Are gaps in the Andromeda galaxy filled with dark matter? This NASA telescope could find out 

 NASA's forthcoming Nancy Grace Roman Space Telescope will zoom in on streams of stars in the Andromeda galaxy to hunt for dark matter. 

https://cdn.mos.cms.futurecdn.net/zbjGXZSys2MY8c2W3HJgLH.png

https://www.space.com/gaps-andromeda-galaxy-dark-matter-nasa-roman-telescope