The year 1950 was chosen because it was the standard astronomical epoch at that time. It also marked the publication of the first radiocarbon dates in December 1949, and 1950 also antedates large scale atmospheric testing of nuclear weapons, which altered the global ratio of carbon-14 to carbon-12.
Why cant we use carbon-14 to date objects older than 50000 years?
Carbon dating also cannot be used on artifacts over about 50,000 years old. These artifacts have gone through many carbon-14 half-lives and the amount of carbon-14 remaining in them is miniscule and very difficult to detect.
Why is carbon dating used?
What is Radiocarbon Dating? Radiocarbon dating is a method that provides objective age estimates for carbon-based materials that originated from living organisms. An age could be estimated by measuring the amount of carbon-14 present in the sample and comparing this against an internationally used reference standard.