Redshift Wrangler

Look back in time to the early universe using light from distant galaxies! As a Redshift Wrangler, you’ll examine data from the Keck Observatory and Hubble Space Telescope, looking for bumps and wiggles.  Using the tools of spectroscopy - the study of light across different wavelengths – we’ll use the bumps and wiggles to measure how big the universe was back when the light was released. That information, called the “redshift” of a galaxy, reveals in turn how galaxies evolve across oceans of time.

Learn More


18 and up







What you'll do

  • Help us find the bumps and dips in galaxy spectra that will reveal the redshifts, and therefore distances, of galaxies.
  • Help us spot problems in the automated modeling that our computers perform once we know a galaxy’s redshift.
  • Connect with other volunteers through the project’s bulletin board.


  • Time to get started: 5-15 minutes to complete the tutorial
  • Equipment: Web-connected device
  • Knowledge: None. The in-project tutorial provides all the instruction you’ll need.

Get started!

  1. Visit our project webpage
  2. Click on either “Task 1: Identify Spectral Features” or “Task 2: Check Spectra Fits”. They might not both be available.
  3. Complete the tutorial.
  4. Start evaluating data!

Learn More

Learn all about the science of Redshift Wrangler in our website’s Research section. Still want to know more? Check out the Education tab for links to more detailed discussions of spectra, the Early Universe, and more.

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On the left side of this wide image we see the bright white flash of the Big Bang. Along the top is a timeline. On the far right we see the universe as it is today, with spiraling galaxies floating about, evenly dispersed through black space. Along the bottom is the redshift scale, which starts at 1000 at the far right and ends at 1 at the present day. In the center of the diagram we see the phases of the universe: the rapid expansion in yellows and pinks, recombination at next the long Dark Age in deep blue from 400,000 years post Big Bang to 0.1 billion years. Next is the formation of the first astronomical objects, which extends through time to 1 billion years post Big Bang. In this period, the solid blue gives way to translucent irregular blobs with bright spots in their centers. This section is also labeled “reionization.” Where that label becomes “fully ionized” at 1 billion years, we see the first galaxies, which appear as little clusters of white spots. At roughly 4 billion years, the clusters of spots begin to be organized in familiar spirals.
This timeline describes how galaxies have changed since the first galaxies formed nearly 14 billion years ago. We can better understand the universe and our place within it by studying these far away - and long ago! - systems. The timeline begins with the Big Bang on the left and progresses forward in time to the right. The marker along the bottom tracks redshift, which we use to determine the distance light has traveled. This type of cosmic timeline helps us connect time and space - the left side of the timeline represents long ago in the past AND far away in space.
Credit: Redshift Wrangler website
At Redshift Wrangler, you’ll examine data that splits up light according to wavelength.
Longer wavelengths of light tend to look more red. Of course, the human eye can only see a narrow range of wavelengths, shown by the rainbow in the center of the figure.
Floating in the black of deep space we see a jaunty astronaut in a white suit. He is sporting a red cowboy hat. In his extended hand is a lasso, the looped end of which has encircled a rainbow colored spiral galaxy.
Infographic titled “What is Cosmological Redshift?” explains cosmological redshift, or the stretching of light waves due to the expansion of space between galaxies. The infographic is divided into three parts: When Space Expands, Light Stretches; Redder than Red; and Seeing the Past. Part 1 shows the universe expanding over time, while the wavelengths of light also expand as they travel through expanding space over time. Part 2 shows the difference in wavelength between emitted light (shorter wavelength) and received light (longer wavelength), using an illustration of the electromagnetic spectrum for reference. Part 3 illustrates the universe over time, showing the limit of Hubble’s and Webb’s views through space and time.
As the universe expands, light waves from distant galaxies stretch, becoming “redshifted.” The farther away the galaxies are, the greater the redshift. For a more thorough explanation, visit the and click on “view description.”
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