Dark matter

1\. Which of the above graphs best shows the v-against-r relationship for planets orbiting the Sun?

(b)B

2\. Which of the above graphs best shows the v-against-r relationship observed for stars orbiting the centre

of a galaxy?

( (a) A

3\. Physicists can calculate the mass of the Sun using their measurements of the radius of

(d) a planet's orbit and the planet's speed.

4\. When astronomers measure the mass of the galaxy Triangulum using the Brightness Method, the result they get is much less than when they measure the mass using the Orbital Method. This fact can best be explained by the fact that

(c) the galaxy Triangulum contains a large amount of unseen mass.

5\. Observations that indicate the presence of dark matter have been made in

(c) every galaxy that has been examined for dark matter.

6\. Evidence for dark matter comes from observations of

((b) the orbits of stars and gravitational lensing.

7\. The mass found by gravitational lensing agrees with the amount of mass found by

(a) the Orbital Method.

8\. Dark matter is called "dark" because it

(d)does not emit or reflect any type of radiation or light.

9\. Most physicists think that most dark matter is made of

(a) WIMPs or axions.

10\. Which of the following is true?

(a)Physicists have some ideas about dark matter, which they are currently tested by experiments.