This is probably what you're referring to http://news.bbc.co.uk/2/hi/science/nature/3897989.stm
Hawking was the first to come up with the idea, that black holes could evaporate in the 1970’s.
The point is – that up until now – he believed that any information falling into a black hole would be lost forever. This basically contradicts quantum mechanics and has been the subject of much debate in the past 30 years.
Hawking now seems to believe, that the information is not completely lost.
Well how do you percieve time is?
Is the present Now and the past is done and beind us and the future is yet to be done.
Or
Is time like a film from the beginning of time to the end of it, and we are acting out just a small portion of this ever changing film-like thingy??
Omega> I ment that in the example where you try and fail to kill your grandfather, the future must be allready set because you are inable to change it. In that case we must be unable to change the future from where we are in the present because our present is the past for someone in the future.
But in the "Able to change time" example the future is not set so time travel will eradicate itself.
Not that I necessarily disagree, but Hawking has been known to change his mind.
Basically, we know not nearly enough about things to make definitive judgments here- and anyone who has ever laughed at the ignorance of the past should be VERY wary of declaring something totally impossible just because we cannot see how it would logically work.
Hawking's point about travellers from the future is only as insoluble a point as earlier astronomers who tried to work out why, in an infinite universe, there were any visible gaps in the starfield. Later understanding caused hypotheses to be created that answered this point and this MAY happen with time travel as well. Or it may not, but like I say, if the only problems you can find are ones of logical understanding, I would be very wary of writing the concept off.
If TT were possible and the future has not been written then going back in time is our only possible course. However in changing the past, we alter the future and thus the butterfly effect comes into play. We affect ourselves and everything around us. However if we play to the scernio that every action we don't do is played out in an alternative reality, then changing one event in the past collides with an alterative one that this event has occured...so both realities could cancel each other out or over lap the other creating a rip in the fabric of time...which could destroy foul things up royally?
Tpt> You’re referring to what’s known as Noviko’s Consistent Histories hypothesis.
This hypothesis allows time-travel, but sets up restriction on “free will.” Or rather, the universe somehow conspires to prevent you from, say, killing your grand-dad.
This is the exact reason why I dismiss Novikov’s hypothesis. The entire Universe has to set its “will” against me, toss a meteor in my head, make MY gun malfunction right there, make me miss, make me stumble, be unable to locate my granddad, get eaten by a lion etc. etc. etc.
Ush> Hawking is not the only one who adhere to his hypothesis. It merely carries his name. And it’s not at all a question of insoluble points. His empirical “proof” runs deeper than that.
Where ARE the time-travellers from the future?
No matter what “restrictions” you set up, they fall.
“People are not allowed to.” (Some villain steals a time-machine)
“People don’t want to.” (None of them? Impossible)
“They can’t travel to 2004.” (Why not?)
“Only the government runs time-machines.” (It’ll become cheaper and easier 1000 years later.)
“It’s too expensive.” (So were mobil-phones 20 years ago).
IF time-travel to the past becomes possible sometime in the future, there will be time-travellers travelling to this here and now (if nothing else, because no one visited 2004 yet).
Among them will be people out to do their own thing.
So comparing Hawkings hypothesis to earlier astronomers musings over gaps in the fields of stars doesn’t work. The gaps are there, and explainable by science. Why there should be a time-traveller gap HERE in 2004, deals not only with science and “we just have to keep solving equations.”
Omega, you seem to spectacularly miss the point.
"IF time-travel to the past becomes possible sometime in the future, there will be time-travellers travelling to this here and now."
Says you! If in 500 years time we find out that time travel is possible and there is a good reason why that didn't happen, people who held absolute views like you will be thought of as cretins.
Only a person with a closed mind says that any restrictions set up always fall.
They cannot travel to 2004- why not? I don't know. But we don't know enough about the subject to write it off. Perhaps it is only developed at a point where it is restricted to the point where no-one ever does it. Perhaps time travel does not work in a way perceivable to people. Perhaps it always shunts into parallel universes. Perhaps it has a range and you can only go back so far. Maybe it is possible but Humans never discover it before becoming extinct. Maybe it is something we cannot even begin to comprehend. You say none of them wanting to do it is impossible? You don't know that- you don't know a damn thing about possible human behaviour in the future. In fact, that use of the word 'impossible' is totally unscientific- at best, it is only implausible. Who the hell knows about any of it? The whole thing is totally unknown territory. Enough genuine scientists still believe it is possible, Hawking Hypothesis or none- and his empirical 'proof' is disputed.
If you seriously think what you say above truly renders time travel totally impossible then I think you are a bit of a fool. One should not be so decisive about things we know so little about- and I totally disagree with you saying it cannot be compared to the starfield. I say it can- the gaps could only be exaplined by hypothesis at first, and not solid science, and so it may be with time travel.
Until you can actually demonstrably prove that time travel is impossible- rather than simply pointing out logical flaws in our current understanding of the issue- I believe no scientist has any business totally writing off the concept- lest he or she risk being ended up bundled with those who thought logic prevented us from creating flying machines, breaking the sound barrier and going into space. Understanding changes over time.
Incidentally, that hypothesis doesn't say you can't- simply that you won't, as evident from that you didn't. I don't necessarily agree with it but dismissing it on the grounds that you don't like the Universe setting its will against yours demonstrates a poor understanding of the concept.
I'v read most everything up through the 1st 2 pages of this thread, don't care to read the rest because i see what everyone is getting at.
And this isn't my idea in and of itself, it's just poorly reguritated from a John Titor website. According to that guy, there is such thing as a multiverse.
As in...if you go back in time to kill your grandma, you would be in a completely different universe or alternate reality to that which you previously lived in. Killing your grandma wouldn't erase YOUR exsistence, but it would eliminate the possibility of your future self in THAT reality.
The idea that you killing your grandma would erase your exsistence would mean that there is only one universe.
I know this comment can be quote and ripped to shreds, but I bring it up more as an alternate way of thinking about things. Kinda like all the different incarnations of Neo in the Matrix Reloaded, where each one of his choices leads to different outcomes.
Well, don't bother quoting this and going through proving it wrong. I, myself am very skeptical. All I can say right now is that, time travel MAY be possible...we're just not far enough along as a race or species to know.
no, i get what you mean.
the theory of the multiverse...you go and kill your grandma and then when you come back you don't exist. those don't oppose eachother....it's just saying that the multiverses are linked together. story-like theories, though...
as omega said. where would you get the energy of creating a totally diffenre universe (one without you in it if you kill your grandma) simply because i modified something in the past.
It actually seems as if it is YOU who miss the point, Ush.
”Says you! If in 500 years time we find out that time travel is possible and there is a good reason why that didn't happen, people who held absolute views like you will be thought of as cretins.”
Wrong! As I spend some lines pointing out, there is nothing to explain why time-travellers from the past shouldn’t travel to 2004. All explanations belong in the same category as the feeble attempts at explaining why God doesn’t interfere or why the aliens from Sirius doesn’t.
Claiming there must be some – extraordinary - reason as to why the time-travellers do NOT chose 2004 is not open-minded (unless your explanation is good), it becomes semi-religious.
If you wait long enough the improbable will happen. So let’s say this time-machine is invented in deep secrecy in the year 2504. Only some special elite corps of specially trained people are allowed to use this device under very special circumstances, with a set of time-travel laws to prevent them from creating temporal anomalies.
But if it IS possible, someone else is bound to build the same device sooner or later. When it comes to he point in time in the future, from which our tourists travel, it is of no consequence. They can leave in 2504, in 22504, in 222504 or a million years later.
“But we don't know enough about the subject to write it off.” You may not, but some scientists do. Hawkings hypothesis wasn’t thought up over a beer at the local pub, but also has deep philosophical implications.
“Perhaps it is only developed at a point where it is restricted to the point where no-one ever does it.” There is nothing in the physics apparently/seemingly allowing for time-travel, that sets up such restrictions. It’s an either/or situation.
“Perhaps time travel does not work in a way perceivable to people.” See above. Again, there is nothing in the science that indicates anyone will transform into some immaterial state.
“Perhaps it always shunts into parallel universes.” Such do not exist. If they did, we’d see matter/energy seemingly disappearing from and re-appearing into our Universe from said parallel dimension. This has never been observed, and should happen if possible. Should a parallel dimension exist we’re thus unable to interact with it.
“Perhaps it has a range and you can only go back so far.” See first answer.
“Maybe it is possible but Humans never discover it before becoming extinct.” Then the future has become set, and you have no free will.
“Maybe it is something we cannot even begin to comprehend.” Such as? You must understand that we have the math and physics that got scientists interested in this concept in the first place.
“You say none of them wanting to do it is impossible? You don't know that- you don't know a damn thing about possible human behaviour in the future.” Only that if you choose the “none of them want to” you’re eliminating free will from now until the time-machine becomes operable.
You seem unable to understand, that time-travel is more than a science-fiction concept, and that serious scientists actually work with this matter. Thereby it is NOT unknown territory.
So I still see no disputing Hawkings empirical proof. I see the same explanations as I see for aliens and Gods.
You must get into your head, that the number of humans capable of time-travel from the invention of the time-machine to the destruction of the solar system is immense. Subjecting humans – and human nature – to the above explanations is ridiculous at best.
And about star fields and time-travel: The gaps in the Universe were THERE when the scientists first noticed them. Here – in the present. The explanation didn’t depend on some hypothetical future invention and what mankind in the future would or would not do. And whether or not the explanation would but restrictions on present human doings and actions.
The gaps in the time-travelling tourist department does.
Can you demonstrate the impossibility of faster-than-light travel? Then, do you believe it is possible for a macroscopic object of a mass greater than 0 to reach speeds faster than light? (Barring quantum tunnelling for the moment as it is not really movement)
Novikovs hypothesis has zip to do with what I – personally – like.
It’s in the same category as the “If I travel back in time the Universe clones itself like in Back to the Future II”. The idea, that just as I can’t walk up a straight wall due to the laws of physics, there will be laws restricting my actions in the past sounds plausible at first. Until you decide to attempt 100 times… or 1000 times.
vvvrulz> Ionizing human matter would not allow it to travel faster than the speed of light. Ionizing simply means removing or adding electrons to the atoms.
Shaber> You view the past whenever you look around! 🙂 Light from what surrounds you have to reach your eyes first…
Ok I have two theories first of all I believe travelling back in time is possible but going into the future is not.
I am first going to start with travelling back in time. Most people think that by travelling back in time you can go to any year or day in the past. I believe that to be impossible the reason for this is because we have not yet invented a time machine
Ok let’s say today I make some sort of time machine and I turn it on today. What if next week if I used it I would only be able to travel back to the time I switched it on!!!
So I think in 50 years time someone will invent the first time machine but they will be only able to travel back to the point they switched it on.
Ok Travelling into the future I mean what does it mean I mean how can we travel into the future if has not been invented yet I mean travel back in time is ok because its already happened!! They only way to travel into the future would be if my body was frozen and in twenty years time I was awaken to me it would seem like I had travelled into the future.