The more accurate carbon clock should yield better dates for any overlap of humans and Neanderthals, as well as for determining how climate changes influenced the extinction of Neanderthals.
“If you have a better estimate of when the last Neanderthals lived to compare to climate records in Greenland or elsewhere, then you’ll have a better idea of whether the extinction was climate driven or competition with modern humans,” says Paula Reimer, a geochronologist at Queen’s University in Belfast, UK.
An “isotope” is any of several different forms of an element, each having different numbers of neutrons.
The illustration below shows the three isotopes of carbon.
Take the extinction of Neanderthals, which occurred in western Europe less than 30,000 years ago.
Archaeologists vehemently disagree over the effects changing climate and competition from recently arriving humans had on the Neanderthals' demise.
Bronk Ramsey’s team aimed to fill this gap by using sediment from bed of Lake Suigetsu, west of Tokyo.
Two distinct sediment layers have formed in the lake every summer and winter over tens of thousands of years.Atoms are made up of much smaller particles called protons, neutrons, and electrons.Protons and neutrons make up the center (nucleus) of the atom, and electrons form shells around the nucleus.Organisms capture a certain amount of carbon-14 from the atmosphere when they are alive.By measuring the ratio of the radio isotope to non-radioactive carbon, the amount of carbon-14 decay can be worked out, thereby giving an age for the specimen in question.Many people have been led to believe that radiometric dating methods have proved the earth to be billions of years old.