SourceData from two Hubble Space Telescope surveys shows star formation in the Andromeda galaxy has undergone a 500-million-year decline.
- Combined data from Panchromatic Hubble Andromeda Treasury and Panchromatic Hubble Andromeda Southern Treasury surveys mapping two-thirds of Andromeda's disk.
- Measured approximately 200 million individual stars across the galaxy.
- Star formation dropped from one solar mass per year 500 million years ago to one-fifth solar mass per year today.
- Identified satellite galaxy M32 as a likely suspect for interacting with Andromeda's disk roughly 60 million years ago.