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![The low-surface-brightness galaxy CDG-2, shown in this image from the NASA/ESA Hubble Space Telescope, is dominated by dark matter and contains only a sparse scattering of stars. This galaxy is nearly invisible, but by using advanced statistical techniques, scientists identified it by searching for tight groupings of stars called globular clusters at the centre of this image. The Hubble observations include those from programme 15235 (W. Harris). [Image description: A field of space with a dozen white foreground stars and a number of small, yellow background galaxies.]](https://media.cnn.com/api/v1/images/stellar/prod/galaxy-field-of-low-surface-brightness-galaxy-cdg-2.jpg?c=16x9&q=h_270,w_480,c_fill)
