Developments in Brief : Galactic Speed Rate? Astronomically Fast

Clusters of galaxies appear to be moving through the universe at millions of miles per hour, propelled by explosions or unexplained gravitational pull, according to three astronomers.

Neta Bahcall, a top scientist with NASA’s Space Telescope Science Institute, said a recent examination of clusters of galaxies as large as the Milky Way indicate that while the universe appears to be expanding smoothly, the galaxy clusters seem to be moving at unexpectedly high speeds.

“The high-speed motions within these structures, which are superimposed on the smooth expansion motion of the universe, may be similarly caused by either gravity or explosions.

“In either case, the new observations change our view of the dynamics in the universe,” Bahcall said.

Galaxies are groups of billions of stars like the sun. The clusters may contain thousands of galaxies, which in turn can be grouped in “super-clusters.”

“The surprising high-speed motion within these super-clusters of galaxies may indicate the very strong gravitational attraction of a vast mass pulling on systems within the super-clusters,” Bahcall said.