radioactivity

The Red Forest surrounding Chernobyl's reactor number four registers up to 100 microsieverts per hour in some areas — enough to deliver a full year's worth of normal background radiation in approximately one hour. Yet in Ramsar, Iran, people have lived for generations in homes that sit on naturally radioactive hot spring mineral deposits delivering up to 260 millisieverts per year — more than 80 times the global average background dose — with no statistically detectable increase in cancer rates. Radiation is one of the most misunderstood topics in public science communication. Understanding the most radioactive places on Earth requires understanding what radiation actually is, how it is measured, and what dose levels actually pose health risks.

In 1896, Henri Becquerel accidentally discovered radioactivity when uranium salts fogged a wrapped photographic plate in the dark. Learn the full story of what happened next.

In 1932, James Chadwick proved the neutron exists in just 10 days of experiments using polonium, beryllium, and paraffin wax. Learn exactly how he did it.

Ernest Rutherford discovered the atomic nucleus, named alpha and beta radiation, and mentored 11 future Nobel laureates. His biography, gold foil experiment, and legacy.

Carbon-14 dating lets scientists calculate the age of once-living organisms with remarkable accuracy. Here is the physics behind how a radioactive isotope became archaeology's most powerful clock.

Marie Curie's biography, discoveries, and verified quirks: radioactive notebooks, radium in her pockets, two Nobel Prizes, and the scandal that nearly ended her.

Atoms are not all stable. Some nuclei spontaneously transform, emitting radiation as they go. The process powers nuclear medicine, reveals the age of ancient artifacts, and tells us the age of the Earth itself.

Marie Curie's discovery of radioactivity and isolation of radium revolutionized physics and chemistry. The first woman to win a Nobel Prize, she sacrificed health for science.

Radioactive decay provides Earth's internal heat, drives plate tectonics, and powers the magnetic field. If it stopped, Earth would cool, tectonics would cease, the magnetic field would die, and life would face increased radiation. Over billions of years, Earth would become a cold, geologically dead world.