Mastermold Posted January 31, 2003 Posted January 31, 2003 What does everybody think of time travel? Regarding the possibilities and impossibilities?
PogoC7 Posted January 31, 2003 Posted January 31, 2003 *Nothing to add information wise.* I watched a good show on the science discorvery channel about Time travel. If I wasn't so lazy and about to go to taco bell I would write something, but im just asking if anyone saw the same show I saw. It was called "Understanding".
PogoC7 Posted January 31, 2003 Posted January 31, 2003 Time travle to the future and past can exsit. If you think of different dimentions them time travel is possible. Future time travel is not to much of a disscusion subject cause it has been proved. Traveling to the past is were people become sceptical. People say that Time travel to the past can not be done because you can kill you grandfather. If you kill him, you never excisted, so you could not have gone back in time to kill him. This is understandable. But if you were in a different dimention then you could kill him, although; you would be stuck in that time of place, so you wouldn't excist in the time when you traveled back in time. Or another thoery is that, you travel back in time, but no matter how hard you tried, you could not alter the present. You would not be a physical force in that time.
fafalone Posted January 31, 2003 Posted January 31, 2003 I believe travelling into the future can be accomplished through extremely powerful gravitational fields causing time dilation; i.e. if you were extremely close to the event horizon of a black hole, stayed there for a few years, and had the power to escape it, hundreds to thousands of years will have elapsed for the rest of the universe. Similarly, near-light travel would have the same effect.
PogoC7 Posted January 31, 2003 Posted January 31, 2003 When we talk time travel, does it only count if we can return to the same point in time we left. If we could breakdown out atom and put them into a machine where we can ethier: Suspend the atoms (zero kelvin) and restore ourself in the future. Or take those atom and in a lab created black hole. Enter a event horizen and after about five minutes return in our human form; in the future.
fafalone Posted January 31, 2003 Posted January 31, 2003 Well as current understanding goes matter can't travel faster than light, which is the escape velocity of a black hole. Hence why I said right near the event horizon, where the escape velocity is still less than c.
Piccolo Posted January 31, 2003 Posted January 31, 2003 What if light wasnt trying to escape the black hole but instead was going right for it along with the speed of the black whole that would be fast. Just a thought I know its not matter.
Piccolo Posted January 31, 2003 Posted January 31, 2003 What I meant was how fast would it be for light to travel into the black hole not how fast it is while getting sucked in and trying to escape.
aman Posted January 31, 2003 Posted January 31, 2003 Posted in the Theoretical Physics Forum, Dr. Strangelove has an interesting paper (A Unification Theory) that has a different slant on what travel to the past would be like. On page 21 of his summary he has a section on quantum mechanics, it's only a page long but I don't want to copy it, I'm old and your young. If you go read it, you may find it very interesting too. Just aman
Mastermold Posted February 1, 2003 Author Posted February 1, 2003 I have read at least a few Physicists' responses on time travel. One notable person has said that it would be relatively easy to travel into the future, but travelling into the past is either entirely impossible... or it would be infinitely improbable to arrive at the proper time. In other words, you would not have a choice in what time or location you arrived into... But one important ramification of time travel is that it may violate the 2nd? (I don't remeber if it's 1st or 2nd) law of Thermodynamics that states (paraphrased), "Matter and energy can neither be created nor destroyed, only converted into forms of each other." So if you travelled into a past destination... your matter (you and your ship/device) would exist in two places... on Earth in that past time, AND at your destination. And since it IS a 'law'... supposedly we can't violate it, but who knows. Time travel into the future has been proven and was predicted by Einstein and others. If you travel at a very high speed, as was mentioned by Fafalone, you experience time dilation and time slows for you... while it remains constant for observers. This was shown with two atomic clocks.. one was placed aboard a high speed aircraft and the other remained on the ground. Both were exactly synchronized, and after the aircraft landed... it was found that the clocks were milliseconds (or maybe even microseconds) apart, a substantial difference if you consider that an atomic clock is supposed to only lose a few milliseconds every million years or so (I believe it's something along that scale). But another important thing must be considered about time travel into the past... if it IS possible, you should be worried because our future ancestors may never get far enough to create it. Conceivably, if the method of time travel is discovered... SOMEONE, somewhere in the future, can utilize the knowledge to construct their own device and cause problems in the past. (Some people could easily make an atomic weapon if not for the extremely rare products necessary) And in the infinite breadth of time... eventually someone would mess with the past. It may have already happened after all... but someone else would just travel into the past and stop it before it happened. It could be happening all the time! Pretty scary actually...
fafalone Posted February 1, 2003 Posted February 1, 2003 Conservation of energy can obviously be violated, or no energy would exist. I don't fully understand the mechanisms of vacuum fluctuations that lead to a part-antiparticle pair spontaneously being created and destroyed, but that sounds like a violation of energy conservation too. The laws of thermodynamics are great for macroscopic systems under ordinary circumstances, but clearly do not always hold, especially at small scales. The 2nd law (entropy) has been confirmed to be violated in small systems in small amounts of time.
RAB Posted February 4, 2003 Posted February 4, 2003 Seems to me if anyone or anything went back in time it would have to be in some state other than the matter we currently exist in. Otherwise we would alter history by our presence. Even if we altered the position of only one atom in the past, we wouldnt be viewing the past; only an altered past.
PogoC7 Posted February 4, 2003 Posted February 4, 2003 If you think about traveling to the past based on what we see in our universe. It's not very feasible. Lets say that a Big asteroid hit the moon. What would be the chances of going back in time and stopping this asteroid. Nothing in our universe gives us the evidence we can go back in time. Not like going to the future, which our universe shows it can be done. Dimensional travel to the past is more likely; although, no proof in that ethier. And it wouldn't do any good for the people in the future if the person is in a different dimension. What has happened has happened.
Mastermold Posted February 4, 2003 Author Posted February 4, 2003 I would like to see any information you have about this Fafalone, because my Physics book that was just revised in 2002 states without hesitation that, "It is impossible for any process to have as its sole result the transfer of heat from a cooler to a hotter body." Entropy (2nd law) will always increase because if a process was found that contradicted this law, then perpetual motion machines would be possible, or a machine could run itself on its own energy indefinately. Also, when I applied the 1st law (energy conservation) to the Universe. I am assuming it is a closed system, and so must retain all internal energy regardless of interactions. Otherwise, energy/matter could be lost, but then you would simply consider the closed system to be the universe plus this 'other' place that it escaped into.
Radical Edward Posted February 4, 2003 Posted February 4, 2003 if you do the maths, there is actually an infinite amount of vacuum energy, so there really isn't any violation.
fafalone Posted February 4, 2003 Posted February 4, 2003 G.M. Wang et al., Experimental Demonstration of Violations of the Second Law of Thermodaynamics for Small Systems and Short Time Scales, Physical Review Letters, 89(5), 29 July 2002. And if energy cannot be created, then it could not be in existence.
JaKiri Posted February 4, 2003 Posted February 4, 2003 Originally posted by fafalone And if energy cannot be created, then it could not be in existence. Without the universe, there is no concept of time. And light in a vacuum always travels at c.
Mastermold Posted February 5, 2003 Author Posted February 5, 2003 I definately have to read that paper. It sounds very interesting because it could really make way for some interesting devices. Do you know if the paper is published online? Or will I have to do some actually leg work (not the library!! ::shudder: hahaha. Also, energy is created easily.. the reverse is what is very difficult. Matter can be converted into energy, but the question remains... how can energy be converted into matter? Nuclear fission results in loss of mass and that mass is converted to energy via Einstein's famous E=mC^2. If anyone has any articles about attempts t convert energy into matter... please post them. It would be very interesting.
fafalone Posted February 5, 2003 Posted February 5, 2003 Originally posted by MrL_JaKiri And light in a vacuum always travels at c. So where might I find 100% accurate refutes of evidence suggesting it has changed over time?
Mastermold Posted February 5, 2003 Author Posted February 5, 2003 You mean over the span of a large amount of time? It sounds possible... because the speed of light is only a threshold, light has been slowed down experiementally, but it cannot be accelerated.. only retarded. lol I know that word is always funny in any serious context.. but seriously, I didn't want to say decellerated because it's not a mechanical issue.
RAB Posted February 5, 2003 Posted February 5, 2003 If you knew the exact location of every particle of matter in the universe at any given point in time you could conceavably reconstruct the past exactly as it was (an fore-tell the future as well), but it would not be traveling back in time. I dont believe time travel is possible.
JaKiri Posted February 5, 2003 Posted February 5, 2003 Originally posted by fafalone So where might I find 100% accurate refutes of evidence suggesting it has changed over time? c being defined as the speed of light in a vacuum.
JaKiri Posted February 5, 2003 Posted February 5, 2003 Originally posted by RAB If you knew the exact location of every particle of matter in the universe at any given point in time you could conceavably reconstruct the past exactly as it was (an fore-tell the future as well), but it would not be traveling back in time. I dont believe time travel is possible. No, you can't. Laplacian Determinism went out with Quantum Theory.
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now