Largely unknown. However- you are theoretically traveling in time as we speak- and you do not find yourself floating in space. Now- in ONE possible theory- “traveling through time” isn’t just so one dimensional. If you were to have a way to set a desired time and travel to it- WHERE would you be in that time? You’d need to specify ALL dimensional points. Here’s the simple version:
Take a graph with an X/Y axis only. Now- if I say “I want to travel on the X axis...” I can specify a place on the X- like X23 for example. But there IS NO X-23 on an X/Y graph. You’d at minimum need Y -1, Y 0, or Y 1. Thus I could say “I want to travel on X to X23, Y0.” Expanding that to 3 dimensions (X,Y,Z) gives us a general system of special reference. Adding at least one additional dimension would give us time, meaning we’d need to specify at least 4 points minimum in theory.
So if you specified a point where there’s no solid ground... yeah. But that’s no different than moving without time. If you get in a rocket and fly to a space the earth isn’t- you’ll be in space too.
Of course this could explain why there are no time travelers. Traveling through time may have been figured out but the space travel bit may have been lacking. Nothing like getting ambitious and traveling 500 years in the past only to find yourself a lightyear away from earth. Of course this whole concept isn't new. T.A.R.D.I.S. There were a couple of episodes where they ended up in the right time but wrong space.
True. It’s An old theory because it’s one that an easily be reached using observation or Newtonian physics- even algebra. The earth revolves around the sun once every 356 days. So if we traveled to exactly 1 yet ago it’s fine right? No. 1. Earth doesn’t take 365 to travel around the sun. That’s why we have leap years. So every year on the 5th of June or whatever date you pick- the earth is slightly behind where it was the previous year and so on- until you go far enough back to have it line up again- a looong time.
But perhaps more important is that even if the earth had a perfectly circular orbit with no tilt, and even if the orbit around the sun was perfect- we tend to forget that the entire solar system isn’t just sitting in one place spinning. It’s blasting through the galaxy at insane speeds while the galaxy does the same with the universe.
That means even a single second of time travel to past of future could be your death. Conveniently we usually see that when a person travels through time in fiction they “teleport” or enter some extra dimensional space. What suggests that would be the case?
The graph example sums it up. While you are moving through the time axis you MUST move through the dimensional axis- relatively at least. When you pull a table cloth out from under a vase quickly- the vase stays and the cloth moves. It doesn’t matter though since from the cloths perspective the vase moves.
Say our cloth has checkers on it. We number and letter grid it like a chess board. The middle where the vase is is E14. As you pull the cloth under the vase it moves through D14, C14, etc. so the vase is still moving on the 2D axis.
Adding time as a 4th dimension, as you go to the store you move on the 3D axis but you also move along the 4D. As you sit perfectly still, the planet and universe are moving in 3D and 4D and you’re locked in reference so are moving with them. When you jump into the air, even though earth is spinning thousands of miles per hour you don’t land miles or even inches from where you jumped. You’re locked into a system with earth.
So a major question is: do such things hold in time travel? That’s the basis a time machine functions on usually isn’t it? If the Delorean from back to the future reaches 88mph and goes back- why aren’t you left in the present flying along at 90 inches above the ground before ending up in the trauma ward?
Just as if you jump on earth you don’t end up on another continent- when you jump on a bus you don’t smash into the rear window. Throw a penny in the air while driving and it lands in your hand. This same principal is often involved in time travel theory and fiction. That if your time machine goes back in time- whatever shares it’s “temporal momentum” or what not- passengers, cargo, fuel, whatever- goes with it.
But let’s dig deeper. What would happen when you time travel? That’s very important. If your matter doesn’t stop existing, “blink” out, cross some threshold to another world- you’re still here. What’s changed? As we speak you are traveling “forward” through time AND space. Can you walk through walls? No? Then why would you not be effected by matter if you’re “time traveling?” Why would you stop existing in physical space just because you are traveling through time- when you’re traveling through time now and here you are in physical form?
what is meant by “time travel” is critically important. If we say we are using some sort of teleportation- every atom and bit of information and all the energy and anything else that makes up “you” is being instantly taken from one point in space and time and sent to another- that’s theoretically simple as discussed. You couldn’t and wouldn’t make a teleportation mechanism that doesn’t requires some type of destination be specified. In this case you’re only going to end up wherever the heck you decided to send yourself or the “phenomenon” sends you. That isn’t “time travel.” It’s teleportation with an axis for time.
If we are discussing some theoretical quantum teleportation on a complex level like an entire person- we already have done small scale quantum teleportation. We know how that works. No reason to think the principals wouldn’t apply. So the question in these cases is misleading as you are not “traveling through time” but “teleporting to a different point in space time.” The space part is wherever you aim for- so wether you end up in space is largely up to you. It’s semantics since if you aim for “the same place you are right now..” that place has moved in reference to the rest of the universe and thus you already must know where the place you are now is then before you set out for there- so if you aim for where you are now you’ll hit that spot in a different time because where you are now is still somewhere- just not where it is now.
But everything else moved to- so unless you’re teleporting with an unknown destination- which if you know you’re teleporting through time then the destination can’t be completely unknown- where you go is where you say you’ll go, and why would you choose to end up in space unless you wanted to?
Now- some sort of “worm hole” is again- not strictly time travel. Said “worm hole” traverses physical space. You’re traveling from point A to point B. Point B is wherever the hell it is. If there wasn’t a wormhole in that spot “then,” there won’t be now. So you have some idea where you ARENT going anyway. If you don’t know where said hole goes- you have no reason to believe it would drop you anywhere in earth regardless. So the question in that light is like asking: “if you jump into a cave, will you end up in a lake?” Well... if there’s a lake in the cave then yes.
Lastly is “time travel.” This would be like being able to walk to 1704ad the same way you walk to the store. In that sense, if you are experiencing linear time- most likely things would appear to be moving backwards to you, and you could still move in 3D space all the while. Meaning that you simple have to not fall of the earth. Keep your feet on the parts of the planet which are solid as it spins beneath you.
You’re still physically in space. You haven’t ever left the part of the graph with our up/down, left/right/forward backward axises. You’re still in the same system with earth. You’re still “on the bus.” If the bus is moving 30mph and you walk towards the front- you’re moving about 1-2mph in relation to the bus but 32mph in relation to a stationary object. You’re still spinning along in space with earth and you don’t fly off or anything.
So if you don’t remove yourself from the existing physics systems you’re a part of- there is no reason to think they’d act differently than before. Why would time travel free you of the effects of gravity or inertia? If things are “moving backwards”- you threw a ball in the air and at the apex of it- now reverse time- what does the ball do? It comes back down.
When you throw the ball you impart a force on it against gravity. Overcome the gravity. The ball rises and the force you imparted weakens. The force is now pushing the ball down as it increases in force. You catch it, the force the ball had goes back to you. Ok. So what changes if we reverse time at the apex? The ball comes down, you catch it. The force in the ball returns to you- the one who imparted the force to begin. The ball is back in your hand.
If we keep things in mind like the fact we can’t destroy energy- the energy of an even flows from source through object to object- then in reverse it would flow from object, to object, back to source. We have to remember conservation of energy, momentum, inertia- all our basics of physics don’t stop applying just because we hit rewind on the tape.
Of course in order to experience and understand your travel through time, time for you would have to continue moving forward while everything else moves backward. This would mean you'd have to have someway of separating yourself from the current time stream. Meaning it's likely that gravity wouldn't affect you or your time machine at least the gravity outside your self-contained bubble. In fact because for you "time" is still moving forward while for the rest of the universe "time" is moving backward you may find yourself repelled away from outside gravity sources. Granted we don't really understand gravity other than it appears to work and can affect almost anything.
It becomes an interesting question though and we are again forced to ask: how does physics work when moving through time? What is “you”? If “you” go back in time- what makes up you? Let me put this another way. We build a sled. It has a chair on it. There are suitable restraints at your head and neck and spine etc. to hold you solid. We accelerate the sled to some near supersonic speed and then stop it completely in the space of 100 yards. What happens to you?
Most likely- you die. Or come pretty close. The restraints keep you from whiplash and such- but your body is full of fluids and organs. Those fluids and organs are moving at the speed of you and the sled. When the sled stops they do not. The differences in mass between things like your bones and your kidneys and blood mean they all keep going with differing force. Your brain smacks against the front of your head, capillaries burst from sudden rises in blood pressure while other areas see sudden huge drops.
So when “you” travel through time- we are talking about a bunch of discrete components that are somewhat attached or in contact with each other traveling through time- not one solid block. If “you” travel back in time 1 second but your blood doesn’t- you die as soon as you arrive. If “you” travel back but not your artificial hip or your filings or your pace maker... that could be bad.
So what are we talking about? We need every atom, every particle and every bit of quantum information we will call “you” to go with you right? The water and sugar in your cells, the bacteria in your intestines, your white blood cells, red blood cells, mucous- it all has to go or else it will be very bad for you when you arrive no?
Now- gravity is tough. We don’t know a lot about gravity. Some say it is a force which “pulls” or “pushes.” Some say it is a distortion in the plane of space time we experience. We don’t have a lot of hard evidence but one theory holds that gravity propagates throughout space time regardless of direction. The standard model holds gravity acts on all dimensions including time. Most quantum models do too.
In fact- in many string theories gravity is seen as a strong force which we perceive as a weak force. Say whaat? Let me explain. For all intents a purposes a drawing is 2D. You can’t interact with the drawing itself- just the page it is on or the medium. But- light reflecting off that drawing can be perceived by your 3D eyes. You can even make a drawing which looks 3D.
If you draw a tank in a 2D world- that’s very powerful. In our 3D world that drawing of a tank lacks its theoretical functional ability in its dimension. But! You can still see some effect of it. Poor analogy but they all really are.
The point is that gravity- having theoretically the ability to interact on all dimensions- could itself not be a native force to our dimension- but the observed effect of a force originating in another dimension. In the standard model gravity cannot be disconnected from space time- it is a part of space time or a quality of it. In quantum theories we can view gravity a few ways. The most popular is the idea of the graviton.
Smaller than atoms are things like quarks and leptons. It’s theorized that even smaller particles exist. A leading theory is that these particles have a “spin” or direction. It’s theorized these particles exchange tinier particles as part of their interaction- and that the Higgs-Boson is the particle responsible for imparting mass upon other particles- with photons for some reason not being a valid target for the Higgs boson and hence having no mass.
Since we have never observed it- we can’t say- but basically every known model and theory of physics falls flat on its face if we have a situation in which gravity is not effected by time as a dimension. We have observed that gravity does in fact distort time- we can see the relativistic effects of gravity when we compare the progression of time as it acts on a control sample in a given gravity and an experimental sample in another intensity of gravity.
We also know that velocity in space has effects on the passage of time. So far we have no data to suggest that movement through time does not require movement through space- and as per the earlier graph reference- you cannot move on an X,Y,Z,A graph on only one axis. No matter where you are on the graph- the point you are at will have a reference for each axis, and any movement on one axis will change your relative position to the others.
If we simplify- X is distance and Y is time. You are at X1, Y1. If you do nothing you will be moved to X2, Y2 because the universe is moving and time is moving. If you could travel as you pleased on the Y- and decide to go from X2, Y2 to X2, Y1- you would be in X3, Y3 and would still have to cross X2, Y2 to return to X2, Y1. Unless you could teleport. The closest we have to that would be quantum “teleportation” however that doesn’t allow for physical transportation- just the transmission of information about the quantum state of a particle.
If we could apply this to an entire person somehow- the missing piece is that in order to perform quantum teleportation you need to send a bit of classical information for every q bit sent- the quantum teleportation cannot be complete until this classical information reaches both sending and Recieving teleportation sites.
That restricts the ability to send information faster than light because while the teleportation is “instantaneous” the Classic information is limited in speed. If you cannot send the classical information then you cannot decipher the quantum information sent.
The theoretical implication there is that you could only travel in time between two points which physical information can travel. In other words- we can travel to the future- because we can send classical information to the future. That information can only be sent as far ahead as we have the ability to revive and decipher the data. The human consciousness may actually be a limiting factor there- as our brains have a limit on how long or short the delay between recieving information can be in order for them to function properly.
That would mean that if we could create man made time travel through teleportation- it’s very possible you could only effectively travel between points where time travel has already been invented. This is because only these points would have the ability to receive the classical data required to decipher the state of information you are being sent as.
So- say you teleport to a planet 3,000 light years away. A classical data transmission is sent to decipher your quantum state so that you can be “materialized” at the destination. You are limited in your travel by the distance. Using light speed communications with no delays- you couldn’t manifest on that world until 3,000 years had passed and the signal reached that planet. If your signal was deflected, if no entity was there in 3,000 years to decipher the classical information- you wouldn’t be able to manifest at all.
Now- in order to pull off such a feat to go BACK in time- you’d probably need some sort of signal that could travel back in time. Tachyons are the go to sci fi fodder for “particle that supposedly can go back in time.” That’s questionable but let’s just run with it for now. So- you’ve figured out a way to send classical information back through time. The problem of that piece is solved. You could not theoretically send yourself back using teleportation. Send the q bits and send the classical information....
BUT! If no one back in time has the ability to receive your information you couldn’t be reconstructed. That information wouldn’t be useful to anyone until you came along and discovered how to do it. But quantum information can’t be copied. There’s a no copy rule.
So- if you wanted to travel back to 1965, or let’s say 1201, or perhaps... the Big Bang? Well- who will be there with sophisticated equipment and an understanding to receive the quantum and classical information to open the “quantum channel” and allow the teleportation? No one. So the teleportation wouldn’t work.
This would limit the actual distance you could travel in “time” to a range where SOMEONE at your destination place and time had the ability to receive and interpret the signals you sent; AND where the classic signal was not somehow intercepted or distorted; AND keeping in mind that the state couldn’t be teleported until the classical information (sent at sub light speed) had been received.
So- recall earth and the very universe itself are moving. You will be thousand of miles from where you were when you started reading this when you finish. So if you invented time travel at 9:00pm 11/31/19- then at 11:00pm 11/31/19 wanted to travel back to 10:00pm 11/31/19- you have a problem. Your classic communications need to reach the point in the past you want to go to- but there is a delay from when the transmission is sent- to when the transmission reaches the point you’ve specified based on distance. This leaks that there are certain times you can’t reach because the time between now and then isn’t enough for the transmission of classical information to reach.
But here’s a BIG problem. If we look at the situation as: we must specify an absolute point in space to travel to- you want to be on earth yesterday you need to specify where earth was yesterday or it won’t be there right? Yesterday earth wasn’t where it is now. So you need to specify a point.
It's really amazing what speculation can lead too and rather unfortunate that we have such a poor understanding of how things actually work. We also have a major issue in the fact that once you've determined the quantum state of a particle you have in fact changed it. Now in some far off future where we can manipulate that change you could create the correct state to enact your teleportation. Throw in the whole entanglement process and you may be able to negate the delay in your scenario.
If there is such a thing as a graviton and the fact that antimatter exists it would mean that it's also possible for an antigraviton exists too. Now gravity affects time but it's still linear it can slow down the perception of time. Nothing we've found can reverse time or completely stop it. And it's also possible that time continues pass at normal speeds but it's gravity that enacts it's own bubble in the universe. This could mean that our perception of time is limited to our bubble and the universe is a series of these bubbles but not constant without gravity.
Now if antigravitons exist instead of slowing time in large concentrations it may speed up the perception of time. Conversely these very particles would be necessary to move backwards in time because while gravitons only work on the forward momentum of time antigravitons would work on the reverse momentum. But like I said it's really all speculation and it may not be something we can even test until we can place ourselves in a large enough area without any gravity, namely the space between galaxies. Which means any real understanding would require either massive amounts of time or an accident leading to FTL. It would be another of those we know this works now lets find out why scenarios, like gravity.
Lol. All very well said and plausible. In the end we do have to somewhat throw up our hands and shrug until we can get some more information- we are perhaps at the sort of “Ancient Greek” phase where we can look and see things happening but can’t explain them- but can make some logical deductions as to SOMETHING being behind it. Wether luck or brilliance or intuition- some of these ancient thinkers made pretty correct guesses about scientific concepts we wouldn’t be able to prove for millennia. They were also totally wrong about some things of course; but credit where credit is due.
We could also be in a sort of “miasma” or “humor” state where we are basically story telling in those regards. Trying to apply intuitive solutions based on our everyday to a problem which we just aren’t on the right track. And of course- it could be more of a late 1930’s through 40’s phase- where we have the right “big picture” and great ideas but just don’t have the technology yet to put some of these big ideas into use or even proper testing... but will soon if we keep trying.
The question of time travel depends HUGELY on the nature, the “rules” and “architecture” of time itself- and if “time” actually exists as a discreet entity. For example- we’ve never seen anything that doesn’t move- that we know of, and would have almost no time to study such a thing.
That is to say: if there were some observable entity which did not move at the atomic or subatomic level, that was not roped in to the physics of another system and so had 0 universe with the planets or galaxy or universe- a truly stationary object. The earth’s spinning while orbiting a sun while that sun orbits in a spinning galaxy which is moving. A fixed point in space would seem to disappear almost instantly, and would not cross the same point in reference to the observe effectively ever again. We would get a glimpse of such a thing for a fraction of a second at best and then never again. With current technology we couldn’t gather meaningful data nor perform experiments really.
So we perceive time as moving, and we think of it on 3 dimensional terms such as moving forward and backwards. But it is not necessarily a 3 dimensional space. What would “moving sideways” in time look like? Is there a “sideways” in time? But 2 big questions are: does time “move” as we perceive it to? Could you theoretically “stop” time? Not as in do we have the ability- is it even possible? Is time something that “flows” or does the nature of time make it something that simply is or isn’t?
Is it possible that “time” is already “stopped” and that time doesn’t move at all- that it is simply an overlay and it is us who are moving? Is the relativity of time in the nature of time? That is to say that like magnetism or gravity is time a force which acts upon things differently based on what those things are and the conditions locally?
So that there isn’t anything to be reversed or stopped in such a sense? Is the nature of the universe persistent? If you were to “time travel” to 1950- are YOU traveling- or is the entire universe needing to revert to that stage while you remain in your present state? The latter is consistent to relativity. Where you fly a lightyear or two at near light, light, maybe even faster than light, return in
What to you has been months or years: but find everything else hundreds or thousands of years in “the future.” You did not “time travel to the future.” The universe did and you were kept in a different state of temporal reference.
So it may just be that any time travel would be relativistic- that you wouldn’t be traveling but instead would merely be in a state where you were not affected the same by “time” as the rest of the universe.
Of course- “time” could just be a component of distance and perception. The “time” on a clock is not “time.” It’s a measure of perception. Like a metronome does for musicians it is a metric we use to help sequence events so we can comprehend them. We do not observe animals to follow “time” in a clock yet animals are excellent at keeping schedules. When to sleep, Hunt, migrate, pets knowing about what time they go for walks or get fed or when you come home.
We observe it as “wow. They know when it’s 5pm it’s walk time..” or “every winter they know to migrate..” But that’s not the case. Migration and sleep patterns and such as disturbed by changes to the environment. Animals don’t perform these actions at any given “time” they associate certain cues with the actions; when those cues are present they behave accordingly. It isn’t winter that causes migration but temperature etc.
So “time” as we see it on the clock is tangentially related to “time” as a force. It is just a device to measure our local perception of time; and the key being our perception- our concept of how we experience time being not inherently linked to the actual workings of time.
In that regard and by traditional models “time” as a force would simply be an aspect of speed and distance and not an actual entity. Time wouldn’t move at all. Time would not exist without distance or speed. Time would simply be a unit of measure like a kilogram, and the question of how one travels through time would be like asking how does one travel through kilograms? You can’t travel through a measurement.
If the universe stopped moving, if everything stopped moving down to the basest level of matter- we could say time had stopped. Nothing would age, nothing would happen. There would be nothing to measure and no way to measure it. So this theory would say that time is inherent to distance, and time simply measures movement.
Of course in string theory if “everything stopped” the universe might disappear since the string wouldn’t vibrate and the universe as we know it would just be vibrations of that string. Lol. But- it may be entirely possible that time travel is just distance travel!
If you wanted to go back to yesterday, 3:00pm, your favorite food spot, and re eat the same burger you had- you’d need to go back to that EXACT spot. It would merely be a point in space we could designate with coordinates and make a map for.
As discussed though- the planets have moved and other things too. So say you fly to that exact point in space? You now have “gone backwards.” Earth isn’t there. Neither is your burger. Well- it’s not just your body that has moved is it? Your cells have changed. Your state has changed. You’d need to revert your genetic and biological state. Then you’d need to move the earth and everything else in the universe to where it was when you were at this spot last time.
But your very presence there alters things because you bring information which didn’t exist here previously! So to truly travel back to that point in time- you’d have to move the universe and rewrite your genetics and then wipe your mind to the exact state which it was in when you were there last.
There is no paradox this way- as you’ve simply moved everything to its previous position, so after these events play out it will just continue moving-
No “duplicate reality” or “alternate futures” no “past self” to bump into because you aren’t in the past you are in the present but it is a present where everything is exactly as it was as it passed through this point in space.
We tend to think that “turning back time” would just revert everything to where it was “before” but as examined- what force would be able to do that? What force do we know if that can reverse changes to complex DNA and erase memories and move planets and solar systems and reconstitute matter? Time can do all that now?
Of course- all events in the universe could exist as a single dot on a paper. Everything that is or was or will be could be happening simultaneously and “time” could merely be a construct of perception sequencing those events artificially to allow us to understand them. If that were so, time travel would simply be within the mind- and to an outside observer would likely appear to be someone who has gone insane but is actually just perceiving a different time or sequence of time while you are perceiving them. That one is a stretch- but as you say: we don’t really know.
What to you has been months or years: but find everything else hundreds or thousands of years in “the future.” You did not “time travel to the future.” The universe did and you were kept in a different state of temporal reference.
No “duplicate reality” or “alternate futures” no “past self” to bump into because you aren’t in the past you are in the present but it is a present where everything is exactly as it was as it passed through this point in space.