Materials that originally came from living things, such as wood and natural fibres, can be dated by measuring the amount of carbon-14 they contain.
For example, in 1991, two hikers discovered a mummified man, preserved for centuries in the ice on an alpine mountain.
Paleontology seeks to map out how life evolved across geologic time.
They believe that neutron radiation caused by an earthquake could have induced the image of a crucified man -- which many people believe to be that of Jesus -- onto the length of linen cloth, and caused Paul Carlsson, a paleometagenomicist working to establish his own career after an abusive childhood at the hands of his scientist father, has never known a world that wasn't 5,800 years old--a figure that, according to his father, had been proven by the Shroud of Turin, the magic bullet and the Kennedy assassination, Romanov bones and DNA matches, Hitler's skull, tracking the killer virus of 1918, testing the Titanic rivets, and identifying Osama bin Laden.
The layers of sedimentary rock, or strata, can be seen as horizontal bands of differently colored or differently structured materials exposed in this cliff.
The deeper layers are older than the layers found at the top, which aids in determining the relative age of fossils found within the strata. Such index fossils must be distinctive, globally distributed, and occupy a short time range to be useful.
The approximate time since the organism died can be worked out by measuring the amount of carbon-14 left in its remains compared to the amount in living organisms.
Carbon dating has a certain margin of error, usually depending on the age and material of the sample used.