Wednesday, January 24, 2018
TIMELINE

SPINNING AROUND

We live on a giant ball of rock spinning around the Sun, which we call the Earth. Let us explore how this vast planet came into existence!

There have been many theories about the earth that may seem strange to us today, but which were widely believed during their time.The ancient Egyptians, for example, thought that the earth was a flat square under a pyramid-shaped sky, and people in medieval Europe believed that it was the sun that revolved around the earth, and not vice versa. Similarly, before the technology enabled scientists to understand more about the interior of the earth and its composition, people suggested that the earth was hollow!

 c.4,600 mya

The Earth and other planets formed, as parts of a vast cloud of hot gases from a giant Nebula and dust circling the sun begin to cluster together due to attraction by mutual gravitational forces.

 c.4,300 mya

The formation of the Earth’s crust, that is the outer layer of rock that varies in thickness all over the surface of the earth. This was the period when the Earth was going through massive changes and before life evolved.

 c.4,200 mya

As the earth cools, gas bubbles and water vapour rise from the interior to form a cloudy atmosphere

 c.4,000 mya

Separation of the crust and mantle by a boundary called Mohorovicic discontinuity or Moho.

 c.3,800 mya

The first signs of life were unicellular bacteria.

 c.3,000 mya

The atmosphere becomes oxygen-rich as ocean plants (marine life) absorb sunlight and release oxygen into the air during photosynthesis. This was one of the key factors that allowed life to flourish on earth as O2 is essential for respiration.

 c.1,500 mya

Protists, such as amoeba are the first complex living cells that can move (using pseudopodia), engulf food and carry out life processes. Later, protists join up to form sponge,. the first multi-cellular organisms.

 c.570 mya

A huge variety of complex life forms developed in the seas and oceans of Earth.

 c.440-400 mya

During this time period, Land-based plants and animals became widespread.

 c.220 mya

According to the theory of continental drift proposed by Alfred Wegener, there was a single, vast land mass called Pangea which due to to the shifting of plates broke up into smaller land masses, which we now call continents.

 c.200-70 mya

The era of the Dinosaurs

 c.100,000 ya

First modern humans appear

In today’s contemporary world there has been much of growth and advancement in various fields of science, technology, medicine. This development should be accompanied by treating mother Earth with love, care,compassion and respect.

Mahek Arora

Student-Reporter

May-2016