An image of galaxy NGC 1052-DF2 taken by the Hubble space telescope. The lack of dark matter in the galaxy has stumped scientists. A distant galaxy that appears completely devoid of dark matter has baffled astronomers and deepened the mystery of the universe’s most elusive substance. The absence of dark matter from a small patch of sky might appear to be a non-problem, given that astronomers have never directly observed dark matter anywhere. However, most current theories of the universe suggest that everywhere that ordinary matter is found, dark matter ought to be lurking too, making the newly observed galaxy an odd exception.(Photo/Agencies)