The age of the earth is not definite. The creation of the earth itself is a theory.Theories have been around , but almost all of them are interesting and could make us an estimate of the life of the earth. The dimension of the earth and other planets are the result of measurablity due to the various methods specially to gifted to us by our ancestors ,the scientists and mathematicians who developed and contributed to the knowledge for our universal conscoiusness.The present estimates of the age of the earth is determined by the half life cycles of varoius radioactive isotope decays that are found in the rocks of the earth. Here are a few estimates:
By the absence of plutonium-244 in rocks the age of earth is estimated at least 30 half life cycle of it = 2.4 billion years. Here one half life cyle of plutonium-244 is 80 million years.
By the presence of uranium-235 (at 1%level in rocks), whose half life cycle is 0.71 billions, the age estimated is around 14.2 billion years.
The lead-207 decay points the age around 6 billion years.
The geologists,taking several estimates into considerations, consider it to be around 4.5 billion years.
Earth is one of the 9 planets that circle around the Sun. With a diameter of about 13,000 kilometers, it is the fifth largest planet of th Sun, and circles at a distance of about 150 million kilometers from the Sun.
The earth estimated to be about 4.5 billion years old. Scientists estimate the age of Earth by estimating the age of oldest rocks found on earth. Age of the rocks is estimated by aid of measuring radioactive isotopes. All rocks contain uranium which gives out radiation, and in the process gets converted to earth. Longer the age of a particular rock more is the amount of lead in it. The scientists measure the amount of uranium and lead in the rocks and then estimate their age by the ration of uranium and lead contained in it. Age of the oldest rocks found on the earth estimated by this method is about 4.3 billion years old.