What in the Universe: Cosmic Microwave Background

Video Player

Video Versions

 What does this map of the sky from the Planck Space Telescope show? 

Produced by the Space Telescope Science Institute’s Office of Public Outreach in collaboration with NASA’s Universe of Learning partners: Caltech/IPAC, NASA Jet Propulsion Laboratory, Smithsonian Astrophysical Observatory, and Sonoma State University.

  • Planck Space Telescope image of the Cosmic Microwave Background:  ESA and the Planck Collaboration 
  • Map of the sky with constellations: Leah Hustak (STScI) 
  • Animation of photons: STScI (The Great Photon Escape https://www.youtube.com/watch?v=tSO8evHlafA)

Written by Margaret W. Carruthers 
Designed by Leah Hustak and Dani Player 
Editorial and design input from Claire Blome, Dr. Brandon Lawton, Leah Ramsay, Timothy Rhue II 
Music from Music for Nonprofits

Red square against starry sky. Icons, star, galaxy, constellation, asteroid, solar system. Text, what in the universe.
Image of spots of blue, red and orange. Text, this is a map of the entire sky.
It was made based on observations from the Planck space telescope.
What does this map show?
A., Dust clouds in the milky way, B., Exoplanets orbiting other stars, C., light left over from the big bang, D., gamma ray bursts from distant galaxies.
C is highlighted.
Planck space telescope, microwave light.
Cosmic microwave background, CMB. 380,000 years after the big bang. The entire sky glows with microwave radiation, a form of light that is invisible to human eyes. Images of constellations on map. The light, known as the cosmic microwave background, originated with the big bang, roughly 13.8 billion years ago.
At first, light bounced around, unable to escape the dense fog of particles that made up the very early universe. But over time, the universe expanded and cooled, clearing the fog.
Light was finally able to escape and travel the cosmos. It is this light that we detect as the Cosmic Microwave Background, the oldest detectable light in the universe.
The pattern of different colors on the map represents slight variations in temperature. Regions colored red are slightly warmer, while those in blue are slightly cooler.
These differences in temperature correspond to differences in density of the early universe. Cooler ares are denser, with more matter.
Warmer areas are less dense with less matter.
Researchers think that the cooler, denser regions are where the first stars and galaxies would later begin to form.
The Cosmic microwave background is like a fossil, an imprint that provides a view into the structure of the universe.