An image of the relatively close galaxy cluster Abell 2218 showed a collection of spiral and elliptical galaxies, along with about 120 filamentary arcs. |
Today, we can create computer models of how spiral and elliptical galaxies formed. |
The long-standing theory has been that spiral galaxies merge with each other forming most of the elliptical galaxies in the Universe. |
The Milky Way has about 100 globular clusters, whereas giant elliptical galaxies are surrounded by thousands of globulars. |
After losing the raw material needed for creating more supernovas, postcollision spiral galaxies become populated with aging stars, as are elliptical galaxies. |
However, BL Lac objects are the active cores of elliptical galaxies. |