Uploaded August 2021 | Updated September 2026, 2 hours ago
If you'd like to support me in this adventure of creating a home-made Masters level course for everyone, please consider donating $1/month at patreon.com/spacebutmessier
In this video, we’ll learn about the history of our universe and our current understanding of how it came to be.
Before we begin, you may wonder, how do you know what the universe was like in the past? Well we don’t fully know, but I’ll tell you what science does allow us to know. And you actually are already familiar with it.
Remember from Jeff Bezos’s dollar bills that the further you look in space, the further back in time you are looking. So by simply looking deep into space, you can see how the universe behaved all those years ago.
So this… is actually a sort of time machine, enabling us to observe the history of the universe.
Now, Telescopic observations of distant galaxies show that the entire universe is expanding, meaning that the spaces between galaxies are increasing with time. This implies that galaxies must have been closer together in the past, and if we follow this trend far enough back in time, we would eventually see that the universe had a beginning. We call this beginning the Big Bang, and scientists use how fast the universe is growing to calculate that that beginning was about 14 billion years ago.
The universe as a whole has continued to expand ever since the Big Bang, but it’s not only the force that acts on these galaxies. While space is pushing things apart in space, gravity is working to bring it all together.
You see, as the universe first burst into existence, some of the matter clung to each other. The more that stuck together, the more mass that clump of matter had. As time went on, some of these clumps of matter became so big, their gravity would pull other matter to itself faster than the universe could push it away. And thus, galaxies were born.
Then within each galaxy, smaller clumps of matter would clump together, grow in mass and therefore produce stronger gravitational forces and eventually collapse these clouds of gas and dust to form stars and star systems, ultimately producing planets and life on Earth. Now this goes much more in-depth, but we are keeping it more surface level today and we’ll dive in a little deeper to the specifics on tha process soon.
A quick note though.
Most people are familiar with the terms solar system and galaxy, but few realize how incredibly different they are. Our solar system is a single star system, while our galaxy is a collection of more than 100 billion star systems—so many that it would take thousands of years just to count them. In fact, our galaxy is about 100 million times larger in diameter than our solar system. So be careful not to mix those up!
Our universe began with a bang and it continues to expand as far as we can see. But this is something I want you to keep in mind. The Big Bang Theory is exactly that. It is a theory. While it’s currently the most agreed upon theory, I mean hack, even the Pope thinks it could be true, it hasn’t been ultimately proven. So, use what you learned in this lesson to question everything you know about the universe. How do we know the universe had a beginning? Why is it expanding? How can you really tell that everything is moving away from us? What is it moving towards? We’ll cover all of that and more in coming lessons. Thanks for watching, please consider supporting this youtube channel for as little as a dollar a month, and don’t forget to subscribe to be alerted when our lessons drop each week. See you next time!
If you'd like to support me in this adventure of creating a home-made Masters level course for everyone, please consider donating $1/month at patreon.com/spacebutmessier
In this video, we’ll learn about the history of our universe and our current understanding of how it came to be.
Before we begin, you may wonder, how do you know what the universe was like in the past? Well we don’t fully know, but I’ll tell you what science does allow us to know. And you actually are already familiar with it.
Remember from Jeff Bezos’s dollar bills that the further you look in space, the further back in time you are looking. So by simply looking deep into space, you can see how the universe behaved all those years ago.
So this… is actually a sort of time machine, enabling us to observe the history of the universe.
Now, Telescopic observations of distant galaxies show that the entire universe is expanding, meaning that the spaces between galaxies are increasing with time. This implies that galaxies must have been closer together in the past, and if we follow this trend far enough back in time, we would eventually see that the universe had a beginning. We call this beginning the Big Bang, and scientists use how fast the universe is growing to calculate that that beginning was about 14 billion years ago.
The universe as a whole has continued to expand ever since the Big Bang, but it’s not only the force that acts on these galaxies. While space is pushing things apart in space, gravity is working to bring it all together.
You see, as the universe first burst into existence, some of the matter clung to each other. The more that stuck together, the more mass that clump of matter had. As time went on, some of these clumps of matter became so big, their gravity would pull other matter to itself faster than the universe could push it away. And thus, galaxies were born.
Then within each galaxy, smaller clumps of matter would clump together, grow in mass and therefore produce stronger gravitational forces and eventually collapse these clouds of gas and dust to form stars and star systems, ultimately producing planets and life on Earth. Now this goes much more in-depth, but we are keeping it more surface level today and we’ll dive in a little deeper to the specifics on tha process soon.
A quick note though.
Most people are familiar with the terms solar system and galaxy, but few realize how incredibly different they are. Our solar system is a single star system, while our galaxy is a collection of more than 100 billion star systems—so many that it would take thousands of years just to count them. In fact, our galaxy is about 100 million times larger in diameter than our solar system. So be careful not to mix those up!
Our universe began with a bang and it continues to expand as far as we can see. But this is something I want you to keep in mind. The Big Bang Theory is exactly that. It is a theory. While it’s currently the most agreed upon theory, I mean hack, even the Pope thinks it could be true, it hasn’t been ultimately proven. So, use what you learned in this lesson to question everything you know about the universe. How do we know the universe had a beginning? Why is it expanding? How can you really tell that everything is moving away from us? What is it moving towards? We’ll cover all of that and more in coming lessons. Thanks for watching, please consider supporting this youtube channel for as little as a dollar a month, and don’t forget to subscribe to be alerted when our lessons drop each week. See you next time!
