What is the only type of heat transfer that can travel through space

Radiation

Explanation:

Heat is a form of energy that can be transfered from one medium to another through three main different ways:

1: Conduction

2: Convection

3: Radiation

If we talk about the transfer of heat energy in space then it can happen only during radiation mechanism. This is because transfer through conduction requires direct contact with the source of heat, for example a heat pipe or a cylinder linked to a pipe. Moreover, in Convection mechanism there is a need of moving fluid or medium such as water or air. If we talk about radiation, they don't need a source in close proximity or a medium and there are photons which carry heat from one place to another in an empty space or vacuum.

Hope it helps!

yes its like the dead sea which is full of salt which makes you stay afloat

so yes an egg will float in salt