Heat Death: The Cold, Dark, Lonely End to the Universe
Astrophysicist Katie Mack explains the concept of heat death, the most likely fate of our universe. Despite the name, heat death isn’t fiery — it’s a cold, desolate ending often called the Big Freeze. As entropy spreads and the universe expands, everything drifts further apart until no usable energy remains. Katie walks through how astronomers discovered in the 1990s that the universe isn’t slowing down but actually accelerating in its expansion — a strange result that makes heat death the leading theory for how it all ends.