hard
Which planet is so light for its size that it would float in water, given a big enough bathtub?
- Neptune
- Uranus
- Jupiter
- Saturn
Why D? And why not the others?
Correct answer: D. Saturn
Saturn is the only planet in the solar system less dense than water — its average density is about 70 percent that of water — because it is a vast, puffed-up ball of the two lightest elements, hydrogen and helium. Jupiter is the tempting choice since it is made of much the same gases, but its colossal mass squeezes its interior so hard that it ends up denser than water and would sink. Uranus and Neptune sound plausible as gassy outer worlds too, yet they are 'ice giants' rich in heavier water, ammonia, and methane, making both comfortably denser than water.
Source: NASA Science: Saturn facts (science.nasa.gov/saturn/facts/) and Britannica: Saturn