The distance to the galaxy from Earth, derived by surface brightness fluctuation, is 19±1.7 Mpc. Due to close proximity, it is assumed to be associated with the elliptical galaxy NGC 1052 and to lie at a distance of about from NGC 1052.. On 3 June 2019, however, a separate team used a full observing dataset on the same object to review this claim, and found out that the actual distance of the galaxy was different, and that it may contain dark matter after all. A more recent study on NGC 1052-DF2 suggests the previously reported distance of the galaxy was greatly exaggerated. Consequently, the galaxy now looks "normal" in every way. Using five independent methods to estimate distances of heavenly bodies, a team of researchers from the Instituto de Astrofísica de Canarias found the correct distance of NGC 1052-DF2 to be 42 million light years, not some 64 million light years from the Earth. The total mass of the galaxy is around one-half of the mass estimated previously, but the mass of its stars is only about one-quarter of the previously estimated mass. This implies a significant part of NGC 1052-DF2 could be made up of dark matter, like any other galaxies.
Dark matter
The apparent lack of dark matter in NGC 1052-DF2 may help prove that dark matter is real: If what appears to be dark matter is really just a currently unknown effect of the gravity of ordinary matter then this apparent dark matter should also appear in this galaxy. Further study will be needed before this and any other possible implications can be confirmed. If confirmed, the absence of dark matter may also have implications for theories of galaxy formation, as dark matter has been thought to be needed for galaxy formation. A later study purports to show that the galaxy may contain more dark matter than initially reported. It may have a mass-to-light ratio towards the low end of expected values for a dwarf galaxy. However, a follow-up study on 20 March 2018 and a new discovery of a second ultra diffuse galaxy, NGC 1052-DF4, also apparently lacking dark matter, challenges the prior study's conclusion.
Other similar galaxies
Astronomers discovered a second Galaxy with no dark matter, NGC 1052-DF4, which is another ultra diffuse galaxy - quite large, spread-out, and faint to observe. Discovering another galaxy with very little to no dark matter means the chances of finding more of these galaxies are now higher than cosmologists previously thought.
