The text discusses the eventual fate of Earth as the Sun becomes hotter and brighter, making life impossible on the planet's surface. It explains how the Sun's increasing brightness is a result of its nuclear fusion process and the buildup of helium ash in its core. The text also outlines the delicate balance between the Sun's gravitational forces and nuclear reactions that keeps it stable. It estimates that life on Earth may become nearly impossible in about 500 million years.

• Earth's eventual fate as the Sun gets hotter and brighter
• The Sun's nuclear fusion process and the buildup of helium ash in its core
• The delicate balance between the Sun's gravitational forces and nuclear reactions
• Estimate of life becoming nearly impossible on Earth in about 500 million years