I’ve been sitting thinking about what topic to write this article about for the last half hour before it hit me → why not start from the very beginning: The Big Bang Theory And no, I’m not talking about the TV show. Soo… What is the Big Bang? Most physicists believe that the universe was born around 13.8 billion years ago in an event that we now refer to as the Big Bang. The basic idea is that the energy making up everything around us today, in fact everything in space: planets, stars, galaxies was at one point compressed into an extremely small space, even smaller than an atom. It is then said that this unbelievably dense (and hot) soup of all of that makes up the cosmos underwent rapid expansion which formed the basis for everything we can see in space today. Surprisingly, our knowledge of the universe in the immediate aftermath of the Big Bang is actually quite good. This is because we’re able to mimic those intensely hot and pressurized conditions quite accurately inside particle colliders such as CERN to see the kinds of things that happened billions of years ago. Anyways, we know that the laws of physics which we talk of today were established very quickly after the Big Bang, it was these laws and rules after all which allowed matter to form. First came the subatomic particles such as quarks, followed by bigger particles such as protons and neutrons which themselves eventually came together through fusion (the temperature of the universe was very hot at the time) to form nuclei. Eventually (like half an hour after the big bang lol), the universe cooled enough that fusion could not take just take place anywhere in space. There was then a wait of 400,000 years before eventually, the universe cooled enough to form the first atoms and then a few more hundred million-odd years before the first stars began to form and the universe resembled what we see today as these stars fused heavier elements to give us kinds of materials that make up our own planet. An Expanding Universe and Einstein’s error 🙈 Yes, Einstein made mistakes too. So you may be wondering how we know all this about the universe. Well, the short answer is Einstein’s theory of general relativity. Now, the physics of the theory itself is extremely complicated but it essentially describes how space, time and gravity work throughout the universe. Anyways, as another physicist, Alexander Friedmann was looking through Einstein’s equations, he realized that they described a universe that was either shrinking or expanding, unlike Einstein’s own belief in a ‘static’ universe. He was the first to propose the Big Bang Theory → that everything stemmed from a single point of infinite density. As you may have expected, Friedmann’s work was largely looked over. After all, who was going to take his word over Einstein's? Fast forward a few more years and many more scientists began to agree with Friedmann. They too were ignored. Eventually, it was only after world famous astronomer Edwin Hubble (The Don who the telescope is named after), provided irrefutable data in support of this (and the later discovery of cosmic microwave background radiation, CMBR, by Robert Wilson and Arno Penzias in the ‘60s) that people began to believe that we lived in an expanding universe. SOO, that's all for this week’s article. I hope you found it informative. For more be sure to check out the OnlyPhysics podcast, new episodes fortnightly!
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