FAQs About Solar Expansion

Have you ever wondered what will eventually happen to our sun and solar system? In the very far future, Earth's source of energy, anchor and guiding light, the Sun, will gradually lose mass and expand as it grows into a red giant.

Q: When will the Sun expand and grow into a red giant?

A: Approximately 5 billion years from now, the Sun is predicted to grow into a red giant star, engulfing Mercury and Venus, and likely also devouring Earth and expanding to 200 times its current size.

Q: Why is the Sun growing into a red giant?

A: As the Sun exhausts the supply of hydrogen nuclear fuel in its core, it begins burning the hydrogen outwards and expanding, cooling, losing 40% of its mass and shifting its color toward the red spectrum.

Q: Do scientists know of other red giants in the universe?

A: Absolutely; in fact, Betelgeuse in the constellation of Orion is a well-known and visible red supergiant. The Sun is on the "main sequence" of stars, which includes many other ordinary red giants.

Q: What will happen to humanity and the earth if the sun expands?

A: 1 to 3 billion years from now, the increasing solar energy will evaporate the water on Earth; over time, the atmosphere and biosphere will also vanish, leaving a barren, molten rock. Humans have only existed for 200,000 years on Earth, and it is highly doubtful anything resembling a human will live on Earth in 1 billion years. Some scientists believe Earth will escape the Sun through a widening orbit, due to the decreasing mass of the Sun as it expands. Others believe that the Sun will simply absorb the Earth. In the near and foreseeable future, there is absolutely no need to worry about the impact of solar expansion on humanity and the Earth.