Time scale of the cosmos
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Cosmological time scale 1
What I've done here is I've copied and pasted a bunch of pictures that signify events in our history, when you think about history on a grander scale, that most of us have some relation to or we kind of have heard it talked about a little bit. And the whole point of this is to try to understand, or try to begin to understand, how long 13.7 billion years is. So just to start off, I have here-- this is the best depiction I could find where it didn't have copyrights. This is from NASA-- of the Big Bang. And I've talked about it several times. The Big Bang occurred 13.7 billion years ago. And then if we go a little bit forward, actually a lot forward, we get to the formation of our actual solar system and the Earth. This is kind of the protoplanetary disk or a depiction of a protoplanetary disk forming around our young Sun. And so this right here is 4.5 billion years ago. Now this over here-- once again, these aren't pictures of them. These are just depictions because no one was there with a camera. This is what we think the asteroid that killed the dinosaurs looked like when it was impacting Earth. And it killed the dinosaurs 65 million years ago. So until then, we had land dinosaurs. And then this, as far as the current theories go, got rid of them. Now, we'll fast forward a little bit more. At about 3 million years ago-- let me do this in a color that you can see-- about 3 million, so three million years ago, our ancestors look like this. This is Australopithecus afarensis. This is I think a depiction of-- this is Lucy. I believe the theory is that all of us have some DNA from her. But this was 3 million years ago. And you fast forward some more and you actually have the first modern humans appearing on the planet, people that looked and thought like you and me. This is 200,000 years ago. That's right over here. Obviously, this drawing was done much later. But this is a depiction of a modern human, so 200,000 years ago. And then you fast forward even more. And I don't want to keep picking on Jesus. I did that with him getting on the jet liner. And I genuinely don't mean any offense to anyone. I just keep picking Jesus because frankly our calendar is kind of-- he's a good person that most people know about, 2,000 years ago. And so when we associate kind of a lot of modern history occurring after his birth. So this right here is obviously a painting of the birth of Jesus. And this is 2,000 years ago. And then this might be a little bit American-centric. But the Declaration of Independence, it was a major event. Actually even on a worldwide basis, it was the first secular democracy based on a kind of a constitutional democracy that showed up on the planet. They said we don't want the king of England anymore. And this was about 234 years ago. And I always remembered because I was born almost on the 200th anniversary. So you just have to add my age to 200. So this is 234 years ago. So these are all events or periods of time that we've heard about and we've talked about. And people throw around these type of years. But what I want to do in this video is relate it to time scales that we can comprehend. So instead of the Big Bang occurring 13.7 billion years ago, let's pretend like it occurred 10 years ago. Because most of us, especially if you're over the age of 10, can kind of understand what 10 years is. It's a very, very long period of time. But something that's well within our lifetimes, well within our experience. So let's say the 13.7 billion-- instead of saying the Big Bang occurred 13.7 billion years ago, let's pretend like it occurred 10 years ago. And if we pretend that it occurred 10 years ago, let's think about how many years, or minutes, or hours ago each of these events would have occurred. So if Big Bang, which is really 13.7 billion years, if it really had occurred 10 years ago, and we scaled everything down, if we had scaled everything down, then the Earth would have been created about 3.3 years ago. So this would have been 3.3 years ago. So there's nothing kind of amazing about this. This is a significant fraction of the age of the universe. So not that mind blowing just yet. But if we go all the way to when the dinosaurs were extinct, the last land dinosaurs, now the 65 million years-- and this will give you an appreciation of the difference between million and billion-- if the universe was only 10 years old, then the dinosaurs would have been extinct 17 days ago. Not even a month ago, the dinosaurs would have been extinct. So if the universe was created when I was just graduated-- well, I'm in my '30s now, so when I was 24-- just last month, the dinosaurs would have gone extinct. And it gets even crazier. 17 days ago, the dinosaurs would have extinct. Australopithecus afarensis would have walked on the Earth 19 hours ago, yesterday. 19 hours ago, she would have been walking around on the planet. And modern humans wouldn't have shown up until 80 minutes ago, 80 minutes, a little over an hour. There wasn't even a modern human. Then the universe was 10 years, it didn't take until just very recently, the last hour, for us to see someone that looks something like us, looks and thinks something like us. Fast forward even more, the birth of Jesus, if the universe was 10 years old instead of 13.7 billion-- and we scaled everything down-- then the birth of Jesus would have been 46 seconds ago. And then if we fast forward all the way to the Declaration of Independence, this would have occurred five seconds ago. So this isn't quite as mind blowing as the scale of the universe. But in my mind, this is still pretty amazing. I mean all that's happened since 1776 on a global basis could have been encapsulated in five seconds if the age of the universe was 10 years. So hopefully, that gives you a little bit of a perspective. In the next video, instead of condensing things in time, I'm going to compare this scale to kind of a distance scale. So we can kind of say, hey, if the universe was the number of pixels on my screen, how big would each of these things be?