A remote sensing. monitors the electrical resistance of soils in a restricted volume near the surface of an archaeological site; buried walls or features can be detected by changes in the amount of resistance registered by resistivity meter.
Ground penetrating radar
Remote sensing. Radar pulses directed into the ground reflect back onto the surface. Showing prescence and depth of possible buried features.
At first the pyramids were dated historically according to hieroglyphics on the pyramids.
Due to speculation that the pyramids were actually thousands of years older Nakhla and Hawass decides to radiocarbon date the mortar that held the stones together since it contained pieces of charcoal.
The Charcoal actually gave them a date a 100 or so years older because of the old wood problem…