Test: The Origin And Evolution Of The Earth

The mean distance between the sun and the earth is 149,598,000 km. In terms of light years, it is 8.311 minutes of a year.

The terrestrial planets were formed in the close vicinity of the parent star where it was too warm for gases to condense to solid particles. Jovian planets were formed at quite a distant location.

Firstly life on the earth was originated in oceans. Ocean began to have the contribution of oxygen through the process of photosynthesis.

A Belgian priest named Georges Lemaître first suggested the big bang theory in the 1920s, when he theorized that the universe began from a single primordial atom.

The inner planets mean planets between the sun and the belt of asteroids. Mercury, Venus, Earth and Mars are called the inner planets as they lie between the sun and the belt of asteroids.

The first four planets are called Terrestrial, meaning earth-like as they are made up of rock and metals, and have relatively high densities. The rest four are called Jovian or Gas Giant planets. Jovian means Jupiter-like. Most of them are much larger than the terrestrial planets and have thick atmosphere, mostly of helium and hydrogen.
 (i) The terrestrial planets were formed in the close vicinity of the parent star where it was too warm for gases to condense to solid particles. Jovian planets were formed at quite a distant location.
(ii) The solar wind was most intense nearer the sun; so, it blew off lots of gas and dust from the terrestrial planets. The solar winds were not all that intense to cause similar removal of gases from the Jovian planets.
(iii) The terrestrial planets are smaller and their lower gravity could not hold the escaping gases.

Continuous volcanic eruptions contributed water vapour and gases to the atmosphere. As the earth cooled, the water vapour released and started getting condensed. The carbon dioxide in the atmosphere got dissolved in rainwater and the temperature further decreased.

The earth’s oceans were formed within 500 million years from the formation of the earth. This tells us that the oceans are as old as 4,000 million years.

Fossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. Fossils vary in size from microscopic, such as single bacterial cells only one micrometer in diameter, to gigantic, such as dinosaurs and trees many meters long and weighing many tons.

The distance between the galaxies is found to be increasing and thereby, the universe is considered to be expanding.