Heat transfer by radiation
All objects transfer thermal energy by infra-red radiation. The hotter
an object is, the more infra-red radiation it gives off. No particles are
involved in radiation, unlike conduction and convection.
This means that thermal energy transfer by radiation can even work
in space, but conduction and convection cannot.
One good example is the sun. Even though it is millions of kilometres
away in space, we can still feel its heat. Radiation is how we can feel
the heat of the Sun.
The thermal energy is transferred by
You can read more on electromagnetic waves here.