Skip to comments.How Professor Maxwell changed the world
Posted on 04/05/2011 11:57:34 AM PDT by neverdem
TO MUCH fanfare, Italy celebrated 150 years since its unification two weeks ago. Less exuberantly, America is commemorating the 150th anniversary of the outbreak of the civil war, a failed attempt to undo its union. Amid this flurry of historical fissions and fusions it is easy to overlook another, arguably more significant unification set in motion in spring 1861. In March of that year James Clerk Maxwell, a Scottish physicist (pictured above), published the first piece of a four-part paper entitled "On physical lines of force". Sprinkled amid the prose in the Philosophical Magazine were equations which revealed electricity, magnetism and light to be different manifestations of the same phenomenon.
By the mid-19th century scientists had a fair understanding of each of the three components of electromagnetism, as the phenomenon has come to be called. They knew, for instance, that the distribution of electric charges was linked to the pattern of electric fields and that magnetic poles cannot exist in isolation, in other words that there were no single magnetic charges. They also knew that a moving magnet generates an electric current in a wire coil, as demonstrated by Michael Faraday several decades earlier at the Royal Institution (a short walk from The Economist's offices in London). However, no one could explain precisely why that was.
Maxwell's aim was initially to forge a mathematical link between electricity and magnetism that would capture these experimental results. (The issue was a burning one for the Victorians who had just been spectacularly stymied in their efforts to get the trans-Atlantic telegraph connection to work. Understanding how electricity and magnetism interacted, it was thought, would help to overcome the problem of the delay and deterioration experienced by the signal as it travelled along the underwater cable.)
He also realised that varying the strength of an electric field would generate a changing magnetic field, even in empty space with no moving electric charges to speak of. A changing magnetic field, of course, gives rise to an electric field, as had been established by Faraday. Might the two fields nudge each other along in a self-perpetuating, wave-like manner? Maxwell's calculations made it clearthey could. And the speed at which such an electromagnetic wave would propagate through a medium was inherently linked to the medium's electrical and magnetic properties. When Maxwell plugged the relevant values, which had been obtained recently by experimenters in Germany, into his equations, out popped Fizeau's figure for the speed of light. Convinced that this was no accident, Maxwell went on to suggest that light is, in fact, an electromagnetic wave. Physics had got its first unified theory.
2011 is awash with anniversaries of notable events from the annals of the physical sciences. Chemists will be celebrating 350 years since the publication of Robert Boyle's "Sceptical Chymist", a tract which marked the birth of their science, at least in its modern guise. One hundred years ago in April, meanwhile, Heike Kamerlingh Onnes, a Dutch physicist, discovered that some materials are superconductorsas they are cooled towards absolute zero they allow electric charge to flow with no resistance. In May of the same year Ernest Rutherford, a New Zealand-born British boffin, put forward (also in the Philosophical Magazine) the familiar model of the atom as composed of a dense nucleus orbited by tiny electrons. Although physicists have since come up with more elaborate projections of the subatomic reality, the Rutherford model is, unlike the earlier plum-pudding version, basically rightwhich is why it continues to be taught to schoolchildren the world over. And it has been 30 years since Alan Guth, an American particle physicist, published a paper suggesting that instants after the Big Bang the universe underwent a phase of rapid expansion; the inflationary theory has since become cosmological received wisdom and forced astrophysicists to take particle physics seriously.
Worthy intellectual accomplishments, all. Yet they pale in comparison with Maxwell's. This is not just because, unlike a lot of subsequent theoretical advances, his insight has already yielded a century's worth of tangible results, from radio to mobile phones. (Only a century because it took scientists several decades before they grasped the theory's full significance and put it into practice.) Nor is it because he championed the abstract idea of fields, a fecund notion that underpins much of modern physics. No, Maxwell's greatness lies elsewhere still. He showed that nature ought not to be taken at face value, and that she can be cajoled into revealing her hidden charms so long as the entreaties are whispered in mathematical verse. In doing so he paved the way for the pursuit of physicists' holy grail: the grand unified theory, a set of equations which would explain all there is to know about physical reality. As tends to be the case with grails, this one, too, may prove unattainable. Unless there are inherent limits on human understandingitself an unfathomable premisethere will always be more apparently disparate phenomena to explain at one fell swoop.
Maxwell remains the great unsung hero of human progress, the physicists' physicist whose name means little to those without a scientific bent. His life's work, which also includes remarkable contributions to thermodynamics (not to mention taking the world's first colour photograph, also 150 years ago) is among the most enduring scientific legacies of all time, on a par with those of his more widely acclaimed peers, Isaac Newton and Albert Einstein. It deserves to be trumpeted.
... and there was light!
But remember, only leftist artists and authors are truly creative.
Always been partial to Faraday myself.
William Rowan Hamilton (of Hamiltonian Mechanics fame) re-cast Maxwell's original equations into a shorter version, which were 10 differential equations in ordinary differential equation form. It was not until Oliver Heaviside invented operator calculus that the form we see today was first expressed, so these are more formally known as the Maxwell-Heaviside Equations of electromagnetism.
Heaviside himself was criticized by the more rigorous mathematicians of his day for using operator calculus without really understanding the underlying mathematical theory. He was said to have remarked, somewhat raffishly, that he didn't understand the process of digestion, either, but that did not stop him from enjoying his dinner.
Maxwell is well remembered and revered among people who actually contribute to human progress.
Ah, ya beat me to it.
Sorry, the Hamilton reformulation used quaternions, not ordinary differential calculus.
There was a wonderful article on Heaviside in the IEEE spectrum about 15 years ago by a Dartmouth Professor. Heaviside is one of history’s underappreciated geniuses, for sure.
Yeah, I always do a little aside about him when we talk about the (Heaviside) step function in linear system theory. We truly stand on the shoulders of giants.
That’s what I thought. He’s not up there with Newton or Einstein, but anyone with a reasonable high school education should have heard of him at least.
In fact, his name was used more than any others I think.
And this is just one current!
These so-called "scientists" are so full of it.
Sheesh, fields and physical lines of force could feed the monkeys flying out of Hillary Clintons ample derriere. Maxwell Schmaxwell.
I missed my calling. I spend all my time making sh!x up and posting it on FR for free when I could have got my PhD in making sh!x up and been paid for it.
Magical fields, imaginary numbers and other crap... similar things were concocted to create the Global Warming Crisis.
Ignoring reality in an attempt to support a theory. It's what these scientists do. It's just like GODZILLA. He is the 'invisible lines of Maxwell' that destroyed Japan. The reason no one has ever actually SEEN Godzilla, is because he is 'invisible'.
I admit I don't get it. But neither do 'they'. Their 'theories' are just ways to explain what they don't 'get' yet, ya'know?
IBTSH (In before the science haters)
But that it powers our society, and did pretty good jobs on the Japanese to end WWII.
Until then I'll keep wearing my sticky boots.
Yes, sorry. I should’ve explained. Those seven paragraphs were similar to seven comments I got on just one cosmology thread I posted recently. A person can’t post anything about science around here without attracting the science-hating knuckleheads. So, I thought if I distilled the essence of what they usually say and put it in one comment, they’d be satified and go away.
FReepmail me if you want on or off my health and science ping list.
I have to disagree there. His accomplishment is ever bit as significant and astonishing as Einstein. Newton is in a class by himself all alone.
Good one! Oh, wait a minute...you’re being facetious, you scamp you. Making fun of Hillary’s behind. Next thing you know, you’ll be standing around that nuclear reactor telling naughty jokes and wearing a lampshade on your head.
Knuckleheads of the world unite!
You had me there for a second until I saw the IBTSH.
Essence? Like you've ever seen an essence much less distilled one. What rot. ;-)
What these folks usually say is a bunch of bloated flapdoodle and non sequiturs, right? Then as you zoom in and look at it at smaller and smaller scales, trying to get to the essence of it, you find it's bloated flapdoodle and non sequiturs all the way down. Fascinating.
Technically Maxwell’s Equations in vacuum, but I digress... :)
Nice GIF — I’ll have to swipe it!
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Yeah, but can it clean out a nuclear reactor?