The greatest threat from space?

Electo Magnetic Pulse (EMP)

EMP is a burst of electro-magnetic energy and comes from a variety of sources:

Lightening
Solar storms
Nuclear weapon detonation

Nuclear EMP (NEMP)

According to Wikipedia: [1] "A nuclear electromagnetic pulse (nuclear EMP or NEMP) is a burst of electromagnetic radiation created by a nuclear explosion. The resulting rapidly varying electric and magnetic fields may couple with electrical and electronic systems to produce damaging current and voltage surges. The specific characteristics of a particular nuclear EMP event vary according to a number of factors, the most important of which is the altitude of the detonation."

The article goes on to say that EMP is released in 3 stages:

E1: Intense electromagnetic pulse which causes Electrical Breakdown
E2: Follows E1 (moments later) and is similar to Lightning
E3: Similar to Solar Storms and is a longer pulse linked to a distortion of the earths magnetic field

Electrical breakdown is when an insulator of electrical equipment is hit so hard it effectively becomes a conductor [2] and the electrical circuit is then open to the energy attack. This is the moment at which electronic equipment would be seriously damaged except for the proper protection from things such as a Faraday cage.

Solar EMP (SEMP)

In 1859 a huge solar flare was observed by a couple of UK scientists (including a Richard Carrington) in what has become known as the Carrington Event [3]. During the flare, telegraph users turned off their batteries to communicate but were still able to do so powered purely by the electro magnetic output from the storm. It is estimated that at 2013 values an equivalent event could cause a devastating 15% loss of GDP for the US economy alone [4]. Its worth stating that this figure relates to the "electric grid" but you imagine how many devices and electrical systems would be affected and damaged by such an outburst [5].

The threat from Solar EMP unlike its nuclear counterpart is the impact on the Energy grid. The reason being is that the longer pulse uses the electrical supply wires and hurtles towards the transformers along the way. These could blow up / fuse etc and effectively render the electrical grid destroyed. Equally there are impacts on Satelite systems and GPS units as well

The UK government is fully aware of the impact of this (as any government should) and more detailed reports can be read about this in [6] and [7]. The 2023 National risk register [9] describes these types of events as having a significant impact with upto a 25% chance of happening. This points out that satelites are "are particularly vulnerable to space weather effects, and can be damaged or temporarily disabled". "The impacts of severe space weather would be global, although the magnitude would vary, with the key dependencies being latitude, reliance on access to space for the operation of key services and the resilience of engineered and digital infrastructure."

For a more scientific article on Solar flares - see link [8]

Civil Defence today

Electo Magnetic Pulse (EMP)

Nuclear EMP (NEMP)

Solar EMP (SEMP)

References/Links