How do scientists and archaelogists date pyramids?

Answer 1

Oh this one is complicated...but ever so simple if you understand basic nuclear physics. So here is a crash course.

A normal carbon atom (carbon 12) contains 6 electrons in its energy shells, and 6 protons and 6 neutrons in its nucleas, or center. However, there is a radioactive isotope (variety) of carbon atom (carbon 14) that contains 2 extra neutrons (therefore 8) in its nucleas and they would like not to be there. (The 12 and the 14 refer to mass (weight) of the atom, keeping in mind the electrons add no measurable mass.)

Over a very long period of time, these extra neutrons escape through a process called nuclear fission, reducing each of the atoms back to normal carbon (C12). This occurs at a known rate called a half-life.

A scientist, such as a paleontologist or archaeologist can measure the remaining C14 found in the artifact or ruin and compare it with the normal amount of C14 existing in the area and determine how many years the structure or thing has been in existence, by the amount of C14 remaining.

This is called carbon dating.

It could be done with other radioactive substances but most break down too quickly to determine an accurate dating. The half-life of C14 is about 5700 years. This is the point where half the original amount will remain. In another 5700 years half the half will remain, and in yet another 5700 years, half the half the half will remain and so on. So you can see how it can be used almost indefinitely to measure elapsed time, since it never completely disappears.

Sure that's how organic material is dated but stone is not organic and therefore carbon dating does not work. (Any organic materials found in the vicinity doesn't necessarily prove when a structure itself was built)

So how DO they date them?

The ancient Egyptians were obsessive record keepers and references found pertaining to the building of structures (and their physical likeness, statues etc.) are dated by whichever dynasty was in power at the time. Problem with this is many Pharaohs would take credit for work done by their predecessors. To the point of defacing them and removing references to them and THEN rewrite the records and re-carve the statues. In some instances the preceding King was stricken from the records entirely.

Best guess in many cases are how they date ruins. Bbqman