## Got Calcium?

## 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

^{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

= (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 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,

- Each cow produces 1800 lbs = 816.5 kg per month or 26.3 kg per day for a 31-day month. (The conversion to days is not necessary, but is more meaningful.)
- With each glass of milk being 237 gm, each cow produces 111 glasses per day.
- All the cows in the U.S thus produce (8.44 x 10
^{6}cows) x 111 glasses/cow = 9.4 x 10^{8}glasses of milk per day. - With Cas A having the equivalent of 6.7 x 10
^{31}glasses of milk, it will take all the cows in America

^{31}glasses / 9.4 x 10

^{8}glasses/day

or

7.1 x 10

^{22}days

or

2.0 x 10

^{20}years

The universe is only 13.7 x 10^{9} years old.