The mystery of the missing mini-galaxies
"But the discovery of these galaxies also gave us hope that the most glaring small-scale failure of dark matter, the missing mini-galaxies, might actually have a solution. All we’d need to discover, then, would be the theorized tiny dwarf galaxies missing in intergalactic space.
Well, a new type of telescope was recently developed, the Dragonfly Telephoto Array, that uses eight telephoto lenses that can suppress internally scattered light to an unprecedented degree thanks to special coatings on them. This makes them ideal for detecting low-surface-brightness galaxies, the kinds of galaxies we were unable to detect before.”
On the largest scales — whether you’re looking at the cosmic microwave background, large-scale structure or gravitational lensing — there’s no viable alternative to a Universe with dark matter. But on the smallest scales, a number of predictions have gone unrealized for a long time. The worst culprit? The expectation of very small, low-surface-brightness dwarf galaxies as both satellites around larger galaxies and existing in isolation in what’s presently identified as intergalactic space. Three years ago, we had nothing, and now we think we’ve found the first examples of both missing populations. If the Hubble Space Telescope’s follow-up observations confirm this, dark matter will rule both the small-scales as well as the large ones!