Scientific american carbon dating
Geologists, paleontologists and archaeologists have pieced together a fairly detailed account of how Earth and its inhabitants evolved.But just how do researchers determine the ages of the materials they unearth?
ANCIENT ARTWORK, such as this Chinese horse, can be evaluated using thermoluminescence.
Now, nearly 100 years after Boltwood's groundbreaking work, it is estimated that Earth formed at least twice as long ago as he had claimed.
The following summaries offer a quick introduction to some of the dating techniques researchers have been using to explore and reconstruct our planet's past, from 4.5 billion years ago to the present.
Indeed, just last month researchers described a fossil that pushes the origins of key mammal features back some 45 million years.
And last week scientists announced that new dates for an extinction event that claimed most of Australia's large animals show that humans, not the climate, wiped them out.
In the case of carbon 14, for example, the half life is only 5,730 years.