Post by glactus on Oct 14, 2008 6:24:01 GMT
The Cartwheel galaxy
The Cartwheel Galaxy (also known as ESO 350-40) is a lenticular galaxy about 500 million light-years away in the constellation of Sculptor. It is about 150,000 light-years across, with magnitude at 15.2
The galaxy was once a normal galaxy like the Milky Way before it underwent a head-on collision with a nearby galaxy. When the nearby galaxy passed through the Cartwheel Galaxy, the force of the collision caused a powerful shock wave through the galaxy, like a rock being tossed into a sandbed.
Expanding at a rate of more than 300,000 km/h, this cosmic tsunami left a burst of new star creation in its wake. Images taken by the Hubble Space Telescope, including the one shown here, have resolved bright blue knots that are gigantic clusters of newborn stars and immense loops and bubbles blown into space by supernovae.
The Cartwheel’s old spiral structure is beginning to reemerge, as seen in the faint arms or spokes between the outer ring and bull's-eye-shaped nucleus.
The ring contains at least several billion new stars that would not normally have formed in such a short time span and is so large – 150,000 light-years across – that our entire Milky Way Galaxy would fit inside it.
Credits: This is a NASA/Hubble image