Jupiter's diameter is 142,857 km, compared to Earth's petite 12,391 km, making Jupiter 11.52 times wider: if we take Niels at 185 cm and give him a relative Earth height to Jupiter's diameter, he becomes only 16 cm tall. Or, just to be silly, we could imagine a Jupiter Man of Niel's relative proportions walking around Earth, who would be over 213 meters tall.)

However, Sender claimed to be the size of Great Britain, which was a good guess, since he/she/it seems to be shaped approximately like a 900 km long "flatworm"; about 200 km wide at the "head" and tapering away to a few km at the "tail", being roughly 80 km thick.

This is much greater than the relative size a Jupiterian "human" should be, and even a Blue Whale at 30 meters would only measure up to 3.5 km: Sender is proportionally 257 times larger than Earth's largest living creatures.