Elliptical galaxies make up approximately 10-15% of large galaxies in the Virgo Supercluster. Elliptical galaxies are designated with the type En, with n equal to: where a is the galaxy's major axis and b is its minor axis. In general, elliptical galaxies range from E0 to E7. Beyond E7, an instability called the firehose instability occurs which causes the galaxy to buckle up and become rounder. The most common type of elliptical galaxy is E3. Well-known elliptical galaxies in our universe include IC 1101 (one of the largest known galaxies), M87, and Maffei 1.