Astronomers Making Observations in Our Galaxy Have Been Able to Rule

question 14

Multiple Choice

Astronomers making observations in our Galaxy have been able to rule out a number of suggestions for what the dark matter in the Galaxy might be. Which of the following have we NOT been able to rule out (which suggestion is still "in the running") ?

• A) black holes
• B) hydrogen gas that is at low temperatures compared to stars
• C) Jupiter-mass planets or brown dwarfs
• D) large quantities of dust (like we find in nebulae)
• E) a new kind of subatomic particle
• Section 25.4: The Center of the Galaxy