Before sunrise on a truly dark night, a faint glowing pyramid of light can rise from the horizon and fool observers into thinking dawn has arrived. That glow is the zodiacal light, sunlight scattering off a vast pancake-shaped cloud of interplanetary dust spread along the plane of the solar system. This episode explains why forward scattering makes the glow brightest near the hidden sun, why particles only 10 to 300 micrometers across and kilometers apart can still add up to a visible pillar, and how the gegenschein and zodiacal band stretch across the whole sky under pristine conditions.

We trace the debate over where the dust comes from, from the Poynting-Robertson effect that spirals grains into the sun to the Rosetta mission's COSIMA instrument attributing over 85 percent of the dust to crumbling Jupiter-family comets, and the Juno spac ...