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PSC Class 140: Geological Time and Age of the Earth

Posted by Arun Mohan ~ on ~ 0 comments

Geological Time and Age of the Earth: It is believed that the age of earth is 460 crore years.

Scientists divided the era after the formation of Earth as Precambrian era, Paleozoic era, Cenozoic era and Mesozoic era.

The lengthiest era of Earth after formation is Precambrian era. About Four Hundred Crore years is its period. The formation of Bacteria, Jelly Fish, and Virus etc took place during the Precambrian era.

Paleozoic era is about 258 million years. During this Paleozoic era, the various forms of lives started its formation. Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian and Permian are the geologic periods of Paleozoic. Fishes, arthropods, amphibians and reptiles all developed in the Paleozoic period.

It was in Cambrian Period (544 million years ago), the jawless fishes were first born. Also it was in Silurian Period (440 million years ago), plants and coral reefs were formed. Sharks, Amphibians, small micro organisms were formed in Devonian Period (410 million years ago). Earlier Trees and Reptiles were formed in carboniferous period (360 -325 million years ago). It was in Permian period (286 million years ago), plants with seeds were formed.

It was in Mesozoic period (100 million years ago), the Dinosaurs exists in the earth. The Triassic, Jurassic, and Cretaceous were in Mesozoic period.

The Triassic period (248 million years ago), saw the formation of first mammals in Earth. Tortoises, Crocodiles and Dinosaurs were formed in Triassic Period. Dinosaurs were largely ruled the world in Jurassic period (213 million years ago). Also the birds were formed during this Jurassic period. The first blossoming flower in Earth is formed during Cretaceous period (145 million years ago). Also Dinosaurs started to die and later exiled from earth during this Cretaceous period.

The length of a day in earth is 23 hours, 56 minutes and 4 seconds, whereas the length of a year in earth, ie, the time taken for earth to rotate the sun is 365 days, 5 hours, 48 minutes and 45 seconds.

Mercury has the least number of days in a year among other planets. The 88 days in Earth is equal to a year in Mercury.

A year in Venus is equal to 224.7 days in Earth.

Mars is almost equal to Earth.

A day in Mars is equal to 24 hours and 37 minutes. Also there are four seasons in Mars like Earth. One year in Mars is equal to 687 days in Earth.

The Jupiter have the least day night time. One day for Jupiter has only Nine hours and 55 minutes. The 11.86 years in earth is equal to one year in Jupiter.

A day in Saturn is equal to 10 hours and 40 minutes. The one year in Saturn is equal to 29.46 years in Earth.

The length of a day in Uranus is 17 hours and 14 minutes. Uranus needs 84.3 years to rotate one round of Sun.

The length of a day in Neptune is 16 hours and 6 minutes. Neptune needs 164.7 years to rotate one round of sun.

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