StarDate: May 23, 2009

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The Sun is already a standout. It's bigger and brighter than about 90 percent of the other stars in the galaxy. As it ages, though, it'll gradually get even bigger and brighter. In several billion years, as it nears the end of its life, it'll puff up to giant proportions, so it'll outshine all but a handful of the Milky Way's other stars.

In other words, it'll look a lot like Arcturus, the brightest star of Bootes, the herdsman. Arcturus is high in the southeast at nightfall, and due south around midnight. It's one of the brightest stars in the night sky, and shines with a yellow-orange color.

Arcturus probably hasn't reached its full "gianthood" yet -- it's still puffing up as it continues to undergo changes deep in its core. It's burned through the hydrogen in its core to make helium, and it's probably started to burn the helium to make carbon. When it uses up the helium its core will get much hotter, and its outer layers will push out even more, making Arcturus even bigger.

Even so, it's already about 25 times wider than the Sun is. If it took the Sun's place in our solar system, it would cover an area more than 600 times greater than the Sun does as seen from Earth.

Not that anyone would be around to appreciate the spectacle. Even though Arcturus is a good bit cooler than the Sun, because of its great size it puts out far more energy. It would long ago have boiled away Earth's oceans and atmosphere, leaving a stripped, barren chunk of rock.

Script by Damond Benningfield, Copyright 2009

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