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Research suggests that heavier elements can be found in greater quantities closer to the center of a spiral or elliptical galaxy. Henry & Worthy (1999) summarized several measurements of ratios...
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#1: Attribution notice removed
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2020-06-01T14:13:49Z (over 4 years ago)
Source: https://worldbuilding.stackexchange.com/a/40483 License name: CC BY-SA 3.0 License URL: https://creativecommons.org/licenses/by-sa/3.0/