What keeps the mantle hot?

It's an intriguing question indeed, "What keeps the Mantle hot?" The mantle, as we know, is the layer of rock beneath the Earth's crust, and it's responsible for a significant portion of our planet's internal heat. So, what exactly keeps this vast layer of rock simmering away? Could it be the residual heat left over from the Earth's formation billions of years ago? Or is there a continuous source of heat that keeps the mantle warm? Perhaps it's a combination of both. We also know that radioactive decay plays a role in generating heat within the Earth's interior. Could radioactive elements within the mantle be responsible for keeping it hot? Furthermore, tectonic plate movements and the movement of molten rock known as magma could also contribute to the mantle's heat. But how exactly do these processes work together to maintain the mantle's temperature? It's a complex and fascinating topic, and scientists are constantly studying the Earth's interior to better understand the mechanisms at play. So, what do you think keeps the mantle hot?