Time travel is impossible
I've always felt that this is the case, sometimes because I feel that time is simply our perception of separating now from then, sometimes because it just causes too many problems.
Well, I was thinking on a genie granting a wish for a super power; the ability to travel through time, but without interacting with anything and thus unable to make no changes, but rather simply to observe. Well, this brought up a few problems. If I can't interact with anything, then that would include air and light. Thus, not only could I not breathe, but I would be blind and deaf. More importantly, there would be nothing exerting pressure on me and I would explosively decompress. That would suck.
So then I thought that the ability would need to allow a twin copy of each molecule I would need to interact with just to exist and observe to be created as it interacted with me and destroyed once it was done. I would need to keep the twin oxygen...but then what to do about my carbon dioxide? It raises several problems in and of itself, let alone the problems with conservation of matter and energy.
That's when it hit me: time travel would require violation of conservation of matter and energy.
Okay, we have to assume that time is continuous.
Let's say, for a second, that time is discrete. If it is, then there exists a quantum unit of time. Defining a 'moment' as a point in time, that would mean that moving from one moment to the next would move any given particle from one position and velocity to the next with no presence in between those two points; particles would 'jump' from position to position each incremental moment along the time line. Something would have to be causing that to happen; I think of a computer processor. If we invert the quantum unit of time, we would get the frame rate of the universe (FRU). If we multiply this rate by the number of clock cycles required to calculate the next position and velocity of a particle and then actually move it (change cycles - CC) and by the number of particles in the universe (N), we get the minimum processor speed of God's computer (PSC);
PSC = FRU x CC x N
Discrete time implies that the universe is running on God's computer. Possible, but not the point of this discussion.
So, time is continuous. Keeping with the same definition of moment, then, the number of moments between two different moments is infinite. Time travel would require all the matter and energy in the universe to exist at any moment to which I would want to travel. Or, more to the point, the amount of matter and energy in the universe would need to be whatever it is at any given moment multiplied by the number of moments from the beginning to the end of time. But there are infinite moments along the time line, implying an infinite amount of matter and energy existing. That violates conservation of matter and energy.
Thus, time travel is impossible.
Well, I was thinking on a genie granting a wish for a super power; the ability to travel through time, but without interacting with anything and thus unable to make no changes, but rather simply to observe. Well, this brought up a few problems. If I can't interact with anything, then that would include air and light. Thus, not only could I not breathe, but I would be blind and deaf. More importantly, there would be nothing exerting pressure on me and I would explosively decompress. That would suck.
So then I thought that the ability would need to allow a twin copy of each molecule I would need to interact with just to exist and observe to be created as it interacted with me and destroyed once it was done. I would need to keep the twin oxygen...but then what to do about my carbon dioxide? It raises several problems in and of itself, let alone the problems with conservation of matter and energy.
That's when it hit me: time travel would require violation of conservation of matter and energy.
Okay, we have to assume that time is continuous.
Let's say, for a second, that time is discrete. If it is, then there exists a quantum unit of time. Defining a 'moment' as a point in time, that would mean that moving from one moment to the next would move any given particle from one position and velocity to the next with no presence in between those two points; particles would 'jump' from position to position each incremental moment along the time line. Something would have to be causing that to happen; I think of a computer processor. If we invert the quantum unit of time, we would get the frame rate of the universe (FRU). If we multiply this rate by the number of clock cycles required to calculate the next position and velocity of a particle and then actually move it (change cycles - CC) and by the number of particles in the universe (N), we get the minimum processor speed of God's computer (PSC);
PSC = FRU x CC x N
Discrete time implies that the universe is running on God's computer. Possible, but not the point of this discussion.
So, time is continuous. Keeping with the same definition of moment, then, the number of moments between two different moments is infinite. Time travel would require all the matter and energy in the universe to exist at any moment to which I would want to travel. Or, more to the point, the amount of matter and energy in the universe would need to be whatever it is at any given moment multiplied by the number of moments from the beginning to the end of time. But there are infinite moments along the time line, implying an infinite amount of matter and energy existing. That violates conservation of matter and energy.
Thus, time travel is impossible.