It is wonderful watching a little kid play with a magnet for the first time. They have become so used to pushing or pulling something directly to get it to move that this motion at a distance breaks the model they have of the world and brings delight.
When people started to ask questions about what was happening, the answers brought fundamental changes to society.
You've probably done the experiment in grade school where you can change the direction a compass indicates by placing a current carrying wire next to it. The other part of the experiment is equally beautiful. You move a magnet next to a wire and cause a current to flow in the wire. What is going on?
Before going a bit into that, take a look at Richard Feynman's high level comments on electricity. He has a beautiful and delightful way of expressing himself
He mentioned Maxwell's equations as one of the most impactful discoveries anyone has made. About the time the American Civil War started, Scottsman James Clerk Maxwell published a four part work called On Physical Lines of Force.1 A few additional works were published and the summary of the work did not arrive right away, but we are left with four beautiful equations that are part of the foundation of our society.... If you did any technical work in college you are intimately familiar with them, but even if you didn't you may have seen them on a T-shirt.2
For those who aren't familiar with what they're saying, here is a summary in English2
° a magnet always has north and south poles
° the strength of an electric field depends on how much charge is in the vicinity
° an electric field is created by a changing magnetic field
° a magnetic field is created by either a current or a changing electric field
These are terrifically powerful and much of modern technology rests on electricity and magnetism. The calculations for real world problems can be non-trivial, but it is all there - all that is required is a bit of curiosity and tenacity.
Consider the last two equations. If you remove any charge you get an electric field is created by a changing magnetic field and a magnetic field is created by a changing electric field. You can solve these together with a bit of math and the result is astonishing - you get a mutually sustaining electromagnetic field. The changing electric field gives rise to an electric field which, in turn creates an electric field. The energy oscillates between these two forms, which turn out to be at right angles to each other, as the wave merrily propagates through space perpendicular to both the electric and magnetic fields. What is special is the speed of this wave is constant and just happens to be the speed of light.
About 25 years after the papers were published Heinrich Hertz showed that a spark could create such a wave. Hertz didn't realize it at the time, but others showed that what he created was really a form of electromagnetic radiation - a certain frequency band of which we sense as visible light. A major revolution in physics was underway, but none of the original people thought it would have practical value - little things like electric generators, motors, radio, television, computing and so on...
With this fundamental change came a major problem. How was this electromagnetic wave propagating? Waves traditionally required some medium to propagate though. A material called the luminiferous aether was proposed. A bizarre substance that filled the universe and had the property of being hugely stiffer than any known substance and very ephemeral - any normal substance could easily pass through it unimpeded.3
The whole notion of the aether seems silly today, but a fundamental change in how we thought about physics was required. Somehow this bizarre substance was not as bizarre as what followed. It turns out one of the puzzles it seemed to solve was how could light always travel at a fixed velocity. It allowed the light to travel at a fixed velocity in it rather than worrying about the relative velocities of bodies that were moving at different rates.
One of Feynman's better observations was
First you guess. Don't laugh, this is the most important step. Then you compute the consequences. Compare the consequences to experience. If it disagrees with experience, the guess is wrong. In that simple statement is the key to science. It doesn't matter how beautiful your guess is or how smart you are or what your name is. If it disagrees with experience, it's wrong. That's all there is to it.
Albert Michelson and Edward Morley did the experiment with something called an interferometer - a device that is very sensitive to movement as well as changes in the speed of light in different directions. They showed that the speed of light was constant in any direction relative to the moving Earth.4
This was such a startling result they spent years working on improvements to the experiment to find any error on their part. The results got better and better and with it the case for the luminiferous aether vanished and it became clear that electromagnetic waves could propagate though a vacuum.5 It also gave a certain Swiss patent clerk who was doing amazing physics on the side reason for coming up with something he coined Special Relativity.
The Michelson-Morley experiment is one of the fundamental experiments in all of physics. Its results were so unexpected that it was assumed to have been a failure, but careful probing of it by them and others as well as careful thought about what it really meant changed our concept of the universe on the scale that Galileo or Copernicus did.
Our imagination is stretched to the utmost, not, as in fiction, to imagine things which are not really there, but just to comprehend those things which are there.
This is the time of the year when I think of a few things I've done - some of them are predictions. In retrospect our memory tends to paint a pretty picture of how we predicted the future. I have been very lucky and have been in on some discoveries as well as inventions. We had what appears to be a good track record, but a more careful examination reveals more than a few failures.
In the past decade I try to spend some serious time thinking about failed - or what appear to be failed - predictions mean. I've come to place a huge value on my "failures" -what is really going on and what additional information did I need to discover there was a flaw.
This process of learning has given me tools and methods to work on unexpected areas. This generates serendipity and it exposes ignorance in a way that I can learn from many people and results including the failures of myself and others.
Aa observation - this process is similar to weather and climate. Weather is a short term projection and is extremely difficult to get right. The particulars are incurably difficult to understand. Climate is a longer term feature It is often much easier to predict the climate a decade out than the weather in two weeks. The same is true for projecting technologies. Rough directions are much easier than exact particulars.
Over the years I've been learning huge amounts from my failures. The amount seems to increase with time, which seems like the proper direction.
My New Year's wish to you is may you be as lucky with failure!
1 It is interesting to note that Charles Darwin's On the Origin of Species was published in late 1859. It is difficult to think of any other discoveries in the last few hundred years that have brought more profound change to civilization than these two...
2 Not as precise as it should be, but close enough. It also turns out there are several equivalent ways to write down Maxwell's equations, so the T-shirts may look a bit different.
3 Upper limits to its mass were calculated - the density was smaller than a hundred trillion times lower than that of air.
4 More precisely they sent a limit - the Earth's velocity relative to the aether had to be less than a sixth the Earth's measured orbital velocity.
5 luminiferous aether would make a great song title or band name
before the recipe, an image to fire your imagination
Allegory of Winter
Ambrogio Lorenzetti c.1338-1340
A lassi as delicious as it is inauthentic
A Rich Seasonal Mango "Lassi"
° a canned mango pulp at just a bit above freezing (I like Rellure Kesar Mango Pulp)
° lightly stir the mango pulp into the eggnog. Finally add a blob and artistically swirl it.
° top with toasted pistachios or sliced almonds (optional)