Galaxies born the same way as snowflakes

Tuesday, February 22, 2011

SYDNEY - Giant galaxies that contain billions of stars are born in much the same way as delicate snowflakes, scientists say.

Professor Duncan Forbes, from the Swinburne University of Technology (SUT), has provided the first direct evidence to support a theory of galaxy formation that he has likened to the birth of a snowflake.

Forbes and his team analysed data from three telescopes in order to help confirm this galaxy formation theory proposed last year by German astronomer Ludwig Oser and colleagues, the Monthly Notices of the Royal Astronomical Society reports.

What weve found is that galaxies form in two phases. Firstly, an inner region of stars is formed from collapsing gas. This region then acts as a core, or ’seed, around which the galaxy grows as the result of stars which are acquired from other smaller galaxies, he said, according to a SUT statement.

Snowflake formation requires a ’seed’ to get it started. In the case of snowflakes, that ’seed’ is a microscopic dust grain. Having a core from which to build upon is comparable to the formation of a giant galaxy, Forbes said.

Then, in much the same way as water vapour accumulates to grow the snowflake, small galaxies and their stars are accreted onto the galaxy core, he said.

The astronomers based their conclusions on observations of the massive elliptical galaxy NGC1407, one of the largest galaxies in the southern skies with over 10 billion stars.

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