Author Question: The primary way that we observe the atomic hydrogen that makes up most of the interstellar gas in ... (Read 102 times)

cnetterville · **on:** Jul 27, 2018

The primary way that we observe the atomic hydrogen that makes up most of the interstellar gas in the Milky Way is with ________.

A) radio telescopes observing at a wavelength of 21 centimeters
B) X-ray telescopes
C) space-based ultraviolet telescopes
D) ground-based visible-light telescopes

Question 2

To calculate the masses of stars in a binary system, we must measure their ________.

A) luminosities and distance from Earth B) orbital period and average orbital distance
C) absolute magnitudes and luminosities D) spectral types and distance from Earth