One person just has to hit a button and the nuclear holocaust would come. Scientists have run tests and simulations to understand what life will be like after the bomb.

Some people will survive. But life in the smoldering remains of a devastated World will be completely changed.

Moments after the atomic bombs hit, a hard black rain will fall. They will be thick, black globs with a texture like oil, and they might kill you.

There is enough radiation in that liquid to make changes in a person’s blood.

When a nuclear explosion goes off, it sends out a pulse of electromagnetic radiation that can shut down an electrical system or even the electric grid for an entire country.

The lights will go out and every refrigerator will shut down. The data on every computer will be erased. Worst of all, water treatment facilities will break down and we will lose clean drinking water.

The areas around the blast centers will be charged with an incredible amount of energy and will burst into flames.

Everything that can burn will burn. Buildings, forests, plastic, and even the asphalt in the roads will burn.

A dark cloud of smoke 15 kilometers above the surface of the Earth will grow and move, shifted by the winds, until it covers the entire planet, blocking out the sky.

With the sun blocked from the sky, the temperature will drop.

Depending on how many bombs are launched, this could be a devastating shift. In extreme cases, it is expected that the global temperature could drop by as much as 20 degrees Celsius.

Growing food will be all but impossible. Animals around the World will starve to death, and vegetables will wither and die.

A year after the bombs hit, some of the process put in motion by our contaminated atmosphere will start to tear a hole in the ozone layer. The World will be devastated by UV rays.

Plants will die around the World, and the living things that survive will struggle through crippling mutations of their DNA. Even the most resilient crops will become weaker, smaller, and far less likely to reproduce.

Billions of people will starve to death.

Those who survive will have to find ways to get food, but this will not be easy. People living by the ocean may have a slightly better chance because the seas will be slow to cool.

But life in the oceans will still be scarce. The majority of people who survive the explosions will not make it through the first five years. Food will be too scarce, competition too vicious, and most will die.

Even with food to eat, though, the survivors will have to struggle with widespread cancer. Shortly after the bombs hit, radioactive particles will go up into the sky and then fall down all around the World.

When they land, they will be so small and so spread out that we won’t be able to see them. But they will still be able to kill us.

During those first two or three years of frozen darkness, we can expect the World to be racked by stlrms unlike any we have seen.

Until things go back to normal, we can expect a near-constant rain to fall on the Earth in heavy storms. Hurricanes and typhoons will wreak havoc across the World’s coasts, and they will rage on for years.

Billions of people will die in the nuclear holocaust.

We can expect about 500 million people to die immediately in the explosions of the war. Billions more will starve or freeze to death while they struggle in the new World.

There is every reason to believe, though, that a hardy handful of people will make it through. Life will go on, and people will rebuild. But the World will never again be the same.