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Author Question: Why are all spiral tracers young? What will be an ideal ... (Read 19 times)

magmichele12

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on: Jul 27, 2018
Why are all spiral tracers young?
 
  What will be an ideal response?

Question 2

Most stars generate their energy by the thermonuclear fusion of ___________________ _ to form ___________________ _.
 
  Fill in the blank(s) with correct word


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sierrahalpin

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Reply #1 on: Jul 27, 2018
Answer to Question 1

Spiral tracers are young objects, formed recently, astronomically speaking. O stars, for example, live for only a few million years. Their typical orbital velocity is about 200 km/s, so they cannot move more than about 500 pc in their lifetimes. This is less than the width of a spiral arm. Because they don't live long enough to move away from the spiral arms, they must have formed there.

Answer to Question 2

hydrogen; helium


magmichele12

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Reply 2 on: Jul 27, 2018
Excellent

triiciiaa

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Reply 3 on: Yesterday
YES! Correct, THANKS for helping me on my review

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