How did Earth form? What happened before life began? Did life begin on Earth or elsewhere?
These questions are some of the most fundamental ones humans ask themselves.
Yet they remain unanswered.
The history of our planet is shrouded in mystery. Scientists have found evidence of water, volcanoes, and even meteorites hitting Earth, but none of these events explain how Earth came into existence.
Earth has always existed, but scientists don’t know exactly when. They believe that Earth formed around 4.5 billion years ago, but they aren’t sure where it came from.
So, let’s dive into the history of our solar system.
Billion years ago, there was no sun, earth, or moon in our solar system. Instead, there was only a cloud of frigid dust particles moving through empty space, according to scientists. This cloud of gas and dust was disturbed, the most likely explanation for this disturbance is the explosion of a distant star upon its death, which is known as a supernova.
The supernova caused the dust cloud to collapse as gravity pulled everything together. Then, it turned into a solar nebula, which is a massive spinning disc. The quicker the cloud spun, the more dust and gas gathered in the core, increasing the nebula’s speed.
As the movement increased, hydrogen atoms began to form at the center of the nebula. The hydrogen atoms started fusing together and turned into helium. The nuclear fusion at the center of the cloud became the Sun, the giant and fiery ball that is the source of light and life.
The Sun was the first entity to have formed in the solar system.
How was Earth formed?
The formation of the Sun used up more than half of the matter in the nebula. After the Sun was formed, the remaining matter started to clump together, forming different masses.
The cloud was still spinning, and clumps of matter collided with one another.
Some of those matter clumps grew big enough to sustain their own gravitational pull, forming the planets we know today, including Earth.
Heavy elements collided and bound together to form the Earth’s rocky core first. Dense matter sunk to the planet’s core, while lighter matter formed the crust.
How old is the Earth?
The Earth is estimated to be around 4.5 billion years old. When the planet was newly formed it was uninhabitable. According to scientists, the Earth’s surface was almost entirely covered up by molten lava. It also had no atmosphere at the time.
Eventually, the planet began to cool over the course of a few hundred million years, and thus began the emergence of oceans consisting of liquid water.
The heavier elements began to descend through the oceans and magma toward the planet’s core.
As a result, Earth separated into layers, with the outermost layer consisting of a solid covering of relatively lighter material, while the denser, molten stuff sunk to the planet’s core.
Almost a billion years after the formation of Earth, microorganisms started to grow on the surface. Some of those microorganisms used photosynthesis and contributed to the emergence of Oxygen in the planet’s atmosphere. And thus, through billions of years of evolution, Earth is now the only known planet to be inhabited by humans and other living creatures.