BULLETIN
Dark matter-free galaxy confirmed
The find challenges our knowledge of how galaxies form and stay together
A distant galaxy could throw our understanding of galactic formation into question, after recent Hubble Space Telescope measurements have bolstered previous claims that it’s free of dark matter.
According to our current understanding, galaxies are held together by a mysterious substance known as dark matter. Spheroidal galaxy NGC 1052-DF2 (DF2 for short), however, seems to be an exception to this rule. Although it is as wide as the Milky Way, the galaxy contains 200 times fewer stars, and initial measurements (made in 2018) suggest that it has 400 times less dark matter than astronomers think it should have – according to our current understanding of how galaxies grow and evolve.
An alternate possibility, however, is that the galaxy is closer than its initial measurement of 65 million lightyears. This would make it intrinsically fainter, meaning it has less mass and less dark matter.
