A U.S. Air Force base in Texas has taken the first steps to guard against an electromagnetic pulse (EMP) attack. But what, exactly, is an EMP, and how big is the threat?
Officials at the Joint Base San Antonio in Lackland, Texas, issued a request for bids to carry out a survey of a facility called the Petroleum, Oil and Lubrication Complex. The survey will identify any equipment that could be vulnerable to an EMP ahead of more detailed vulnerability testing, according to the request. After that, officials would figure out ways to keep that equipment safe in the event of an EMP attack.
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What is an EMP?
An EMP is a massive burst of electromagnetic energy that can occur naturally or be generated deliberately using nuclear weapons. While many experts don’t think EMPs pose a big threat, some people argue that these types of weapons could be used to cause widespread disruption to electricity-dependent societies.
“You can use a single weapon to collapse the entire North American power grid,” said defense analyst Peter Pry, who served on the Congressional EMP Commission, which was set up to assess the threat of EMP attacks but shut down in 2017.
“Once the electric grid goes down, everything would collapse,” Pry told Live Science. “Everything depends on electricity: telecommunications, transportation, even water.”
According to the request, the testing at Lackland comes in response to a 2019 executive order issued by then-President Donald Trump for the federal government to strengthen its infrastructure against EMPs. Pry, who has consulted on the project, said the survey and resulting upgrades are part of a broader initiative by the U.S. Air Force to beef up its defenses against this type of threat.
Why EMPs are so dangerous
An EMP releases huge waves of electromagnetic energy, which can act like a giant moving magnet. Such a changing magnetic field can cause electrons in a nearby wire to move, thereby inducing a current. With such a huge burst of energy, an EMP can cause damaging power surges in any electronics within range.
These pulses can occur deliberately or naturally. Natural EMPs occur when the sun occasionally spits out massive streams of plasma, and if they come our way, Earth’s natural magnetic field can deflect them. But when the sun spits out enough plasma at once, the impact can cause the magnetic field to wobble and generate a powerful EMP. The last time this happened was in 1859 in the so-called Carrington Event, and while electronics were still rare then, it knocked out much of the recently built telegraph network.
Then, there’s the possibility of deliberate EMPs. If a nuclear weapon were to be detonated high in the atmosphere, Pry said, the gamma radiation it would release could strip electrons from air molecules and accelerate them at close to the speed of light. These charge-carrying electrons would be corralled by Earth’s magnetic field, and as they zipped around, they would generate a powerful, fluctuating electric current, which, in turn, would generate a massive EMP. The explosion could also distort Earth’s magnetic field, causing a slower…