Who first used RR Lyrae variable stars to determine distances in our Milky Way galaxy?
a. Henrietta Leavitt
b. Edwin Hubble
c. John Glenn
d. Carl Sagan
e. Harlow Shapley
e
Physics & Space Science
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Two stars, Fred and Barney, are of the same size. Fred has spectral type F, while Barney has spectral type B. Which one is more luminous? What are their relative locations on the HR diagram?
What will be an ideal response?
Physics & Space Science
What is the direction of 
at point P?
A. A B. B C. C D. D E. E F. F T. Zero
Physics & Space Science
The only spacecraft to go into orbit around Jupiter was:
A) Voyager 2. B) Pioneer 10. C) Cassini. D) Galileo. E) Viking I.
Physics & Space Science
Potential energy belongs to a system, and not to a single object alone
Indicate whether the statement is true or false
Physics & Space Science