nuclear-physics

Werner Heisenberg discovered the uncertainty principle during a hay-fever retreat, then led the Nazi nuclear program. His verified biography, including the contested Copenhagen meeting.

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.

One splits atoms to release energy; the other fuses them together. Both tap the same fundamental force — and both are transforming how we power civilization.

Atoms are almost entirely empty space. If you compressed all of humanity to nuclear density, the result would be about the size of a sugar cube. Here's the quantum physics behind why that doesn't work in ordinary matter, and where stars do it anyway.

Neutron stars pack more mass than the Sun into a sphere about the size of a city. This guide covers how they form, what lies inside them, how heavy they can get, and why pulsars, magnetars and neutron star mergers matter to physics.