HW 1, Due Feb. 6
CID # ______________________________________________________
1) You want to estimate the number of planets in the Universe.
a) What three things do you need to “know”? (10 points)
b) List your estimates of these three things. (Saw how you got these estimates and give
a reference if needed) (10 points)
c) Calculate the number of planets in the universe. Show all work. Give your answer in
scientific notation. (10 points)
2) Calculate the number of meters in a light year. Show all work. Give your answer in
scientific notation. (10 points)
HW 1, Due Feb. 6
3) What is your zodiac sign? Is the constellation related to your zodiac sign visible
throughout the evening of your birthday? Why or why not? Use Stellarium to get your
answer. (10 points)
4) Assume a star has a mass of 1 solar mass.
a) What is the mass of 1 solar mass in kg? (You can look this number up on the
internet) (5 points)
b) What are the masses of a proton and a neutron in kg? (5 points)
c) Assume a star is made entirely of hydrogen (atomic mass of 1) and has a mass of one
solar mass. How many hydrogen atoms are in the star? Show all work. Give your
answer in scientific notation. (Do not use the mass of an electron in your
calculations.) (10 points)
d) Assume a white dwarf star is made entirely of carbon (atomic mass of 12) and has a
mass of one solar mass. How many carbon atoms are in the star? Show all work.
Give your answer in scientific notation. (Do not use the mass of an electron in your
calculations.) (10 points)