What happens when a nuclear bomb explodes?

Vladimir Putin put Russia's nuclear deterrent forces on high alert in the last few weeks, citing "aggressive statements" by Nato and tough financial sanctions as a reason.

As of 2019, there were 15,000 nuclear weapons on planet Earth – 90 per cent of which belong to Russia and the United States, according to the Federation of American Scientists. In the improbable scenario of a full-scale nuclear war, humanity could be wiped out. That's not just a direct result of the number of deaths but also the aftermath of global cooling.

But what would happen if a nuclear bomb exploded?

There are so many factors to be considered to determine the impact: the time of day, the weather, the exact location and whether it exploded on land or in the air. Clothing is also a surprising aspect as white clothes can reflect some of the energy of a blast, while black clothing can absorb it.

The type and size of the nuclear weapon can also impact the outcome. Modern bombs start by triggering a fission reaction, according to Live Science. They explained: "Fission is the splitting of the nuclei of heavy atoms into lighter atoms — a process that releases neutrons. These neutrons, in turn, can careen into the nuclei of nearby atoms, splitting them and setting off an out-of-control chain reaction."

A fission explosion would be devastating – though many modern weapons have the potential to cause even more damage. Fission bombs, also known as atomic bombs, destroyed Hiroshima and Nagasaki, Japan, in 1945.

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If a nuclear bomb were to explode on land, the explosion would cause instant death. For example, a bomb equivalent to the size of the Hiroshima and Nagasaki bombs would kill 50 per cent of people in a 2-mile radius, according to a report from a Preventive Defense Project workshop. An air detonation is said to have a wider blast radius.

Causes of death go beyond the explosion itself. There would be fires, radiation exposure, collapsed buildings, flying shrapnel in a 0.5-mile (0.8 km) radius of the detonation.

In order to survive a hypothetical nuclear blast, you'd essentially want to avoid countries with access to nuclear weapons and those involved in nuclear agreements.

While worries are understandably high surrounding a nuclear war defence secretary Ben Wallace said Putin's phrasing was a "battle of rhetoric".

"This is predominantly about Putin putting it on the table just to remind people, remind the world, that he has a deterrent."

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