Radio waves emitted from cold hydrogen gas clouds provides evidence of:
A. spiral arms extending across the entire Milky Way disk.
B. the central supermassive black hole.
C. dark matter.
D. unequal amounts of matter and antimatter.
Answer:A
Radio waves emitted from cold hydrogen gas clouds provides evidence of:
A. spiral arms extending across the entire Milky Way disk. B. the central supermassive black hole. C. dark matter. D. unequal amounts of matter and antimatter.