The spiral galaxy rotation curves provide evidence for dark matter because ....
Group of answer choices
The mass enclosed by the orbit keeps rising well outside the visible disk of the galaxy suggesting an extended dark halo
The rotation curve falls steeply with radius suggesting that most of the galaxy's mass is in the central supermassive black hole
They show that light is bent by the gravity of a large mass
The correct answer is:
The mass enclosed by the orbit keeps rising well outside the visible disk of the galaxy suggesting an extended dark halo