The North Star Is Changing

Polaris getting brighter over the centuries
By Matt Cantor,  Newser User
Posted Jan 28, 2014 12:31 PM CST
In this photo made by combining 264 20-second exposures, stars leave rings of light behind as they wheel around Polaris over Newfound Gap in the Great Smoky Mountains National Park, Dec. 1, 2013.   (AP Photo/Knoxville News Sentinel, Adam Lau)

(Newser) – Polaris is famed for its consistency, but the North Star we see today is brighter than it was in the 1800s. In fact, if historical records are correct, the star has gotten about 2.5 times brighter over the course of the past two centuries, researcher Scott Engle tells What's more, it may be 4.6 times as bright as it was in ancient times, the site reports.

But the star is among those known as Cepheid variables, which means it pulsates—and in the early 1990s, researchers found that it was actually dimming. About a decade later, however, Engle and his team discovered that it was getting brighter once again. Engle's research can be difficult, notes, because it requires old technology that can be hard to find. The high-tech digital camera on Engle's telescope was actually too sensitive to accurately measure the star's brightness, so "we have to beg, borrow, and steal to find people who use older photoelectric equipment," he says. (Read more Polaris stories.)

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