Glue – but make it galactic-grade! 💫 Most galaxies rotate so fast that gravity generated by gas and stars alone is not enough to keep them together. Dark matter is thought to be the invisible glue that holds these galaxies together – making up the bulk of the universe’s matter. When researchers found a galaxy lacking the invisible stuff – it would have the potential to upset theories of galaxy formation and evolution. With observations collected by NASAHubble, astronomers found that this ghostly galaxy doesn’t appear to have a central region, spiral arms, or a disk – and contains about 1/400 of the amount of dark matter expected by astronomers. Sitting almost as wide as the Milky Way galaxy and about 72 million light-years away, this oddball galaxy contains only 1/200 of the number of stars as our galaxy. The observed number of stars accounts for most of the galaxy's gravity. Credits: NASA, EuropeanSpaceAgency, STScI, Zili Shen (Yale), Pieter van Dokkum (Yale), Shany Danieli (IAS)...