A nova occurs following the build-up of a thin layer of hydrogen on the surface of a white dwarf - a highly evolved star with the diameter of the Earth and the mass of the sun. The hydrogen is provided by a close binary companion. As the pressure in the layer of accreted hydrogen builds and the temperature reaches a critical level, it triggers a thermonuclear runaway. The light from the explosion significantly exceeds the star's normal brightness and the outer layers are ejected away at high velocities. Over time, the star slowly fades as the fireball expands and cools. The CHARA Array can image the expanding fireball at the earliest stages after a nova explosion.