Want to know the effect of a nuclear bomb on your home town? There's an app for that

Since the end of the Cold War more than 20 years ago, the prospect of nuclear Armageddon has gradually faded from the popular consciousness.

But with approximately 23,000 nuclear warheads still thought to be in existence, there is still more than enough nuclear firepower available to basically end life on Earth.

Now those interested in finding out how much damage a nuclear strike would cause in their home town can find out, thanks to a new online app.

This picture, taken from the Nukemap, shows the level of destruction that would be caused if the Tsar Bomba - the largest USSR bomb designed - was dropped on London

A wider view shows just how apocalyptic the circle of destruction would be

CIRCLES OF DEVASTATION: A KEY TO THE NUKEMAP DATA These figures are for the proposed 100megaton Tsar Bomba, the biggest bomb ever designed.

Fireball radius: 3.03 km / 1.88 mi

Maximum size of the nuclear fireball; relevance to lived effects depends on height of detonation.

Radiation radius: 7.49 km / 4.65 mi

500 rem radiation dose; between 50% and 90% mortality from acute effects alone; dying takes between several hours and several weeks.

Air blast radius: 12.51 km / 7.77 mi

20 psi overpressure; heavily built concrete buildings are severely damaged or demolished; fatalities approach 100%.

Air blast radius: 33.01 km / 20.51 mi

4.6 psi overpressure; most buildings collapse; injuries universal, fatalities widespread.

Thermal radiation radius: 77.06 km / 47.88 mi

Third-degree burns to all exposed skin; starts fires in flammable materials, contributes to firestorm if large enough. Source: nuclearsecrecy.com/nukemap



Alex Wellerstein, historian of science at the American Institute of Physics, has designed the Nukemap to show the scale of destruction nuclear weapons can cause.

The app, which uses Google Maps, allows users to choose any destination in the world and then drop a nuclear bomb of their choice on it.

Dragging the marker to London and detonating the Russian Tsar Bomba - at 100 megatons, the biggest bomb ever designed - shows just how terrifying the prospect of nuclear war would be.

A 100 megaton nuclear bomb would be equal to the effect of exploding 100milllion tons of trinitrotoluene (TNT).

According to Dr Wellerstein's calculations, the radius of the fireball would be 1.88 miles, obliterating everything from St Pancras in the north to Kennington in the south.

The radiation radius would stretch to 4.65 miles, coating the whole of London transport zones one and two with a 500 rem radiation dose, which would kill up to 90 per cent of people within weeks.

But most of them would already be dead thanks to the air blast radius of 20.51 miles, which would demolish even most heavily built concrete buildings as far afield as Enfield, Woking and Slough.

And even though the bomb was dropped in central London, the thermal radiation radius stretches to 47.88 miles - meaning people as far south as Eastbourne and as north as Cambridge would suffer third-degree burns and be trapped by firestorms.

This Nukemap image shows how a Tsar Bomba H-bomb would pretty much wipe the entire North West region off the face of the planet

Other shocking results in other parts of the country show how even the Yorkshire Dales and Sheffield could be wiped out with a blast in Manchester and Nottingham and Northampton affected by one in Birmingham.

Thankfully, Russian engineers lost their nerve before building the Tsar Bomba. Afraid of the global effects of such a massive explosion, they only ever tested a version of half the strength.

Nevertheless, that still caused an explosion bigger than would have been caused by a conventional bomb packed with all the explosives used in the Second World War.



Dr Wellerstein, who is a Ph.D graduate from Harvard University, says he uses the 'Nukemap' to bring help his students understand the implications of nuclear warfare.

'I've done different types of map based teaching for the students because I've found that students don't really have a sense of how big a nuclear explosion is,' said the 30-year-old, who lives with his wife in Washington, DC.

'What I like about the map is it makes the explosions look large and impressive but it shows it isn't the end of the world.

'I think a lot of people think a nuclear weapon goes off and everybody gets blown up or disappears.

'The reality is the buildings would collapse and you would be set on fire, which makes it real and scarier.'

If a Tsar Bomba were exploded over the centre of Birmingham, almost the entire Midlands would suffer

Dr Wellerstein, who specialises in the history of nuclear weapons, says because of Google Maps' limitations it isn't possible to calculate the scale of the death toll.

But he thinks it wouldn't be that hard to work out by taking into account the population sizes of the area you destroy.

'The calculations match historic events well. It matches Hiroshima almost exactly but they are approximations,' added Dr Wellerstein.

'You're talking about the effects it could have on different landscapes and whether the buildings are built from wood or concrete, but the map does give you a very good idea of what the major effects would be.'

A Tsar Bomba dropped in Glasgow would cause devastation from coast to coast in Scotland Of course, jokers will choose their least favourite town and drop the bomb just to see the effects, and Dr Wellerstein says humour is a good defence given the dark subject matter. He said: 'It has a response from people who say, "Haha I've just nuked my home town". But on the other hand you have the dread and that's very potent. 'It's a dark realisation, I've plotted a terrorist bomb at the capital where I live and thought "that's not very good for me" quite a few times.'

If Cardiff were to be targeted with a mammoth bomb, the effects would be felt across Devon and Cornwall

The Nukemap's reception has taken the historian by surprise - with a staggering 700 people using the app and 1,500 individual detonations within its first three days online.

And while people could accuse the 'Nukemap' of promoting violence, Dr Wellerstein says he only created the app to display facts and insists there is no political motive involved.

'Most of the people who talk about it are anti-nuclear protesters,' he said.

'They like it because it highlights the danger they create. I'm sort of in the middle on all this so I don't see it as having a particular message.