Events: Nagasaki 70 years on

What if the 1945 "Fat Man" bomb was dropped on Melbourne today?

Following on from my "Trinity Day" post a few short weeks ago, a chilling reminder. It is now 70 years ago since, on August 9th, 1945, at 11:01:47am the Fat Man bomb exploded some 500m above Nagasaki, Japan, outright killing between approximately 39,000 and 80,000 people. The blast was estimated at around 20kt, and it set fires through the mostly wood and paper construction of the city that left it devastated, even before the radiation effects began to manifest.

What if a 10kt "dirty bomb" was detonated in downtown Melbourne?

Some very clever people at Stevens Institute of Technology, namely nuclear historian Alex Wellerstein developed  “NukeMap” which allows you to overlap various atomic and nuclear events over a regular GoogleMaps view. You've seen this kind of effect with the Sea-Levels which I discussed in my Rising Sea-Levels post. The NukeMap application demonstrates the estimated (and extrapolated from actual tests) effects of these weapons on built-up areas, including "Fireball radius", "20psi Air Blast radius", "5psi Air Blast radius", Radiation Radius" and "Thermal Radiation Radius", each with a descriptor of the kinds of damages you could expect to see, and survivability of those effects.

What if the currently deployed 800kt Russian "Topol SS-25" ICBM munition was dropped on Melbourne?

It also then overlays that with estimated population density in the areas covered by the various zones, and estimates immediate fatalities, and injuries. For explosions of either sufficient size, or proximity to the ground to kick up fallout (high air-busts hit harder, and wider, but don't kick up as much fallout, it's inefficient to do so, apparently), NukeMaps will also plot prevailing winds and density of fallout.

What if the currently deployed 800kt Russian "Topol SS-25" ICBM munition was detonated in downtown Melbourne?

You can pick your location, and from a variety of historically documented devices, from the North Korean tests, Pakistani and Indianweapons, the Trinity and WW2 bombs, all the way up through the Cold War era tests and production weapons, from estimated improvised terrorist weapons to the state-irradiating Tsar Bomba weapon.

Its a very sobering tool to visualize both the destructive capacity we have been capable of for the past 80 years, but also as a reminder of how fortunate we are to have only ever had these forces brought to bare in anger only twice.