The team of 12 scientists from five countries found the objects, so small they looked like stars, hidden in the nearby Fornax cluster of galaxies, they said in a statement issued in Sydney.

The Fornax cluster is 60 million light-years away, "in astronomical terms,on Earth's doorstep", they said.

Michael Drinkwater, the team leader from the University of Queensland, said the galaxies belonged to a class dubbed "ultra-compact dwarfs" (UCD).

UCDs were unknown until the same team using the Anglo-Australian telescope in northwestern New South Wales state discovered six of them in the Fornax cluster in 2000.

The new discovery was formally announced Thursday at a meeting of the Royal Astronomical Society in Britain.

Drinkwater said researchers now believe the dwarf galaxies outnumber conventional elliptical and spiral galaxies in the central region of the Fornax cluster. Eight UCDs have also been found in the Virgo galaxy cluster, he said.

"It's likely that at least some are left-over examples of the primordial

building blocks that formed large galaxies by merging together," he said.

The scientists believe the UCDs are the nuclei of galaxies that were originally larger but have been stripped of their outer stars.

"It could be that they are very common, but scientists have overlooked them because they resemble nearby stars at first sight," he said.

Discovery of the existence of UCDs will help scientists trying to identify how much matter is in the universe and to understand the ways galaxies are formed.

"This is very exciting -- it will significantly advance our understanding of how galaxies form and evolve in environments where they are surrounded by swarms of other galaxies," said Joss Bland-Hawthorn of the Anglo-Australian Observatory.

Follow-up observations with the Hubble Space Telescope and the European Southern Observatory's Very Large Telescope revealed that while Ultra Compact Dwarfs have masses similar to those of previously known dwarf galaxies, they are much smaller -- about 120 light years across.

"Tens of millions of stars are squashed into what is a tiny volume by galaxy standards," the observatory said in a statement.

SPACE.WIRE