The person who wrote these words lived in the 1800s, many years before archaeologists could accurately date materials from archaeological sites using scientific methods.
Rasmus Nyerup's quote reminds us of the tremendous scientific advances which have taken place in the 20th century.
Willard Libby, the principal scientist, had worked in the team making the nuclear bomb during World War 2, so he was an expert in nuclear and atomic chemistry.
After the war he became very interested in peaceful applications of atomic science.
All plants and animals on Earth are made principally of carbon.
During the period of a plant's life, the plant is taking in carbon dioxide through photosynthesis, which is how the plant makes energy and grows.
After twice that time (about 11000 years), another half of that remaining amount will have disappeared."Everything which has come down to us from heathendom is wrapped in a thick fog; it belongs to a space of time we cannot measure.We know that it is older than Christendom, but whether by a couple of years or a couple of centuries, or even by more than a millenium, we can do no more than guess." [Rasmus Nyerup, (Danish antiquarian), 1802 (in Trigger, 19)].Libby of the University of Chicago after the end of World War 2.Libby later received the Nobel Prize in Chemistry in 1960 for the radiocarbon discovery.