What's your take on time travel?

[Explorer]

Much respect to @USMarine75 for covering the points I immediately thought of. I just went7 back and gave you positive rep in the past, bro!

 

[USMarine75]

Much respect to @USMarine75 for covering the points I immediately thought of. I just went7 back and gave you positive rep in the past, bro!

Well, all that money on a degree I never used now seems worth it lol...

 

[Seabeast2000]

I'm from the future and realize time travel is not yet a thing. Fm!.

 

[KnightBrolaire]

TLDR: time is a lazy river and back to the future gave me unrealistic expectations about how easy it would be to get auto-lacing nikes

 

[crankyrayhanky]

I say yes

1) everything happened already: gives us the feeling of "it was meant to be"
2) seemingly infinite choices resulting in seemingly infinite universes: gives us the feeling of Free Will

So I'm thinking likely YES on moving backwards and forward in time (rayhanky, 2019).

 

[TedEH]

Even if the multiverse thing were to be proven true somehow (and it sounds more like science fiction than any realistic scenario to me), you would still need a mechanism to move between these universes, and even that wouldn't necessarily move you through time, just through potential versions of the present.

 

[USMarine75]

Even if the multiverse thing were to be proven true somehow (and it sounds more like science fiction than any realistic scenario to me), you would still need a mechanism to move between these universes, and even that wouldn't necessarily move you through time, just through potential versions of the present.

Multiverses would likely have different laws of physics, resulting in incompatibilities with life/existence as we know it.

https://phys.org/news/2018-02-possibility-life-universe-weak.html

 

[p0ke]

Multiverses would likely have different laws of physics, resulting in incompatibilities with life/existence as we know it.

https://phys.org/news/2018-02-possibility-life-universe-weak.html

Well at least a large part of the other multiverses would, but there would be ones with similar specs too (if there is indeed a multiverse for each combination of variables). If time travel was possible within our own multiverse, we would already see the repercussions of it right? So I'd say the only chance for time travel being possible is that it would indeed create a new version.
A funny thought: What if time would be like a huge git-repository, in which all time travelers have their own branches, and then they have to be merged into the master branch when they return to the present time

 

[jaxadam]

Multiverses would likely have different laws of physics, resulting in incompatibilities with life/existence as we know it.

https://phys.org/news/2018-02-possibility-life-universe-weak.html

By default, multiverses would theoretically contain all possible combinations of all physical laws and possibilities (and, well, impossibilities).

Another hitch to going back in time is location. The earth would be in a far different position in the universe than it is today.

 

[USMarine75]

By default, multiverses would theoretically contain all possible combinations of all physical laws and possibilities (and, well, impossibilities).

Sure, if you start with a premise of infinite multiverses, but my point is the vast majority would be incompatible with complex matter and energy (e.g. humans) from our universe - negating moving between universes.

You change one of the forces, even by a few percent, and life doesn't exist as we know it. You change the elements, or even the very building blocks (e.g. electrons, quarks, atomic structure, probabilities, decay rates, spin, etc...)

If time travel was possible within our own multiverse, we would already see the repercussions of it right?

Assuming we're talking our universe here? Similar to Relativity, the notion of time as experienced by the bystander would be different than the traveler. So to you, as the traveler, you experience forward and backward travel - you are the constant and everything around you is moving in forward and backward time motion. The bystander would only see things unfurl forward, in accordance with the natural arrow of time.

FWIW... Some theorists have posited that, similar to how an electron from an atom in your body has a probability of being anywhere in the universe, no matter how small the chance... there has been the discussion that some particles could have the similar ability to probabilistically move forward or back in time (re: quantum entanglement).

https://curiosity.com/topics/entangled-quantum-particles-can-communicate-through-time-curiosity/

There is also the basic concept in Relativity, that the greater the speed as a percentage of the speed of light, the slower the perception of time is to the traveler. So, at the speed of light, time is zero. So, we currently theorize (and it holds true via empirical data) time can be manipulated in the forward sense (via speed, as can object length by the same reasoning i.e. Lorentzian contraction).

https://futurism.com/time-travel-bend-time

 

[jaxadam]

Sure, if you start with a premise of infinite multiverses, but my point is the vast majority would be incompatible with complex matter and energy (e.g. humans) from our universe - negating moving between universes.

You change one of the forces, even by a few percent, and life doesn't exist as we know it. You change the elements, or even the very building blocks (e.g. electrons, quarks, atomic structure, probabilities, decay rates, spin, etc...)

Agreed. I wasn't debating the multiverse premise, just reiterating.

 

[penguin_316]

Time travel is some bizarre obsession of mine and I enjoy most things related to its exploration. As mentioned previously there is the theory that at the speed of light time will bend for those moving at the speed of light, as gravity has an effect on time.

So some people mentioned time travel backwards is not possible and while I agree it might be possible to bend time for certain persons to not age relative to people on Earth.

If we move at the speed of light though, we’ll disintegrate. So, I guess it has its obstacles.

PS-check our the movie Primer, and the Netflix series Dark. Both were awesome for different reasons. Dark season 2 should be out soon, I’m amped.

 

[USMarine75]

As mentioned previously there is the theory that at the speed of light time will bend for those moving at the speed of light, as gravity has an effect on time.

For anyone that cares but is confused... Speed has an effect on the perception of time (relative to the observer vs subject), which leads to gravity also having an effect on the perception of time. The reason gravity and speed are interrelated is: speed is a function of distance traveled, and gravitational fields are a stretching/distortion of the space-time (see pics below), which leads to it taking longer to travel through that stretched space. Per relativity, there is no way to differentiate who the effect of this is on - the observer thinks time went slower for the traveler, and the traveler thinks time passed quicker for the observer.

A. Travel via stretched space-time:

VS

B. Travel via flat space-time (with no distortions):

Here is a good breakdown for anyone interested:

How Gravity Changes Time: The Effect Known as Gravitational Time Dilation

Interstellar and come out wondering how any of it was possible? It is mind-boggling to comprehend that one hour can pass by on one planet while seven years pass by on Earth.

The explanation comes down to what scientists call Gravitational Time Dilation. This effect measures the amount of time that has elapsed between two events by observers at different distances from a gravitational mass. In other words, time runs slower wherever gravity is strongest, and this is because gravity curves space-time.

Think of it this way — time follows a simple equation:

speed = distance / time

Light (in this case, speed) is always constant and travels at a speed of 180,000 miles per second. Imagine two beams of light: one in a weak gravitational field traveling between points a and b, and the other in a strong gravitational field traveling between points c and d.

The path between c and d is longer due to the curving of space and time so it takes longer for light to travel between the two points. This effect has been proven by several experiments and is used to run and maintain something most of us use almost every single day: GPS.

Global Positioning System (GPS) satellites are positioned about 12,550 miles above Earth’s surface and therefore are not as close to Earth’s gravitational field. The clocks on these satellites tick faster than the clocks on Earth’s surface so scientists have put a correction into the satellite programs to ensure that the GPS data sent back to Earth’s surface have matching times. Without this correction, GPS satellites would not be the useful tool that we know them to be.

http://thescienceexplorer.com/unive...time-effect-known-gravitational-time-dilation

 

[jaxadam]

This is a pretty interesting article that popped up that has to do with the brain's take on encoding time.

https://www.quantamagazine.org/how-the-brain-creates-a-timeline-of-the-past-20190212/

 

[Xaios]

We seemingly spend all day distracting ourselves from the only truth which is right now.

(Sorry for the necro-quote. )

Here's the thing though. If our only concept of the past is memory, then similarly, our only concept of the present is our sensory input. Further, if we entertain the premise that our perception of the universe external to our physical forms is both a) limited in scope, and b) just as much of a construct as our perception of memory, then it can't reliably inform us of the nature of objective truth. Doing so would be like trying to observe something through a telescope a) through fog, and b) what we were told is a telescope is actually a hamster. While there is technically a non-zero possibility of correctly perceiving an obscured object in the distance through an rodent that has, shall we say, limited utility as an optical magnification instrument, the odds are stacked against us.

Sure, if you start with a premise of infinite multiverses, but my point is the vast majority would be incompatible with complex matter and energy (e.g. humans) from our universe - negating moving between universes.

(Sorry for the necro-quote to you to. )

Eh, under the premise of infinite universes, given that there would be both an infinite number of universes with physical laws identical to ours as well as with physical laws that are completely incompatible with our own, the odds of landing in either even if we could travel between universes is... well, utterly incalculable.

Also, given that we're dealing with something that literally can't be counted, can we really say that there would be a majority of anything, or that such a concept is even applicable? It's not like we're dealing with grains of sand on the earth where, even though it's an absolutely massive number, we can statistically make reasonably accurate determinations on the average composition of that sand, or even something like the composition of this universe where we can assume that, taken over a massive scale, it's generally homogeneous.

 

[DudeManBrother]

(Sorry for the necro-quote. )

Here's the thing though. If our only concept of the past is memory, then similarly, our only concept of the present is our sensory input. Further, if we entertain the premise that our perception of the universe external to our physical forms is both a) limited in scope, and b) just as much of a construct as our perception of memory, then it can't reliably inform us of the nature of objective truth. Doing so would be like trying to observe something through a telescope a) through fog, and b) what we were told is a telescope is actually a hamster. While there is technically a non-zero possibility of correctly perceiving an obscured object in the distance through an rodent that has, shall we say, limited utility as an optical magnification instrument, the odds are stacked.

One must free themselves from thought to experience the present. Your scenario tries to predict potential future possibilities and subsequent issues based on past experience and learned thinking behaviors. These are the types of thought that keep you from experiencing right now. Just engage your “sensory input” and brush away any thought that tries to compare it to the past. Don’t allow your mind to wander into endless scenarios. Just see things exactly as they are. Wouldn’t a rose by any other name still smell sweet?

 

[TedEH]

our only concept of the present is our sensory input

Wouldn’t a rose by any other name still smell sweet?

That's not the question you're asking though. You're asking "does a rose smell good if you don't let yourself think far enough to even ask the question in the first place?" Memory and prediction are as much a part of the experience of a given moment as your direct sensory inputs would be. Consider just the concept of being "scared" for example. Most people would describe fear as a very immediate and "in the moment" kind of experience, but fear and surprise are functions of memory, prediction, violation of expectations, etc. This very immediate and present emotion and concept can't exist on the basis of the experience of the present moment being made up of literally only the current state of your physical sensory input. It's not like you can just choose not to consider the thing you're afraid of in the moment.

What about enjoying a sunset? Appreciation of a view doesn't function without the comparison to everything else you've seen in the past and aren't currently looking at. Consider how someone might describe a really awesome view as mundane if they see it every day, but a newcomer would be blown away by it.

Remembering to stop and smell the roses (which I think the is figure of speech you were aiming for) is a nice sentiment, and maybe a good device to keep a sense of perspective, but it's not much more than that. Limiting your experience to just your immediate senses I'm pretty sure is impossible, but even if it was, it would be incredibly impractical - maybe even detrimental. I mean, hey, don't need to put gas in the car -> That's prep for the future and the future isn't reaaaaal maaaaaaaan. Don't need to avoid that guy that I remember hates me. He can't have ever punched me in the face, or be likely to do it again, if the past doesn't exist either, right?

 

[Miek]

it's kind of blase but my answer to the central point of the op is "no" or "not until the first time machine turns on but even then it can only send limited things back in time that are of little value unless you really like Big Math Problems"

 

[DudeManBrother]

That's not the question you're asking though. You're asking "does a rose smell good if you don't let yourself think far enough to even ask the question in the first place?" Memory and prediction are as much a part of the experience of a given moment as your direct sensory inputs would be. Consider just the concept of being "scared" for example. Most people would describe fear as a very immediate and "in the moment" kind of experience, but fear and surprise are functions of memory, prediction, violation of expectations, etc. This very immediate and present emotion and concept can't exist on the basis of the experience of the present moment being made up of literally only the current state of your physical sensory input. It's not like you can just choose not to consider the thing you're afraid of in the moment.

What about enjoying a sunset? Appreciation of a view doesn't function without the comparison to everything else you've seen in the past and aren't currently looking at. Consider how someone might describe a really awesome view as mundane if they see it every day, but a newcomer would be blown away by it.

Remembering to stop and smell the roses (which I think the is figure of speech you were aiming for) is a nice sentiment, and maybe a good device to keep a sense of perspective, but it's not much more than that. Limiting your experience to just your immediate senses I'm pretty sure is impossible, but even if it was, it would be incredibly impractical - maybe even detrimental. I mean, hey, don't need to put gas in the car -> That's prep for the future and the future isn't reaaaaal maaaaaaaan. Don't need to avoid that guy that I remember hates me. He can't have ever punched me in the face, or be likely to do it again, if the past doesn't exist either, right?

What you described as fear I’d call startled. That is something that happens and can very much make you present, even if momentarily. Fear usually consists of unrealized events created in the mind that you’ve convinced yourself to be coming.

The newcomer viewing the sunset would shut off his mind to take in the beauty. The only thing in his head might be “wow! That’s beautiful” and for the moment spent in admiration: no thought of past or potential future exists. It’s obviously a short while until thought pops back in and he continues on as usual.

The line about roses is an idea about the importance of a name; as originally credited to Shakespeare. It was in response to a telescope being called a hamster.

I’m not trying to invent a new philosophy. I’m not saying thought is bad, or that it’s even possible, or preferable to live without thought. It’s just an observation of mine.

The thought of future events help dictate the present. If you see a gas light on; that puts you on a slightly alternate course to fuel up. If you really want a new amp, you might start saving money you’d otherwise blow etc. I’d say the past doesn’t exist; only our memories of past events exist right now. We tend to trust our memories, and they usually prove reliable; but: existence is. The past was. That which was cannot be is, otherwise it would still be is. I must open my eyes and see the present. I can close my eyes to “see” the past.

 

[BenjaminW]

I think you can argue that time travel is more dangerous than nuclear weapons because of how drastically people can/could alter events in time.

A good example is like preventing Franz Ferdinand from getting shot and World War I starting. The good is that it would've not led to the Cold War and World War II, but the bad is that the technological advancements that we have today, also wouldn't have probably made since World War I never happened.