Carbon-14 is a radioactive isotope of carbon and has a half-life of approximately 5,730 years. This means that half of a given mass of Carbon-14 will decay into a non-radioactive element in 5,730 years. 100 kg of Carbon-14 today will become 50 kg of Carbon-14 in 5,730 years (the rest is nonradioactive), then to 25 kg 11,460 years from now, then 12.5 kg in 17,190 years, etc. Carbon-14 was used to date the ages of artifacts found in archeological digs. The increased burning of fossil fuels since the beginning of the Industrial Revolution has increased the amount of Carbon-14 in the atmosphere so scientists have had to find another way to accurately measure the age of ancient objects.