How is the time period set up for the world in the reference to dates of 1400-2007 in definition of A.D &B.C

Explain how many years the earth has been here. Giving dates.

How is the time period set up for the world in the reference to dates of 1400-2007 in definition of A.D %26amp;B.C
The old professor says: A.D. are the initials of the term "anno-domini" Latin for "year of our Lord" B.C. stands for "before Christ". We no longer use B.C. but prefer BCE meaning "before the common era". Geologic time is too expansive for this, so we prefer to say BP or "before present".





Now to try to answer your question...renaissance to modern? End of medieval to present? 1400-2007 AD or 1400-2007 negative BC? or negative 1400-2007 BC? Also there is some problem here due to the fact there was no year "0" when going between BC and AD. Go figure!





As for the age of the Earth....no one can give dates or even years because the Earth formed over billions of years and is still evolving. We can not say exactly when the proto-planet/planetesimal phase stopped and the planet phase began. Evolving things are hard to pin down. The Earth started to form during the early accretion disk period and we are still accreting meteoritic materials to the tune of over 2 tons per day. Meteorite dates go back to 5.5-5.7 billion years, and if they were part of the original solar accretion disk, then the stuff the Earth is composed of is at least that old.
Reply:The earth has been here about 4.5 billion years based on uranium dating. There were no dates back then.
Reply:I am not sure I understood your question correctly.


It appears you are confused between AD/BC type of measurement of time with the geological time. The age of earth is about 4.6 billion years. Geological time scale is huge, as it measures an event in terms of million years mostly. AD or BC refers to the time of recorded history of human civilisation. Compared to geological time, the span of time for human history (less than 10,000 years old) is really negligible.

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