October 7, 2008--National Science Foundation's Mayall 4-meter telescope captured a spectacular intergalactic collision in the Virgo Cluster, some 50 million light-years from Earth.

The elliptical galaxy M86 (right) and the disturbed spiral galaxy NGC 4438 are linked by 400,000 light-year-long filaments (red) of ionized hydrogen gas.

Scientists say such colossal collisions could explain why star formation shuts down in the universe's biggest elliptical galaxies. Gravitational interactions may keep gases hot so they can't cool down and spawn new stars.