒ yuán |
| accretion/əˈkreʃn/ | 吸积 | xī jī |
The Sun's family
- At the centre of the Solar System 太阳系 is one star — the Sun.
- Around it move eight planets 行星, plus moons, asteroids 小行星 and comets 彗星.
- Gravity holds the whole family together.
太阳的家庭
- 在太阳系(Solar System)的中心是一颗恒星——太阳。
- 围绕它运动的是八颗行星,加上卫星、小行星和彗星。
- 引力把整个家庭凝聚在一起。
The eight planets
- In order from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
- The four inner planets are small and rocky 岩石.
- The four outer planets are large and gaseous (no solid surface).
- Jupiter and Saturn are gas giants 气态巨行星; Uranus and Neptune are ice giants.
Jupiter, the largest planet, with its swirling bands of gas
八颗行星
- 从太阳起的顺序:水星、金星、地球、火星、木星、土星、天王星、海王星。
- 四颗内行星小且岩石。
- 四颗外行星大且气态(没有固体表面)。
- 木星和土星是气态巨行星(gas giants);天王星和海王星是冰巨行星(ice giants)。
木星,最大的行星,有它旋转的气体带
Watch the planets race · 观看行星赛跑
The closer a planet is to the Sun, the faster it orbits — Mercury in 88 days, Jupiter in 12 years — because the Sun's gravity is stronger close in. · 行星离太阳越近,绕行越快——水星 88 天,木星 12 年——因为太阳的引力在近处更强。
Put these planets in order, nearest the Sun first. · 把这些行星按顺序排列,最靠近太阳的在先。
From the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune — so of these, Mercury, Earth, Jupiter, Neptune. · 从太阳起:水星、金星、地球、火星、木星、土星、天王星、海王星——所以这些中,水星、地球、木星、海王星。
How do the inner and outer planets differ? · 内行星和外行星有何不同?
The four inner planets are small and rocky; the four outer planets are large and gaseous (gas giants and ice giants). · 四颗内行星小且岩石;四颗外行星大且气态(气态巨行星和冰巨行星)。
Other objects
- Dwarf planets (like Pluto) and asteroids — most asteroids lie in a belt between Mars and Jupiter.
- Moons (natural satellites 卫星) that orbit the planets.
- Comets — small icy bodies on very stretched orbits.
A giant telescope fires a laser to study the night sky
其他天体
- 矮行星(dwarf planets,像冥王星)和小行星(asteroids)——大多数小行星位于火星和木星之间的一个带中。
- 绕行星运动的卫星(天然卫星,satellites)。
- 彗星(comets)——在非常拉长的轨道上的小冰冷天体。
一台巨型望远镜发射一束激光以研究夜空
Orbits and gravity
- The Sun's gravity reaches out and keeps the planets in orbit; it is weaker further out, so outer planets orbit more slowly.
- Most orbits are ellipses 椭圆 (stretched circles), with the Sun at one focus (not the centre).
- A planet moves faster when closer to the Sun: as its gravitational PE falls, its kinetic energy rises (energy is conserved).
轨道与引力
- 太阳的引力伸展出去并保持行星在轨道上;它在更远处更弱,所以外行星绕行更慢。
- 大多数轨道是椭圆(ellipses,拉长的圆),太阳在一个焦点(不是中心)。
- 一颗行星在更靠近太阳时移动更快:当它的引力势能下降时,它的动能上升(能量守恒)。
What keeps the planets in their orbits around the Sun? · 什么保持行星在它们绕太阳的轨道中?
The Sun holds most of the mass of the Solar System, and its gravity pulls the planets into orbit. · 太阳持有太阳系大部分的质量,而它的引力把行星拉入轨道。
A planet on an elliptical orbit moves fastest when it is: · 一颗在椭圆轨道上的行星在它以下时移动最快:
As the planet comes closer, its gravitational PE falls and its kinetic energy rises (energy is conserved), so it speeds up. · 当行星靠近时,它的引力势能下降而它的动能上升(能量守恒),所以它加速。
Light travel time and how it formed
- Space is huge, so we use light travel time: $\text{time} = \dfrac{\text{distance}}{\text{speed}}$, with light at $3.0 \times 10^8\ \text{m/s}$.
- Sunlight takes about 8 minutes to reach Earth.
- The Solar System formed by accretion 吸积: gravity pulled a spinning cloud of gas and dust into a disc; most fell to the centre to form the Sun, and the planets grew from the rest.
- Near the hot young Sun only rock and metal stayed solid → rocky inner planets; far out, gases collected too → giant outer planets.
The Solar System
光传播时间和它如何形成
- 空间巨大,所以我们用光传播时间:$\text{time} = \dfrac{\text{distance}}{\text{speed}}$,光以 $3.0 \times 10^8\ \text{m/s}$。
- 阳光约花 8 分钟到达地球。
- 太阳系由吸积(accretion)形成:引力把一团旋转的气体和尘埃云拉成一个盘;大部分落到中心形成太阳,而行星从其余部分生长。
- 在炎热的年轻太阳附近只有岩石和金属保持固体 → 岩石内行星;在远处,气体也聚集 → 巨大的外行星。
太阳系
The Sun is about $1.5 \times 10^{11}\ \text{m}$ away. How long does its light take to reach Earth, in seconds? (light speed $3.0 \times 10^8\ \text{m/s}$) · 太阳约 $1.5 \times 10^{11}\ \text{m}$ 远。它的光花多长时间到达地球,以秒计?(光速 $3.0 \times 10^8\ \text{m/s}$)
$\text{time} = \dfrac{d}{v} = \dfrac{1.5 \times 10^{11}}{3.0 \times 10^8} = 500\ \text{s}$ (about 8 minutes). · $\text{time} = \dfrac{d}{v} = \dfrac{1.5 \times 10^{11}}{3.0 \times 10^8} = 500\ \text{s}$(约 8 分钟)。
Why are the inner planets rocky? · 为什么内行星是岩石的?
Close to the hot Sun, gases could not condense — only rock and metal stayed solid, so the inner planets are rocky. · 靠近炎热的太阳,气体不能凝结——只有岩石和金属保持固体,所以内行星是岩石的。
You've got it
- eight planets: four rocky inner, four gaseous outer (gas giants + ice giants)
- the Sun's gravity holds the planets; outer ones orbit slower
- orbits are ellipses with the Sun at a focus; planets move faster when closer
- light from the Sun takes ~8 min; the system formed by accretion of gas and dust
你掌握了
- 八颗行星:四颗岩石内行星,四颗气态外行星(气态巨行星 + 冰巨行星)
- 太阳的引力保持行星;外面的绕行更慢
- 轨道是椭圆,太阳在一个焦点;行星在更近时移动更快
- 来自太阳的光约花 8 分钟;系统由气体和尘埃的吸积形成