I think I messed up by not telling you how the universe cools down let's fix that the Universe started with a bang a big bang right after it was super hot like a cosmic oven but as it expanded it began to cool down kind of like taking a hot pizza out of the oven and letting it sit over billions of years as galaxies formed and stars were born the universe kept stretching and cooling imagine blowing up a balloon more space inside means less heat packed in today the universe is around 2.7 de Kelvin almost absolute zero that's colder than any winter on Earth and guess what it's still cooling down so next time you feel a chilly Breeze remember the whole universe is cooling off one Cosmic second at a time stay curious space fans