On space-time relativity:
I have read enough of relativity to understand that although the speed of light in a vacuum is constant, time and space change relative to the observer. A person observing someone who is traveling at the speed of light will observe the traveler as not moving and extremely thin. I also understand that nothing can accelerate to the speed of light because the equations show that to attain the speed of light would require an infinite amount of energy. What, however, is the consequence of one traveler who is moving at 51% of the speed of light in one direction and another traveler moving also at 51% the speed of light but in the opposite? The speed at which they are separating would be at 2% above the speed of light. What then would either traveler observe if a laser beam were directed from one to the other? According to Einstein, the laser would leave the one at the speed of light. To the other, once the light arrived, would still appear to be traveling at the speed of light. As I see it, there are only two possible results, one, the light never reaches the observer, or two, it reaches the observer at some other frequency than it was emitted at.
Another question of which I’ve not read about is in the case of two travelers accelerating in opposite directions such that, when measured, their velocities relative to each other is greater than the speed of light in a vacuum. What would one observe of light emitted from the other? I don’t know.
I can imagine how this would appear; let’s say that one traveler is accelerating toward the speed of light. The traveler, as he is accelerating, continuously emits a laser light towards an observer. As the acceleration continues, the observer would notice that the wavelength keeps getting longer. If the traveler were to eventually achieve the speed of light, the wavelength of light would become infinitely long. What is a photon without wavelength? If we extend the scenario further and they are accelerating away from each other at 102% of the speed of light, what would be the result? I have read that if something moves faster than the speed of light it would appear to an observer as moving backwards in time. If both travelers were to observe each other would it appear to them that the other is moving back in time? Or since they are both moving through time in the same direction would they still see each other as moving forward in time. To a third observer that is stationary relative to the two travelers, obviously, they are both moving more slowly forward through time at 51% of the speed of light. Hmmmm… I’ll have to think about it some more.
On the nature of quantum reality and our everyday experience:
The reality of our everyday experience is the arithmetic mean of all the quantum measurements that occurred up to our observation.
Our reality seems so “normal” when compared with the quantum world because our reality is the mean of all the measurements of quanta. Every time a quantum particle affects or is effected by another quantum particle a measurement takes place. Even though we don’t perceive the individual measurements that are occurring we do make a measurement when we observe our macro world. What we observe is the arithmetic mean of every measurement that has occurred up to that point. The reason why there are no macrofunctional multiverses where, for example, Hitler won WWII is because the difference between all possible quantum states in our universe and the mean that we observe cannot exist cohesively.
For clarity, let’s say that particle “a” has possible states “x” and “y”. A measurement of the particle is just as likely to result in state “x” as state “y”. Overtime the result is that the mean will be that half of the measurements will result in the x state and half will be in the y state. But, now, let’s suppose that a different particle which we will also call particle “a” and which also has possible states “x” and “y” does not exist with a 50/50 probability but a 60/40 probability. This particle then is more likely to give “x” results then “y” results. Now to expand further, let’s suppose that there are one hundred particles, some of which may have two possible states some may have three or more. Some of the particles have states that are more likely than others some have 50/50 probabilities. At any instant in time, if we were to measure all one hundred particles and repeat the measurement one hundred times we would observe that the collective difference in the particles would vary little with each measurement even though the individual measurements could vary greatly. If this thought were expanded to included all the quantum particles in a human body and all quantum particles that interact with that body it is easy to see that a functioning human body will always be the result and that there will never be a result where a human will in an instant become a bird.
Now then, what happens to the less likely particle states? Did those particles states cease to exist once a measurement was made? Or did those particle states branch off into their own universe? I believe that if they continued to exist in other universes, those particles would probably not function well together. Because those particles are already less likely if they interacted the result of their interaction would be even less likely which leads to an ever increasing cascade of unlikely ness; the opposite effect of our reality. Those universe would spawn alternative universes of the least likely outcomes. I imagine these as universes of particles popping into existence, popping out, annihilating each other, spinning off in random directions, and basically now one would exist to observe it.
So is there a universe where Hitler won? My answer is no. Are there “multiverses” Sure, why not, but it wouldn’t be a nice place to live.