Astronomers have found the edge of the Milky Way at last
Our galaxy spans 1.9 million light-years, a new study finds
![Milky Way](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2020/03/032020_kc_milkway_feat.jpg?fit=1028%2C579&ssl=1)
In this image from the Fermi space telescope, the Milky Way's stellar disk, which runs horizontally along the middle, glows in gamma rays. A vast halo of dark matter engulfs the disk and emits no light at all, which makes measuring the galaxy’s total size a challenge.
Fermi LAT collaboration/DOE/NASA