Here's why:

* Heat Transfer Methods: There are three main ways heat is transferred: conduction, convection, and radiation.

* Radiation: Radiation involves the transfer of heat through electromagnetic waves. These waves don't require a medium to travel, and they move at the speed of light (approximately 299,792,458 meters per second).

* Examples: This is why you feel the warmth of the sun, even though there's a vacuum of space between us. The heat from the sun travels to Earth as electromagnetic radiation.

Important Note: While the speed of light is constant in a vacuum, it can be slightly slower when traveling through other mediums, like air or glass. However, the difference in speed is usually negligible for everyday purposes.