A team of Japanese astrophysicists have discovered a cluster of galaxies about 9 billion light years away from the Earth -- a discovery that could rewrite the conventional theory on the formation of galaxies.

The finding of the researchers from Tohoku University, Kyoto University and the University of Tokyo will appear in the July 10 edition of Nature magazine. The scientists say they detected X-ray emissions that indicate the presence of the galaxy cluster.

"This is the most distant galaxy cluster discovered by X-rays so far," the team said. It has generally been believed that galaxies are only 3 billion years old, but the latest finding disproves this theory.

The scientists based their conclusions on theoretical formulas for identifying distant stellar objects. They said they identified an extended X-ray source that bears the fingerprint of a distant galaxy cluster.