Astro 250: Sample Exam #2 answers 1 - typo, replace Galaxy B with M51. Then the answer is b) 2 - c) but could argue for b) 3 - e) 4 - e) 5 - c) 6 - a) 7 - a) 8 - b) 9 - e) 10 - e) 11 - e) 12 - d) 13 - c) 14 - d) 15 - b) 16 - d) 17 - c) 18 - a) 19 - a) 20 - d) 21 - e) 22 - a) 23) a) matter that exerts gravity but does not interact with light; neutrinos are non-baryonic (but insufficient in number to be a big contributor) b) rotation curves of galaxies require a value of omega in excess of 0.1 - but 0.1 is the upper limit based on nucleosynthesis computations 24) without considering 'dark energy' the insistence that omega=1 for inflation to work, coupled with Ho=72, would mean that the Universe is younger than the stars it contains (one possible answer) 25) a) hot jupiters b) metallicity trends (others possible...) 26) a) 13.6 Gyr b) way bigger c) check your notes...