Okay so I understand at a very basic level how radiometric dating works, but I have a question. How do scientists know the half-life of isotopes, when some of them are measured in millions or billions ...

Geologists have calculated the age of Earth at 4.6 billion years. But for humans whose life span rarely reaches more than 100 years, how can we be so sure of that ancient date? It turns out the ...

When a researcher picks up an object — whether it’s a scrap of leather from a dig site, a fossil from a museum drawer or a newly fallen meteorite — their first question might be, “What is this thing?” ...