Author Question: The greatest rift valley system yet found is ________ on Mars. Fill in the blank(s) with correct ... (Read 25 times)

future617RT · **on:** Jul 27, 2018

The greatest rift valley system yet found is ________ on Mars.

Fill in the blank(s) with correct word

Question 2

The first attempt to map the Galaxy via star counts was done by

A) William Herschel in the late eighteenth century.
B) Edwin Hubble with the new 100 Mt. Wilson telescope in the 1930s.
C) Harlow Shapley with the RR Lyrae variables in 1920.
D) Edward Barnard with long exposure photos about 1900.
E) Galileo in 1612.