4.5 Billion Years in 1 Hour

Experiencing Earth’s History: An Hour-Long Train Ride#

So, imagine Earth is 4.5 billion years old. That’s a number way too big for your brain to really get a handle on. So, here’s an experiment to help: we’re going to take a musical train ride, looking out the window, and pass through all of Earth’s history in just one hour.

On this ride, every second that passes is like 1.5 million years zooming by. It’s a way to really experience how incredibly long a billion years actually is. You can have this playing in the background, maybe while you’re studying, or just sit back and enjoy the journey. I’ll pop in from time to time to say a few words about what we’re seeing.

The Early Earth: Lava, Collisions, and Bombardment#

4.5 billion years ago: This is right when Earth was born. It was a real hell of lava.
Pretty early on, Earth had a massive collision with a Mars-sized object named Theia. This huge impact is what formed the Moon we see in the sky today. Back then, the Moon would have looked enormous in the night sky. Over hundreds of millions of years, it will slowly shrink as it orbits further away from Earth.
We are in the very first eon of our planet’s history, called the Hadean. It’s named after the Greek god of the underworld, which seems fitting given the conditions!
At this point, the atmosphere was mostly CO2, and the ground was quite literally lava.
Most of this era is actually invisible to us now because almost none of it has survived through time.
Even after 90 million years have passed, we’re still in this hot, lava-filled phase. Settle in, this part takes a while!
Surprisingly, even though it was a lava hell, we’ve found minerals called zircons that suggest there might have been some water around during this early time.
During this period, the young solar system was a chaotic place. Earth and the inner solar system got constantly smashed by a heavy asteroid bombardment that lasted for several hundred million years.
Our Sun back then was about 30% less bright than it is today. But don’t let that fool you – there were so many greenhouse gases in the atmosphere that it was still very hot and, perhaps surprisingly, quite comfortable temperature-wise (if you could survive the other stuff!).

Life Begins & Oceans Form#

Around this chaotic time, we think life begins to enter the stage.
Just a few hundred million years after the very beginning of everything, the first cells started spreading across our still incredibly deadly planet.
Earth continued to cool down. It probably rained for millions of years as our vast oceans began to form, eventually covering the still young planet with water.
Those bubbling hydrothermal vents you might see, where hot minerals come up from below, might have been the very place where life first developed. But, honestly, we don’t know for sure.

Entering the Paleoarchean & Early Evidence of Life#

So much time has flown by! We are now entering the Paleoarchean eon.
Most of Earth is still underwater.
In the deep depths below, the first supercontinents are starting to form.
The Earth’s days are shorter back then because the young planet was spinning faster.
Good job if you’re still watching! You’ve just witnessed a billion years go by so far.
From this ancient time, we actually still have some evidence: Stromatolites. These are sedimentary rocks built by microorganisms and are some of our first real evidence of life on Earth.
Life is also starting to figure out how to use the Sun’s energy – photosynthesis might have begun as early as around this time.

The Mesoarchean: Continents and Hot Tubs#

3.2 Billion Years Ago, we’re in the Mesoarchean. This is really the era when continents start taking shape.
Tectonic plates begin to crash into each other. Some parts get pulled deep into the Earth where they dissolve, while others get pushed up. This process is the basis for the continents we have today.
The oceans back then were seriously hot – about the temperature of a hot tub, over 40°C.
Microbes are expanding and spreading out everywhere.
We still don’t have plants yet to gobble up the greenhouse gases, so it remains really, really hot. You would basically die immediately in that atmosphere!
Crucially, there is still no oxygen in the atmosphere yet.

The Neoarchean: More Life, Still Single Cells#

2.8 Billion Years Ago, the Neoarchean begins.
Earth is still a terribly hostile place for us.
But finally, we have proper plate tectonics working. This means more chemicals from inside the Earth are getting mixed around and brought up to the surface.
Life can use these new chemicals to build new things!
Some time around here, Prokaryotes like bacteria start spreading and colonizing the planet.
Life is starting to diversify more and more. But even after all this time, life is still just single cells.

The Siderian & The Great Oxidation Event#

2.5 Billion Years Ago, in the Siderian period, a massive event is about to kick off that will change the entire planet forever: The Great Oxidation Event.
Oxygen, which was being produced as a waste product by tiny critters called cyanobacteria, starts reaching the atmosphere in huge amounts. This is a game-changer, paving the way for much more complex life down the road.
All this new oxygen reacts with methane in the atmosphere, forming CO2 and water. This chemical reaction causes the planet to cool down rapidly.
Probably for the first time ever, the planet completely freezes over. This starts a period of multiple ice ages that last for millions of years.

The Rhyacian: Thawing and Evolution#

2.3 Billion Years Ago, the Rhyacian period begins.
Lots of volcanoes start erupting, helping to heat Earth back up.
Earth slowly starts to unfreeze again.
The melting ice washes toxic elements into the oceans.
But life is tough! It quietly puts up resistance and keeps on evolving.

The Orosirian: Impacts and Mountains#

Some time around 2.05 Billion Years Ago, in the Orosirian period, a truly massive asteroid slams into Earth. This creates the largest verified impact structure we’ve found on Earth.
All over the planet, giant mountain ranges are being shoved into existence as early continents with wild names like Ur, Nena, and Atlantica crash into each other.

The Statherian: Supercontinents and Reactors#

1.8 Billion Years Ago, in the Statherian period, the supercontinent Columbia has formed.
And get this – a natural, self-sustaining nuclear reactor wakes up during this time, just from scattered uranium deposits in the ground! Weird, but true.

The Calymmian: The Rise of Eukaryotes#

1.6 billion years ago, around the edge of the Calymmian period (give or take a few hundred million years), something incredibly important happens: the first Eukaryotic cells appear.
These are cells with a proper nucleus. They likely merged from two other types of cells.
This is one of the most important moments in the history of life.
Yeah, it might not look that impressive – still just cells – but trust me, it’s a big deal!
Earth’s crust continues to thicken, and heavy continents keep forming.
The oceans are becoming shallower.
Also, the first fungi-like organisms start extending their tubular arms and doing whatever fungi do.

The Ectasian: The Inner Core Forms#

Some time in the Ectasian period, 1.4 Billion Years Ago, Earth’s inner core is actually forming.
Kind of weird, right? It feels like it should have been there from the start.
But around this time, it begins to solidify into a solid iron crystal surrounded by hot liquid metal. It’s only going to grow from now on.

The Stenian: The Invention of Sex#

1.2 Billion Years Ago, in the Stenian period, honestly, not a whole lot of dramatic stuff is happening globally.
Except… the algae species Bangiomorpha pubescens might have invented sex.
That’s a pretty big reproductive improvement for life, for a whole bunch of different reasons!

The Tonian: Predators Emerge#

1 Billion Years Ago, the Tonian period begins.
Another age where Earth is mostly rocks, puddles, and oceans.
Life is still invisible to the naked eye. It does feel different seeing it pass by like this, doesn’t it?
Not everyone is having a great time though. We’ve found evidence of the first unicellular predators emerging around this time.
The long dominance of bacteria starts to end as the big-boy eukaryotes start planting their flags in the oceans.
An arms race between microbes begins, which again leads to a huge amount of diversity. Some even develop tiny armor!

The Cryogenian: Another Ice Age#

720 Million Years Ago, in the Cryogenian period, Earth freezes over again. Sure, why not?
How life managed to survive this global freeze? We’re not entirely sure.

Gondwana & The Rise of Multicellular Life#

635 Million Years Ago, the supercontinent Gondwana forms. A huge chunk of it is still around today! Wow!
Suddenly, something amazing happens! Life gets BIG!
In what feels like a hot second (geologically speaking), multicellular organisms become widespread!
They still look like strange aliens to us, but can you imagine it took this incredibly long for this to finally happen?

The Cambrian Explosion#

539 Million Years Ago, the Cambrian explosion begins.
We see life bursting with variety!
The ancestors of almost all of today’s major animal groups appear here.
Meanwhile, the plants are starting to discover the land.
Life is finally getting really exciting!
But, of course, a big mass extinction happens right after, wiping out most species in the ocean.

Life on Land Takes Off#

Plants spread across the planet. They create the soil on the ground and drastically change the atmosphere by eating up CO2.
Things are escalating now! Flora and fauna are getting better and better at living on land.
We start seeing trees and forests.
Fish are around, and the first vertebrates decide that this land thing looks like something they need to try out!

The Carboniferous: Forests and Coal#

359 Million Years Ago, in the Carboniferous period, forests and lush marshlands are absolutely at their peak.
These vast forests will eventually turn into the coal that humanity burns today to keep ourselves warm.
It’s all happening so fast now! Life is changing incredibly quickly on geological timescales!

The Permian & The Great Dying#

Some time around 299 Million Years Ago, in the Permian period, Pangea, the very last supercontinent, has formed.
And then, after just a few tens of million years, the largest mass extinction in history occurs. It kills the vast majority of all species on Earth. Thanks, volcanoes.

The Triassic: Dinosaurs Emerge#

252 Million Years Ago, the Triassic period begins.
Oh hey, look – a dinosaur!
We are now truly in the age of reptiles. Dinosaurs are everywhere!
The ancestors of the birds are doing their birdy things.
Life, uhh, finds a way!
Earth starts looking more and more familiar to us. Such a paradise! Life is thriving. Nothing could possibly go wrong… wait, what’s that?

The End of the Dinosaurs#

And then… an asteroid hits Earth.
This killed the dinosaurs and most of the species on the planet. What a bummer.

The Paleogene: Mammals Take Over#

66 Million Years Ago, in the Paleogene period, the continents look roughly the same as they do today.
Mammals start to take over the planet.
It is our time now! We’re almost home.
Seriously, don’t blink here or you might just miss all of human history!

We Are New#

And that was it. You’ve seen it all pass by in an hour.
Earth is ancient. We are new. So, so new in the grand scheme of things.

About This Project#

This video was a project born purely out of passion.
We’ve been working on it on and off since 2019. As you can imagine, it took forever to make!
But we did it – we finished it just in time for our tenth (10th) year anniversary.
If you liked this kind of experimental video and want to support us making more, please like, share, and subscribe, and maybe hit that bell icon too.
You can also keep exploring time with our new Timeline of Evolution poster. It shows you how long it took for those first cellular blobs to evolve into fishes, then dinosaurs, and finally into mammals. You’ll even encounter some amazing creatures you’ve probably never heard of along the way.
This poster is part of our Education Edition series. These posters aim to make complex topics understandable through extensive research and detailed illustrations. They’re great for teachers, students, and anyone who loves science.
You can get them from our shop and directly support what we do on this channel.
Anyway, if you made it all the way to the end, thank you so much!
Hope you felt something watching Earth’s epic story unfold.