This week, we’re having a “supermoon”on Saturday night, one of three this year.
A supermoon is a full moon that occurs when the moon is close to Earth.
The moon’s orbit is not circle, but slightly oval shaped. That means the moon is closest to Earth at 225,804 miles and farthest away at 251,968 miles every month.
This week’s full moon will be a little larger, but in November we’ll have a supermoon, that’s the closest one of the year.
In the meantime, I want to feature the star Vega. As soon as it is dark on October evenings, look for the brightest star in the very high western sky. That’s Vega.
Right now it’s the second brightest star in the celestial dome in the early evening. Only Arcturus, which is very low in the western sky, is brighter.
Vega is about twice as massive and twice the diameter of our sun —almost 2 million miles in girth.
The main reason it’s so bright in our sky is because it’s relatively close, although it’s not exactly a weekend trip away. It is around 25 light-years away, (and one light year equals nearly 6 trillion miles).
Vega also spins on its axis crazily every 12 hours. If it was spinning a little faster it would break apart. By comparison, it takes our sun about a month to make one rotation.
What really makes Vega significant is that it marks the direction of “the solar apex.” That’s the direction the Sun travels as it orbits around our galaxy.
The Sun is dragging the Earth and the rest of our solar system in the general direction of Vega at a breakneck speed of just under 140 miles per second. We, of course, can’t feel the motion because it’s a constant speed, like cruising in an airliner. Even at half a million miles an hour, it will still take about 225 million years to make just one orbit around the center of our home galaxy.
So when someone asks you just where this world is really going, take them out to your backyard and point them in the direction of Vega.
Mike Lynch, amateur astronomer and broadcast meteorologist for WCCO radio in Minneapolis, is author of “Stars, A Month by Month Tour of the Constellations,” published by Adventure Publications.
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