etcetcetc00

No. 100m is a length. a meter is just a measurement invented by man to come to terms with length. length exists without meters. 10 seconds is a duration. a second is just a measurement invented by man to come to terms with duration. duration exists without seconds. A clock is fundamentally no different than a meter stick. They both measure things that exist without them. As an argument, saying time does not exist because man made minutes is like saying mass doesn't exist because the kilogram is just something man made up.

I'm talking about the everett multiple worlds interpretation of quantum mechanics. Let me try to clarify. Whether the Big Freeze or the Big Crunch happen to our universe based on circumstance, was the alternative ever possible? At the time of the big bang, was it possible that, assuming MWI, either outcome could have happened based on the way things went? Would it have been possible that the universe split into an alternative universe where it crunched and one where it froze?

First, I know light speed travel is impossible. It's a hypothetical question. Second, I chose something relative to the speed of light. Me. Presumably on earth where I've always been. Every detail need not be explicitly stated. I'm asking to try to gain some perspective on these principles. If an object (Let's go with a photon) travels at the speed of light, there is time dilation. It's time runs slower relative to me (On Earth). The fact that it's traveling this fast while experiencing slower time than me would make me think it would seem to go much faster than the speed of light. From what I gather, though, the reative length the photon travels is longer than the length I would witness it traveling. This would give it symmetry. Am I getting this?

Ok. If an object travels at the speed of light, it's time slows down severely relative to ours as a result of time dilation. This might make me think that it should go much faster than the speed of light because it travels at the speed of light and its time slows down, but it still moves at the speed of light relative to me because the length it travels becomes longer?

This thread is terrible. You can't describe anything by the sum of its parts. You can't tell someone what a car is by telling them how big it is, what color it is, what it's made of or any of that. You certainly cannot describe the phenomena of consciousness by electrical activity, as consciousness is not a property of electricity. You cannot say it is the awareness of itself or its surroundings, because that is just something it does, it is just a characteristic of the whole thing. Abstract thought is just something it is capable of. My car can play cd's but it's not a cd player. I think you get the point. I just don't see how everyone can respond to this thread with their partial answers and still expect it to get somewhere. If mankind stopped explaining the sun as something hot and yellow in the sky that goes away every night, we wouldn't have gotten anywhere. It's like we're all blind men trying to figure out the Mona Lisa.

I have a problem with this post. Seconds, minutes and hours are forms of measurement, as are meters, grams, and liters. Take a liter of water. The liter measures volume. Take away the measurement and the volume is still there. Same goes with a meter stick. Take away the markings, it still has length. Take away the measurement of he time is took me to write this post, and there's still a difference discernable between the two points in time where I started and where I finished. The duration is there, and the change still occurs over time. Scientists do one of two things in scientific development. They either invent, or discover. The change of states of things from one minute to the next exists with or without our measurement. We discovered that. We invented seconds, minutes and hours to keep track of the change, but they do not constitute time, only reference it. General relativity, I think, throws our conception of time into question. How can an abstract mathematical concept be altered by gravity? There should have to be some sort of physicality involved, or else how could it change? On a side note, can anybody explain what Einstein meant in his letter to Michael Besso's widow where he talked about time not really existing like we thought?

I'm just so confused by this concept of relativity. I watched people on TV like Michio Kaku talk about theoretical time travel well beyond our technology, but the possibility alone is what's strange. How could we even consider time travel if there weren't different points in time for us to travel to? What's more, how can there only be one present time, when we can't even establish an objective present? I hope nobody on this forum feels I'm wasting their time with these basic conceptual questions, but I want to learn about this stuff because it's how the world works. If anybody has a good book reccomendatio they can give me that will help explain this, that would be great.

I'm looking for an explanation of what four dimentional space-time means in terms of understanding the nature of time. Admittedly, I cannot really conceive of what a four dimenional structure would look like. I've heard all the analogies of imagining a two dimensional space with time as the third dimension, so I'm not looking for anything like that. Calling time a fourth dimension and weaving a "fabric" of space-time seems to give time some spatial qualities that I'm having trouble reconciling. If all points in a 1 dimensional line are present within a 2 dimensional plane, all ponts on a 2 dimensional plane are present within a 3 dimensional cube, all points in a 3 dimensional cube are present at a given moment in 4 dimensional time, is it that all moments are present along a hypothetical 5th dimension? Forgive me for asking against dimensionary reduction in the explanation while using it to ask my question, but it's the best way I can think to ask it. Imagine the whole universe from the moment of the big bang to the ultimate end of the universe are put into an elevator. At the bottom floor is the big bang, and at the tip floor is the end of the univese. Imagine this building is astronomically tall. Each minute between the big bang and the end of the universe is represented by one floor on this building, and at each floor the contents of the elevator represent the universe at those moments. As the elevator (space) travels up the elevator shaft (time) it changes accordingly. Does relativity mean that all these floors exist? The elevator moves as it does, and I am in no way trying to suggest the possibility of time travel because it's not like a normal person can drive a normal elevator in a normal building. I just don't understand what the fabric of time means.

Are his ideas taken seriously in the Biology field? What is the concensus in the scientific community regarding SENS?

I'm looking for an explanation of what four dimentional space-time means in terms of understanding the nature of time. Admittedly, I cannot really conceive of what a four dimenional structure would look like. I've heard all the analogies of imagining a two dimensional space with time as the third dimension, so I'm not looking for anything like that. Calling time a fourth dimension and weaving a "fabric" of space-time seems to give time some spatial qualities that I'm having trouble reconciling. If all points in a 1 dimensional line are present within a 2 dimensional plane, all ponts on a 2 dimensional plane are present within a 3 dimensional cube, all points in a 3 dimensional cube are present at a given moment in 4 dimensional time, is it that all moments are present along a hypothetical 5th dimension? Forgive me for asking against dimensionary reduction in the explanation while using it to ask my question, but it's the best way I can think to ask it. Imagine the whole universe from the moment of the big bang to the ultimate end of the universe are put into an elevator. At the bottom floor is the big bang, and at the tip floor is the end of the univese. Imagine this building is astronomically tall. Each minute between the big bang and the end of the universe is represented by one floor on this building, and at each floor the contents of the elevator represent the universe at those moments. As the elevator (space) travels up the elevator shaft (time) it changes accordingly. Does relativity mean that all these floors exist? The elevator moves as it does, and I am in no way trying to suggest the possibility of time travel because it's not like a normal person can drive a normal elevator in a normal building. I just don't understand what the fabric of time means. Merged post follows: Consecutive posts mergedI'm not talking about any 5th dimension already established in any theories like strimg theory or what have you. My idea of a 5th dimension is a dimension that is to the 4th dimension what the 2nd is to the 1st.

Here's my question. If the multiple worlds interpretation of quantum mechanics is true, wouldn't the universe reach more than one possible outcome, like a big freeze and a big crunch? I guess to be more specific, if all our evidence leads to a big freeze scenario, does that rule out a big crunch scenario, or is it dependent on circumstances that led the universe to one end or another? Or vice versa? Is there more than one possible end for the universe?

I thought the Cyclical Universe idea was thrown out with the discovery of dark energy, but I read an article in an astronomy magazine today that said String Theory involves a cyclical model where the universe contracts after the dark energy spreads the universe out because of a spring force that wasn't explained very well in the article. The magazine said that our universe was part of a cycle that repeats every trillion years or so. Is this an actual aspect of string theory? I've always been interested in the idea of eternal return. I wonder, if all of the particles in the universe were condensed back to the big bang moment, and the process were repeated in the same way, wouldn't we all come back again? I understand we wouldn't have any memory of it, but the world as it is is a product of how the universe was created before. If the same process happens with the same material, especially if MWI interpretation is correct, wouldn't we all come back? Is it possible we're all involved in a never-ending cycle of the universe? Please correct me if I'm wrong. Don't just ignore this thread if it sounds ridiculous. Merged post follows: Consecutive posts mergedRoger Penrose is the name of the guy whose theory it is. Can anyone explain in a step by step fashion how it works?

what if you were to go back 12 hours? I was in bed then. Could you theoretically access that system? I guess the best way to put it is this: We can travel across the first three dimensions. If we could travel in time, would there be a path to travel on? If you could see time flowing backwards, would it look like a film running in reverse?

Ok, let's put some context into it, then. In 12 hours, I'll be in bed. If someone were to travel in time to that point and enter my room, would they see me asleep? Then, if twelve hours had passed for me, and only a few minutes for them, we would have different present times at the same world time. (1:15AM EDT) I know this is impossible now, but physicists do talk about theoretical time travel. My question is: when they talk about this time travel, do they expect past or future systems to be accessible? Is there too much quantum uncertainty involved to tell? Have they even gotten that far in their discussions?

If my future is not your future, how does that work outside of the context of MWI? Wouldn't a single Universe have a single time line?

I think I'm trying to define time travel. If twin A stays on Earth, and Twin B travels at light speed on a tour of the galaxy and comes back, he will be younger than Twin A. The amount of time it took Twin B to make the trip in his relative frame of reference was less than the time his trip took within the relative frame of reference of Twin A. I don't understand the math behind this, these are just hypothetical numbers, but let's say Twin B was gone a month in his time, and 50 years in Twin A's time. The 1 month point for Twin A is in the past of the 1 month point for Twin B. Their relative "presents" are at different points in time. How could there be only one present under these circumstances? Merged post follows: Consecutive posts mergedWhat other possibilities?

Still confusing. My question pertains to the philosophical concepts of presentism vs. eternalism. Presentism contends that the only objects that exist in the universe exist now, and that all past systems no longer exist, and that future systems do not yet exist. Eternalism argues that past systems still exist, and future systems exist now too. Like in the movie Back To The Future, Marty's parents still existed in their past states when Marty went back to 1955, and his kids existed when he went to 2015. It seems to me that, if the twin were traveling at light speed and came back at a time that is ahead of what his normal time would have been, there would have to have been that future for him to access.

I don't understand what you mean by that

The philosophy of time that only the present moment exists, versus the eternalist belief that all points in time exist equally in different points in time.

The Twin Paradox seems to suggest that presentism can't be valid. How can an objective present time be established in these circumstances?

Time seems to me to be inversely related to speed. The faster a person moves, the slower time moves for them. I don't understand fundamentally how hypothetical light-speed travel causing a person to arrive at a point in time beyond where they would have been at rest doesn't constitute as time travel, though.

Anyone care to just explain it here?

Why not? If a man travels so fast it takes him beyond the point in time he would have been in had he not been moving so fast, that seems like time travel to me. Help me out.

Time seems to be inversely related to speed to me. If I speed up to just under the speed of light, physical restrictions not withstanding, time slows down for me relative to anyone not moving as fast. It almost seems like we are constantly traveling forward through time as we are now, and can affect the speed at which we travel through time by increasing the speed at which we travel through space. If a man could bypass the flow of time of the rest of the universe by traveling quickly, it implies to me that time is an established dimension that can be traveled along just the same as the three spatial dimensions. My question is to what degree does this relativistic property of time constitute as time travel, and if it does constitute as time travel, how does that not explicitly suggest Block Time? Also, if a point in time contains all points in the three subsequent dimensions, how can string theorists talk about eleven dimensions without the whole of the time dimension contained within one of those higher dimensions? I am a layman, and I may be making large assumptions. If that's the case, have a heart and let me know instead of passing on it if it seems ridiculous.

Duration. Once more. Big Bang Theory. Have you ever heard of it? Or do you subscribe to a religious understanding of the nature of the universe? Real scientists have used WMAP satellite imagery to gain the image of the entirety of all the matter and energy (Which are the same thing, if you didn't know that) contained in our universe. They have measured the motions of other galaxies over time and discovered they all are expanding outward from the same location. If you don't believe this, I can offer you evidence that, if it's possible to achieve such a thing, help you to understand the reality of something you do not currently understand. The Universe originated from one point. Since the speed of light is an absolute speed limit that cannot be exceeded, the radius of the universe can be calculated by multiplying the calculated speed of light by the amount of time the universe has been expanding and THAT has been determined by cosmologists smarter and more reasonable than you who dedicated careers to measuring the movements of stars and galaxies so we could come to this understanding. No real scientists debate this fact. This is what the scientific method has led us to discover. If you do not subscribe to the scientific method, you should not discuss science in a scientific forum. Even more than that, the question I posed, which has not had the opportunity to be discussed due to this childish back and forth you've instigated is a hypothetical question based on pre-assumed conditions that you clearly do not understand. You are ill equipped to address my question and therefore I ask that you leave me alone so that real experts might have the chance to shed some light on what I'd like clarified.