You know the thing about time travel is that it is a 1 way trip. Meaning: Once you arrive at your destination, in the past, you have ultimately changed all linked events proceeding thereafter. This reaction forever shifts the entire chain of timeline event, thus shifting the outcomes of your departure time. Please allow me to elaborate:
The
Hawthorne effect is a form of
reactivity whereby subjects improve or modify an aspect of their behavior being experimentally measured simply in response to the fact that they know they are being studied,
[1][2] not in response to any particular experimental manipulation.
Essentially, anything that you observe, you also change, due to the nature of your interfering observation. This fundamental concept is actually how network security is maintained on fiber-optic networks. The observation of a photon of light is also the interference from its departure location to its final destination. Such interference immediately breaks network communications, thus, creating a network security breach.
You could always attempt to return to the present, after visiting the past, but it would not be the present that you left, due to your interference in the past. The journey is a 1 way trip, and the deviational shift associated with the timeline cannot be undone. This concept is commonly referred to as the multi-universe theory. It states that all possible outcomes essentially exist due to an infinite number of probabilities. So yes my friend, you could travel back to this morning and force your past self to eat a strawberry pop-tart, instead of a blueberry pop-tart, but when you returned to the present, things would be slightly different, as your actions had changed the rest of the outcomes of the timeline throughout your day.
Because time travel is a 1 way trip, any time travelers that have ever intervened in our past, will ultimately return to us at their set destination times. They may be very unhappy that they are not able to return to the timeline they might refer to as "home", but we should do our best to make room for them in our timeline because it was their actions that ultimately created the deviation in our timeline from their own.
The
Heisenberg uncertainty principle is a concept in
quantum mechanics that states that of all the things you can measure about an object, there are some things that cannot be known at the same time. An object's location for example, no matter how small or large, can never be known exactly if you know even a little bit about how fast the particle is moving or what direction it's moving in. This also works the other way around: the more one knows about how fast the particle is going and the direction it is going, the less one knows about where it is right now.
It is impossible to measure simultaneously both the position and velocity (or momentum) of a microscopic particle with absolute accuracy or certainty.
In
1927,
Werner Heisenberg became the first person to propose this law. This law became a central principle of
quantum mechanics.
In
quantum physics, the outcome of even the best
measurement of a system is not already a fact, but instead is shown by a
probability distribution. The larger the related
standard deviation is, the more "uncertain" we might say what we are showing is for the system.
The uncertainty principle is often confused with the
observer effect.
A lot of people get the Uncertainty Principle confused with the
observer effect (even by Heisenberg, at first), and a lot of people accidentally think that the Uncertainty Principle is caused by the observer effect. The two are not actually related.
The Observer Effect says that when you try to observe (watch) something, you will always change something about it, even if you do not want to. That means that your measurement will never be exactly right. People (including Heisenberg, until he made a correction based upon Einstein's counter-example) used to think that a
thought experiment called
Heisenberg's microscope proved that the Observer Effect makes the Uncertainty Principle happen.
The Observer Effect only happens when you
observe something in order to measure it. In
quantum mechanics, scientists do not
have to
observe a particle in order to understand it within a model. In the models, particles cannot have arbitrarily precise position and velocity, regardless of whether they are measured or not.