Skip to Content

How long would Earth last if sun blew up?

Quick Answer

If the Sun were to suddenly explode in a supernova event, the Earth would be bathed in intense radiation and heat that would start evaporating the oceans and stripping away the atmosphere in a matter of days. However, the planet itself would remain intact for somewhere between a few weeks and a few months before succumbing to the harsh conditions.

What Would Happen If The Sun Blew Up?

The Sun will not explode as a supernova for billions of years until it burns through all of its hydrogen fuel and starts fusing heavier elements in its core. However, if a supernova were to occur prematurely, it would have catastrophic consequences for the Earth.

A supernova occurs when a massive star runs out of fuel and its core collapses, triggering an explosion that sends a shockwave racing outwards at incredible speeds. This expanding bubble of gas can briefly outshine the rest of the galaxy it resides in.

If our Sun suddenly went supernova, the first effects felt on Earth would be a flood of high energy neutrinos and gamma radiation. These particles and rays would bombard the planet at the speed of light, instantly ionizing the atoms in our atmosphere and exposing everything at the surface to harmful radiation.

Next, the initial flash of the visible supernova light would arrive, heating up the ground and vaporizing anything it touches. The intense light could even ignite widespread fires over the planet’s surface. This supernova flash is so bright it would be visible even during daytime on Earth.

The expanding cloud of stellar gas would take longer to reach us, but once it does it would interact with our atmosphere and strip it away via ram pressure. This means everything on the surface would be exposed to the vacuum of space.

Without an atmosphere and magnetic field to protect us, the solar wind from the supernova would start to blow away Earth’s oceans and scour the crust. Given enough time, our planet could be reduced down to the bare core.

How Long Would It Take?

Based on simulations and our understanding of supernovas, the planet Earth would likely remain intact for somewhere between 2 weeks and 2 months before being rendered uninhabitable.

The initial neutrino and radiation blast reaches us in about 8 minutes, the same light travel time as sunlight. The visible flash arrives in about 12-36 hours. The slower moving ejected stellar gas takes 1-2 weeks to pass by Earth and finish stripping the atmosphere.

After the atmosphere is gone, the erosion of Earth’s surface by high energy particles could take anywhere from a few more weeks to a couple months. Some simulations show the complete evaporation of oceans happening over the span of about 58 days.

So while the planet might hold together for a month or longer, life on Earth would perish in a matter of days after the Sun goes supernova. The process is longer than the instant doomsday you might expect, but still relatively quick on astronomical timescales.

Could Anything Survive?

Given how extreme the conditions on Earth would become, it is highly unlikely any current lifeforms would survive if the Sun exploded. However, there are a few possibilities where life might endure:

  • Bacteria deep underground or ocean trenches could potentially ride out the event for a while.
  • Future humans with advanced technology and shelters may last for some time.
  • Seeds and spores in bunkers could be re-planted on an atmosphere-less Earth.
  • Colonies established on other solar system bodies like Mars could live on.

So while most surface life would perish, there are scenarios where the complete extinction of humanity and all biology could be avoided. Much of evolution could still be reset. But it would require planning and technology that does not exist today.

For most plants and animals the end would be inevitable if our star unexpectedly detonated.

Could We Prevent a Supernova?

While extremely unlikely to happen naturally, some far-future civilization may one day possess the power to intentionally induce their Sun to go supernova. Or they may worry about external threats like a nearby gamma ray burst triggering the event. Could the explosion be prevented in this case?

Some possibilities include:

  • Stellar engineering to safely dispose of nuclear fuel building up in the star’s core.
  • Powerful magnetic fields generated around the star to contain explosions.
  • Artificial lowering of the mass and pressure in the core through mechanically removing outer gas layers.
  • Forced fusion of material in the star to create harmless radiation instead of a supernova.

The energies involved in stellar processes are tremendous though. So practically engineering solutions to block a supernova may prove difficult even for an extremely advanced civilization.

More realistically, they may opt to migrate their civilization to another star system once detecting the unavoidable signs of impending doom in their own Sun. With enough notice, an advanced culture could preserve itself by moving to a safer home long before the supernova occurs.

Conclusion

Based on our current knowledge of supernovas and Earth’s environment, a sudden explosion of the Sun would devastate life on Earth within a matter of days. While the planet itself may hold together for up to a couple months, the harsh radiation and loss of atmosphere would kill most lifeforms very quickly. Surviving such an event would require extensive preparations like building underground shelters or establishing colonies off planet. So while the complete obliteration of Earth would take some time, the practical survivability for current life is low if our Sun blew up. Advanced future civilizations may find creative ways to prevent their star from exploding or otherwise survive the event using technologies we can only currently imagine.

Event Time to Impact Earth
Initial radiation blast 8 minutes
Visible flash 12-36 hours
Supernova ejecta arrival 1-2 weeks
Atmosphere stripped 2 weeks
Surface evaporation 2 weeks – 2 months