Hi Anna,

To figure out how many Plutos would fit inside the Sun, we just need to compare the volumes of Pluto and the Sun. If we assume that both Pluto and the Sun are spherical, then their volumes can be determined from V=(4x pi x R^3)/3. The radius of the Sun is about R=695,000 km, so the volume of the Sun is about V=1.4x10^18 km^3. I wrote this down in scientific notation (the x10^18 part) because it is kind of a pain to type 1,400,000,000,000,000,000 (I hope I counted my zeroes correctly!). The radius of Pluto is about R=1153 km, so Pluto's volume is about 6.4x10^9 km^3. If we divide the volume of the Sun by the volume of Pluto, we get about 2.2x10^8, which means that 220,000,000 Plutos would fit inside the Sun.