If you could find a bathtub big enough for Saturn, the planet would: a. precipitate more helium. b. float. c. explode due to its liquid metallic hydrogen. d. catch fire, as liquid sodium reacts with water. e. sink due to its metallic interior.
The correct answer and explanation is:
Correct Answer: b. float.
Saturn would float in a large enough bathtub of water because it has a very low average density. Saturn’s average density is approximately 0.69 grams per cubic centimeter, which is less than the density of water (1 gram per cubic centimeter). In physics, if an object is less dense than the fluid it is placed in, it will float. That is why the idea of Saturn floating in water is scientifically accurate, although hypothetical.
The planet Saturn is composed mainly of hydrogen and helium gases. These elements are very light, especially hydrogen. Despite Saturn’s massive size and volume, its mass is not very high in comparison. The gas layers and the small core mean its overall composition does not add up to a heavy planet. As a result, when compared to water, Saturn is less dense.
This comparison is only theoretical, since it would be impossible to create a bathtub large enough to fit a planet with a diameter of around 120,000 kilometers. However, it serves as a useful illustration of how low Saturn’s density is. No other planet in the solar system has a lower density than Saturn.
This low density is one of the unique physical characteristics of Saturn. It indicates that much of its volume is taken up by gases and not heavy solid materials. Planets like Earth, which are made mostly of rock and metal, have much higher densities and would definitely sink in water.
Therefore, if such a large body of water existed and could somehow contain a planet, Saturn would indeed float. This surprising fact helps explain how the gas giants are very different from the terrestrial planets in terms of composition and physical behavior.