The Universe is a fantastic place. It has mysterious stars, galaxies, and black holes. But, you’ll ask, ‘How did it start and grow?’ Well, here’s the simplified history of the Universe.
The birth of the cosmos
There was an ‘explosion’ that caused the Universe to form, which is the Big Bang. So, why do scientists think this way? Well, they have already found out that the Universe is constantly expanding and cooling down. Therefore, they thought there’s a time that the whole world was just one infinitely tiny spot before it inflated 13.8 billion years ago.
However, we can’t prove the theory with direct observations since we can’t observe the Universe in its childhood. This is because, before that, the cosmos was so hot and dense that photons couldn’t move freely. Regardless, for the smallest size possible to observe for the Universe, it was 17 centimeters wide.
Before the first stars appear
There were lots of things that took place before the first stars illuminate the Universe. At first, the Universe was so hot that the four forces were bound together. Later, gravity, the strong nuclear force, the weak force, and electromagnetic force respectively became individual. When the cosmos cooled down enough, particles started to form, but we couldn’t see anything there yet. These tiny particles then formed atoms we see today.
Stars illuminate the Universe
Finally, 380,000 years after the Big Bang, the Universe allowed molecular clouds to collapse, forming the first stars to light up the cosmos. These stars then got around black holes, and when enough stars are formed, the group becomes a galaxy.
The Universe expanded and expanded and finally becomes what we are familiar with 13.8 billion years from the Big Bang. Still, the Universe is contiuously ballooning in size, but all things will come to an end.
To find out the original image, please visit here.
The Demise of the Universe
Because the cosmos is still alive, we don’t exactly know how the Universe will die yet. But, there are a few possible theories if the Big Bang is correct. How can the Universe keep on expanding despite gravity? Well, the energy that drives the cosmos is dark energy. It is named this because it can’t interact, either reflect or refract, with Light.
First of all, gravity may slow down and reverse the expansion, causing the Universe to contract. If that is true, the Universe will go back to its original state 13.8 billion years ago, probably triggering another Big Bang. But, gravity might not ever win the forces of the Big Bang, and the cosmos will continue expanding, and expanding…… until no other galaxies can be seen in the observable Universe. Thus, we might need to be grateful that we’re at the right time to observe the Universe extensively.
Conclusion
So, this article is a brief explanation of the history of the Universe, and every event is remarkable. I think the most fascinating part of history is right after the birth of the Universe. To know more, please visit the websites in the Credits.
Credits
- Ethan Siegel, “How Big Was The Universe At The Moment Of Its Creation?”, Forbes, Mar 24 2017, https://www.forbes.com/sites/startswithabang/2017/03/24/how-big-was-the-universe-at-the-moment-of-its-creation
- “The Story of Our Universe”, Planck | NASA, May 7 2014, https://www.nasa.gov/mission_pages/planck/multimedia/pia16876b.html
- “Hubble Ultra Deep Field”, NASA Scientific Visaulization Studio, May 15 2018, https://svs.gsfc.nasa.gov/30946