During the daytime, the sun heats the surface and bubbles of air form and rise into the sky, like the bubbles on the bottom of a pan of boiling water.

白天，太阳将地表加热，空气团上升到天空中，如同一锅沸水锅底的气泡。

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Adam Block, program coordinator at the Mount Lemmon Sky Center at the University of Arizona, snapped his first Pan-STARRS picture March 10.

CNN: Stargazers capture images of comet