Here's why:

* Conduction requires direct contact between molecules. In an empty space, there are no molecules to transfer heat energy.

* Empty space is a vacuum, meaning it's devoid of matter. Without matter, there's nothing for the heat to travel through.

Instead of conduction, heat transfer through empty space occurs via radiation. This involves the transfer of energy through electromagnetic waves, like infrared radiation.

Here's how it works:

1. Thermal energy in a hot object causes its atoms to vibrate and emit electromagnetic radiation.

2. Radiation travels through the vacuum of space at the speed of light.

3. When the radiation strikes a cooler object, it's absorbed by the object's atoms, causing them to vibrate more and increasing the object's temperature.

Examples of heat transfer by radiation:

* The Sun warming the Earth – The sun's energy travels through the vacuum of space via radiation.

* A campfire warming you – The heat from the fire reaches you through infrared radiation.

* Microwave ovens – They use microwaves (a form of electromagnetic radiation) to heat food.

So, while conduction requires a medium, radiation can transfer heat through empty space.