How was earth was formed?

The planet that we live on today is not been the same since the dawn of time.

Neither did it exist forever. According to science, there are multiple theories about how our mother earth was formed.

A little about the planet itself

Earth has a radius of 3,959 miles (6,371 kilometers). It is the biggest of the terrestrial planets and the fifth largest planet overall. It is the only habitable planet in the current solar system.

From an average distance of 93 million miles (150 million kilometers), Earth is exactly one astronomical unit away from the Sun; This is because one astronomical unit (abbreviated as AU), is the distance from the Sun to Earth.

This unit provides an easy way to quickly compare planets' distances from the Sun.

Scientists have discovered that it takes about eight minutes for light from the Sun to reach our planet.

The basic idea of the formation of the planet

To summarise how the Earth was formed, we can look at the time the solar system was settling into its current formation.

Around 4.5 billion years ago the solar system settled into its current layout.

Earth formed when gravity pulled swirling gas and dust in to become the third planet from the Sun.

Like its fellow terrestrial planets, Earth has a central core, a rocky mantle, and a solid crust.

Different theories on how the Earth was formed

Two theories that explain the formation of the Earth are as follows: 

1. This first one is famously called the core accretion model. 

2. This model suggested that before the formation of the Earth, the solar system was a cloud of dust and gas known as the solar nebula. 

3. The summary focuses on the same model as it is the most widely recognized theory that has been accepted by the majority of scientists.

4. Due to gravity, the materials were collapsed in on themselves as they began to spin, which formed the sun in the center of the nebula. 

5. The small particles ended up binding into large particles due to the effects of gravity.

6. The solar wind swept away lighter elements leaving heavy rocky materials to create the terrestrial world. 

7. As the heavy elements collided and bound together, Earth's rocky core formed first. 
This dense material sank to the center and the lighter pieces created the crust. 

8. Some of the lighter elements were captured by gravity to make up the planet’s atmosphere.

9. The second one is the disk instability model. 

10. This model suggested gas giants need to evolve rapidly to grab hold of the significant mass of lighter gases they contain. 

11. This process normally takes a million years which was longer than the light gases were available in the early solar system. 

12. Hence, this model suggested that clumps of dust and gas are bound together early in the life of the solar system. 

13. The clumps slowly became compact, creating a giant planet. 

14. These planets can form faster than their core accretion rivals, allowing them to trap the rapidly vanishing lighter gases. 

These two theories also gave way to other theories about other elements and bodies on Earth.

Scientists believed that oceans formed from the escape of water vapor and other gases from the atmosphere.

When the Earth's surface had cooled to a temperature below the boiling point of water, resulting in rainfall.

The water ended up draining into great hollows in the Earth’s surface.

This led to the formation of the giant bodies of water, oceans that we marvel upon today.

Mountains were believed to form due to the result of Earth's tectonic plates smashing together.

When two tectonic plates converge, two plates will grind together, resulting in one plate lifting and rocks being pushed up into the air.

As these tectonic plates push up the mountains and hills, erosion by water and wind can wear downland and create landforms.

These processes happen over a long period, sometimes millions of years. 

There are a total of four types of landforms. 

Massive earth movements due to plate tectonics led to the formation of the structural landforms. 

Weathering landform was created by the physical or chemical decomposition of rock through weathering. 

Erosional landform came to existence due to the removal of weathered and eroded surface materials by wind, water, glaciers, and gravity. 

A depositional landform was formed from the deposition of weathered and eroded surface materials. 

The magnetic field is believed to generate deep down in the Earth's core.

At the heart of the Earth is a solid inner core, which is primarily composed of iron.

The temperature of the iron is 5,700°C, the crushing pressure caused by gravity prevents it from becoming liquid.

Surrounding this is the outer core, a 2,000 km thick layer of iron, nickel, and small quantities of other metals. 

Lower pressure than the inner core means the metal here is fluid.

The differences in temperature, pressure, and composition within the outer core cause convection currents in the molten metal. 

All these different processes together have formed the current Earth that we know.

These all factors are crucial to the formation of Earth, even though it keeps evolving.