Star light, star bright and getting brighter
07:58 PM CDT on Monday, May 31, 2004

By ALEXANDRA WITZE / The Dallas Morning News
 
 

DENVER – Julius Caesar might have said he was as constant as the northern star, but it wasn't much of a boast. Over the last two millennia, the star Polaris has brightened by 250 percent, astronomers announced Monday.

And they can't explain why.

"It should not be getting that bright that fast," said Edward Guinan, an astronomer at Villanova University in Pennsylvania. "It's not behaving as expected. It's kind of scary."

Scientists knew that Polaris was inconstant but in a different way. About every four days, the star increases and decreases ever so slightly in brightness.

But the new work is the first to examine the star's overall brilliance during the last 2,000 years. Dr. Guinan and his colleagues scoured ancient literature, reading star catalogues back to the one compiled by Ptolemy in the 2nd century.

By comparing those studies with modern observations, the astronomers measured the true brightness of Polaris. The team reported its findings in Denver at a meeting of the American Astronomical Society.