I. For each question below, answer T for TRUE or F for FALSE.
F: 1. Cosmic rays travel in straight lines, like light.
(Paths are bent by magnetic fields.)
T: 2. The H-R diagram can be used with
spectral information to determine a star's distance.
(method is called "spectroscopic parallax;" see activity 10)
F: 3. Interstellar clouds must be made of gas,
since dust does not absorb light as well.
(Must be made of dust, since gas does not absorb light well.)
T: 4. Cepheid variables absolute luminosity varies with their period of oscillation.
(This was the point of one section in assigned reading.)
F: 5. Reddening is caused by red light scattered into light travelling through the interstellar medium. (Blue light is scatterd out, NOT red scattered in.)
F: 6. Most cosmic rays originate outside the Milky Way.
(Text mentioned this, and proceeded to calculate how many
times cosmic ray particles circled the galaxy before hitting Earth.)
II. Circle the term in parentheses that makes each sentence below correct.
1. Extrasolar planets found so far have been
(less/more) massive than the Earth. (MORE -- perturbs host star more)
2. The extrasolar planets that are easiest to
detect are those (close to/far from) the star they orbit.
(CLOSE TO -- perturbs host star more, and more quickly)
3. (Blue/Red) light scatters most easily. (BLUE)
4. (Parallax/Cepheid variables) can be used to
find the distances to other galaxies.
(CEPHEIDS -- parallax only works for nearby stars,
not ones in far away galaxies)