Think Tank: Time and Time Travel

Before I start, this is a Think Tank. in other words, you bring your ideas and thoughts on the subject, not on who is right or wrong. This is used to gather information, and to make new ideas.

Is time travel even possible?

is time itself?

it have mass?

it a fluid or solid or a gas, or something else?

it be Measured?

Now, if we can answer these questions, then and only then i believe that we can truly travel through time. But after we answer these questions, we must also ask:

How do we travel through time safely?

Do you travel through time as a solid, like as in a time machine?

Do you de-materialize like a transporter in star trek?

If we can answer those questions, then we can figure out what we need to build before we even think of travel.

finally, the last questions we must ask:

if we do travel through time, what consequences do we bring to the world we know?

what changes will occur if we do step into the past?

or will there even be any changes?

do you really change the future, or just go into a parallel universe?

are their even any parallel universes?

reply to post by Angelsoftheapocalypse


This is an interesting thread! I don't know a whole lot about the topic but I will try lol. IMO Time travel would not be possible, but traveling between dimensions would be a diferrent story. Like I said, I don't know much just giving you my .02 and a bump

Not to long ago I wrote an article on this exact subject. It grew into a huge thread with all kinds of great scientific info and theories about time travel and how it may be possible.


It actually suggests that time travel is possible scientifically but technologically we are not there yet....

It will be a great help to this thread.

Check it out.

www.abovetopsecret.com...



[edit on 12-2-2010 by gimme_some_truth]

I believe time travel is possible, I think is has to do with speed.
The closer we get to the speed of light, the more we will learn.
I remember reading about an experiment where there was 2 atomic clocks, one was on the ground, one was placed in a supersonic plane and then taken on a flight. when the plane landed, the clock in the plane was behind the one on the ground. I will try to find the story..

[edit on 13-2-2010 by Pseudools]

My first encounter with time travel took place in 1960. I was a reluctant, cynical child back then (how things change), and I didn't appreciate being carried by my parents into a darkened movie theatre to view "The Time Machine," starring Rod Taylor. The pseudo-scientific banter on screen didn't especially impress me, nor did the primative stop-motion special effects. Only one scene in the film really interested me, as a matter of fact: It was that contrived moment (which H.G. Welles never penned) when Rod Taylor is buried in a lava floe, and the Time Machine's time-bubble-effect prevents him from being incinerated. Taylor waits for ages as natural processes erode the igneous material away from his time bubble, until daylight eventually falls upon him 800,000 years later.

It was then, enamored with the Minoan murals of the walls and ceilings of the "El Capitan" theatre, that I experienced a childish revelation: "Space moves AROUND a time traveler."

That was some 48 years ago, and I've been thinking about time travel in much the same way ever since — not that molten lava physically morphs around a time traveler, but that the human perspective observes the universe MOVING past us. The inseparability of space and time is reinforced by Newtonian and Einsteinian observation — that what we call Space and Time are only perceptual facets of a continuum: "Past, present and future are only illusions, however persistent."

Relativistic space/time theory usually bounces off modern physics students as a "given" — when we traverse space, we also traverse time, within the limits of a light-speed-maximum universe. But the inverse must be true, as well: When we traverse time, we also traverse space. The Earth of 100 years ago is far removed spatially from our Earth of today, relative to an imaginary fixed point "outside" of this universe. This revelation has colored my view to such an extent that I have to cringe at most popular representations of time travel, for these representations shape popular expectations, which, in turn, shape popular pursuits.

In the case of "time travel," the pursuit may indeed be a goose chase.

Let's put this into perspective. The typical human time travel scenario follows: A.) Human builds a Time Machine. B.) Human briefly deliberates on the possible consequences of time travel. C.) Against all logic, human hops into the Time Machine and takes a spin. D.) Human emerges in the future or past on Earth to find a radically different society, and so attempts to alter human outcome. This is the basic outline for virtually every human time travel fantasy yet concocted: Human-Earth-Centric-Regret-Fantasy.

The problem is, it can't happen that way in the Einsteinian universe. Should we physically defy Time, we necessarily defy Space, creating or accessing a dimension OUTSIDE of this space/time continuum (an alternate-space/time-effect). The "alternate dimension" scenario is essential if we are to retain any sense of continuity; otherwise, we would never know if our time traveling efforts were successful. Indeed, in defying Space/Time, we have also defied the rest of spatial physics — including GRAVITY.

So, WHAT force is causing our Time Machine to adhere to Earth's surface as we move forward or backward in time? How do we step into a Time Machine in 20th Century Topeka, Kansas, and emerge in Topeka, Kansas, 100 years in the past or future?

The answer is, we DON'T, if we merely defy the Space/Time continuum. Instead, the moment we activate our fiendishly complex Time Machine, we sidestep physical law, becoming a stationary non-entity relative to the rest of this cosmos. We are unaffected by macro-gravitation. When and if we finally re-enter normal space/time, the Earth is nowhere to be found, nor is the rest of our solar system. Depending on the intensity and duration of our "time warp," we may find ourselves deep in interstellar space — with no recognizable constellations to guide us home — or even outside of the Milky Way altogether, lost in the intergalactic void.

At this point, we come to fully appreciate the expanding universe theory, and we realize that time travel is not all it's cracked up to be. Whatever reasons we had for attempting this experiment in the first place are forgotten — We have pulled over to the shoulder on the superhighway of existence, and our entire universe has moved past us while we were parked. How is it that this dreadful pitfall is never addressed in the popular consideration of time travel?

Come to think of it, the only way a time traveler might emerge from the alternate-time-arrow-effect and find himself back on Earth, at some past or future date, would be if the Earth was indeed stationary, at the virtual center of the universe. Charles Fort would have fun with this concept, I can imagine.

In fact, Fort addressed a vaguely similar topic when considering repeated skyfalls on specific points of the Earth's surface. Likening the Earth to an apple tossed into the air, Fort envisioned a chaotic flock of birds zooming in and selectively pecking only one small spot on the apple's spinning skin. This seemed such an unlikelihood to Fort that he theorized the Earth is not spinning nor moving through the universe at all — it must be stationary, at the center of a shell-like universe, and that specific locations on Earth's surface were "targeted" for repeated skyfalls over long intervals.

Fort may have rendered his "notions" tongue-in-cheek; however, many respected scientists today — and certainly ALL of our science fantasy authors — subscribe to the stationary earth theory (whether or not they realize it) when pondering time travel.

I've heard several notable mouthpieces of the scientific establishment, including Carl Sagan and Stephen Hawkings, comment on the plausibility of time travel — breaking it down so far as quantum gravity paradox and exploding time machines and so forth — yet they always seem to return to the highschool drama of some hypothetical time traveler killing his hypothetical great-great-grandfather, thus altering linear time/space. Many of the greatest minds apparently make this leap of reasoning, without explaining HOW or WHY a time traveler would arrive back on Earth at all.

Just from a common sense perspective, a time traveler would never meet his distant ancestors or descendents, unless the time traveler was also exceptionally gifted in interstellar navigation and was in possession of the precise spatial coordinates of Earth, relative to the rest of the expanding universe, for a precise Earth date and time (in addition to possessing an interstellar propulsion system). That's one tall order. The much more difficult aspect of time travel is FINDING YOUR WAY HOME.

As we have seen in more recent science fantasies, the science of time travel is not nearly as vital to the storyline as is the imposition of our modern political correctness onto distant past and future generations. Again, any explanation of HOW we arrive back on Earth following time travel is artistically swept under the carpet.

— Doc Velocity





[edit on 2/13/2010 by Doc Velocity]

reply to post by Angelsoftheapocalypse


Is time travel even possible?
I beleive it is.
is time itself?
It's only measured by the motions of the sun relative to the planetary bodies. observable, but outside of this 3d world, time is irrelevant.
it have mass?
No

it a fluid or solid or a gas, or something else? It is none of those it's only existance depends on our observance of it.

it be Measured? yes, by the motoin of the planets aand the sun/moon phases, this is what time is.


How do we travel through time safely?
well, there are many ways, through ap or obe, with mechanical help, or by shedding our physical bodies/advancing.

Do you travel through time as a solid, like as in a time machine?
this can be possible, possibly by bending time/space around a device, but you would be stationary, it would be the space/time around you that has been manipulated.

Do you de-materialize like a transporter in star trek?
This may be possible as well.



finally, the last questions we must ask:

if we do travel through time, what consequences do we bring to the world we know?
probably none, it would not change our timeline...we'd only be able to affect another, and that would be one which involved our travelling there, and the outcome had/is already determined due to the knowledge of our interference or we'd be unable to interfere(as in the ap or obe case)

what changes will occur if we do step into the past?
none for reasons explained above

or will there even be any changes? no

do you really change the future, or just go into a parallel universe? parallel universe if physically going/ if mentally the only thing we could change is if we were to see something that's directly in our future through projection or out of body, then we'd still have the freewill to change it, have a different outcome, because the future has many possibilities, and every decision we make changes it.

are their even any parallel universes? yes I believe there are.

[edit on 13-2-2010 by ldyserenity]

No, time travel in any shape or form is not possible, if you really truly think about it.

Most of the time when we think of time travel (no matter what style) we think in long expanses of time, like years or decades (or longer). We also usually only think of going back and forth maybe once or twice (at most). It seems there should be no problem with it.

However, if when you imagine time travel ocuring over shorter time periods, like say minutes (10 minutes), and traveling many dozens of times in that short time period, it becomes quite clear how impossible time travel would be.

Just think about it like that: a 10 minute window, you, and a time travel box you need to get inside to travel.

My point is you will usually end up in some impossible circumstances and the idea always collapses in upon itself.

another weekly time travel thread, .... no disrespect intended.


i came up with a pretty good one a few months back, if anyone is interested in this topic please feel free to post.



www.abovetopsecret.com...

reply to post by IntastellaBurst


LMAO I can't help it sometimes these threads make me smile, geting on topic this is one issue I have a lot of questions about. I belive we can travel without the use of a machine and I have had that experience a few times... interesting because not only did my alien experience show me that communication through the mind has never been discussed in threads like this so far.

Is time travel even possible? not sure

is time itself? not sure waht this means

it have mass? not sure what this means

it a fluid or solid or a gas, or something else? not sure what this means

it be Measured? yes, with a clock

How do we travel through time safely? not sure

Do you travel through time as a solid, like as in a time machine? just as liekyl as any other way i guess

Do you de-materialize like a transporter in star trek? not sure

if we do travel through time, what consequences do we bring to the world we know? not sure

what changes will occur if we do step into the past? not sure

or will there even be any changes? not sure

do you really change the future, or just go into a parallel universe? not sure

are their even any parallel universes? it is likely

I am not an expert either but I believe that time travel would only be possible if you could somehow leave your physical body behind. Your physical body right now is part of this present moment now and has to stay that way.

I think light does have something to do with it but I don't know about the speed or anything.

Maybe the only way to time travel is out of body experiences, meditation, psychic trances, psychic dreams, deja vu and near death experiences.

And even then it's just glimpses into the past or future.

Sorry if I sound vague...I think time travel is an interesting subject.

Originally posted by elaine
Maybe the only way to time travel is out of body experiences, meditation, psychic trances, psychic dreams, deja vu and near death experiences.

Quite. I've always maintained that Science and Spirituality will eventually meet, and that this meeting may take place possibly in the not too distant future. Science is a toy. A commodity. Science can be purchased to entertain us and feed our gaping maws and wash our butt holes, but in the end it comes back to the Spirit. You may quote me.

— Doc Velocity

Originally posted by elaine
I am not an expert either but I believe that time travel would only be possible if you could somehow leave your physical body behind. Your physical body right now is part of this present moment now and has to stay that way.

I think light does have something to do with it but I don't know about the speed or anything.

Maybe the only way to time travel is out of body experiences, meditation, psychic trances, psychic dreams, deja vu and near death experiences.

And even then it's just glimpses into the past or future.

Sorry if I sound vague...I think time travel is an interesting subject.

Who IS an expert?!

For an expert, you did well in answering correctly.

How ironically foolish for the same scientists who claim no Creator to even toy with the idea of physical time travel. Think!

If one could physically time travel by means of going faster than the speed of light, being 186,000 miles per second, then that person would actually BE DARKNESS. But alas, can you intercept light still? Yes, at all TIMES. At all points. Any light that exists would seem just like the stars in the sky do - frozen points. In fact, to be darkness is to be the fastest because darkness exists totally, but light must travel. However, darkness perceives light to travel either almost not at all or simply not at all. It must travel a LITTLE bit, or else it would not be visible (nor existing) - MUCH LIKE DARKNESS.

So, it is possible to time travel in the sense that you could be as fast as darkness (instantaneous transmission) - but you can not go backward in time because you would have to rewind all of existence while you stay put. You could fast forward existence in your own perception while preserving your presentness by BEING DARKNESS (sleep anyone?), but you cannot reverse the effect. If you were to travel forward, you would be there for good... except for holographically.

For example, say you want to see 50 years in the future. Well... if you are able, you could create a computer (or use our vastly imaginative and quick brain) which would predict what the future most likely will be like in 50 years based on ALL of the variables that exist.... YEAH... that's a WHOLE FRIGGIN' BUNCH OF VARIABLES. That computer should take into account VALID HISTORY (If there is any such thing) to determine what the most likely scenario would be in 50 years at a given place. The ability to do this is WELL beyond any computer... but not our imaginations. Imagine... the ability to PROPHESY! Being able to take into account ALL things, including the butterfly effect!... and yet, even come within a few light years of the reality (metaphorically speaking). Phenomenal it would seem!

And yet... people are SO very predictable. It may be harder to distinguish the finer points of each individual, but as a group people are EASY. Enter "democracy"!!!

Physically, the best you can hope to accomplish is darkness which is the ability to see all things frozen; including light itself.

If you were DARKNESS on earth, you would forever be staring at the sun 8 1/2 minutes ago. The moon, a few seconds ago. Us? Ahh... if you were to be darkness in orbit around the earth, you would see the earth as it is always - a fraction of a second ago.

So... therefore, if you were to find a technology that allowed you to become darkness and unbecome darkness momentarily, you would be able to inspect every detail of all things that have ever happened in existence. BUT, in doing so, you therefore have no future. All is as it will ever be.

I could go on and on... and on.

edit to add that THERE ARE NO PARALLEL UNIVERSES - The word universe sorta is meant to cover ALL OF EXISTENCE... I'm sorry, but I keep wondering why people don't realize this?

Yes, there are parallel dimensions. And there are perpindicular ones as well. And ones at every angle and every angle in between every angle. You cannot count the number of dimensions... just like you cannot keep cutting something in half and come up with nothing.

However, I have heard that if you split an atom, it goes BOOM! Enjoy

Edit again to add that when I say ALL OF EXISTENCE - I mean all of PHYSICAL existence. Spiritual existence is outside of the universe. It is not in a universe of its own either because it does not have limits (as we would perceive them). How do demons and angels affect us then? Because they are "forces" - not matter. They "force" existing matter and mold it to their will... or His...

Okay, I'm done.


[edit on 2/13/2010 by TarzanBeta]

[edit on 2/13/2010 by TarzanBeta]

On another thread discussing that time does not exist, I postulated that time does exists based on human perceptions of the 5 senses and a whole lot more said.

Scientists had observed through quantum mechanics that light - an energy matter source does have the ability to travel through time and space, but I argued that humans cannot for we are biological matter and not energy particles, unless we can reduce ourselves into such.

With this thread, it got me thinking, what creates our consciousness in the first place? It is believed to be due to neural activity. There exists neurons within our brains and body - sparks of electrical charges that reacts with biomatter to move, to taste, to sense, to see, to touch, and to remember.

How did neurons came about? We have no batteries to create that electrical charges, yet it occurs. Electromagnetic waves from our environment perhaps?

If you had read Col Phillip Corso's deathbed confession book on roswell, you will realize he mentioned about the roswell craft being found with no signs of engines as we know of, except for plenty of silicon chips and fibre optics cable back in the 50s.

Could the extra-terresterials be harnessing advance electromagnetic waves for travel, the way our brains are harnessing EMW from the environment to power up our consciousness?

Another aspect is the religious belief of soul. According to theologians, the soul is our consciousness, unseen yet lives within us which makes us humans, living beings. Our bodies are only shells.

Can our souls then be described as our consciousness, made up of neurons - energy particles powered by EMW? If so, we may be able to finanly reduce ourselves technologically as an energy particle and be transported via quantum mechanics through time and space, and then re-animate into shells - biological bodies.

I have not read the book on Avatar, nor had come accross the author's tech explainations, but the tech and concept I am speaking here is something akin to how a human kind was 'transported' into an alien biological body.

If such technics - of using and harnessing our understanding of neurons is used - that dream of time travel may be possible.

I could be wrong, just sharing an insight, and hope developement may not overlook the utilization of energy particles within our human bodies, even as neuroscience is still in its infancy yet.



[edit on 13-2-2010 by SeekerofTruth101]

Originally posted by TarzanBeta
If one could physically time travel by means of going faster than the speed of light, being 186,000 miles per second, then that person would actually BE DARKNESS. But alas, can you intercept light still? Yes, at all TIMES. At all points. Any light that exists would seem just like the stars in the sky do - frozen points. In fact, to be darkness is to be the fastest because darkness exists totally, but light must travel. However, darkness perceives light to travel either almost not at all or simply not at all. It must travel a LITTLE bit, or else it would not be visible (nor existing) - MUCH LIKE DARKNESS.

What you're talking about is creating an alternate Universe, a little bubble of ME that exists outside of the Physical Universe. That's where you arrive when you exceed the speed of Light, it's where you arrive in the gut of a Black Hole in the singularity itself.

Call it whatever you want. Eleventh dimension. God's Pressbox.

It's the place where everything we think we know about Physics goes bye-bye. And that's where we have to go in order to Travel across Time — specifically, backwards in time, because that's the No.1 dream of Mankind.

We don't just want to go back and discreetly "observe" moments in history, we don't want to obey a "prime directive," we wanna go back and CHANGE things.

I don't care how much lofty intellectual discussion transpires on the subject of Time Travel and Quantum doojiggers and tachyon nonsense... The reason we want to travel in time is so we can go back and SAVE Jesus Christ from being crucified! We want to go back in time and KILL little baby Adolf Hitler! And, by God, we want to go back to Dallas on November 22, 1963, and storm that fekking book depository and WASTE Lee Harvey Oswald before he even touches his rifle.

Oh, hell yeah!

THAT is what our dreams of Time Travel are all about. It's about...

REGRET

Oh, man, if I could just go back in time and tell Buddy Holly NOT to get on that airplane! And I gotta time-travel to New York in 1980 so I can stop Mark David Chapman from killing John Lennon!!

Sweetie, that is why we DON'T have a Time Machine, and we DON'T WANT one! Because we would unquestionably use it to change the past, and that aint good.

I don't care if you're a Linear Time Continuum disciple or a Multiple Parallel Universe fanboy, going back in time is such a bad idea that it licks the bathroom floor. And that's bad.




— Doc Velocity




[edit on 2/13/2010 by Doc Velocity]

reply to post by SeekerofTruth101


Hmm... Your theory is very Battlestar Galactica-ish. Like, except, you're not talkin' about Cylons dude. You're talking about Hewmens!

The soul is the body and the physical mind. Blood and guts and brains. Once you die, you no longer possess a soul.

I'm sorry theologians are deciding to be so very.......deceptive.

Now, if you want to talk about CONSCIOUSNESS! That's a doozy.

Consciousness is possessed by all living things with a heart. Conscience... by all things with a brain.

But, our unique perception.. what IS it?! First, beware. Just because we are the gods of this planet (although slaves to Evil itself) it does not mean that we are the only creatures capable of THOUGHT. We just do not speak their language.

See... but we have something that does set us apart. Hmm. F-lee Dahm!

No one said it like Mel Gibson. Except for William Wallace, I suppose.

No... we aren't just conduits for energy -- We get to choose where it goes!! We don't just blindly follow instinct (all of us anywhow) - we make well thought out decisions based upon an incredible imagination! Still the brain. But... it's a brain that cannot be recreated. Ahhahaha, yes... It's so badass that it would take...with our current technology... a computer the size of the solar system to recreate such power! PACKED IN OUR BRAIN PANS.

Oh, Fine. I will stop being silly.

We are flesh. We are not of the spirit. If we were of the spirit, then we would know our Father. But we do not. Our Father has not yet granted us a way to exist spiritually... not all of us, anyhow.

Theologians are here to mess with yer dang heads! And make God look a'fool. 'N'fore ya sayit, I ain'no dag-gum weit-NASS.

Okay FINE. I will stop being silly... I don't know what is coming over me...

I'm just a truth seeker. If you had sought it, you would find it! It ain't hard to find.

And you wanna know why the Jehovah's Witnesses are the way they are?! Because they rely on book smarts... which most Christians don't... and they suck in the intellectual this way. Or they intimidate those who aren't intellectual. YES INDEED! They offer real book-challenged truths (some of them) in exchange for your ...not so eternal soul. (God DID say that He placed eternity in our hearts - yes, we seek it... yes, we can ONLY imagine eternity and not the opposite...but nowhere does God say that we are eternal. In fact, He states QUITE the opposite! For the wages of sin is death. Last I checked, death meant...dead.)

So, do not follow the JW if you seek to time travel! No, no, no. They bury seeds of lies within those ham-sandwiches of truth.

TALK TO GOD. TALK TO JESUS TO TALK TO GOD. TALK DAGNABBIT! AND THINK! And be honest with yourself.

If you want to truly continue this time traveling we've been doing in the light all this time (because, in fact, that is what our 'vessels' do seeing as how we are not darkness)... ask God 'bout it

"Give me liberty or give me freedom!"

Oh, P.S. - The Spirit of God can enter you... but that does not mean that you have a spirit. Spirits do exists, but they AIN'T HUMAN. They are... in the dark.

Enjoy.

reply to post by Doc Velocity


Sorry Doc, but darkness is not an alternate universe. Get the head out of the text book... or the selfish scientist's brain.

I do not know how to reiterate... it is as I said it. Where you get alternative universe and bubbles is all you. These do not exist . IF you are darkness, then you are darkness. There is no bubble. Pay attention to the words.

Pay attention to the reality and -think-. We cannot travel to the past. No one will ever and nothing will be changed from the past...except that it be the will of God Himself. But as His natural laws (which He can break at any time) stand, it is physically impossible for us to do the things of which I spake.

It is all the reality of a situation we cannot cause to happen of our own will.

Physical time travel is, by God's natural laws that are currently in place, impossible. Beyond limit. Darkness is the fastest thing in our universe. It is instant and exists everywhere except where light overcomes it. Light only overcomes it in our perception because if no one is there to see the reflection, the light would perceptually not exist because light cannot be seen in its pure form except for by staring at the source of the light.

How does time work for the blind?

Eternity has been placed in our hearts... God did not just give us physical eyes.

Enjoy your time traveling today!

Edit to change "where" to "is there". I... have many edits under my belt.

[edit on 2/13/2010 by TarzanBeta]

Is time travel even possible? the answer is yes.

one of the biggest mistakes humans have made is that the speed of light is not a Constant. it is a variable. the way it works is that the speed of light is effected by gravity. the more gravity you have the slower the speed of light. but remember that time is relative to the observers position.

time travel forward and backwards is actually a natural phenomenon. one of the bigger problems with time travel and space is that if we ever leave this solar system we will not be able to get back; nor get to the star we were headed for. its kind of hard to understand but if we point our spaceship at a star and leave the gravity well that we are in now between all the star systems is backwards time because the speed of light frame reference change. thus we would get to the spot in space before the star became a star.

there are a few more keys to it, but i can't tell those because of unified physics, its not my place to change the world.

reply to post by TarzanBeta


Thank you for your post, and I did read it in its entirety. My question to you for your theological beliefs now is:-

Would you freak out if I told you that the sons of light, mentioned in many theological and psychic beliefs, MAY be literally taken to mean an advance civilisation of scientist, engineers and techicians who are capable of reducing our souls/consciousness into light/energy particles and then upload it into biological matter over time and space, purposes of which are relatively unknown to us yet?

When the atom bomb was discovered and created, some thought they could harness such efficient but dangerous energies. They thought wrong and through free will, had seen the proliferation of nukes by every fearful govt and war mongering dictators hell bent on wiping off humans for their own selfish desires.

Is this such forms and expressions of free will, an excuse which may be a hope of returning to good, for giving sentient life to man by the sons of light?

And being an advance civilisation, a thinking society ,be filled with people such as Doc Velocity in his recent post to stop too much interference of events in time and space?

Conjectures here perhaps but some say many more not be able to handle the truth, sometimes which can only come from different sources and from a corner of the unknown darkness such as the annonymous but fearless internet. But what if the truth is told to you in this post, today? Can you handle it?

Will you freak out?

PS: Here's some some music to help flow your comprehension, if the red wine doesnt. Peter Brown



[edit on 13-2-2010 by SeekerofTruth101]

With astral projection a person can move into the future or into the past because in that plane time/space don't exist. The problem would be chane the past.