If the Sun Explodes, We'll Have Just Enough Time to Scream
Then it will get very, very warm
The sun will blow up one day. And when that happens, the warm yellow orb at the center of our solar system will transform into a cooler — but still broiling — red giant. It will consume Mercury, Venus, and Earth. It’ll probably make Mars into a dessert. And yes, this will happen quickly. One day Earth will be there, and the next it will be gone. But don’t worry, there will be enough time for some suffering.
There’s a few things you ought to remember about the sun. Light that’s emitted from our host star takes eight minutes and 20 seconds to hit our planet. If the sun suddenly blew up, we actually wouldn’t know it happened for — you guessed it — eight minutes, 20 seconds — since even that explosive light show would only be traveling, at maximum, the speed of light. The death and destruction would follow very, very shortly after that.
But when the sun does blow up, it’s not simply going to extinguish like a small flame in a candle. It’s going to shoot out some really gnarly, very powerful stuff. All that energy — about as much as you would observe if you blew up a few octillion nuclear warheads — will almost instantly kill all life on Earth. Chances of survival will near zero.
Even if the Earth miraculously survived, and life found a way to go on without the energy from the sun, the resulting radiation would decimate the planet. A supernova 30 light years away would probably result in a destruction of the ozone layer and mass extinctions. A supernova 8.3 light-minutes away? Annihilation. Explosions would vaporize the surface of the planet facing the sun. The other side would hit temperatures 15 times hotter than the surface of the sun right now. The entire planet would probably disintegrate in a few days.
So, yeah, we’re not going to be able to walk it off.
Now, it’s also important to remember that perhaps we might actually feel the effects of the sun’s departure, even during those eight minutes of impending doom. If the sun exploded, Earth would no longer have a celestial body to rotate around. And when the center ceased to hold, the gyre would widen. There are more nuanced ways of considering how this would actually work from a math and physics perspective, but the general notion is that Earth would go from planet to spaceship to nothingness over the course of relatively little time.
Of course, you’re not supposed to worry about any of this. Our sun has only made it about halfway through its expected 10 billion-year lifespan. The sun is not going supernova tomorrow.