Borrowing the Ship of Imagination:
Staying up late, listening to your favorite track, under a clear, night sky filled with thousands of twinkling souls and a cold breeze blowing, has this question ever crossed your mind- How had it all begun? Even I wonder why and here's my answer to it.
So, it all started with a bang. Boom! The Big Bang, as scientists call it. For the next couple of minutes, let’s borrow Neil deGrasse Tyson’s ‘Ship of Imagination’ and go on a voyage to find an answer to that question. Or let me answer it for you as I had already been on that extraordinary journey.
Credit: Ship of Imagination|Pinterest
Let’s start with an analogy. As I have already mentioned, I will answer it all myself and will try to explain it to you as long as you will read along with me.
Seasons in the Universe:
Like you, here on the Earth, experience seasons in a year, the Universe in its beginning had seasons too, which lasted from a tiny fraction of a second to billions of years. Unlike the Earth, the Universe did not seem to follow that yearly trend for seasons. Temperatures, then, were so high that even the hardest diamonds would vaporize. Scientists, from our planet, formally like to call these seasons, the Eras or Epochs. And thus, I will prefer calling them that way. There were like ten-ish of them as I noticed while rushing back in time on the Ship of Imagination. And the one known as the Quark Era was the time during which the fundamental building blocks of everything you can or cannot see, were forming. Pretty obvious, the simplest of all the elements, the Hydrogen was made or say cooked from these quirky quarks. The reason I am calling them quirky is that they are so. Their behavior and what is within them makes them quirky. Also, when I observed them through my (Oops, Neil deGrasse Tyson’s) Ship of Imagination, I was mind boggled. And, talking of Hydrogen here makes sense because it is the simplest element, it was the first one to be created. Not just Hydrogen, quarks are the basic ingredients even for baking a chocolate truffle pastry.
Credit: Chocolate Truffle Pastry|Cooking Channel TV
Nucleosynthesis and Fusion:
Making Hydrogen out of these quarks is a process known as Nucleosynthesis, which started at the time when the Universe was just 3 minutes old. (Aww, baby Universe) Now, for simplification purposes, break this complex term ‘Nucleosynthesis’ into two parts- Nucleo and Synthesis. Nucleo, derived from the word Nucleus, signifies something at the very center of, the core, or the heart. Synthesis means to synthesize or make up something. Talking of this two-worded combination process is not that simple a task. It, further, involves another process called fusion. (As the name suggests, fusion means to fuse or combine two or more things to get a new something).
From Quarks to Subatomic Particles:
These quirky quarks, which I was talking of earlier, are of 6 types- Up, Down, Charm, Strange, Top, and Bottom, out of which combination of two kinds of them formed protons and neutrons- the subatomic particles. I noticed that two Up and a Down quark fused to make a proton and two Down quarks and an Up quark combined to form a neutron. When minutely observed, from the big window of the Ship of Imagination, a lot of quirkiness was going on within these protons and neutrons. Such quirkiness is beyond the scope of this article.
Credit: Standard Model in Particle Physics|CERN
Now, these protons and neutrons had formed in what is called to be the Hadron Era, which was just 1 second after the Big Bang. The temperatures were seething enough due to which the matter as we see today did not exist at the time. Everything was so tightly packed and opaque that it felt like suffocating. It was like someone had poured gallons of water in a 20ml sipper. Everything seemed like an energetic hot soup of protons, neutrons, and some other particles which managed to form during this period. It took somewhere between 1 second to 3 minutes after the Big Bang for the electrons to come into existence. If you’ll search Google, this era is called the Lepton Era.
Nucleosynthesis:
As I had noted it down in the logbook, the nucleosynthesis, which means making up the nucleus, began at around the time, t = 3 minutes, and continued until the time, t = 20 minutes. Three-ish minutes after the Big Bang, the temperature was still seething at approximately 1,000,000,000 K (Kelvin). At such high temperatures, the protons, which I now bother to refer to as the Hydrogen (protium) nuclei, had started to fuse with neutrons to make deuterons.
Now at this point, I feel that I should give a pretty basic idea, to you, of what fusion is or at least how it works. Imagine you have a pea and a chickpea, almost identical in size, right? So are the neutrons and protons. Consider this pea to be a proton (P for Pea, P for Proton; remember that) and chickpea to be a neutron, and let’s suppose you also have a superglue. Now you apply this superglue to the chickpea or the pea, your choice, and stick the other one onto it. Congratulations, now you have imagined making a chickpea-pea. The superglue is analogous to the force that binds a proton and a neutron to form a deuteron. Now, ironically, proton, neutron, and deuteron are the fancy names given to the fundamental particles. There will be more such names which I will be using further.
So, moving on next to what I was talking previously about. After a lot of deuterons being formed, they fused to create what seemed like the little greek fishies, the alpha particles, or instead, call them Helium nuclei. The reason why I am calling them little greek fishies is because they are represented by a greek letter 𝝰 (alpha), which seems to me like a tiny fish. This process of making Helium nuclei from fusing the heavy Hydrogen nuclei (deuteron) continued until the end of the 20th minute after the Big Bang. Till this time, the temperatures cooled down to 10,000,000 K. So, no more fusion for the time being. This number contains two zeroes less than the one mentioned above, so it is relatively lower in temperature, and hence, colder. But the iron would still have been vaporized. You can also think of this fusion to be analogous to welding two metal balls of the same size. The welding won’t be possible if the temperature is not sufficiently high.
If I bother to mention some statistics here, as I had noted down in the logbook, by this time, around 25% of the deuterons got converted to alpha particles. Well, the Universe did it pretty fast. So, this marked the end of what is called the Big Bang Nucleosynthesis.
Latter in Time:
It was scorching and suffocating, so I rushed through the next 380,000 years after the Big Bang. The temperatures were dropped down to 3,000 K as recorded by the thermometer aboard the Ship of Imagination and electrons, which were earlier freelancers in the hot soup combined with the Hydrogen and Helium nuclei to form neutral atoms. And the matter, as we know today, came into existence.
While moving further and faster in time, I observed the formation of heavier nuclei taking place in the core of the stars as they continued to burn up their fuel.
Also, on my way back home, I witnessed a fierce but the most beautiful and mesmerizing event in the Universe- a Supernova explosion. I was awestruck but still managed to do some science- the heavier nuclei formed under the extreme conditions of this explosion.
Aah! The journey was quite hot and blazing, but pretty amazing. Finally, I leave you all with a delicious recipe of apple pie from one of my favorite chefs, i.e., Carl Sagan (Cosmologist).
Credit: Carl Sagan's Apple Pie|Carl Sagan
Now, lie down, relax, and enjoy the beauty of the wondrous Universe under the sparkling night sky having a tasty apple pie.
References:
[1] Hawking, S.W., A Brief History of Time, Bantam, NY, 1988.
[2] Longair, M., The Origins of the Universe, Cambridge UP, Cambridge, 1990.
[3] Weinberg, S., The First Three Minutes, Basic Books, NY, 1977.