Due to the lapse in federal government funding, NASA is not updating this website.

Suggested Searches

 

1 min read

Conditions During the Era of Reionization (Illustration)

Four-part illustration. Top left: Tiny teal irregular blobs appear over a lighter medium blue background. Top right: The irregular blobs are all bigger, and the middle two are overlapping. Bottom left: Bigger irregular blobs that still have varying sizes, many adjoining. Bottom right: Continuous dark blue background has hazy spiral shapes across the scene.

More than 13 billion years ago, during the Era of Reionization, the universe was a very different place. The gas between galaxies was largely opaque to energetic light, making it difficult to observe young galaxies. As stars and young galaxies continued to form and evolve, they began to change the gas around them. Over hundreds of millions of years, the gas converted from neutral, opaque gas to ionized, transparent gas.

What allowed the universe to become completely ionized, leading to the “clear” conditions we see in the present-day universe?

Researchers using the James Webb Space Telescope found that galaxies are overwhelmingly responsible toward the end of this period. Read about their findings.

  • Release Date
    June 12, 2023
  • Science Release
    NASA’s Webb Proves Galaxies Transformed the Early Universe
    Read the release
  • Credit
    Illustration: NASA, ESA, CSA, Joyce Kang (STScI)

Downloads

  • Full Res, 5584 × 2167
    png (1.27 MB)
  • Full Res, 5584 × 2167
    jpg (633.75 KB)
  • 2792 × 1084
    jpg (272.21 KB)

Related Images & Videos

Thousands of tiny galaxies appear across the black expanse of space. The galaxy colors vary. Some of the smallest galaxies are shades of orange and pink. Most galaxies are so distant they appear as single points of light. At the center is a pink object with six diffraction spikes. This is quasar J0100+2802. It appears slightly smaller than the foreground stars, which appear blue.

Quasar J0100+2802 (NIRCam Image)

There are more than 20,000 galaxies in this field. This James Webb Space Telescope view is found between the Pisces and Andromeda constellations. Researchers using Webb anchored their observations on quasar J0100+2802, an active supermassive black hole that acts like a beacon....

Six galaxies appear in boxes, three by two. All carry an EIGER label at top left. The galaxies look like faint smudges: faint paintbrush strokes with dots, or small points of light. Most appear in pinks and reds, though a few contain some purple or blue.

Distant Galaxy Samples Near Quasar J0100+2802 (NIRCam Image)

The James Webb Space Telescope has returned extraordinarily detailed images and spectra of galaxies that existed when the universe was only 900 million years old. “In Webb’s near-infrared image, we can see structures in every individual galaxy that the telescope detected,”...

Quasar J0100+2802 image with compass arrows, scale bar, and color key.

Quasar J0100+2802 (NIRCam Compass Image)

This image centered on quasar J0100+2802, captured by Webb’s NIRCam (Near-Infrared Camera), shows compass arrows, scale bar, and color key for reference. The north and east compass arrows show the orientation of the image on the sky. Note that the relationship between north and...

Share

Details

Last Updated
Aug 28, 2025
Contact
Media

Laura Betz
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
laura.e.betz@nasa.gov

Illustration Credit

NASA, ESA, CSA, Joyce Kang (STScI)

Related Terms

Keep Exploring

Discover More Topics From NASA

James Webb Space Telescope

Space Telescope

Science Overview

Webb Observatory

Webb Image Galleries