Below are the arguments Heber Curtis put forward in the Curt

Below are the arguments Heber Curtis put forward in the Curtis-Shapley debate on the nature of spiral nebulae. Which of these arguments are still regarded as basically correct? Select all correct answers; there may be more than one

-The spectra of spiral nebulae (absorption spectrum combined with an emission spectrum) could be explained as the spectra of normal stars plus the spectra of star-forming nebulae.
       - The Milky Way is about 15,000 light-years in radius.
       - Spiral nebulae have a band of obscuring material around them, just like the dark lane of the Milky Way.
       - The Sun is near the center of the Milky Way.

Solution

The correct answer is spiral nebulae have a band of obscuring material around them, just like the dark lane of the milky way.