AST201H1 Study Guide - Electromagnetic Spectrum, Nucleosynthesis, Accelerating Expansion Of The Universe

A few multiple choice questions im having trouble with...

1. If a star formation switched off in a spiral galaxy, whichpartof it would get fainter? Bulge, disk, halo, dark matter orglobularclusters?

2. What is the essential difference between formation of spiralandelliptical galaxies?
a. random motions of stars are larger in ellipticals?
b. spiral galaxies had a more recent tidal encounter withanothergalaxy?
c. ellipticals form stars before they collapse; spiral formstarsafter they collapse?
d. spiral galaxies rotate faster
e. ellipticals had a more recent violent encounter withanothergalaxy?


3. The temperature of the background radiation is almost the sameinall directions
a. this is suprising, because the radiation from oppositedirectionsin the sky is comming from places that are beyong eachothers lighttravel horizon
b. this is expected because the big bang was a veryhomogenousexplosion
c. this was a measurement error in early observationsnowdiscredited.
d. the statement is not true, the temperature shows alargefluctuation all over the sky
e. none

thanks in advance!!!

The diameter of our disk-shaped galaxy, the Milky Way, is about 1.0 &times105 light-years (ly). The distance to the Andromeda galaxy , which is the spiral galaxy nearest to the Milky Way, is about 2.0 million ly. If a scale model represents the Milky Way and Andromeda galaxies as dinner plates 25 cm in diameter, determine the distance between the centers of the two plates.

The diameter of our disk-shaped galaxy, the Milky Way, is about 1.0 × 10⁵ light-years (ly). The distance to the Andromeda galaxy (Fig. PI.57), which is the spiral galaxy nearest to the Milky Way, is about 2.0 million ly. If a scale model represents the Milky Way and Andromeda

galaxies as dinner plates 25 cm in diameter, determine the distance between the centers of the two plates.