First Stars or Stray Stars? A Cosmic Infrared Mystery

Our sky is filled with a diffuse background glow, known as the cosmic infrared background. Much of the light is from galaxies we know about, but previous Spitzer measurements have shown an extra component of unknown origin.

Our sky is filled with a diffuse background glow, known as the cosmic infrared background. Much of the light is from galaxies we know about, but previous Spitzer measurements have shown an extra component of unknown origin.