Your body achieves a higher power density than the Sun’s core because ATP production and the thousands of chemical reactions it drives are packed into the minuscule volume of trillions of cells, running at a mild 37 °C with the help of ultra-efficient enzymes. In contrast, the Sun’s core needs temperatures of 15 million °C and enormous pressure to fuse hydrogen at a relatively leisurely pace, producing far less energy per cubic centimeter. Gram for gram, your cells are far more intense energy factories than the heart of a star—making the human body, in this very specific sense, more powerful than the Sun.