Even the Greeks and Romans realized that layers of sediment in rock signified old age. But it wasn't until the late 1700s -- when Scottish geologist James Hutton, who observed sediments building ...

There are three general approaches that allow scientists to date geological materials and answer the question: "How old is this ... magnetism in rocks can be used to estimate the age of a fossil ...

The glow we see from distant galaxies is as old as Earth’s ancient rocks One photographer put the age of starlight into perspective with stunning projections on some of Earth's oldest rock ...