Cosmic Background Radiation
Cosmic background radiation explained in an easy to understand way:
Imagine waking up to the smell of a delicious dinner you cooked the night before. Just as the aroma lingers in your home long after the meal is finished, cosmic background radiation is like the scent that remains from the "cooking" of the universe during the Big Bang. The connection here is that both the smell and the radiation are remnants of an earlier event, with the aroma being the leftover evidence of your culinary creation, while the cosmic background radiation is the electromagnetic "scent" that fills the universe, indicating the Big Bang's occurrence billions of years ago.
Practice Version
Cosmic Background Radiation: The electromagnetic radiation left over from the big bang. Cosmic background radiation. It is the faint glow of light that fills the universe, a remnant from its very early stages after the big bang.