The Planet That Could (Almost) Float
It sounds like science fiction, but one planet in our solar system is light enough that, in theory, it could float in water.
Image source: NASA Science
That planet is Saturn—a gas giant made mostly of hydrogen and helium, the two lightest elements in the universe. Its average density is about 0.687 grams per cubic centimeter, which is lower than water’s 1 gram per cubic centimeter.
According to NASA, that means Saturn “could float in a bathtub, if such a colossal thing existed.” But as scientists point out, that’s more a thought experiment than a real possibility. A bathtub big enough to hold Saturn would have so much pressure at its depths that liquid water couldn’t exist—it would collapse into something closer to plasma. And Saturn itself, being a ball of gas with a dense metallic core, would lose its shape long before it could actually “float.”
Still, the comparison highlights just how light and diffuse Saturn truly is. Even though it’s the second-largest planet in the solar system, it’s also one of the least dense—proof that not everything massive is heavy.
Learn more about the science behind Saturn’s surprising density.Heard another science fact that sounds impossible but checks out? Post it in the forum—we love discoveries that make you think twice.
