Error in carbon dating
The radioactive carbon has six protons and eight neutrons in its nucleus, giving it a total atomic mass of 14.This atom is not stable, and will break down, releasing nuclear energy in the process.
The problem, says Bronk Ramsey, is that tree rings provide a direct record that only goes as far back as about 14,000 years.Usually a proton is knocked out of the nitrogen atom's nucleus and is replaced with the neutron.The proton takes an electron with it and becomes an atom of hydrogen.When they strike ordinary atoms in the upper atmosphere, the cosmic rays smash them apart. Some of these neutrons then collide with nitrogen atoms.This collision is less destructive than the initial collision that produced them.Marine records, such as corals, have been used to push farther back in time, but these are less robust because levels of carbon-14 in the atmosphere and the ocean are not identical and tend shift with changes in ocean circulation.
Bronk Ramsey’s team aimed to fill this gap by using sediment from bed of Lake Suigetsu, west of Tokyo.
Radioactive carbon (Carbon 14) is formed in the upper atmosphere as a byproduct of cosmic radiation.
Cosmic rays are positively charged atoms moving at enormous speeds.
The technique hinges on carbon-14, a radioactive isotope of the element that, unlike other more stable forms of carbon, decays away at a steady rate.
Organisms capture a certain amount of carbon-14 from the atmosphere when they are alive.
Archaeologists vehemently disagree over the effects changing climate and competition from recently arriving humans had on the Neanderthals' demise.