Electromagnetic Pulse (EMP)?
What Is An Electromagnetic Pulse (EMP)?
An EMP is an invisible burst of electromagnetic energy, that’s a combination of electric energy and magnetic fields.
It travels at the speed of light, potentially affecting all of the devices with sensitive microelectronics it encounters.
Nuclear HEMP Weapon
When the USA was testing nuclear bombs in the 1950s, they noticed that nearby electronic equipment failed due to currents inducted in them from the resulting EMP.
It didn’t take them long to realise the potential of a nuclear EMP as a weapon and they soon developed the High-altitude Electromagnetic Pulse (HEMP) weapon. A nuclear bomb optimised for EMP output rather than outright destruction, detonated in the upper atmosphere for maximum EMP range.
A standard nuclear bomb generates an EMP of 50,000 volts per square metre but the optimised HEMP weapons are rumoured to generate up to 200,000 volts per square metre.
While the EMP is generated by a nuclear detonation, it happens so high in the atmosphere (250 miles / 400km) that it isn’t considered a nuclear event. The EMP reaches the ground but the nuclear residue remains high up in the atmosphere.
Non-Nuclear EMP (NNEMP) Weapon
The US military also has cruise missiles capable of emitting short range EMPs, without any nuclear component, designed to disable electronics in buildings and vehicles.
The Counter-electronics High-powered Advanced Missile Project (CHAMP) uses high power microwaves to knock out electronics in multi-story buildings.
Coronal Mass Ejection (CME) From The Sun
The Sun has a roughly 11 year cycle from the solar minimum to the solar maximum and the next solar maximum is due to happen in the back end of 2024. At the solar maximum the Sun’s north and south magnetic poles flip, starting the next cycle.
Processes in our sun occasionally produce something called a sunspot, which are visible on the surface of the Sun. These sunspots can occasionally eject billions of tons of coronal material and strong magnetic fields into space, which is known as a CME. Sunspot and CME activity is greatly increased leading up to the solar maximum.
A CME can travel through space at anywhere from 150 miles per second (250 kilometres per second) to 2000 miles per second (3000 kilometres per second). That’s anywhere from 15 hours to several days for the ejected geomagnetic storm to reach Earth if the direction is right.
When a solar storm hits the Earth’s atmosphere it creates the Aurora Borealis or Northern Lights. The process is basically the same as passing electricity through a neon sign. It looks amazing, but remember it is the result of Earth’s magnetic field protecting the Earth from loads of “very nasty space energy”.
When the energy hits the Earth’s magnetic field it charges it. This energy will naturally try to couple into really long antennas (think of a really long car aerial), in our case the power lines which make up the National Grid.
Unfortunately this energy has to go somewhere and that’s where the problems start. It has the potential to fry the power transformers which step down the high electricity voltage used on the grid to a lower voltage which can be used safely in our homes.
Large transformers are very expensive, not stored anywhere as a backup, take 1-3 years to make and there aren’t many places to source them from. If suddenly needed by multiple countries to repair multiple grids, we could be looking at a long time without grid power.
The big problem for individuals is what happens when the energy exits the grid into our homes. There is a chance that anything plugged in might be fried, especially if it is a modern device full of delicate microelectronics.
That’s your boiler, TV, washing machine, fridge, oven, Wi-Fi router and most likely your phone if it is plugged in to charge.
The last large CME to hit Earth happened in 1859 and was dubbed the Carrington Event by the astronomer who noticed it. It caused a massive Aurora Borealis lightshow across the planet and took down the telegraph system.
A less intense solar storm hit the Earth in 1989 and caused a complete blackout for up to 12 hours in a region of Canada called Quebec.
A large CME will hit the Earth again at some point in the future. It’s a matter of when, not if and the last big one in 2012 missed us by only 9 days.
Estimates vary, however the chance of a Carrington Event level CME hitting Earth are reported to be 12% per decade or roughly 1% per year. These statistics mean it happens on average every 100 years. The Carrington Event was 164 years ago so we are, unfortunately, overdue for another one.
NASA has a dedicated satellite called Solar and Terrestrial Relations Observatory (STEREO) watching for sunspots, so we might get some warning when one does end up heading in our direction.
On the plus side, if you are prepping to cope with a Sun CME or a WWIII EMP then you have almost certainly reached a level where many of the other SHTF scenarios are less problematic.
If you receive any warning of a CME heading towards Earth flip the main circuit breakers in your house to cut it off from the grid and then unplug all your appliances
What Is The Difference Between A Nuclear EMP And A CME EMP?
Quite a bit, as it happens. Let’s start with a worst case nuclear HEMP and the distinct three waves it generates:
E1: Instantaneous, spread across very low to very high frequencies and high voltage (couples to iPhones, laptops, cars, power station control systems etc.)
E2: Very fast and less powerful (similar to a lightening strike, less damaging)
E3: Slower and less powerful (couples to the power grid)
A nuclear HEMP produces all three waves, so it’s the worst case scenario. Small devices like mobile phones and cars are instantly affected, even though they aren’t plugged into the grid. The E3 wave then couples into the grid, taking out transformers and any devices plugged in to it.
On the plus side, a CME caused by the Sun is more likely and it only produces the E3 wave.
What Would An EMP Do To A Human?
The good news is, almost certainly, nothing. You wouldn’t hear it, see it or feel it and the only signs would be devices with sensitive microelectronics around you suddenly failing.
Hollywood depicts an EMP from a HEMP weapon as:
The lights flicker as the power from the National Grid shuts off
Your iPhone / iWatch suddenly shutting off, with no chance of re-starting them
The electronics in modern cars shutting down, causing the vehicles to slow to a final resting place
Planes and helicopters fall from the sky, as the electronics keeping them airborne fail
Would An EMP Stop A Plane?
Older planes, with purely hydraulic or cable controls, would potentially be fine. Finding somewhere to land safely without air traffic control could be the main issue.
Newer commercial planes, relying on fly-by-wire systems, could become uncontrollable but they are designed to be flight stable and would likely glide to the ground rather than pancaking straight down. Whether they happen to touch down in a nice open area, with minimal obstacles, is another matter.
Most military planes have some level of EMP hardening / shielding designed in, so are less susceptible.
What Would Survive An EMP?
A few factors make a device less likely to survive an EMP:
It relies heavily on sensitive microelectronics e.g. a home computer
It is connect to the national grid via a wall socket e.g. a TV
It is connected to an antennae e.g. a wifi router
Anything which doesn’t use electricity should be fine e.g. hand tools, manual door locks.
Vintage electronic devices, which use vacuum tubes instead of transistors, should also be fine e.g. an early radio.
Basic AA / AAA / 9V batteries should be fine but newer fancy batteries with integrated charge controllers could suffer damage.
Older cars / motorbikes, which don’t rely on digital fuel injection or electronic engine management systems, could be completely unaffected however they are increasingly rare.
Power tools with very simple motors should be unaffected.
Has An EMP Weapon Ever Been Used?
Sort of. The two nuclear bombs dropped on Japan by the USA in WWII did have an EMP component, although it wasn’t considered to be the main point of the bombs at the time.
An optimised HEMP weapon was tested in 1962 by the US military 250 miles (400km) above the ground and roughly 900 miles (1,450km) from Hawaii. It was codenamed Starfish Prime and yielded an EMP far higher than expected.
No dedicated HEMP weapons have been used in a warzone to date but some smaller non-nuclear EMP (NNEMP) weapons have been deployed e.g. to take out Iraqi TV in 2003.
Further Research On YouTube
Practical Engineering - A really in depth look from an Engineer at the grid reliant systems like water, natural gas and sewage.
Physics Girl - A look at Coronal Mass Ejections (CME) from a Physicist.
EMP Doctor - A really unique overview of EMP threats and how they differ from Dr Arthur Bradley, Branch Head Electronic Systems at NASA.
Canadian Prepper - A great interview with expert Jonathan Hollerman about how an EMP strike on the USA might play out.
Sony Picture Entertainment - Trailer for The 5th Wave, a fun movie about aliens launching an EMP weapon on the earth. Stick it on your watchlist.