science π New star stream could crack the dark matter code
Astronomers discovered the first known extragalactic globular-cluster stellar stream, named Oyashio, located 115 million light-years away. This stream was spotted by the Hubble Space Telescope inside the ultra-diffuse galaxy UGC 9050-Dw1. Researchers determined this ribbon of stars provides the first stream-based constraint on the dark matter halo of such a galaxy. By analyzing its shape, scientists estimated the dark matter mass surrounding UGC 9050-Dw1. Future telescopes might find more streams to help measure dark matter density in distant galaxies. π