Astronomers Discover Ghostly Galaxy Dominated by Dark Matter

The nearly invisible Candidate Dark Galaxy-2 challenges our understanding of galaxy formation.

Apr. 12, 2026 at 7:41am

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A highly textured, abstract painting in muted tones of blue, purple, and grey, featuring sweeping geometric shapes, intersecting waveforms, and precise spiral patterns, conceptually representing the complex structures and forces within a dark matter-dominated galaxy.An abstract visualization of the ghostly, dark matter-dominated Candidate Dark Galaxy-2, challenging our understanding of how galaxies form and evolve.Columbus Today

Astronomers have discovered a mysterious galaxy, dubbed Candidate Dark Galaxy-2 (CDG-2), that is almost entirely made of dark matter. This faint, elusive object was found nestled within the Perseus galaxy cluster, hidden from traditional telescopes. The discovery was made by analyzing data from the Hubble Space Telescope and using sophisticated statistical models to identify the galaxy's presence through a tight grouping of globular clusters.

Why it matters

CDG-2 represents a potential new class of galaxy that is dominated by dark matter rather than visible stars. If confirmed, this finding could challenge our current understanding of how galaxies form and evolve, potentially unlocking new insights into the nature of dark matter itself.

The details

To uncover CDG-2, a team of astronomers led by David Li of the University of Toronto applied a clever method. They analyzed data from the Hubble Space Telescope's PIPER survey, treating points of light as belonging to three overlapping populations: clusters drifting freely, clusters tied to normal galaxies, and clusters potentially linked to nearly invisible galaxies. By applying a sophisticated statistical model, they identified CDG-2 as a likely candidate for a hidden galaxy, with the odds of this configuration appearing by chance being about 1 in 67,000.

  • The discovery of CDG-2 was made in 2026 using data from the Hubble Space Telescope's PIPER survey.
  • The team used the Euclid telescope to independently observe the faint emission around the globular clusters, further confirming the existence of CDG-2.

The players

David Li

A researcher at the University of Toronto who led the team that discovered Candidate Dark Galaxy-2.

Hubble Space Telescope

The space observatory used to gather the data that led to the discovery of CDG-2.

Euclid telescope

The European Space Agency's space telescope that independently observed the faint emission around the globular clusters, confirming the existence of CDG-2.

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What they’re saying

“CDG-2 is 'almost definitively' a real galaxy, though spectroscopy from the James Webb Space Telescope could provide the final proof.”

— David Li, Researcher, University of Toronto

What’s next

The team plans to use the James Webb Space Telescope to conduct spectroscopy on CDG-2, which could provide the final confirmation of its status as a real galaxy.

The takeaway

The discovery of CDG-2 challenges our current understanding of galaxy formation and the role of dark matter in shaping the universe. If confirmed, this ghostly galaxy could unlock new insights into the mysterious nature of dark matter and force astronomers to rethink their models of how galaxies evolve.