Takeshi Kobayashi

The universe exists in a state of false vacuum, like water behind a dam. Behind it lies the true vacuum — an abyss with different laws. Normally, water can only seep through the pores in a thin trickle (a quantum effect), barely changing the level.

Light from a distant blazar, an active galactic nucleus whose jet points our way, travels for billions of years. Along the way, it triggers cascades of charged particles that the intergalactic magnetic field deflects sideways. This creates a blurred gamma-ray glow around the blazar: a secondary halo.