Billions of years from now, the Sun’s finale will turn the entire inner solar system into a very nasty place.

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The Sun is an ordinary star. It bathes the solar system with light and heat, making life possible on Earth. It’s as regular as clockwork, and it sets our daily life cycles in conjunction with Earth’s spin. Little wonder ancient peoples revered the Sun as a god. Yet the Sun will not always be steady and reliable. Billions of years from now, the Sun’s finale will turn Earth — and the entire inner solar system — into a very nasty place.

At 4.6 billion years old, the Sun is about halfway through its life. Its adulthood, called the main sequence phase, lasts 10 billion years. When the Sun runs out of hydrogen fuel, it must generate energy by fusing heavier elements.