Washington, Aug 28 (IANS): NASA astronomers have for the first time caught a glimpse of the earliest stages of the massive galaxy construction.

The building site, dubbed "Sparky", is a dense galactic core blazing with the light of millions of newborn stars that are forming at a ferocious rate.

"We really had not seen a formation process that could create things that are this dense," said Erica Nelson from Yale University in New Haven, Connecticut.

"Sparky" produced roughly 300 stars per year, compared to the 10 stars per year produced by our Milky Way.

It is like a medieval cauldron forging stars with lot of turbulence and it is bubbling.

Astronomers theorise that this frenzied star birth was sparked by a torrent of gas flowing into the galaxy's core while it formed deep inside a gravitational well of dark matter - invisible cosmic material that acts as the scaffolding of the universe for galaxy construction.

The combined observations from NASA's Hubble and Spitzer space telescopes, the WM Keck Observatory in Mauna Kea, Hawaii and the European Space Agency's Herschel space observatory led to the discovery.

The team also scanned infrared images from Spitzer and Herschel, which allowed them to see how fast the galaxy core is creating stars.

"The discovery settles the question of whether this mode of building galaxies actually happened or not," concluded team-member Pieter van Dokkum of Yale University.

The study appeared in the journal Nature.