Thursday, 13 October 2016

How was the Earth Formed?

The tale of Earth’s birth

Hello Readers,

In this article, I will be touching upon some models which explain the birth of planet Earth. The models have been proposed by keeping all the physical laws in perspective.

We have 2 models which are widely accepted.
  1. Core accretion model
  2. Disk instability model
The former (core accretion) explains the formation of terrestrial planets(like earth). This model has some problems explaining the formation of more massive ones.  So, the 2nd model makes up for that. 

Now, all I want you to do is sit back relaxed and enjoy the beauty.

The Core Accretion Model

It all started with dust and gas. This aggregation is called nebula. It had really small particles and gas. Then gravity pulled some of the particles on itself, began to spin and gave birth to a young sun. With the sun rising, neighboring particles began to clump up (gravity being the reason) and in this way we got our terrestrial planets. 

The fate of gasses and lighter particles? They were flown away by the solar winds. Away from the sun, solar winds have less effect. This effect caused the gasses and elements to coalesce and formed today’s asteroids, comets, and moons.

Talking of Earth, the core was formed first. Rocky materials collided profusely (due to gravity) and heavy material sunk to the Centre. The lighter elements formed the crust.

Here’s the model of the formation of our planet’s moon- The young earth had faced a devastating Collison by a body. The force was so lofty in magnitude that it broke some part of the Earth’s mantle, plunging the pieces into space. The pieces then got together due to gravity and took orbit in the arms of its mother. The movement in the mantle caused the rocky plates on earth’s surface to rumble. This rumbling gave us mountains (Do you know that Mt. Everest is still alive? It is increasing its height by a quarter of an inch every year.)

The frequency of comets and asteroids getting into the inner solar system is very low today. But, back then, they often passed by. Some even collided with Earth. These icy bodies gave rise to water bodies on our planet. Earth is in the goldilocks zone place where water remains in the liquid state.)

The Disk Instability Model

Why the 2nd model?

1. Gasses, being lighter, can rapidly evolve into planets. Here, the core accretion model poses a contradiction. It predicts the age of planets formed by gasses to be more than the age of the gas from which it has been formed (which is impossible.)

2. It has migration issues. The smaller planets are likely to spiral into the sun (in reality they don’t).

This theory explains the formation of planets from dust and gasses (like the core accretion model). It won’t be wrong to say that dust and gasses are the seeds of any planet. The planets formed as per this model are likely to evolve faster than the core accretion rivals. 

This has been the tale of the Earth (and other heavenly bodies). I hope you enjoyed the ride.

Written by Prajwal Pitlehra
A 12th pass out with science in my pocket and pen in my hand, I hope to make my place in the world.

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