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September 26, 2010

When astronomer Allan Sandage took the first picture of an object known as 3c48, he expected to see a cluster of galaxies. That's because 3c48 produced a lot of radio energy, which comes primarily from galaxies. Instead, though, the picture -- snapped 50 years ago today -- showed what looked like an average star.

And when Sandage and his colleague, Thomas Matthews, studied the object in more detail, it sounded like something out of Alice in Wonderland: curiouser and curiouser. For one thing, its spectrum -- a detailed breakdown of its light -- was unlike any star they'd ever seen. And for another, the star's light varied by about half from night to night -- an indication that it was small.

The astronomers called 3c48 a "quasi-stellar object" -- something that looked like a star but didn't behave like one. Soon, the name was shortened to "quasar."

A few years later, other astronomers found that quasars are a long way away. 3c48, for example, is about four billion light-years from Earth. For it to be so bright, it must be extremely powerful.

Today, quasars are thought to be powered by supermassive black holes in the hearts of galaxies. As matter spirals into such a beast, it's heated to millions of degrees, so it glows brightly. And some of the material is squirted back into space as high-speed jets, producing radio waves. The entire complex is smaller than the solar system -- but more powerful than an entire galaxy of normal stars.


Script by Damond Benningfield, Copyright 2010


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