Final answer:
The nine gigagram mass is one quintillion times heavier than the nine nanogram mass since gigagrams represent a much larger unit of mass than nanograms.
Step-by-step explanation:
The nine gigagram mass is heavier than the nine nanogram mass. A gigagram is a unit of mass equal to one billion (1,000,000,000) grams. In contrast, a nanogram is one billionth (0.000000001 or 10-9) of a gram.
To put it in perspective, nine gigagrams is 9 x 109 grams, while nine nanograms is 9 x 10-9 grams. Therefore, the nine gigagrams mass is massively heavier by a factor of 1018, or one quintillion times heavier than the nine nanogram mass.