Blue Planet: 12 Events That Formed the Earth as We Know It

Given the speed of technological advancement over the past 100 years, many of us are likely to think that a century is a fairly long period of time and that this is a time when the world can change a great deal. Still, things change a lot when we remember that planet Earth itself is more than 4.5 billion years old.

When we think of this scale, we can see that changes that seem very significant to us often end up having little impact on the history of the globe. To further understand these and other issues surrounding the transformations of our beloved blue planet since its inception, here are the key events that helped shape the Earth's surface as we know it.

1 - The formation of the earth

It is very difficult to determine the exact age of the globe, as no rock from the time the planet began to form has survived to this day. Although scientists continue to disagree with each other on a number of details, most researchers agree that the earth appears to have formed from a series of collisions that occurred less than 100 million years after the solar system was established.

More than ten impacts with other bodies have added volume to our growing planet, according to most models of terrestrial formation. By establishing the moon rocks and meteorites found here, scientists estimate that the earth consolidated about 4.54 billion years ago. Our new body had established an atmosphere and an iron core when one last collision changed everything.

2 - Collision with the Moon

The last major determining impact on Earth's formation was with Theia, a rocky planetoid about the same size as Mars. This protoplanet grazed the globe, leaving our planet virtually intact, but destroying itself and eliminating our atmosphere. The vaporized debris from Theia then condensed into what we now know as the Moon.

Some researchers believe that remnants of the pre-collision Earth still exist deep within the Earthen Mantle and the outermost portions of our core. For those who don't know, the cloak is the layer positioned between the surface crust and the planet's core.

3 - Magma Sphere

The force of the impact that formed the moon turned the earth into a large ball of magma. The infernal conditions made for a time the planet resembled Venus because of its cloudy and vaporous atmosphere.

When the earth began to cool, however, the lava turned to rock and liquid water began to condense, giving rise to the first ocean on the planet. The oldest minerals found on the globe, called zirconia, are dated as of this time and are 4.4 billion years old.

4 - The first continents

Today the earth is completely covered by gigantic tectonic plates of continental and oceanic crust. However, the first tectonic plates on the planet were much smaller, made up of recycled volcanic rocks that had been re-molten or buried and turned into metamorphic rocks.

These large metamorphic belts, by the way, usually contain rich deposits of gold, silver, copper and other precious metals. Researchers believe that the new earth's crust grew rapidly and 70% of it had been formed by about 3 billion years. Along the earliest continents, the early markers of life on the planet appeared 3.8 billion years ago.

5 - Breaths of life

Coming with the emergence of photosynthesis, the first doses of oxygen appeared between the rocks about 3.5 billion years ago. Though essential to life as we know it today, scientists define the emergence of the process of gas formation as one of the earliest ecological disasters on earth.

The oxygen that was created by cyanobacteria - also known as blue algae - made the terrestrial atmosphere poisonous to the then dominant life form: the anaerobic microbes that evolved in the absence of gas. Oxygen buildup oxidized iron in the oceans and formed layers of rusty rocks called banded iron formations.

When oceanic iron was finally depleted, oxygen levels in the atmosphere suddenly skyrocketed around 2.4 billion years ago, an event known as the Great Oxygenation Crisis.

6 - Very, very boredom

After the sudden rise in oxygen levels, nothing very significant has happened on Earth for about 1 billion years. The planet was so still that scientists decided to call this timeframe "the tedious billion." The lull also extended to the tectonic plates, so the continents also spent most of the period in a supercontinental traffic jam.

Many researchers believe there is a direct relationship between lack of tectonic activity and the tedious billion as a whole. Thus, the evolution of terrestrial life needed a little push from the continents to overcome photosynthesis and give rise to the first complex organisms.

7 - Supercontinents

The earth has been covered by large continents, called supercontinents, several times throughout its history. The most famous of these, called Pangeia, was the place where dinosaurs emerged, but it was not the first of these large ensembles to emerge.

Researchers believe that the first continents of the planet were also united and separated several times. The remnants of ancient mountain belts help researchers establish how continents fit together in the past, as if they were parts of a large puzzle that changes each time it is completed and dismantled.

8 - Giving an ice

The tedious billion came to an end when a large supercontinent broke about 750 million years ago, triggering a massive global cooling known as the "snowball Earth." This model suggests that the planet has become an inconsistent snowy sphere, almost completely covered by glaciers.

The volcanic eruptions and rocky breakdowns that accompanied the rupture of the supercontinent caused carbon dioxide to be trapped, causing a massive temperature drop across the world. Geologists have found evidence of glaciers on all continents that existed at the time - even those located in tropical latitudes.

9 - Explosion of life

Oxygen levels in the atmosphere began to rise again about 650 million years ago, when the first animals appeared. Living things with rigid parts appeared during the Cambrian period, 545 million years ago. Researchers disagree with the reasons for this burst of life, but many believe that a combination of factors drove this jump from single-celled organisms to complex creatures.

Separation of continents, for example, caused a sudden surge of nutrients to invade the oceans while opening new habitats. Thus, a great evolutionary dispute spread as animals began to attack each other and protect themselves from predators.

10 - Mass killings

The Earth has been plagued by several massive extinctions since the Cambrian period, but the largest record of fossils comes from the Permian period, about 252 million years ago. Scientists estimate that more than 90% of the planet's living things died within 60, 000 years - a figure comparable to 85% during the late Cretaceous dinosaur extinction 66 million years ago.

Even with the high amount of corpses, the main suspect for Permian extermination was not a meteorite impact but a gigantic volcanic eruption in Siberia. Scientists believe that the huge flow of lava has created conditions of toxic greenhouse gases.

Chemical elements in old rocks also record mass extinctions due to simple climate change. One such example is dated 450 million years ago, when more than 75% of marine species died from a great ice age.

11 - Speaking of ice

Throughout its history, the Earth has spent most of its free time on large amounts of ice, with only five major ice ages recorded. About 2.6 million years ago, large ice sheets began to flow from the Arctic to the rest of the Northern Hemisphere.

This type of glacier usually advances during the colder glacial periods and retracts when the planet goes through warmer times, known as interglacials. The current interglacial timeframe began about 11, 500 years ago and no one is sure when it might end.

12 - Era of plastic

Although most of the time since the dawn of humans has been dominated by ice, future researchers are likely to name the present era the Plasticene period. Many scientists believe that we have already consolidated our message for times to come through our plastic waste.

Small pieces of plastic can be found anywhere on Earth, from Arctic ice to the oceans, and some of this waste has now become a kind of rock called plastiglomerate. It is likely that this material has already crumbled into oblivion 1 million years from now, but scientists will certainly still be able to detect its distinct chemical signature.

What legacy do you think we will leave for the distant future? Do you think the next Ice Age is coming soon? Do you think any other big event will still change the face of planet Earth? Leave your theories in the comments.