# How Einstein Discovered Relativity

Updated on December 20, 2017

People have a tendency to ascribe more credit and more blame to individuals than is usually appropriate. In the arts and sciences the old cliché “on the shoulders of giants” remains a cliché because it’s true.

Laypeople often assume that Einstein composed his theories of relativity out of thin air because heuristic descriptions of relativity give weird predictions: Two twins at a space-port. One gets on a rocket, accelerates into outer space and, when he comes back, is young and spry but his twin is a geezer. Weird. Also difficult to comprehend where such a crazy idea could come from. Let’s clear that up.

## It was the late 1800s and it seemed as though physics was complete

Sure, there were a few details to be worked out, but isn’t that always the case? The heavy lifting was done. All of electromagnetism was encapsulated in an elegant theory distilled down to the four cool looking Maxwell equations. Gravity had been tied up over a hundred years before by Newton. Nice work, guys, let’s leave the details to graduate students.

At the time, gravity and electromagnetism were the only known forces. (We’re now aware of another two, the strong and weak nuclear forces. To be sure, the weak force was united with electromagnetism in the 1980s – we call the three of them, electricity, magnetism, and the weak nuclear force, the “electro-weak” force. Tidy. There is currently no compelling reason to believe in a force beyond those listed here.)

## One of the details that needed to be worked out was a simple college physics homework problem

Let me walk you through it – no math, I promise. (If you want the math, drop me a note: ransom at ransomstephens.com and I’ll send you the gory details.)

First, consider two electrons at rest and separated by some fixed distance. They exert repulsive forces on each other. In the classical theory of Maxwell, Faraday, Ampere, Volt, et al., we think of one of the charges as sitting in the electric field of the other. The field of one charge exerts a force on the other charge, pushing it away.

Now, let’s put the two charges in motion. Or better yet, but equivalently, let’s leave them stationary and let’s you and me go zipping past them. In other words, from our point of view, we see the two charges going past us at a constant speed, the same way we might see a street sign go by while we’re sitting in a car.

When we calculate the force between the charges in this reference frame there’s an additional term. Magnetic fields are formed by moving electric charges – this is called Ampere’s Law, by the way. Now, not only does each charge experience the electric field of the other, but they also experience a magnetic field from the other.

## The calculation is pretty straightforward and the result contradicts reality.

The classical theory predicts that, as we move faster, the repulsive force between the two charges decreases until it disappears altogether when the charges reach the speed of light.

Let’s think about that for a second. We, the observers, sit still while the two charges go zipping past. This scenario is identical to having the charges sit still while we zip past in the other direction. This is the grist of relativity, both the old-fashioned Galilean relativity and Einstein’s special relativity. If the charges stop repelling each other in one case, the same thing would have to happen in the other case because, well, we’d be able to see it from either reference frame.

## It gets weirder

If our speed were to exceed the speed of light (remember, in 1900 no one was aware that the speed of light is nature’s speed limit!) then the force between the charges becomes attractive. No longer would the charges repel each other, they’d start attracting each other. Just because we’re moving by them – it doesn’t make any sense and so, must be wrong.

It’s an easy experiment too, you can use a sooped up TV tube to get a bunch of electrons up to half the speed of light and check whether or not the force of repulsion decreases. It doesn’t.

## This is how science usually works

The old theory breaks down. Einstein realized this and figured out what had to change. Once he modified the old theory, he had a mess of crazy new predictions. Other physicists tested as many as they could – they checked out. He also thought his way through and solved, the seeming paradoxes of his new theory. Later, he extended the idea to the analysis of gravity and this is where the general theory of relativity came from.

## Enter experimentalists and other skeptics to check it out and, so far, every prediction of relativity has held up.

Notice another thing. Something quite different from how laypeople tend to think of scientific theory. When the classical theory failed, it wasn’t a great big mistake that brought it down. The classical theory is used every day by electrical engineers. No one is designing electrical devices, like your phone, computer, or watch, with the newer theory. Engineers use Maxwell’s equations except in the isolated cases where they don’t work, namely with transistors and diodes. Similarly, mechanical engineers use Newton’s theory of mechanical forces to build bridges and skyscrapers – no one is worrying about relativistic corrections to the old theory.

## “It’s just a theory”

The point is that it is extremely rare that an established scientific theory falls apart completely. The scientific method is not a process of building theories, throwing them out and building new ones. It’s a system of discovery and modification.

(The author, Ransom Stephens, contends that when using the theory of relativity, it’s helpful to do the math as fast as possible, because if you start thinking about the result too soon, you’ll get lost. Well, he will, anyway.)

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• Akeliev

7 years ago

Hello, I am from Russia. I want to introduce interested persons with my article: «The Einstein's special theory of relativity is the greatest scam in

the history of physic and alternative to it the concept of the Lorentz-Fitzgerald-Planck»

The English version can be viewed on the Internet at the following address:

http://www.akelevnm.narod.ru/aboutsto2.htm Article is discussed at the forum of the Moscow Engineering Physical Institute at the address: http://corum.mephist.ru/index.php?showtopic=20609&...

Akeliev N.

• VoltaireZ

7 years ago

I personally can't do anything like relativity. It's one of those concepts I haven't yet wrapped my head around. Yet, it does seem obvious that if a beam of light hits another beam of light, head on, the impact is a collision twice the speed of light...isn't that what they do at CERN? Yet, again if some how one pace ship was traveling at the speed of light and another was traveling toward it, at the speed of light, then there would be no way of them to observe each other either coming or going; one can't see the light from the sun till it gets here. An observer on a straight line between them, also wouldn't be able to see them. Anyways, again I can't do relativity, but here's my question; let say a space ship circles the Earth at the speed of light, by the observations on the Earth for say an hour, since time slows down for the people in the space ship, but they covered the same distance, regardless, since velocity is distance/time, wouldn't the people in the spaceship calculate that they went faster than the speed of light? I've got to be butchering relativity. I'm going to have to do some wikipedia catchup.

I love science, but I have to confess that I love myths too, and have my own private mysticism. I am an emotional being and therefor irrational, but there would be no rational reason to have this conversation without emotion. Science is a long way (I think) from being able to tell us what is, how deep does the well go? So myths still make some sense to me, to my perceptions, and emotions, that science can't yet. The many worlds theory though, that really resonates with me.

Well have more thoughts but I'm tired, however I'll leave you with this thought on the limit of science and knowledge. Imagine a tree. Now imaging creating a math mathematical model of thought system that can accurately capture every aspect of that tree, including its totality, if you can have that all in your mind, don't you have a tree in your mind? If you can't model the tree 100% can you ever really claim to know with certainty what "treeness" is?

• AUTHOR

Ransom Stephens

7 years ago from Petaluma, California

See, this is why I said, "...when using the theory of relativity, it’s helpful to do the math as fast as possible, because if you start thinking about the result too soon, you’ll get lost." And now I'm lost.

Yes, it's because, as you say, the relative distance is increasing to where the communications signals could never catch up with each other. But I have a feeling it's trickier than that. The curvature of space doesn't play an interesting role here because the information and the space ships both experience that same curvature.

• Marilyn Alexander

7 years ago from Vancouver, Canada and San Jose del Cabo, Mexico

VoltaireZ, I am willing to be persuaded by your logic. It is just one thing that still seems to be dangling. Emotions are illogical and, therefore, difficult to predict. Further, predicting results from emotionally charged situations, especially when the emotions are internalized to a relatively similar degree, are difficult also. Yet, advertisers do it and so do forecasters. Isn't there some way to quantify the effects of a quality?

And then you say, "Math is cold and warm, since we are math." You are way above me here!! :)

Ransom. You say that if two spaceships were travelling towards each other then past each each one going at or near the speed of light, then the speed of their separation is nearly twice the speed of light. If neither one is actually going faster than the speed of light then why can't someone on board each spacecraft not communicate with the other? Is this because the relative distance is increasing to where the communications signals could never catch up with each other? But what if space is curved or shaped like a spiral?

Once again, my thanks to both of you for taking me seriously.

• AUTHOR

Ransom Stephens

7 years ago from Petaluma, California

Wow!

First, I said, "...science provides emotional solace to very few people." I happen to be one of those very few and it sounds like you are too. I suspect if folks were more scientifically and mathematically literate, the "very few" would get bigger. Whatever.

Yes, if two things are going in opposite directions, each at very nearly the speed of light, then their speed of separation is nearly twice the speed of light. No problem here, though, because the objects are not, cannot (within the confines of relativity) exchange information. It gets tricky if we think of how someone on either of those things sees the other.

Okay. On the idea of using religion or sociological statistics to predict human behavior, here's curve for you: physics is to chemistry as economics is to sociological/religious tenets/philosophies.

In principle, perfect physics could predict everything that happens in chemistry. Perfect economic theory could predict everything people and cultures do.

Of course, I could be wrong :)

• VoltaireZ

7 years ago

Very intelligent observations. One of the problems for using religion for predicting "anything" is the danger of its leaders internalizing the beliefs of the religion, and the great differences between their model of reality (religion) and whatever reality is. I like to use the example of a Pharaoh giving advice to his son, "Always insist that you be thought of as a god, but don't ever fool yourself into thinking you are a god." A wise Pharaoh would not think of himself as a god, because then he might assume so many things that would not be true, such as immunity from disease, that his thoughts are divine and therefor right, that he cannot loose a battle, or any number of other such nonsense. The problem of religion is that is it a very bad model of reality (in most regards, in some cases it was thousands of years ahead of science, and some of its brush strokes can't yet be proved false one way or the other, which also depends on how one interprets religion metaphorically or literally)...now where was I...oh, religion is a very bad model of reality and as such it can become a complicated mess to predict as what religious people will do depends upon how many of its leaders have truly internalized its beliefs. It's one thing to walk around in a pleasant fiction, that happens to be highly functional to you (it pays you money), and quite another thing to believe in that fiction so strongly you're willing to start a nuclear war, because God is on your side. Yet, I can understand at groups belief system does allow for some predictability.

Religion, though, isn't nearly as effective of a manipulator as other systems, because again, manipulation works best when the manipulators, haven't internalized a less predictive model of reality. Advertisement has teams of psychologists, sociologists, creative artists and writers, and other experts at manipulation. Media is exceptionally good at manipulating people because there are people in it who understand that is what they are doing. Politics have think-tanks daily trying to figure out how to get what they want, by convincing people of something that isn't true. Lies are sold best, in mass, by the people selling them knowing they are not true, because a "liar" is more prepared to counter evidence that might expose his lie, while someone who believes the lie, may actually be moved from their belief by evidence to the contrary. And money and force are the greatest manipulators of all. What person doesn't believe gold is highly valuable, even though that is just an agreed upon "fiction," an ancient manipulation of people's thinking. A child who hasn't been indoctrinated such a belief system, if hungry, will choose a peanut butter sandwich over a bar of gold, every time. Money is the same thing, its a religion or agreed upon fiction, that has some elements of reality, but we accept our paper money, because our ancestors had their head cut off if they didn't.

So I guess one can look at any system of thought and make some predictions about the people's behavior in that system, but chaos, individual behavior and thought, and how much the leaders and manipulators of the system have internalized the model effect the total behavior, and limit predictability, as perhaps other aspects of reality we can't model yet.

Math is cold and warm, since we are math.

Just some more of my thoughts, hmmm.

• Marilyn Alexander

7 years ago from Vancouver, Canada and San Jose del Cabo, Mexico

If I am way off base here I hope you will tell me.

Religion is more powerful than science in manipulating the masses because religion has been (perhaps more so in the past) more intrinsic in people's lives than science.

I accept that science provides a more accurate mechanism for predicting (outcomes within) systems, both mechanical and natural, but I also believe that religious beliefs can more accurately predict human systems or, relationships, corporate directions, community and national politics. I think that systems are also groups of people and that religion is a more effective predictor of behaviour, in the whole and in the parts.

You seem to ascribe sentimentality to religion and not to science. I can agree here too. But if religion is looked at 'scientifically' (if that is possible because religion's members are so often emotionally involved rather than rationally involved) then it seems to me that religion (a belief system) can be used and therefore measured as a predictor of outcomes.

I'm sure you know Machiaveli's theories, among which he says that because people will vary not only among themselves but also from one time to the next, it is neccessary to have enough force that will 'persuade' them to maintain the strongest position for the benefit of the persuader/conqueror. I guess what I'm saying is, couldn't it be possible to assign a mathematical equation to this 'problem'.

I know that it is done in scientific forecasting so it seems to me that using religious factors one could scientifically predict outcomes.

I admit that fanaticism is a different matter and yet, because of its nature, outcomes are probably more accurately determined scientifically.

I understand what you mean by saying religion brings solace where science does not, but isn't that so because most religious people are so emotional about their faith? And, isn't it that that makes religious people more easily manipulated by power hungry people? And isn't that the fear of so many atheists and agnostics?

I don't think science is cold (and religion is warm), I think mathematics (as beautiful as it is) is cold.

I have one silly question. If two bodies are passing each other, going in opposite directions, and both were travelling near the speed of light, couldn't you say that they were travelling apart from each other at a speed faster than the speed of light?

• VoltaireZ

7 years ago

I'm glad you recognize that religion is manipulated for the purpose of power and wealth, just as economies are, patriotism is, an a host of other things. So many think the opposite, that religion is inherently brutal.

• AUTHOR

Ransom Stephens

7 years ago from Petaluma, California

I'm not aware of any scientist who truly worked alone. Newton comes to mind, not because he worked alone, but because he got so far ahead of his colleagues in such a short time. Though, the time was ripe, several hundred miles away, Liebnitz reproduced some of his work.

Personally, I'm hesitant to ascribe religious doctrine as useful in the same way that scientific theory is useful. Science provides a mechanism for accurately predicting the behavior of different systems. I don't think any of the world's religions can make that claim. On the other hand, science provides emotional solace to very few people.

I'll offer this, though: Whether or not religious stories are accepted as literal truth or as metaphorical guidance, they have been effective in providing social structure. I reckon the social problems that are frequently blamed on religion (including religious-sponsored terrorism, both currently and during the inquisition) are less about the faith than about the power-hungry people who manipulate their followers.

• Marilyn Alexander

7 years ago from Vancouver, Canada and San Jose del Cabo, Mexico

It is amazing to me how an intelligent brain focused on a problem can think it through to a 'correct'or workable conclusion.

I am pleased you pointed out that scientist are not developing brand new theories in most case, but rather modifying existing ones. Good Point.

And as the two commenters above note, those who propose a theory that does not work entirely, provides stepping-off points for others to expand upon.

Good hub. UP and useful.

• blog8withJ

7 years ago

Obviously, scientist tried many experiments and failed many times. It's just that the more they try, the more observant and clever they can be. And so was Einstien...

• VoltaireZ

7 years ago

I was talking about this and am also doing some thinking on the nature of knowledge in this regard. A person who is wrong about something, in some case, or in many cases is just as important as the person who gets it right, because they help discover what isn't. Just thin of how many wrong ideas Einstein had before he had one the fight reality.

This is also the reason I chastise people for being to harsh on religion, since religion was the first explanation for things, and there was no evidence to the contrary. AND religion is also a successful. If a person thinks Jesus is helping him out, but in actuality it is a comforting belief system and a shared social network that is helping him out, it still a working theory. It's not as accurate as other theories, but that is the nature of all of our theories, they become more and more accurate. They go from very very crude with limited predictability, to very refined and greater predictability. I think a thousand years from now, some intelligence on the Earth will look at our present science like, like we look at Aristotle's science, or even like we look are religion.

working