The Milky Way grows its bar
The galaxy's centre stretches into a rotating bar of stars, reshaping everything that orbits it.
- When
- Known to
- ± 2 billion years
- Era
- Enrichment, Stelliferous
A bar forms across the Milky Way's core, a self-sustaining structure that funnels gas inward and drives stars to migrate far from where they were born — including, quite possibly, the Sun. Dating it is contested: stellar-migration and metal-rich-star analyses point to 8–10 billion years ago, while some dynamical models argue for far more recently. The uncertainty here is real rather than a rounding.