Parallax would be easier to measure if
a. Earth's orbit was larger.
b. the stars were farther away.
c. Earth moved faster along its orbit.
d. Earth's orbit was larger, the stars were further away, and Earth moved faster along its orbit.
e. None of the other choices are correct.
Question 2
Which of the following telescopes must be used above Earth's atmosphere?
a. an optical telescope
b. the VLBA telescope
c. an X-ray telescope
d. a radio telescope
e. None of the other choices are correct.