Whispers from a primordial universe surround us with their spectral glow.
What did the universe look like in the beginning? How were the first galaxies formed? We are trying to answer these questions by observing the light that cosmic objects emitted billions of years ago.
Light from primordial galaxies has been traveling towards us since the first stars ignited. Along its journey, the entire space expanded, stretching its wavelength to redder shades. A fraction of this light was even absorbed and re-emitted by cosmic dust, which further deepened its red color. When it finally reaches us, the signal is so faint that is no longer visible to the naked eye; it is now an infrared background. Our telescopes can magnify and reveal this ancient light, telling us stories about the early days of our universe.
What we learn from different types of radiation