The expanding Universe · 膨胀的宇宙
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| expanding/ekˈspændɪŋ/ | 膨胀 | péng zhàng |
| redshift/ˈredʃɪft/ | 红移 | hóng yí |
| Big Bang/bɪɡ bæŋ/ | 大爆炸 | dà bào zhà |
| cosmic microwave background radiation/ˈkɒzmɪk ˈmaɪkrəʊweɪv ˈbækɡraʊnd ˌreɪdɪˈeɪʃn/ | 宇宙微波背景辐射 | yǔ zhòu wēi bō bèi jǐng fú shè |
| Hubble constant/ˈhʌbl ˈkɒnstənt/ | 哈勃常数 | hā bó cháng shù |
A growing Universe
- Look far enough and every galaxy is rushing away from us.
- The whole Universe is expanding 膨胀 — and that tells us how it began.
- The clue is hidden in the colour of starlight.
一个增长的宇宙
- 看得足够远,每个星系都在飞快地远离我们。
- 整个宇宙在膨胀——而那告诉我们它如何开始。
- 线索隐藏在星光的颜色中。
Redshift 红移
- When a galaxy moves away from us, the light we receive is stretched to a longer wavelength — shifted toward the red end of the spectrum. This is redshift.
- The further away a galaxy is, the bigger its redshift.
Redshift of a distant galaxy's spectrum
红移
- 当一个星系远离我们运动时,我们接收的光被拉长到一个更长的波长——朝光谱的红端移动。这是红移(redshift)。
- 一个星系越远,它的红移越大。
一个遥远星系光谱的红移
The expanding Universe · 膨胀的宇宙
v = H₀·d
Galaxies recede faster the farther they are — speed is proportional to distance. · 星系越远退行越快——速度与距离成正比。
Light from a distant galaxy is redshifted. This means the galaxy is: · 来自一个遥远星系的光被红移。这意味着该星系:
A receding source stretches the light to a longer wavelength — toward the red end of the spectrum. · 一个退行的源把光拉长到一个更长的波长——朝光谱的红端。
How does a galaxy's redshift change with its distance? · 一个星系的红移如何随它的距离变化?
More distant galaxies recede faster, so they show a bigger redshift — this is the basis of Hubble's law. · 更遥远的星系退行更快,所以它们显示一个更大的红移——这是哈勃定律的基础。
The expanding Universe and the Big Bang 大爆炸
- Distant galaxies are redshifted, and further ones more so — so the galaxies are moving apart: the Universe is expanding.
- Run that backwards and everything was once together at a single point.
- This is the evidence for the Big Bang theory.
Every galaxy is moving away from us, and the farther ones move away faster — the Universe is expanding
膨胀的宇宙与大爆炸
- 遥远的星系被红移,更远的更甚——所以星系正在分开:宇宙正在膨胀。
- 把那倒过来,一切曾经在一个单一的点聚在一起。
- 这是大爆炸(Big Bang)理论的证据。
每个星系都在远离我们,更远的退行更快——宇宙在膨胀
The redshift of distant galaxies is evidence that: · 遥远星系的红移是以下的证据:
Galaxies moving apart means the Universe is expanding; running it backwards points to a single starting point — the Big Bang. · 星系分开意味着宇宙在膨胀;把它倒过来指向一个单一的起点——大爆炸。
More evidence, and the age of the Universe
- Faint microwave radiation comes from every direction in space — the cosmic microwave background radiation 宇宙微波背景辐射 (CMBR). It is early radiation stretched out as the Universe expanded.
- The Hubble constant 哈勃常数 links a galaxy's recession speed $v$ and distance $d$:
- Turning it around, $\dfrac{1}{H_0}$ estimates the age of the Universe — more support for the Big Bang.
更多证据,以及宇宙的年龄
- 微弱的微波辐射来自空间中的每一个方向——宇宙微波背景辐射(cosmic microwave background radiation,CMBR)。它是随宇宙膨胀而被拉长的早期辐射。
- 哈勃常数(Hubble constant)联系一个星系的退行速度 $v$ 和距离 $d$:
- 把它反过来,$\dfrac{1}{H_0}$ 估计宇宙的年龄——对大爆炸的更多支持。
The cosmic microwave background radiation (CMBR) is found coming from every direction in space. · 宇宙微波背景辐射(CMBR)被发现来自空间中的每一个方向。
The CMBR fills all of space, coming from every direction — it is early radiation stretched into microwaves as the Universe expanded. · CMBR 填满所有的空间,来自每一个方向——它是随宇宙膨胀而被拉长成微波的早期辐射。
The Hubble constant is about $H_0 = 2.0 \times 10^{-18}$ per second. Estimate the age of the Universe ($1/H_0$), in seconds. · 哈勃常数约为 $H_0 = 2.0 \times 10^{-18}$ 每秒。估计宇宙的年龄($1/H_0$),以秒计。
Age $\approx \dfrac{1}{H_0} = \dfrac{1}{2.0 \times 10^{-18}} = 5.0 \times 10^{17}\ \text{s}$ (roughly 16 billion years). · 年龄 $\approx \dfrac{1}{H_0} = \dfrac{1}{2.0 \times 10^{-18}} = 5.0 \times 10^{17}\ \text{s}$(大约 160 亿年)。
The Hubble constant $H_0$ relates a galaxy's recession speed $v$ and distance $d$ by: · 哈勃常数 $H_0$ 通过以下联系一个星系的退行速度 $v$ 和距离 $d$:
$H_0 = \dfrac{v}{d}$; its reciprocal $\dfrac{1}{H_0}$ estimates the age of the Universe. · $H_0 = \dfrac{v}{d}$;它的倒数 $\dfrac{1}{H_0}$ 估计宇宙的年龄。
You've got it
- redshift: light from a receding galaxy is stretched toward red; further = bigger redshift
- distant galaxies all recede → the Universe is expanding → evidence for the Big Bang
- the CMBR (microwaves from all directions) is more Big Bang evidence
- Hubble constant $H_0 = \dfrac{v}{d}$; age of the Universe $\approx \dfrac{1}{H_0}$
你掌握了
- 红移:来自一个退行星系的光被拉向红;更远 = 更大的红移
- 遥远的星系都退行 → 宇宙在膨胀 → 大爆炸的证据
- CMBR(来自所有方向的微波)是更多的大爆炸证据
- 哈勃常数 $H_0 = \dfrac{v}{d}$;宇宙的年龄 $\approx \dfrac{1}{H_0}$