The Whirlpool Galaxy (M51) (see Figure 23-1 of Universe, 11th ed.(in the text) ) shows H II regions outlining the spiral arms. What causes their red color?
A) H II regions have the characteristic red Hα line excited by radiation from the large, hot, newly formed stars in the spiral arms.
B) These H II regions are dominated by red giants and supergiants.
C) The spiral arms are rotating rapidly away from us, and their radiation is Doppler shifted into the red.
D) Gas and dust in the plane of the galaxy cause interstellar reddening (extinction) as the light passes through the galaxy on its way toward us.
Correct Answer:
Verified
Q1: The Milky Way Galaxy:
A)contains almost all the
Q2: In size, the Milky Way Galaxy is:
A)one
Q3: The great debate involving the nature of
Q4: It is the year 1920 and you
Q6: The intrinsic brightness (represented by luminosity) of
Q7: How does the intrinsic brightness or luminosity
Q8: The Cepheid variables that Hubble observed in
Q9: A Cepheid variable is observed in a
Q10: A Cepheid variable is observed in a
Q11: A Cepheid variable is observed in a
Unlock this Answer For Free Now!
View this answer and more for free by performing one of the following actions
Scan the QR code to install the App and get 2 free unlocks
Unlock quizzes for free by uploading documents