Ages of millions of years are all calculated by assuming the rates of change of processes in the past were the same as we observe today—called the principle of uniformitarianism.If the age calculated from such assumptions disagrees with what they think the age should be, they conclude that their assumptions did not apply in this case, and adjust them accordingly.

Like all elements, gold is an atom that gets its identity from tiny particles: positively charged protons in the nucleus, balanced by negatively charged electrons all around, plus neutrons, which have no charge at all. It's virtually indestructible, yet also soft and malleable.

Taking a step was impossible as it made the pain worse, and he suffered from almost permanent headaches.

In such pain and so depressed, the man who formerly 'felt so happy about life' tried to take his own life.

Every day she receives hundreds of samples of earth taken from the mine. …then pulverized to the consistency of baby powder. But two rows above gold is another metal of antiquity that looms large in our lives: copper; symbol Cu; atomic number 29—29 protons, 29 electrons. Bronze helped to spur global trade, and, once forged into tools and weapons, it played a defining role in the empires of antiquity. I'm here because they're about to cast several bells.

This rock face is about a quarter mile below the surface, and, according to John Taule, it's loaded with gold, somewhere. That's where Gayle Fitzwater and the assay team come in. I think I've seen one of these machines at Starbucks. It is, perhaps, the most emotional of the elements. Tin added in small amounts to copper makes bronze, the first manmade metal alloy. This is The Verdin Company, a 170-year-old family-run business in Cincinnati, Ohio.