Hat are different types of testing done to define the length of time a fossil or artifact was found?

Question

like carbon-14 and etc.?

Answer 1

Carbon 14 can only be used to date things about 60,000 years old or younger.  this is due to the fact that to test with carbon 14 you need organic molecules and isotopes which do not last that long.  

Obviously there are similar methods like looking at other isotopes both radioactive and not to get dates.  Any known substance that is radioactive has some kind of radioactive decay which means that the date can be calculated by measuing half lives and things like that.

The best way to data fossils is actually biostratigraphy.  This is the most accurate way because you use the rocks and rock layers that the fossil was found in (and is adjacent to).  This gives you an idea of how old the fossil is because the organism was obviously alive when the rocks were being formed.  

The law of superposition states that any rock layer is older than the one above it and younger than the one under it.  This means that most of the rock layers in the world are dated accurately so any fossil will be easily dated using biostratigraphy.