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Home Q & A Board Science-Related Homework Help Physics
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doit_the_clown doit_the_clown
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7 years ago
Why is it strange to find spiral arms in spiral galaxies (see Fig. 16-4, Comins and Kaufmann, Discovering the Universe, 7th Ed.)?
A)   Spiral arms require new stars, and previous new stars should have already used up all of the interstellar medium; no new stars should be forming now.
B)   The variations in speed of the stars across galaxies are not high enough to twist the shape of the arms into a spiral.
C)   There is no known mechanism to generate spiral arms.
D)   The motions of the stars and differential rotation of the galaxy should have wound their arms tightly and made them blend and disappear.
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Discovering the Universe

Discovering the Universe


Edition: 7th
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Only two things are infinite, the universe and human stupidity, and I'm not sure about the former.

Albert Einstein
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papachulopapachulo
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7 years ago
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doit_the_clown Author
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7 years ago
You make an excellent tutor!
jaray75
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Thank you, thank you, thank you!
riptide
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2 hours ago
Thanks
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