The building of the elements in the Big Bang did not get much past lithium (element 3), with hydrogen by far the most abundant (element 1; 96 per cent) and helium in second place (element 2; 4 per cent); lithium, beryllium (element 4) and boron (element 5) were present only in traces. The list of chemical elements at this time was thus, effectively, only two members long, only one of which is chemically active (helium is chemically inert). The Big Bang brought matter into the Universe and started to mould it into the first few chemical elements, but it was only through its later consequences that the remaining elements came into being, giving us the total of ninety-four naturally occurring elements we have today, and others that are too short-lived to persist and were or are only temporary.
在大爆炸之後的元素組成，鋰(第3元素)並不多，氫至今看來是最多的(第1元素，96%），氦次多(第2元素，4%)；鋰、鈹(第4元素)和硼(第5元素)等等則十分稀少。所以在那個時候，主要的化學元素只有兩種，其中只有一種是有化學活性的(氦是化學惰性的元素)。大爆炸把物質帶到宇宙之中，開始塑造出初始的極少數化學元素，稍後各種作用的的結果是留下了一些元素，讓我們今天擁有共94種天然元素，至於其他的元素則是短暫出現而已。
The Universe had to evolve for hundreds of millions of years before chemistry became interesting. There was hydrogen but certainly none of the other elements that make chemistry, including biochemistry, work. However, almost two-thirds of the number of atoms in the human body, and 10 per cent of its mass, are hydrogen atoms. Most of them were formed in the first few minutes of the Big Bang. Much of the material of our flesh is thus directly traceable back through the life of the Universe to its birth. Our chemical origins are, in part, literally in the Big Bang, although the Big Bang was not in itself enough to make all the chemical elements needed for us to exist.
宇宙經過數億年之後，化學特性才開始產生有趣的變化。一開始只有氫但沒有其他的元素，化學特性或生物化學特性產生變化。不管怎樣，人類身體的原子數有幾乎三分之二是氫原子，佔人的體重的百分之十。那些氫原大部分在大爆炸的前幾分鐘就產生了。我們的化學根源，某個角度看來，就像大爆炸字面上的意思，雖然光是大爆炸還不足以產生我們生命所需要的所有元素。
There was another constituent of the material of the Universe that was made in the Big Bang; we know far less about it although it was crucial to the way the Universe developed immediately afterwards, as well as in the way the Universe behaves to the present day. That component is known as dark matter.
大爆炸還產生了其他宇宙中的物質；我們對它的了解很少，雖然它對於大爆炸之後宇宙的形成很重要，以至於迄今日我們對宇宙的運行並不了解。那就是「暗物質」。
Dark matter is similar to ordinary matter in the respect that it generates and responds to the force of gravity in the same way. In interactions between particles of matter, energy is often released in the form of radiation or light, so if dark matter does not interact, it therefore generates no light. This is why it is called ‘dark’: it betrays little sign of its existence apart from its effects through the force of gravity. There is more dark matter than ordinary matter, so it is very important in ruling the Universe through gravity, but, except by gravity, it interacts very little indeed with ordinary matter.
暗物質和一般物質在某些方面很類似，譬如它會產生重力，也會受重力影響。物質的粒子相互反應時(如碰撞)，能量會以放射線或光的形式釋放出來，所以如暗物質不會發生這種反應，就不會產生光。這是為什暗物質的名稱中有「暗」這個字了，它隱藏了自己存在的跡象，除非受到了重力的影響。暗物質比一般的物質多很多，透過重力對宇宙的影響很大，但是除了重力，它和一般的物質相互之間沒有什麼反應。
How much dark matter is there in the Universe in proportion to ordinary matter? There is five and a half times as much.
在宇宙中，暗物質相對於一般物質的比例為何？暗物質是一般物質的5.5倍
How much matter, dark matter and dark energy are there in the Universe? Ordinary matter makes up 4.9 per cent of the energy in the Universe, dark matter 26.8 per cent and dark energy 68.3 per cent.
在宇宙中，一般物質、暗物質、暗能量各佔多少？一般物質佔4.9% 暗物質佔26.8%，暗能量佔68.3%。(按：我們對宇宙中佔4.9%的一般物質有些了解，但對剩下的95.1%的暗物質和暗能量卻所知不多，所以有物理學家說，這代表人數的無知。)
Unlike the brief flash of a nuclear weapon, however, the cosmic fireball lasted for about 380,000 years, the photons bottled up inside the cloud of electrons. But as time passed, the cloud expanded hydrogen and helium nuclei and formed atoms. At that stage, the photons hitherto trapped inside the cloud by the free electrons were able to escape, the cloud having become transparent. Those photons were able to travel across space from then to now, a length of time of about 13.8 billion years. Travelling undisturbed, they thus preserved an imprint of what the Universe looked like when they became free and escaped and so carry a picture to us of the Universe as it was, aged 380,000 years.
不像核子武器爆炸的瞬間閃光，宇宙火球則持續了大約38萬年，光子被包覆在電子雲裏。隨著時光飛逝，電子雲擴大了氫和氦的原子核然後產生原子。在那個階段，困在電子雲自由電子中的光子終於可以逃脫，電子雲變得透明。那些光子因此可以穿過空間旅行持續一直到現在，時間的跨度是138億年。光子不受干擾的旅行，當它們不再受電子雲拘束之後，因此保有當時宇宙的印記，帶著當時宇宙的相貌，凡38萬年前。
There was one major change in the photons that did not disturb the image they carried but did alter the way we can detect them.They were degraded by the expansion of the Universe during their travel. The wavelengths of the photons were lengthened by the expansion, so that they became less energetic, changing progressively from X-rays to ultraviolet light to light to infrared radiation and ending up here and now as microwave radiation. This is the same kind of radiation that powers a microwave oven and is used to link the towers of telecommunication networks. Microwaves are radio waves that have a wavelength within the range of about I millimetre to about I metre. The microwave photons that originated in the Big Bang impinge on us from all directions in space and form what is known as the Cosmic Microwave Background radiation (CMB).
光子產生的一項主要改變，並沒有改變它帶來的宇宙樣貌，但是改變了我們可以偵測它們的方式。在宇宙不斷膨脹的時候，它們產生了降階。光子的波長隨著宇宙的膨脹而變得更長，也因此減少了能量，逐漸從X光變成紫外光到紅外線，最近在今日抵達地球成了微波輻射。這種輻射和微波爐和電塔間傳輸的網路的輻射是屬於同一種性質。微波是波長介於1𨤳米到1米之間的電波。大爆炸時產生的微波光子從宇宙空間的每個方向影響著我們，它們被稱為宇宙微波背景輻射(CMB)。
The model that worked the best, called Λ-CDM, was the one that had become the standard model even before Planck was launched, where Λ is the Greek capital letter lambda and CDM stands for ‘cold dark matter’. Nearly all astronomers believe that dark matter exists but some believe in one kind of dark matter, others in another. Cold dark matter is made of fundamental particles that move at less than the speed of light, and has the favoured property that it helps produce galaxies and clusters of galaxies by growing them from merging smaller lumps. Λ is the cosmological constant that Einstein proposed in 1917 and imagined would help prop up the Universe and keep it static. In modern cosmological models, it represents a similar push, but not one that keeps a static universe static. It is in effect a force that pushes on an already expanding Universe to make it expand faster.
最好的物理模型是 Λ-CDM，在Planck衞星發射之前就已經成為標準模型。Λ是希臘字母lambda，而CDM代表冷暗物質(Cold Dark Matter)。幾乎所有的天文學家都深信暗物質是存在的，差異只是有些人認為是某種東西，而其他人則認為是其他種類的東西。冷暗物質是由基本粒子所組成，移動速度略低於光，它特別的性質促進宇宙中形成的小塊狀變成銀河及銀河星系。Λ是愛因斯坦在1917年提出來的「宇宙常數」，想像它是支撐並維持宇宙穩定的因素。在現代的宇宙模型中，它代表一種推力，但不是維持一個靜態宇宙的穩定。它反而是一種力量，產生的效果是推動已經擴張的宇宙以更快的速度繼續擴張。
The expansion of the Universe is speeding up, not slowing down. There is some progressive input of energy into the expansion of the Universe. It goes under the name of ‘dark energy’ and its nature is a mystery; it is even more of a mystery than dark matter. In a Universe with both matter (whether dark or not) and dark energy, there is a competition between the tendency of Λ and dark energy to cause acceleration and the tendency of gravity and matter to cause deceleration. This has a big effect on the ‘formation of structure’, the term that astronomers give to the way that the earliest irregularities in the material of the Big Bang grew. The balance between gravitation and Λ controlled the way our Universe is developing.
宇宙的擴張在逐漸加速而不是減緩下來。有些東西逐漸注入的能量促進宇宙的擴張。那些東西叫「黑能量」，它的本質依舊十分神秘，甚至比黑物質更神秘。宇宙中的兩種物質(不管是「黑」的或者不是「黑」的)和黑能量，Λ和黑能量傾向會加快宇宙擴張，而重力和物質則傾向減緩宇宙擴張，兩種力量相互競爭。這對「形成結構」發揮大作用，「形成結構」是天文學家用來形容宇宙大爆炸所生成物質素材最初的不規則狀態。重力和宇宙常數Λ之間的動態均衡控制著我們宇宙的發展。
……
讀後結論
- 在宇宙中有95.1%的暗物質和暗能量是迄今人類尚不了解的，面對宇宙說人類是無知的，並不過份。
- 宇宙的「真空」並不是真的是空的，𥚃面有暗物質和暗能量。「空即是色」，還真是有道理。
- 宇宙並非是穩定的，而是持續加速擴張。
*：Paul Murdin,”The Universe, A Biography,” 2022, Thames & Hudson Ttd, London
2024/2/10 The Universe, A Biography Damakey
