The planet that has enough density to support the weight of a colony is Mars. Scientists have discovered that Mars is relatively similar to the conditions on Earth.
A planet's weight does not determine whether it can float in water. It's density is what determines that. Your question should be "Which planet's density is so small that it could float in water?"
Density of a planet = (Planet's mass) divided by (Planet's volume)
Saturn would float in water if you could find a big enough tub and the water to fill it.
The mantle is a part of a terrestrial planet or other rocky body large enough to have differentiation by density.
Certainly - all matter has density. The density of a gas planet would probably be less than that of a more solid planet but it would still have a non-zero density.
Mercury has the second lowest density of any planet in the solar system. Saturn has the lowest density of any other planet.
As far as we know, the Earth is the only planet fit enough to support life.
Earth's density: 5520 kg/m3 Saturn's density: 690 kg/m³
The planet with the lowest overall density is Saturn.
probably mars because it's not to cold nor to hot.
Saturn is the planet with a density less than water. Its average density is about 0.687 g/cm^3, whereas the density of water is 1 g/cm^3. This low density is due to Saturn being mostly composed of hydrogen and helium gases.
The least small and least rocky planet is probably Saturn. Saturn - as a whole planet - has a density less than water, meaning that if you could find a lake big enough to put it in, Saturn would float!