Combining Newton's and Kepler's laws, we can weigh the Sun, ...

[bio_gurl]

Combining Newton's and Kepler's laws, we can weigh the Sun, provided we know:
 
  A) its density as found by spectroscopy.
  B) its temperature as found by Wien's Law.
  C) the size of the A.U. and exact length of the year.
  D) the Earth's mass and circumference.
  E) the exact timings of the transits of Venus and its diameter.

Question 2

Compared to Jupiter, Saturn's upper atmosphere is notably lacking in the element ________.
 
  Fill in the blank(s) with correct word

[beccamahon]

Answer to Question 1

C

Answer to Question 2

helium