宇宙大爆炸(Big Bang Theory)呢個詞彙﹐就算未讀過物理、無睇過科普書、未聽過霍金吹水既﹐都至少應該由美國電視劇《生活大爆炸/囧男大爆炸(The Big Bang Theory) 》或者G-Dragon既kpop團聽過呢樣野。但你又知唔知作為一個物理理論﹐宇宙大爆炸其實係未完整同有唔少問題?
宇宙大爆炸有問題 (Shortcomings of the Big Bang Theory)
當中其中一個幾嚴重既問題﹐就係佢解釋唔到點解我地個宇宙係宏觀、大尺度上係咁均質(homogeneous)和各向同性(isotropic)。呢個其實係最先由哥白尼(Nicolas Copernicus) 提出﹐即係好似梁、遊咁因為挑戰天主教教廷689/阿爺而不得好死嗰位「過街老鼠」、「滋事分子」﹐又稱為哥白尼原則(Copernican principle)﹐而家已經得到唔少唔同既實驗證實左。當中最為重要既係宇宙微波背景(Cosmic Microwave Background, CMB)。另外一個問題就係佢又解釋唔到我地宇宙既結構點樣形成; 點解我地既宇宙唔係完全均質﹐又或者非常唔均質﹐即係D能量同質量(PS: 質量其實即係能量﹐記唔記得E=mc^2?)好似D股票、期貨指數咁完全雜亂(random)咁分佈係宇宙入面﹐而係相對平均、對稱咁分佈。
(credits: ESA Planck Collaboration)
宇宙「通」脹論(Cosmic Inflation, not economic inflation)
無錯﹐你無睇錯﹐我地既宇宙其實係未發明錢、人類都仲未出現既時候﹐已經有「通」脹呢樣野﹐所以通脹﹐唔係「等價交換」﹐其實先係世界既真理 XD 所以對於每日都面對加價既香港人﹐你而家明點解啦 😛 唔係再怨、投訴啦﹐聽日記得繼續返工去抗衡通脹啦!
為左區分﹐其實宇宙「通」脹論正式既中文譯名叫宇宙暴脹論(cosmic inflation)﹐雖然英文一樣都叫inflation [sosad][sosad] 呢個宇宙爆脹論就係用黎解釋、彌補上面講大爆炸嗰D問題。寫住咁多先(請見諒小弟唔識中文﹐寫得好慢)﹐有時間寫埋下半part﹐心急既可以先睇下面我寫既英文簡略版 🙂
Everyone probably heard of the term ‘Big Bang theory’, at least from the American television sitcom series. But do you know as a scientific theory, it is never a complete theory and have lots of shortcomings? Particularly, it fails to explain why our universe looks so isotropic and homogeneous on very large scales today and where the initial fluctuations that seed the formation of our Milky Way and solar system. Cosmic inflation (not the economic one), a theoretical model which is believed to have happened just moments after (about 10^-36 s) the Big Bang, offers explanations to these problems.
To get some insights about the Big Bang shortcomings and how inflation works, let us consider the following analogy: Imagine two unrelated babies born in a same hospital, but are later separated since their birth. Because of having very little time to interact with each other, we expect them and their lives after separated would be very different.
However, if the babies are twins, who have the same genetic makeup, things would be different. Since they are now related and their interaction time is prolonged, which can be traced back even before their birth, we do expect they may still look somewhat similar even after separated since birth. This is basically the idea of inflation, ‘prolonging’ the interaction time between different parts of the universe by exponentially expanding some very small causal patches to much larger size and even beyond the horizon in a very short time.
What’s more, thanks to quantum mechanics which suggests vacuum fluctuations exist, inflation can also explain the primordial fluctuations that seed structure formation in our universe as well.