Cartwheel Galaxy

The Cartwheel Galaxy, also known as ESO 350-40, is a lenticular galaxy that is about 500 million light years from Earth. It is in the Sculptor constellation. It is about 150,000 light-years across, making it larger than the Milky Way galaxy. The galaxy is thought to have a mass of 3.85×109and it is rotating at km/s. It was discovered in 1941 by Fritz Zwicky.

At one time the galaxy was a spiral galaxy like the Milky Way. About 200 million years ago it was involved in a head-on collision with a smaller companion. When the nearby galaxy passed through the Cartwheel Galaxy, the force of the collision caused a powerful shock wave. The shock wave swept up gas and dust, creating a starburst around the galaxy’s center portion that were unscathed. Scientists have made observations that lead them to believe that the galaxy is returning to its original spiral form. The galaxy has recently been lit up by x-rays from recent star burst(star formation due to compression waves) action at the rim. The galaxy also has an unusually large number of blackholes along its outer borders giving off x-rays.

The Cartwheel Galaxy is a lenticular galaxy is between an elliptical galaxy and a spiral galaxy. Lenticular galaxies are disc galaxies that have used up or lost most of their interstellar matter and have very little star formation, so they consist of aging stars. They are difficult to distinguish from an elliptical galaxy if they are inclined face-on. Lenticular and elliptical galaxies share common properties like spectral features, scaling relations, and both are early galaxies that are quietly evolving. Eventually, all star formation will end and all of the stars in the galaxy will burn themselves out.