Why (my take) on why time travel wont work.

Time Travel

Simply, you cant reverse a physicly decayed person back to the living. Once something has happened there is no way to change. Just think going back to the middle ages.
'oh hey king henry, just stopped by to watch your 6th wife die'
'what are you wearing 0.o'
'oh year, modern day clothes'
'ohh, wait what'
Why arnt we getting visited from people from the future coming back to warn us about upcoming world disasters?
Also, imagin how dangerous it would be, One tiny change and it could alter or stop allot of peoples lives. Out of all the millions of sperm and eggs you were chosen by chance to live, If you go back in time what are the odds of you being born the same person if say change something from the past.
Or, if you went back and killed hitler before he killed 6 million, thow many people would you save, but who from the present day would be affected. Simply its too dangerous even if you could go back.

Viewing the past

however i do believe you can view the past. It kind of works like a cinema, The projecter is the sun, the cinema screen is earth and the viewers are whoever is looking back in time.
In mph (miles) the speed of light travels 670,616,629 miles in one hour. So if you were standing 670,616,629 miles away from the earth and looking directly at it through a telescope (so powerful you can see the earth, all its streets and people walking clearly) it would take one year for you to see this. So as we are getting on with our lives the viewer would be looking at earth 1 year behind. Now theoreticly if you found a way to travel faster than light you could over take it.

So far that you could view back to say 500 years, but now that would prove difficult because light would have had 500 years to travel and would be long gone, but like i said, if you found a way to overtake it you could overtake the light and intercept in. Possibly store it but i dont know
It probably might not work but thats just my theory.

Heres something interesting though- If we wee viewing an earth like plannet 100's of lightyears away, we wouldnt be viewing their present day but past because the time light travels. So if we travelld to that plannet in an ultra fast lightspeed ship it would appear as if we are in their future, allot could change.


www.youtube.com... (if video doesnt work)
i like the idea of this but i dont see how things be physicly altered or change while time goes on. Im not sure about this though

anyone want to share theorys, debate?

~ thank you


sources:
www.theregister.co.uk...

Wait, so apart from the other things, YOUR opinion on why we couldn't travel backwards in time is because you cant age backwards?

I might have skipped a few bits, but...

As long as you're making the rules.. .Oo

reply to post by Blue Goblin


Hey

I always love the idea of time travel. Our modern concept of space-time is bizarre and mind bending and I have a feeling it will get progressively more so the deeper we probe into the mechanics of the universe.

You've touched on a few things in your post such as the idea of a time paradox. Since you mentioned it- in Relativity you cannot change the cause of an event otherwise that event would/will not have occured but since it already has in a linear way, that would be impossible. A scenario consists of two events - event 1 is usually a synchronised point in time and event 2 is a trigger or effect - and these two events are intrinsically linked. As long as you and the body causing the events are in a state of inertia such as standing still or going at a constant speed you can manipulate space and time as much as you want after the cause of the event but you cannot go to a period before the event and alter the outcome.

In relativity time travel forward to any point is theoretically possible, the equation does allow for it. If you go at a constant speed faster than the observer then your time will be slower to an observer (the light clock example in the video but remember everything is a clock in relativity- you and me and even that glass of water). So you want to see what your house will look like in 3000 years and you want to take 30 seconds to travel to that point in space-time (i.e. you want to age 30 seconds but relatively you want your house to age 3000 years) then just plug that into the transformation and out pops a constant speed. Bingo, go at that speed for 30 seconds and your relative time would have been so slow that within what you experienced as 30 seconds was 3000 years to the observer. In reality it is much more difficult since you will have to accelerate up to such a huge percentage of the speed of light that the energy required would be vast. We do use this time effect though- usually exotic particles produced by collisions in particle accelerators would decay in such a miniscule fraction of time that we would not be able to read them fast enough but one useful by-product of having them fly round at near the speed of light is that relative to us their clocks are much, much slower so their decay is ultimately slower enabling us to actually get some readings.

I only mention special relativity in this case since currently it is practical equations. According to the equations going faster than the speed of light is impossible; its built into the equations. However, I still feel that it won't stop us from finding shortcuts and work arounds. When you accelerate beyond the speed of light I have no idea what will happen. I haven't seen anything that would describe the effect in maths (not to say they are not out there, just haven't come across them yet) but I'm sure the effects would be strange as could be. But yea, I guess in theory, if you travel to a point in space-time before information gets there you will be able to observe that information once it reaches that point. The sun is the bulb, the earth is the roll of film and you're getting to that white screen before the light from the projector has reached it.

I personally stay open to these things- travelling back in time in a purely relativistic universe is impossible but at the same time it's only describing a snapshot of reality. Maybe if we maintain a purely subjective universe we could travel back in time and alter events and the universe we were in would branch out from that point with you included and accounted for.

Yours mind warply,
Strange-Quark

Hi!

Time travel fascinates me as well. I've come up with this theory that takes all the physics out of the equation and makes it a bit easier to understand why, even if possible, you wouldn't survive the ordeal.

What happened when Europeans came to the new world? The Native Americans were susceptible to the diseases they brought with them. The same thing would happen if you traveled back even a few hundred years. When they tried to find out if Napoleon was poisoned, they thought they had the answer when they ran toxicology on his remains until they realized that fatal levels of arsenic today were well below the average exposure levels in France during those times.

We've eliminated a plethora of pathogens in recent times. Our bodies would be very susceptible to these old strains. So even if it were "possible," being dumped off into France in the 1800's would mean a very sure and painful death to follow in a relatively short time frame. I would guess you'd only get a few hours or few days before you would succumb to something.

Hi i'm a new user on this forum.
But i think i'v found something you may be interested in ......
This has been posted on you tube so apologies to anyone who has already linked to this video .
www.youtube.com...
Admittedly it seems to be an personal promotion for the guy in the first 2 minutes, but he does have a valid point
Some people have forwarded this as a probable explanation.>>>>
hearing.siemens.com...
My question is why would the lady be talkin to her hearing aid?
Feed back appreciated

There are several theories on how time-travel could be possible. The fundamental flaw in all of them is that they rely on archaic principles of physics that governed Einstein's reasoning. There was nothing wrong with the way Einstein reasoned - in fact, he's been more correct in describing and predicting behavior than even he could have imagined.

The problem with using Einstein's reasoning, however, in today's world, is that we have made a number of new discoveries that are only at odds with Relativity if you equate Einstein's reasoning to the principles of Relativity.

For example - time travel utilizing a worm-hole. Worm-holes are entirely theoretical, problem number 1 - so they are very difficult to define and predict in terms of behavior. Older reasoning suggested a wormhole actually consists of a separate region of space-time that can be influenced by local gravity. However - experiments with entangled particles have demonstrated that two particles can communicate - via some means - in a nonlocal manner. Presuming wormholes could/do exist, this has implications for information sent into a wormhole - namely, that it would appear on the other side, instantly, not having traversed space at all (which makes time-travel via this method impossible).

The other assumption is that gravity influences time. We should, first, take a scientific look at our understanding of time. We measure time in cycles of events - how long it takes a capacitor to charge and discharge through a resistor, how long it takes a crystal to complete a compression/decompression cycle under electrical stimulation, the rate of radioactive decay of certain elements, etc.

We have illogically assumed that gravity influences time. It would be no different if we were to place equal amounts of sugar into a glass of warm and cold water, and conclude time was moving faster in the warm water because the sugar dissolved faster.

We have yet to experimentally verify time as a dimension. We have "space-time" - but that is, again, based on equating changes in rates of subatomic behavior to time - no different than equating chemical reactions being faster in warm water than in cold to a temporal shift.

If time doesn't really exist as a dimension, then you really can't travel through it.

Nice OP, looks like you have spent some time thinking about the subject!

I think it might be jumping the gun a little though to rule out time travel completely as I'm not even sure if anyone alive can even give a satisfactory explanation of what time is, let alone speculate to any degree of certainty on whether we can travel though it.

Given our understanding at the moment we certainly can travel forwards through time as we are all doing it right now.

I like your point about "why don't we see time travellers visiting us" One explanation for this that I have heard postulated is that maybe before we could see people travelling back in time to us we would first have to build a machine capable of receiving them.

This clip is from a BBC program called QI which discusses some interesting things (the bit about time travel starts at about 1:36

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reply to post by Blue Goblin


Here is a man that says he has time traveled into the future and met himself and even has a photo to prove it. Wow, that must be nice to meet yourself in the future and know that you are still alive and healthy years into the future.

www.youtube.com...

I'm pretty sure time travel is possible, but I don't have a clue as to how.

reply to post by Aim64C


i think thats spot-on.

Time isnt a dimension, and as such you cannot travel along its 'axis'. The concept of time merely gives us a useful way to place events in a correct sequence and describe that sequence. It is no more a physical reality than imaginary numbers.

I too have a theory, when you travel back in time, to, say, 1342, your own time will not exist, as it is in the future,
so you would be stuck in 1342.... as 2010/whatever does not exist, so time travel backwards is a waste of 'time',
as for travelling forwards in time, the future does not exist, so I doubt the time machine would even run up to full speed/whatever.
However the future does have an effect on the past, for example, you want to buy a brand new car in five years time, for cash, so you start saving your cash now, (five years before the event) to pay cash for the car in five years time.