LONDON: Young galaxies, so faint that scientists struggled to prove they were there at all, have been discovered by aiming two of the world’s most powerful telescopes at a single patch of sky.

An international group of researchers has identified 27 pre-galactic fragments, dubbed “teenager galaxies,” which they hope will help understand how our own Milky Way reached adulthood.

Cambridge University scientist Martin Haehnelt said his team used the European Southern Observatory’s Very Large Telescope and the Gemini Telescope in Chile to monitor a section of the universe for 92 hours.

“The process was a bit like taking a photograph and keeping the shutter open for a very long time,” Mr. Haehnelt said. “If you expose the image for long enough, you see fainter objects, such as these proto-galaxies. We took the largest telescope we could and stared through it for as long as we were allowed.”

Light takes time to travel across the universe, and powerful telescopes can pick up light which reaches them from extremely far back in time.

In this case, the ultra-long exposure technique allowed scientists to see back 11 billion years or more — to two billion years after the Big Bang — when galaxies were still in their formative stages.

Unprecedented scope

Scientists said the scope of the discovery was unprecedented. “This is the first time that we’ve gone deep enough to detect the first building blocks of galaxies,” said Richard McMahon, an astronomer at Cambridge University who was not involved in the research but has carried out similar work.

He said the fragments discovered were so young they might more appropriately be called “baby galaxies.”

Whether babies or teens, the clusters make a compelling case for the theory that galaxies formed bit by bit instead of all at once, said Carlos Frenk, a cosmologist at Durham University in northern England who did not participate in the survey. — AP

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