Overview
Question 1 – Literary analysis (2 points) Explain what is astronomically inaccurate about the following quotation: “I am constant as the Northern Star, of whose true fixed and resting quality there is no fellow in the firmament.” (Shakespeare’s Julius Caesar ) Question 2 – Need for speed (5 points) a) The Solar System orbits the centre of the Milky Way galaxy in an approximately circular orbit, with a radius of 27,000 light-years and a period of 230 million years. Show that the orbital speed of the Solar System around the galactic centre is approximately 800,000 km/h. Show all your work, including for unit conversion. b) Why don’t we feel like we are going so fast? Question 3 – Solar density (7 points) This question provides another opportunity to practice simple calculations in scientific notation. a) Calculate the surface area of the Sun (in m2 ): A = 4πR2 , where R is the Sun’s radius. b) Calculate the volume of the Sun (in m3 ): V = 4π 3 R3 . c) Calculate the average density of the Sun, defined as total mass divided by volume (in g/cm3 ). How does this compare with the density of water? Question 4 – Seasons (5 points) a) When it’s winter the Northern hemisphere, what is the season in the Southern hemisphere? b) A common misconception is that in summer, the Earth is closer to the Sun than in winter. In one sentence, explain why this could not be true. c) In two sentences, explain why it is warmer in summer than in winter. Question 5 – Angular measurement (4 points) Which appears bigger, a golf ball (diameter 43 mm) held at a distance of 90 cm, or the full Moon as seen from Earth? Show your work. Question 6 – Annual parallax (3 points) A star’s annual parallax is measured as 0.25 arc-seconds. a) Show that the distance to the star is 4.0 parsecs. b) What is the distance to the star, in metres? Question 7 – Order of magnitude estimate (4 points) How many school teachers (K-12) are there in Ottawa? State your assumptions on class size, etc. We are only looking for the order of magnitude (power of ten).