# Einstein and the speed limit of the universe

Einstein did not support the fundamental uncertainty of quantum physics. He stubbornly maintained the idea that reality was permanent and objective and that the observer played not a significant role. Yet the observer plays quite an important role in his best-known work, the theory of relativity. Precisely if you assume that the observer makes the observed ‘true’ and thus actually creates reality, his approach to the relativity of space and time offers a surprising outcome.

## Special relativity

The special theory of relativity can be followed perfectly by using nothing more complicated than Pythagoras and a dose of high school algebra. But I’m not going to do that here now. There is a lot to be found on the internet doing that. Read for example: Special relativity math2410 from Leeds University.

## Symmetry

An extremely important premise for Einstein was that the universe should basically look the same for two observers moving relative to each other. Ultimately, that’s a symmetry argument. Symmetry has been an important criterion in the theories of physics since Emmy Noether introduced it in 1918. He combined this criterion with the insight that the observed speed of light – in a vacuum – must be the same in all circumstances. This followed from Maxwell’s equations for electromagnetic waves and was indirectly confirmed by the experiments of Michelson and Morley who sought to determine the speed at which the Earth traveled through the supposed aether by measuring differences in the speed of light going in different directions with regard to this aether. The outcome was that they could not measure differences in speed, no matter how accurate their experimental set-up was.

## To ride with a light wave

In addition, Einstein had realized from an early age that you cannot overtake or even keep up with a light wave. If you could keep up with light, Maxwell’s electromagnetic wave would no longer oscillate from your moving point of view, it would look like a frozen wave. But since the wave’s propagation is both caused and sustained by its ceaselessly oscillating fields, that couldn’t be right. Light must therefore always move at exactly 300,000 km/s for every observer. This follows also undisputedly from Maxwell’s equations because these do not contain any parameter relative to the position of the observer.

Einstein now imagined two observers moving relative to each other but who should both observe the same speed of light. Imagine a light source C standing still for observer Alice. Alice sees the light of C approaching her at c = 300,000 km/s. Observer Bob whizzes at great speed towards ligt source C, say 1/10 of c. Alice now considers that the light coming from C towards Bob must therefore move at 11/10 of the speed of light for Bob. I hope you can follow Alice’s reasoning. Otherwise, try to think of two cars driving towards each other while Alice watches along the roadside. Car with driver Bob drives at 10 km/h and car C drives at 100 km/h towards Bob and Alice. Car C here stands for the light that comes towards Bob and Alice. Alice observes (with radar) that the speed of car C is 100 km/h and that Bob and car C are speeding towards each other at 110 km/h. Now suppose that Bob would also perceive the speed of the oncoming car C relative to him as 100 km/h. That could only be if Bob’s clock ticked at 10/11 the speed of Alice’s watch. And not only Bob’s clock but also Bob’s entire perception of time would have to be slowed down so that Bob actually experiences the speed of car C as 100 km/h. In that case Bob will live a little bit slower. As far as Alice is concerned, Bob is now aging more slowly than Alice.

## Time slows down and space shrinks

Now back to the light that is always experienced by every observer at the same constant speed. If Bob moves relative to Alice at 1/10 the speed of light and Bob sees the light move at 300,000 km/s, then that is possible if the time for Bob slows down by 10/11. Bob doesn’t feel that way because he himself is sitting in his delayed time capsule, his car.

This simplified estimate of the slowing of Bob’s time is not 100% correct because something also happens with Bob’s yardsticks, but what matters to me is that you get an understanding of relativity reasoning. If you want to do this completely right, then, as already mentioned, some algebra and Pythagoras are involved and the time dilation, the slowing down of Bob’s time, is described with:

Here v is Bob’s speed, relative to Alice (or Alice’s speed relative to Bob). If you enter here 1/10 of the speed of light c for v, then Bob’s clock turns out to tick 0.5% slower than Alice’s clock. Now we apply the principle of symmetry that Einstein argued. There is no absolute speed, speed is always relative. Bob, who experiences himself as stationary, observes Alice moving away from him at 1/10 the speed of light. So Bob also sees Alice’s clock ticking slower by 0.5%. This seems a paradox, but the theory is correct and has been experimentally confirmed in countless experiments. The solution is that Bob and Alice can’t compare their clocks until they come together and for that at least one of them has to turn around which means speeding up and slowing down. This breaks the symmetry.

You can see from the above time dilation formula that the maximum speed that applies in the universe is 300,000 km/s. The term under the radical becomes negative when v becomes greater than c, which would make the time dilation imaginary. That’s too bad because it makes non-imaginary trips to even the nearest stars impossible for us.

From Alice’s point of view, Bob’s rulers also shorten in the direction of his movement. For completeness, this is the formula for the contraction of fast-moving rulers, the so-called Lorentz contraction:

It goes without saying that this sparked a lot of discussion in the first half of the 20th century. Einstein took the position that the observers of the clocks and rulers did not play a vital role in relativity effects. According to him, they could just as easily be left out of the equations. Fast-moving clocks would automatically slow down, fast-moving rulers would shorten without the need for an observer. This elasticity of space and time and of the material objects therein was, and is still difficult to grasp but has been confirmed experimentally time and again. We, the physicists, are more or less used to it now, but we do not really understand it. It’s not natural.

## Einstein fighting versus the probability interpretation of quantum physics

Einstein seriously put quantum physics on the map with his explanation of the photoelectric effect, for which he received the Nobel Prize. Light consists of particles with an energy per particle according to the Planck formula (f here stands for the frequency):

But after that he argued vigorously against quantum physics and especially its implications, to no avail. Especially against the probability interpretation of Bohr, Heisenberg and Born: that the state wave, the solution of the Schrödinger equation, represents the probability that the particle will be found at a given location and time when measured. That went against Einstein’s gut view of the world as an objectively permanent collection of material objects. Einstein’s objection is understandable if you adhere to the materialistic view of the world, because a probablity is not an objective material object. It is something that exists in our mind. A thought.

And that’s exactly my own idea of how the universe works. Everything we experience takes place in the mind. The perception of the measured particle thus becomes identical to the thought of it. The experience is then the same as its creation. That explains to me very well why the laws of physics behave according to mathematical formulas. That is something that many physicists, including Einstein, have expressed their amazement about. So the observers’ mind plays an indispensable role in the universe, it creates it. Mathematics is something of and in the mind. The mind uses apparantly mathematics in its creation of the universe.

## Time and space are concepts of the mind.

That idea suddenly makes things like the slower passing of time, the shrinking yardsticks and the curved space of general relativity, much more palatable. In a dream we would really not notice these things either. There exists no real objective time outside of us that does slow down, there is no objective space outside of us that does shrink, it’s all happening in the mind of every observer.

## Science Fiction?

That offers hope for the possibility of exploration of the cosmos. The maximum speed in the universe that we observe – that of light – seems to be something that the mind has imposed on itself. But as soon as we can accept that time and space is happening within the mind, the possibility opens up that we could move through the universe beyond that limitation. Traveling within the mind is not bound by the restrictions of relativity. This, I believe, is also the correct interpretation of entanglement and instantaneous action over long distances, as confirmed by all those Bell tests. Traveling through the universe by means of the mind could even be the way – one that intelligent beings existing elsewhere in this vast universe already have discovered – to travel through the cosmos despite Einstein’s speed limit. And to visit us. Experiments have already been conducted confirming that quantum tunneling shows speeds greater than that of light.

## A universe like a slowly fading flare

That the universe is a creation of the mind also offers an alternative for the pending entropy death of the universe that physics has been predicting for a century and a half now. Even if that is a immeasurably distant future away, it remains a bleak prospect contradicting any sense of purpose of the world. What was that fantastic spectacle all for if that is to be the end? But if the universe is the product of the creative mind, then that is by no means an unavoidable end to everything. On the contrary.

## Conclusion

What I want to say with this story is that there is a good chance that two apparently incompatible theories – relativity and quantum physics – can be merged together very well when we start to include the all important role of consciousness. The intelligibility of the nature of reality would only increase as a result.