around :32 it drifts out of focus, at :45 its focused back in. ~So here is a golden star that flashes red and green when it’s low in the sky. Why does it do that? The reality is that every star in the sky undergoes the same process as Capella, to produce its colorful twinkling. That is, every star’s light must shine through Earth’s atmosphere before reaching our eyes. The key is that, when you look at an object low in the sky, you are looking through more atmosphere than when the same object is overhead. The atmosphere splits or “refracts” the star’s light, just as a prism splits sunlight. That’s where Capella’s red and green flashes are coming from … not from the star itself … but from the refraction of its light by our atmosphere. When you see Capella higher in the sky, these glints of red and green will disappear.~
Posted on: Thu, 04 Sep 2014 09:46:01 +0000
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