Why rainbows are curved | | A rainbow isn't a flat 2-dimensional image on the dome of sky. It's more like a mosaic, composed of many separate bits ... in 3 dimensions. Visit this post for many beautiful rainbow images. | | |
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How the moon reveals the sun's mass | | How do astronomers determine masses for distant space objects? Here's one example - using the moon's orbit as a baseline to find the mass of our sun - from EarthSky's Bruce McClure. | | |
Tonight … Star-hop to the Coma star cluster | | Long ago, the Coma star cluster represented the Lion's tufted tail. Today, we know it as an open star cluster, whose stars were born together and are still loosely bound by gravity. | | |