Around the third century BC in ancient Greece, produced a list that has reached our days. It lists a series of human constructions that were standing at the moment there are no elements or natural landscapes and ruins, and which together are known as the Seven Wonders of the World Classic. These constructs were: the Great Pyramid of Giza, the Hanging Gardens of Babylon, the Temple of Artemis Statue of Zeus at Olympia, the Tomb of Mausolus, the Colossus of Rhodes and the Lighthouse of Alexandria. Some of them are on record thanks to certain letters or more or less reliable evidence such as the Colossus of Rhodes, which is represented on coins of the time, but there is only one of the wonders he has reached our days in a condition good enough to get a reliable idea of \u200b\u200bhow it must have been over 2,000 years ago. This is the Great Pyramid of Giza.
It was built by Pharaoh Khufu, finishing the work in roughly the year 2,570 BC, becoming the first of the three Great Pyramids that can be found in the Necropolis on the banks of the Nile For 4,000 years, thanks to its 146 meters high, the Great Pyramid was the tallest building in the world, demonstrating the high capacity of organization and the great architectural knowledge, technical and craft that came to be in the Pharaonic era.
But to get to this level of complexity in construction, other pyramids were built before without reaching the majesty of the Great Pyramid, but that should be taken into account. A special mention deserves the Step Pyramid of Zoser, located in the necropolis of Saqqara and is considered the prototype of the Pyramids of Giza and other Egyptian pyramids. This work was the first real character monument built in honor of the Pharaoh Zoser, and is considered the very oldest stone structure in the world. In addition, notable for having found it the tomb of Pharaoh who in 1948 became the first sample tested in history by using the carbon-14 method.
Carbon-14 is one of the isotopes, ie one of the ways in which we find the carbon atom. By majority, in nature we find the isotope carbon-12, but in a very small proportion-around 0.001% - found traces of carbon-14, which differs from the previous it has two more neutrons in its nucleus and which is also radioactive. The fact that it is radioactive gives a number of features such as emitting ionizing radiation or have a half-life that is unique to each atom. This half-life is also known as half-life and is defined as the time required for half disintegrate nuclei were initially in a radioactive sample. For carbon-14, its half-life is 5,730 years, which means that if we measure the amount of the atoms in a sample and we returned to repeat as 5,730 years later, find exactly half of it.
Carbon-14 is generated in the atmosphere, which is in a constant ratio with carbon-12 that is mostly carbon dioxide, and through the process of photosynthesis is taken up by plants, thus entering the food chain making the ratio between two isotopes is constant in all living beings. However, after the death of any body, it ceases to incorporate carbon-14, which will begin to disappear at a rate that, as mentioned, will be marked by its half-life. So, if we measure the amount of radioactivity in a sample of organic origin, we able to calculate the amount of carbon-14 left in it and so we datarla.
Since the radiocarbon dating technique was setup in 1949 by a group of researchers from the University of Chicago, has become the most effective tool to date carbon samples containing up to 60,000 years. But neither has been in the sixty-year period of the controversy. His most controversial episode was trying to date the Shroud known as , although in this case the interests in one way or the other seems, as on many other occasions, they played a role that has nothing to do with science.
