Monday, May 14, 2007

Old Star Doesn't Fade Away


Using the European Southern Observatory's Very Large Telescope, astronomer Anna Frebel and others have discovered that star HE 1523-1901 in the Milky Way is 13.2 billion years old! The entire Universe is estimated to be only 13.7 billion years old. Measuring the age of a star is very difficult. A big telescope like VLT can measure the ratios of uranium and thorium, determining age by decay rates. Fortunately HE 1523-0901 contains large amounts of these elements. This star formed when the Universe was only 500 million years old.

Last October in Nebulae we reported on galaxies formed shortly after the Big Bang. Since it is difficult to form a star without a galaxy, this implies that our Milky Way formed in less than 500 million years. The old hypothesis of a collapsing gas cloud can not explain how a galaxy formed so quickly. Current theories can not explain how heavy elements like uranium could have formed so soon.

When our telescopes look into the distant past of galaxies and quasars, we invariably find supermassive Black Holes. These huge singularities must be primordial, dating from shortly after the Big Bang. Size of a primordial Black Hole is limited by a horizon distance related to the speed of light. Early formation of galaxies is one more indicator of a changing speed of light.

Our galaxy contains at its centre a supermassive Black Hole. Thgis object has 2.6 million times the mass of our Sun. Growing evidence indicates that it was there before the galaxy. Our Milky Way formed around the singularity like a pearl from a grain of sand.

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3 Comments:

Blogger Kea said...

Wow, that's so cool! Will you be watching the NASA press conference on Tuesday re 'Dark Matter' discovery?

5:44 PM  
Blogger L. Riofrio said...

Things are busy here but I'll try. The press conference on "dark energy" failed to impress; this one looks better.

5:56 PM  
Blogger Kea said...

This comment has been removed by the author.

2:20 PM  

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