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February 18, 2018

Here’s a phrase that you probably haven’t heard before: solar antapex. It’s the location in the sky that’s opposite the direction that Sun and Earth are moving through the galaxy. It’s marked by the constellation Columba, the dove, which scoots quite low across the south on February nights.

Like all the other stars in the Milky Way, the Sun is orbiting the center of the galaxy. And its path is taking it in the direction of Vega, a bright star in the summer constellation Lyra. That direction is known as the solar apex. So the opposite direction is the ant-apex.

That point may be the most interesting thing about Columba, which is to the lower right of Sirius, the brightest star in the night sky.

The constellation was created in 1592 by a Dutch astronomer. He used it to fill in a gap between some brighter star patterns.

Columba’s leading light is Alpha Columbae, which actually is quite impressive. It’s perhaps four-and-a-half times the diameter of the Sun, and a thousand time the Sun’s total brightness. But it’s also 260 light-years away — a distance that dulls its luster. So as seen in Earth’s night sky, it’s not much to look at.

Over the ages, though, it’ll get brighter. The star is finishing up the original hydrogen fuel in its core. When the hydrogen is gone, the core will get smaller and hotter. That’ll cause the star’s outer layers to get bigger and brighter. So the dove will have something besides the solar antapex to set it apart.

Script by Damond Benningfield

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