Everything is Running From Us
The human race has always tried to find a way to explain the existence of us and the universe. Early views of this revolved around religion and creation. Modern views are a bit different, though, and I’ll try to explain it the best a high school sophomore can. Up until the early 20th century, astronomers didn’t really know how the universe began. There were far-fetched ideas, but nothing was concrete. It wasn’t until 1929 that a famous astronomer, Edwin Hubble, looked up into the night sky through a telescope and realized that the light emitted from multiple galaxies had a redshift, which means the wavelengths of the light emitted by the galaxies had been stretched. According to this phenomenon, our universe must be expanding. Now you may be asking, how does this have anything to do with the beginning of the universe? Think about it like this: as time goes forward, distant galaxies are moving away from us. This must mean that if you reverse time, all galaxies must be coming towards each other until they are so dense that they are the size of a tiny dot. Something must have caused this expansion, and we call that the Big Bang.
This does cause some unusual side effects not entirely Big Bang-related. From our view of the universe, there is this thing called the observable universe. What this basically means is that there is a portion of the cosmos that we can see today and access with our telescopes. The universe is much bigger than this; we just can’t see beyond a certain threshold. Due to the fact that the universe is expanding, all galaxies will at some point leave the threshold and no longer be visible to us from Earth. In a very long time (not something we have to worry about for a while), the human race will no longer have any visible knowledge of the universe’s beginning or of galaxies, for that matter. They will have to rely on what astronomers before them saw and recorded. This does make many Astrophysicists wonder what crucial parts of the cosmos might be missing from our line of sight today.
.jpg)
During the Big Bang
As everything just seemed to pop into existence and expand, the first few moments of the universe were fierce and deadly. Everything expanded so fast and particles of matter and antimatter smashed into each other. Matter and antimatter are polar opposites, if they meet, they come together and annihilate each other, becoming energy. For some yet to be discovered reason, at the beginning of this expansion, normal matter out number regular matter by the tiniest amount, They were practically equal. If it wasn’t for this slight edge of regular matter, everything in the universe would just be energy; no planets, stars, blackholes, or nebulae.
During these first few seconds, electrons, protons, and neutrons began to form, which then led on to create the first elements in the universe; helium, hydrogen, and a little bit of lithium. Why these elements? It’s because they’re the most basic elements in the cosmos. Hydrogen was the most abundant element, making up 95%, because of its structure, consisting of just one electron and one proton. All the elements more complex than helium, hydrogen, and lithium were forged in stars millions of years later.
Within stars lies one of the most fierce and deadly places in the cosmos: their core. Stars are mainly made up of hydrogen (which is around 75% of the star) and helium (around 25%) at the beginning of their life cycle. But their cores have such high pressures and temperatures that the hydrogen atoms inside fuse together, creating more helium atoms. Once all the hydrogen runs out, helium begins to fuse, creating even heavier elements. This cycle repeats over and over again until it reaches iron, the 26th element, at which point the star can no longer fuse a more complex element. Iron cannot fuel the star, so when too much iron builds up, it begins to collapse under its own gravity. During this collapse, it reaches a point where it explodes, expanding faster and faster; this explosion is called a supernova. This supernova allows the iron that was in the star to be forged into almost all other elements on the periodic table.
The Modern Cosmos
Supernovas spit out all the natural elements in the universe, and these elements create planets, comets, moons, asteroids, other stars, and even black holes. Our own galaxy was created by this star dust. Even you, every part of your body has existed since the Big Bang. Look down at your fingertips and just think about that fact, it’s bizarre. The stardust from supernovas spread across the universe and can come together, such as when our solar system was formed. A cloud of gas began to revolve around our sun after a supernova explosion.
That resulting gas cloud began to clump together into a disk, which is why the orbits of each planet are parallel to each other. The gas particles collided with each other, bonding to create a bigger and bigger object, which, over a long period of time, began to form into our planet, Earth. Earth used to be a hot fireball where the thought of life existing would be laughable. But it began to cool and create a much finer environment for life. How did life form? We don’t have any conclusive evidence that we could call fact, and it still lingers and stumps the brightest of minds. As this process for Earth occurred, it was also happening for all the other planets in our system. Over the course of 4.6 billion years, we arrive at the present day, which shapes our current understanding of the cosmos.