
Answers:
1. The mass of the Sun is 2.0 x 10^{30} kg. With the mass of
Cas A at 20 times the mass of the Sun, and 0.05% of that mass being
calcium, the amount of calcium in Cas A is
= (20 x 2.0 x 10^{30} kg) x 0.0005
= 2.0 x 10^{28} kg of Ca in remnant
2. The total number of glasses of milk is then
= total Ca in remnant / Ca in 1 glass
= (2.0 x 10^{28} kg) / (300 mg x 1kg/10^{6}mg)
= 6.7 x 10^{31} glasses of milk!
3. A number of web sites give the total milk production in the
United States. For example the
National Agricultural Statistics Service (http://usda.mannlib.cornell.edu/reports/nassr/dairy/pmpbb/) gives the monthly milk
production. From this, we learn that during March 2008, the average cow
produced about 1,800 pounds of milk, and there are 8.44 million milk cows in
America. So, performing one of the best astronomy calculations ever,
