Speaker 1 (00:01):
This episode is sponsored by BAE Systems, the global leader in next-generation electronic warfare systems. With more than 60 years of experience and 33,000 people as part of its global defense, aerospace, and security business BAE Systems' electronic warfare systems are found on the most advanced military platforms in the U.S. and around the world. Learn more at baesystems.com/ew.
Speaker 2 (00:32):
Electromagnetic energy is a fundamental part of our universe. Humans discovered ways to use this energy for many purposes from radio to TV, smartphones to Wi-Fi the list goes on. But electromagnetic energy also influenced another major sector, military operations. Along came the Crows, people who learned electromagnetic energy, applied it to military combat operations and for ever impacted modern warfare. Introducing the History of Crows podcast. The History of Crows will take you through the global history of electromagnetic warfare and electromagnetic spectrum operations, from the earliest scientific discoveries to modern military operations around the world.
Speaker 3 (01:29):
During World War II the individuals who first utilized the electromagnetic spectrum for military operations including the allies radar countermeasures, radio monitoring, and communications jamming technologies called themselves Ravens. Today, military maneuvers and defense within these electromagnetic spectrum technologies are undertaken by proud people across the military, government, industrial base, and academia.
Speaker 3 (01:55):
They call themselves Crows and this is their story. The History of Crows is brought to you by the Association of Old Crows or the AOC. An international professional association comprised of people who are experts in the electromagnetic warfare and signals intelligence industries. To learn more about the AOC, please visit www.crows.org.
Speaker 3 (02:22):
What is electromagnetic spectrum operations or EMSO as the Crows call it? Electromagnetism is a fundamental force in the universe without which life as we know it couldn't exist. But what sets electromagnetism apart from the other fundamental forces like strong and weak nuclear force and gravity, is that humans have found it relatively easy to channel, store, modify, and apply it for various purposes. The field of EMSO requires some knowledge of the discoveries that led to our understanding of electromagnetic energy. These discoveries fundamentally changed the way we see our universe.
Speaker 3 (02:59):
The mathematics and experiments that uncovered electromagnetism were the bridge between the scientific past and the science of the future. It was the 18th century discovery that electricity, magnetism, and light are all phenomenon resulting from a different fundamental force in the universe, electromagnetism, which ultimately led to the scientific revolutions of the 20th century. To help us better understand how this new epoch has changed our lives as we know them, we welcome Charles Quintero from the Johns Hopkins University Applied Physics Laboratory.
Charles Quintero (03:33):
The world of natural philosophy that preceded Maxwell was one where people didn't really understand where a phenomenon came from. And Maxwell was really at this transitional period where we went from not understanding things and attributing them to forces that we couldn't understand to really understanding materials and developing the mathematics for them. And it really started with Isaac Newton.
Speaker 3 (03:58):
Sir Isaac Newton was one of the most recognized and highly debated English, Mathematician, Physicists, and Astronomers of the 17th century. The Newtonian worldview of natural philosophy was one of understanding the differential components that contributed to phenomenon, this extended to matter.
Charles Quintero (04:15):
Once we started understanding that matter was made up of smaller pieces and that we started to do some calculations of how those pieces behaved, it was very natural to take the Newtonian worldview and extend it to this smaller world that we were now examining. So we still lived in this time where things were deterministic that if you understood all the, what we would call the state of particles in a model, that if you fully understood it then you could predict everything that could possibly happen to that system as long as it was close to any external influences.
Charles Quintero (04:45):
And that begged the question of what it would really mean to say that there is free will when everything is predetermined. If the electrons going in your brain are following some force law, then how is it possible to say that you can think without all of that that goes into your mind having already been precalculated and predetermined.
Speaker 3 (05:12):
So Newton's example of an apple falling from a tree was more than just about gravity. But also deterministically calculating where the apple is going to hit on the earth as it falls.
Charles Quintero (05:22):
Obviously Newton was right when he said, "If an apple falls from a tree we can calculate deterministically where it will hit the ground." But we started to get into some sort of hitching and that's when you start to get to the very small phenomenon of an atom rotating in response to an electric field. Is that really predetermined by its state?
Speaker 3 (05:43):
This mechanical phenomenon fascinated physicists from Newton to Maxwell, including Charles Augustine de Coulomb, Daniel Bernoulli, and Jean le Rond d'Alembert.
Charles Quintero (05:54):
So when you look at the primary scientists who contributed to Maxwell's work, there's really three. So Coulomb in 1785 [inaudible 00:06:02] a laws of electrostatics. So that was basically just having charges that were stationary and understanding what their fields. We've all rubbed rubber balloons on our hair and seen how it develops this attraction or repulsion to different surfaces. So that was from Coulomb, understanding electrostatics.
Speaker 3 (06:23):
But it was André-Marie Ampère and Michael Faraday who discovered and experimented with electric fields, who most heavily influenced Maxwell.
Charles Quintero (06:31):
Once we had batteries in hand, so 1790 with Volta creating a battery that we could use to put currents down wires that really opened up the field. Where Ampère could start to study how those currents created magnetic fields and influenced a very popular tool at the time was a compass, a magnetic compass. So in the 1820s, Ampère's work with currents and wires showed how the fields generated would affect compass magnets. Now Ampère unfortunately thought of this interaction between magnetic wires and the magnetic fields generated by the currents and the wire as being a one-on-one interaction, as if you had a rope tied between the two and one pulling as a force on the other.
Charles Quintero (07:21):
It wasn't until Ampère studied in more detail in 1825 that he realized that there was actually a field created around the wires. So it started off 1821 with a one-on-one interaction and then that grew into a more understanding of the basic static field of electric fields. The real key to Maxwell's work was Faraday though. And starting in 1831 Faraday did a series of experiments where he extended what Ampère did and said, "Well if a current in a wire can create a magnetic field that affects this magnetic needle, can I do things with magnets that will induce currents in wires?" And so Faraday was paramount in joining electricity to magnetism and showing that there were reciprocal relationships between the two. He did an amazing amount of work developing the electric motor which generated force from electric current, and the dynamo which took force input into the device and generated current.
Speaker 5 (08:23):
At BAE Systems we're developing full spectrum, multi-domain electronic warfare capabilities that outpaced the threats. Our electronic warfare systems are designed to be open, reprogrammable, and exportable to deliver on the U.S. Air Force's operational vision of the electromagnetic spectrum. We're committed to delivering electromagnetic spectrum superiority to the war fighter where it matters most. Learn more at baesystems.com/ew. That's baesystems.com/ew.
Audience (09:07):
[inaudible 00:09:07].
Speaker 3 (09:20):
A paper has just been read to the members of the Royal Society of Edinburgh, describing a simple method for generating geometrically accurate ovals or ellipses. The author is 14-year-old James Clerk Maxwell. A boy genius who was studying at the University of Edinburgh by the age of 16 and a full professor at Marischal College, Aberdeen at 25. Maxwell was known for using mathematics to explain physical properties of the universe. He was the first person, for example, to correctly conclude that Saturn's rings are made of numerous small particles.
Speaker 3 (09:52):
In 1860, Maxwell accepted the Chair of Natural Philosophy at King's College, Cambridge where he met Michael Faraday, who had done some of the earliest experiments in electromagnetism nearly 40 years earlier before Maxwell was even born. Meeting Faraday might have reminded Maxwell of the time his father took him at just 10 years old to a demonstration of electromagnetic force by Robert Davidson, the Scottish scientist and inventor of the first electric locomotive. In any case, this began Maxwell's prodigious period of the study of electromagnetism. It was in 1861 that Maxwell began publishing a series of four papers that would usher in this new epoch scientific discovery.
Charles Quintero (10:39):
In 1961, Maxwell started publishing a series of papers that he called the Lines of Force and molecular vortices. Again you can see in the [inaudible 00:10:50] molecular vortices that he was very much thinking about geometry and trying to understand these collection of experiments and measurements that had been done by all the scientists leading up to this point. The first one was about magnetic phenomenon, and it was really the interaction of current-carrying wires and how they created magnetic fields. The second one is on electric circuit currents and how magnetic induction of those currents worked. In other words, connecting the two. So the electromagnetic properties are really the same and that one is the reciprocal of the other.
Charles Quintero (11:27):
The third was a really interesting paper on what he called statical electricity. And it added to the ideas that Ampère had come up with on magnetic fields around wires. But they've extended it to a new type of circuit that included something called capacitors. So when you look at the equations on the generation of magnetic fields, in addition to Ampère's term where he had current going through a wire, he added this ability to think about the current density being collected in something called a capacitor. And once he started doing that and realized that there could be materials in the capacitor like what we would call a dielectric, something that was developed by Faraday, they changed the way that the light propagated in the way the circuits collected the energy.
Charles Quintero (12:18):
And that was really the key point for Maxwell in as he calculated the propagation speed of these electromagnetic waves in response to these circuits that he designed, he came up with the velocity of light in the material is one over the square root of mu*epsilon. And that number was close to the speed of light. And he made the amazing connection that propagation through free space was the same as the propagation of the electromagnetic fields in the wires or coax or waveguides. And just fabulous real key component of the paper. His last one was on the effect of magnetism on polarized EM waves. Basically that's something that we use a lot in RF devices we can call circulators where we're able to route EM waves by using magnetic lensing effects.
Speaker 3 (13:17):
Maxwell embraced that science was partial and imperfect. In an address to the mathematical and physical society of Britain in 1870 Maxwell told his colleagues, "Every natural phenomenon is to our minds the result of an infinitely complex system of conditions. What we set ourselves to do is to unravel these conditions."
Charles Quintero (13:39):
So in 1864, Maxwell published a compendium of all of his work and added summaries that was called The Dynamical Theory of the Electromagnetic Field. So that's where he took some of the ideas that we had just previously [inaudible 00:13:55] part three of his four-part series on electromagnetics, where he understood the propagation of EM waves through materials. And now he's finally done the extension to say that that same propagation path happens in free space. That review of those papers in 1865 by the Society of Physical Science in England published those as part of the philosophical transactions of the Royal Society. And that's really where it became known to the rest of the world.
Speaker 3 (14:29):
Maxwell's groundbreaking equations did not however amaze the scientific community of the time.
Charles Quintero (14:35):
The series of papers that Maxwell published in the 1860s are pretty cumbersome. If you actually get the reprints for them and you read through them, you won't recognize Maxwell's equations in Maxwell's papers. And that's a notation problem that he had.
Speaker 3 (14:50):
Maxwell's use of mathematical notation from the time of Newton and Leibniz limited how his work was interpreted. Sadly, James Clerk Maxwell died of cancer in 1879 at just 48 years old. While widely considered a genius, his electromagnetism work may have been overshadowed by many of his other discoveries. He helped invent color photography, for example. Had it not been for a self-taught engineer, mathematician, and physicist in whom Maxwell's work ignited interest and imagination, Oliver Heaviside.
Charles Quintero (15:24):
Oliver was a Telegraph Operator and he taught himself the mathematics of Hamilton and he read Maxwell's papers and decided to apply the quaternion theory and vector algebra to Maxwell's work. And his interpretation was what we use now. He took 12 of the equations down to these four equations of vector form of Maxwell's equations that we know. I think in a way you should really call those four equations the Heaviside equations of the Maxwell equations.
Speaker 3 (16:02):
While Oliver Heaviside made Maxwell's equations simpler, the work remained theoretical. His discoveries were pure mathematics, unproven predictions until 25 years later when a German scientist named Heinrich Hertz began experimenting with Maxwell's theories in the laboratory.
Charles Quintero (16:18):
Theory is just theory. But one of the key aspects of the scientific method is that a good theory makes predictions about things that can be done. So in 1888, Heinrich Hertz confirmed the existence of electromagnetic waves by using some of the phenomenon that we had previously talked about. In 1879 Hertz proposed, in fact his doctoral dissertation was about testing Maxwell's theory, so he proposed to the Prussian Academy of Science that anyone who could experimentally prove an electromagnetic effect in polarization and depolarization of insulators are in the propagation of waves to get a prize sponsored by the Prussian Academy. Hertz worked very hard while he was working at Karlsruher on generating those electric currents. And it was really driven by graduate studies and wanted to show that these phenomenology that were predicted worked. Between the 1886 and 1889, he conducted the experiments that really led to his full confirmation of Maxwell in 1888.
Speaker 3 (17:30):
Hertz's experiments showed that he could bounce waves of electromagnetism off the walls in his lab in predictable ways. His work with these Hertzian waves as they were called, later inspired a number of scientists to research them further. At the time however, Hertz saw no use for them. When he was asked what applications his experiments might have he replied, "Nothing, I guess." Heinrich Hertz never saw the impact that his work had. Like Maxwell, he too died young at just 36 years of age only a few years after discovering Hertzian waves, what today we call radio.
Speaker 3 (18:14):
Renown physicist Richard Feynman who was instrumental in bringing quantum mechanics to fruition placed Maxwell on a pedestal, even though today he is hardly mentioned. "In the long view of the history of mankind," Feynman said, "there can be little doubt that the most significant event of the 19th century will be judged as Maxwell's discovery of the law of electrodynamics." Albert Einstein was once told that he stood on the shoulders of Isaac Newton. "No," Einstein replied, "I stand on the shoulders of Maxwell." So it's not an exaggeration that Maxwell and shortly thereafter Hertz paved the way for radar and what we call today electromagnetic spectrum operations.
Charles Quintero (18:52):
When you think about radar systems and electronic warfare, anytime you try to communicate or do something in the realm of war there's always going to be someone who's trying to obfuscate or mess up what you're trying to do. So if you have a radar people are going to build jammers, if you have communications people are going to try to deny those services. So it's important for us to really pay tribute to Maxwell in the development of this mathematical tool and science that allows us to do these amazing, wonderful things. And also to protect those amazing, wonderful things from impact by people who want to stop us from doing it. In summary, I think you could say that there's nothing that we do today that isn't influenced by Maxwell.
Speaker 3 (19:44):
In the next episode of History of Crows, we continue the story of Crows by looking at the life of Guglielmo Marconi and the birth of wireless communications. This podcast is brought to you by the Association of Old Crows. Thank you to our episode sponsor BAE Systems. Learn more at crows.org/podcast. Thanks for listening.