NASA announced on September 30, 2026 a new citizen science project called Overlap Zoo, which asks online volunteers to confirm and describe pairs of galaxies that appear to overlap in the sky so astronomers can study the dust inside them.
What the project studies
NASA said that every so often two galaxies line up from our point of view on Earth, or from a space telescope, and appear to overlap in the sky. According to the agency, these rare alignments give astronomers a chance to study something normally difficult to see: the dust inside distant galaxies.
The agency described the background galaxy as acting like a cosmic flashlight shining through the nearer galaxy, with the backlit dust creating dark silhouettes, like shadows on a screen. Studying those silhouettes lets astronomers map how dust is distributed throughout galaxies and learn how it blocks, scatters and dims starlight, NASA said.
NASA added that measurements of how dust affects light can even help astronomers refine estimates of the distances to faraway objects.
Why NASA wants volunteers
The bottleneck, according to NASA, is finding the galaxy pairs in the first place. Overlap Zoo is asking for public help with that search.
"As new and better observations of galaxies continue to multiply, it is becoming incredibly difficult for astronomers to classify every candidate galaxy pair," said Trevor Butrum, Overlap Zoo project lead and graduate student. "Your help is invaluable to creating the biggest and cleanest catalog of overlapping galaxy pairs for further analysis."
What volunteers do
NASA said volunteers view images that participants in the Galaxy Zoo project have identified as possibly containing overlapping galaxies. Overlap Zoo then teaches users how to verify the presence of galaxy pairs in those images, classify key features of each galaxy and mark their outlines.
Contributions will help build what NASA called the first large-scale catalog of galaxy pairs suitable for dust studies, and enable a step forward in the accuracy of astronomical estimates. The agency said no prior experience is needed and that the project is open to anyone with an internet-connected computer.
NASA illustrated the announcement with VV191a/b, which it described as a prime example of an overlapping galaxy pair, in an image credited to NASA, ESA, CSA and the JWST PEARLS Team.
What to do
- NASA says you can go to the Overlap Zoo project and begin classifying galaxy images right away.
- The project will teach you how to confirm that a pair of galaxies is present, describe key features of each galaxy and mark their outlines, according to NASA.
- NASA says participation requires only an internet-connected computer, with no prior experience needed, and you can classify as many images as you like.
Key facts and where they come from
- Overlap Zoo is a new NASA citizen science project focused on overlapping galaxy pairs.
That's the focus of NASA's new Overlap Zoo project.
- Backlit dust in the foreground galaxy creates dark silhouettes astronomers can measure.
The backlit dust creates dark silhouettes, like shadows on a screen.
- The project lead is graduate student Trevor Butrum.
said Trevor Butrum, Overlap Zoo project lead and graduate student
- Images shown to volunteers come from the Galaxy Zoo project.
you'll view images that volunteers in the Galaxy Zoo project have identified as containing possible overlapping galaxies
- Volunteers verify pairs, classify features and mark galaxy outlines.
verify the presence of galaxy pairs in these images, classify key features of each galaxy, and mark their outlines
- NASA says the effort will build the first large-scale catalog of galaxy pairs for dust studies.
Your contributions will help build the first large-scale catalog of galaxy pairs suitable for dust studies
- No experience is required to take part.
No prior experience needed – just curiosity and a few minutes of your time.