A nuclear warhead is a weapon of incredible destructive power, capable of wiping out entire cities. In the event of an all-out nuclear war on human civilization as we know it, the end is likely to come. But what happens if all superpowers unleash their entire nuclear arsenal at once at a hypothetical enemy?
The explosive power of a nuclear weapon is usually measured in kilotons, or thousands of TNT. Thus, the power of the bomb dropped on Hiroshima is estimated at 16,000 tons of TNT. The warhead aboard the Minuteman III intercontinental ballistic missile has a yield of 300 kilotons. And the B83 free-fall nuclear bomb, carried by the B-2 stealth bomber, has a yield of up to 1.2 megatons or 1200 kilotons.
In addition to huge arsenals in the United States and Russia, nuclear weapons belong to China, Britain, France, Israel, Pakistan, India and North Korea. In total, there are about 15,000 nuclear weapons in the world. Individually, each of these weapons can deal incredible damage. The Kurzgesagt channel estimates that if the world's stockpiles of nuclear weapons were used evenly and hit large cities, then in total they could kill 3 billion people. And if you pack them in a single warehouse and blow them up, the explosion will be equivalent to the eruption of 15 Krakatoa volcanoes.
The detonation of such a warehouse would create a fireball 50 km across, which would turn 4830 square kilometers into a scorched wasteland. It will be followed by a mushroom cloud 48 km high. When the nuclear storm dies down, a nuclear winter sets in - ash and dust particles flying up into the sky will fall into the upper atmosphere and create suspension. It will block sunlight, which is why the temperature in the region (and maybe on the entire planet, given the magnitude of what has happened) will begin to slowly decrease from year to year.
What if humanity extracts all the uranium on the planet (about 35 billion tons) and turns it into a weapon? Well, that's enough to create 10 billion tons of bombs similar to those dropped on Hiroshima. Their joint explosion will be comparable to the impact of an asteroid, which at one time made the planet unsuitable for dinosaurs - people will also be in trouble, unless they will be able to go deep underground in time. Even the ISS crew will not be safe, because the shock wave will reach Earth's orbit.