The sun is around 4.6 billion years old. Our 4.6-billion-year-old sun will become a red giant in about 5 billion years after it burns up all the hydrogen at its core. By that time, it will have extended in size and swallowed up Venus and Mars, and Earth will be long gone.
In fact, the scientists note that Earth will be gone in about a billion years. That’s because every billion years or so, the sun becomes 10 percent brighter as it ages. The increased brightness will be enough to evaporate our oceans, making life on our planet impossible.
After becoming a red giant, the sun will its dying days turn into a planetary nebula, a massive ring of luminous, interstellar gas and dust left behind.
Picture Credit : Google