APOD and General Astronomy Discussion Forum
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The word "etching" bothers me, since it suggests that the hydrogen is being obliterated in some sense. Surely it is simply being pushed aside? Or is there some chemical process going on there that would justify the term "etching"?The brilliant stars are carving deep cavities in the surrounding material by unleashing a torrent of ultraviolet light, and hurricane-force stellar winds (streams of charged particles), which are etching away the enveloping hydrogen gas cloud in which the stars were born.
The hydrogen is indeed just being blown, not altered. My reaction to the word choice is different than yours; the word in this context doesn't make me think of etching in a chemical sense, but in its more mechanical sense, like waves on the beach etching a pattern in the sand. This seems especially so given the use of "carving" at the beginning of the same sentence.rstevenson wrote:The word "etching" bothers me, since it suggests that the hydrogen is being obliterated in some sense. Surely it is simply being pushed aside? Or is there some chemical process going on there that would justify the term "etching"?
