Carbon dating like techniques...Reliable or not??? Hello, As I have learned Carbon, uranium & other elements of radioactive nature are now used for dating how old an object is... I am wondering how does this technique work exactly & how reliable it is... The only samples which are the basis of our 4.5bln years old earth turn out to be Zircon crystals which have been dated as the oldest of our samples (4.5bln) using radioactive uranium... As I am a student of Geology I am willing to know more about the radioactive dating itself, which seems a very intriguing phenomena! Thank you for giving me your time.