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Ikas90
14-05-10, 10:39
I personally don't like the idea of it being possible to accelerate time, but there are some arguments that support the theory. They say that the further you get away from the earth, and the further you get away from it's gravitational pull, the more time speeds up. For example, if you had a twin brother living in outer space, he will age less quickly than you on earth.

They also say that if you travel at the speed of light, you are accelerating time.

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Do you believe in this sort of thing?

jaywalker
14-05-10, 10:40
Everything is relative.. so yes its theoretically possible..

irjudd
14-05-10, 10:52
You've got it backwards bro. With time dilation, time is slowing down as you approach the speed of light. So it's theoretically possible to travel 10 years into the future in only 5 years (to you) if you could go that fast.

Cochrane
14-05-10, 10:53
Accelerating time (or slowing it down, depending on the point of view) is possible and even proven: GPS satellites and receivers have to be aware of this phenomenon, otherwise they would give wrong results.

More interesting is time travel backwards. There are various solutions to Einstein's formulas that do allow it, but they all rely on things that may not actually exist in our universe.

Ikas90
14-05-10, 10:56
You've got it backwards bro. With time dilation, time is slowing down as you approach the speed of light. So it's theoretically possible to travel 10 years into the future in only 5 years (to you) if you could go that fast.

That's essentially what I meant, lol. You're advancing into the future faster than normal, thus, accelerating time. Or accelerating through time, as you might have it. If you were slowing down time, it would take longer to reach the future.

irjudd
14-05-10, 10:58
In the sense of traveling "really really fast", time slows down for the one in motion. But to outside viewers, it stays exactly the same. So it doesn't actually accelerate for anyone in those circumstances.

It does accelerate when you get further away from a massive object, though. That's definitely true as Cochrane pointed out.

Legends
14-05-10, 10:58
Well, no. No matter how much you think about it, time won't change. No one will be able to travel through time. Theoretically, maybe, but no.

Ikas90
14-05-10, 11:07
I'd like to know a bit more about how GPS systems work. Is it really time itself that is changing, or is it just the satellite changing its interpretation of time?

Furthermore, if I took a plane trip, is my "time set" ahead of people who have never taken a plane trip? As there are so many people who have taken plane trips, are all our "time sets" scattered, all different from eachothers? Is any more than one person in the same point of time?

irjudd
14-05-10, 11:11
Think about time like a 4th dimension, and the closer you get to a gravitational well from a large object, the more "surface area" that 4th dimension has to cover to get from point A to point B. Can you visualize that in your brain?

igonge
14-05-10, 11:14
Yes it's possible! I do it everyday, my dinosaur buddies and I laugh at your stupidity.

Seriously though lol, maybe, I'm no scientist.

Ikas90
14-05-10, 11:22
Think about time like a 4th dimension, and the closer you get to a gravitational well from a large object, the more "surface area" that 4th dimension has to cover to get from point A to point B. Can you visualize that in your brain?

Not really, lol. That is.. pretty damn hard to picture. For me at least.

There is a lot that the human mind is unable to comprehend. Everything we know today is but a tiny grasp on the essence of knowledge.

almayah
14-05-10, 11:25
My answer is simple
NO!

Drone
14-05-10, 11:37
According to Stephen Hawking time travel is possible and one day it's definitely gonna happen. Tho it can only be performed in a forward motion. But I still like the idea, I definitely would like to skip 10 or 100 generations.


We can already see how time slows down for objects traveling at high speed by looking at what happens in particle accelerators

It means time isn't absolute, it can be controlled

When we accelerate tiny particles to 99.99 per cent of the speed of light in the Large Hadron Collider at Cern in Geneva, the time they experience passes at one-seventhousandth of the rate it does for us.

'If we could build a spaceship that was fast enough, then it could reach other stars in the lifetime of the crew, but maybe 2.5 million years would have passed by on earth.

I just wonder how all this stuff will change "cause and effect" principle. I'm interested in that.

Rai
14-05-10, 11:46
Maybe not right now, but given time (lol) maybe it will be possible if we can build the spaceships that travel fast enough.

If astronauts travel to Mars, would they be in a different time to us? I mean if it were possible to show them on tv, would it have to be aired at a specific time on earth to catch up with them on Mars?

Punaxe
14-05-10, 11:55
Not really, lol. That is.. pretty damn hard to picture. For me at least.

There is a lot that the human mind is unable to comprehend. Everything we know today is but a tiny grasp on the essence of knowledge.

If you have an Amazon account, go to Stephen Hawking's A Briefer History of Time (http://www.amazon.com/Briefer-History-Time-Stephen-Hawking/dp/0553804367), click "Search inside this book", look for the search term "elevator" (which gets you to page 45) and start reading from there until the end of the chapter. That probably makes it clear.

TRLegendLuver
14-05-10, 11:57
Since truth is absolute, so no.

Theoratically, its possible, but Father Time definitely stays asleep.

Cochrane
14-05-10, 12:14
I'd like to know a bit more about how GPS systems work. Is it really time itself that is changing, or is it just the satellite changing its interpretation of time?
The way it works is that every GPS satellite transmits its current time, generated using an extremely precise time source (an atomic clock). Due to some smart calculations, a GPS receiver will have such an extremely precise time itself. The more a satellite is away, the longer it takes for its message to reach the receiver, and based on that time difference the receiver knows how far the satellite is away. With at least three, though in practice (due to errors) usually four, satellites, you can then exactly find out where you are.

Of course, the satellite also has to transmit which it is, where it currently is on the sky and how it is moving, otherwise you could not get a position. That information is transmitted very slowly, and is the reason why it takes a GPS receiver usually so long to get a signal, because it has to read all this data first. Modern cell phones accelerate this process by getting this information from the internet instead.

The important part is that the time on the satellite passes slower than on earth, because the satellite is moving faster than earth, at a rate of about 7 Ķs/day. There is also a shift due to gravity in the other direction, making the time pass faster again, at a rate of 45.9 Ķs/day, resulting in a total difference of about 39 Ķs/day, which has to be corrected, because due to the high speed of light (and hence messages from satellite to receiver), even such small differences could make GPS completely useless.

It is important to note that time really runs slower for the satellite. No matter how many clocks you put up there, they will all (if they are precise enough) tell you the same thing.

Furthermore, if I took a plane trip, is my "time set" ahead of people who have never taken a plane trip? As there are so many people who have taken plane trips, are all our "time sets" scattered, all different from eachothers? Is any more than one person in the same point of time?
Yes, actually, that has been verified by carrying high-precision clocks around on planes. Actually, the results even differ for whether you travel eastbound or westbound. However, in the end the differences are way too small for anyone but physicists with extremely good instruments to measure.

Sgt BOMBULOUS
14-05-10, 12:27
The way it works is that every GPS satellite transmits its current time, generated using an extremely precise time source (an atomic clock). Due to some smart calculations, a GPS receiver will have such an extremely precise time itself. The more a satellite is away, the longer it takes for its message to reach the receiver, and based on that time difference the receiver knows how far the satellite is away. With at least three, though in practice (due to errors) usually four, satellites, you can then exactly find out where you are.

Of course, the satellite also has to transmit which it is, where it currently is on the sky and how it is moving, otherwise you could not get a position. That information is transmitted very slowly, and is the reason why it takes a GPS receiver usually so long to get a signal, because it has to read all this data first. Modern cell phones accelerate this process by getting this information from the internet instead.

The important part is that the time on the satellite passes slower than on earth, because the satellite is moving faster than earth, at a rate of about 7 Ķs/day. There is also a shift due to gravity in the other direction, making the time pass faster again, at a rate of 45.9 Ķs/day, resulting in a total difference of about 39 Ķs/day, which has to be corrected, because due to the high speed of light (and hence messages from satellite to receiver), even such small differences could make GPS completely useless.

It is important to note that time really runs slower for the satellite. No matter how many clocks you put up there, they will all (if they are precise enough) tell you the same thing.


Yes, actually, that has been verified by carrying high-precision clocks around on planes. Actually, the results even differ for whether you travel eastbound or westbound. However, in the end the differences are way too small for anyone but physicists with extremely good instruments to measure.

It's important to note how minute these deviations are. A satellite moving 14,000 mph (I think that's about right), the slowdown of time would only be 0.000000021787%!!

ryan91
14-05-10, 13:28
i think time travelling is possible but not in human flesh:D, but with spiritual ways. i read in a book once tells that the time travelling is possible with meditation. it was saying that we can't go back as we are, we see the events from a person's eye view that was living in that time, in that moment. and i'm convinced to what that book said. don't think i'm a mad :D

the ancient
14-05-10, 14:39
Bertrand :vlol:

I think in theory I would be possible

Capt. Murphy
14-05-10, 14:50
I like the idea, and I'll have to take the word of others that seem to know what they're talking about and then I can say I believe it.

About the twin brother in space aging slower than you on Earth... This is the same kind of idea that could support the age of the Universe and a young Earth. The farther out you go at the speed of light (or some speed) -you keep doubling the time. (Was it) 6,000 years here on Earth = 15 or so Billions of years out there in the Universe. Or something like that. :pi:

Edit: But I'm aware the Age of the "known" universe has been tweaked -yet again. 13.75?

----------

I didn't answer the question. :o

I was thinking a few days ago (did a lot of thinking that day). While laying in bed (maybe I was depressed) I thought of going into a closet and coming out and it being some several minutes in the future. Then, what if I killed myself while I was laying there on the bed? Then the past me goes back into the closet and it takes me back in time. Then I lay down on the bed. This would mean that the past me would soon come out and kill the present me. ...But, what if I left the room? Then what would happen to time?

So, for this reason I think that Time Travel would be a highly unlikely feat for mortal man to accomplish. :p

patriots88888
14-05-10, 15:15
More interesting is time travel backwards. There are various solutions to Einstein's formulas that do allow it, but they all rely on things that may not actually exist in our universe.

If a time machine were successfully invented, time travel to the past would only be possible for those from the future and only as far back to the point the first time machine became adequately operational. There's an interesting Discovery Channel clip which covers certain aspects of this.

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Chocola teapot
14-05-10, 15:26
No. We will never, ever be able to time travel.

michaeldt
14-05-10, 15:29
it was in the news that Steven Hawkings (I think I spelled it right) said that time travel is possible :) but it would require spaceships going at an incredible speed that we cannot do today.

laralover_07
14-05-10, 15:30
I've wondered this, can anyone dumb down to my level to explain it to me?

Surely, if you had a twin brother in space, he would age at the same time as you? You're both human, and you both age at the same rate, so surely, right?

And if you were to fly a rocket far into space, wouldn't life on earth stay exactly the same? Since it's still there, spinning in its own time, you're just further away from it, if you were then to fly back, wouldn't the earth have aged the time it took to fly away and back?

Regardless, I'm confused, so I'd probably say maybe. Hopefully. I'd like to believe I could own my own Tardis one day.

spikejones
14-05-10, 15:33
No. We will never, ever be able to time travel.

Everyone travels through time every day. Its a one way street as far as we are all concerned though. Theories are of course in existence that state it may be possible to travel further ahead in time whilst your own perception of time is less. IE as judd put it, traveling 10 years ahead in time at a rate of only 5 years. Traveling backwards in time? I'm not sure if any theories yet exist on that concept. Currently though I would have to say that it is not possible given that we do not posses the technology to reach speeds that are theorized for such travel. Interestingly enough however, I am reminded of a piece on time travel theories that I once read in which it was stated that a (real life) person went into outer space for some reason or other, and upon returning, a comment was made that he looked as though he was younger than when he left.

moodydog
14-05-10, 15:33
well we know for a fact that we will never ever learn how to fly back in time, or develop machinery that can do this, regardless of if its possible or not, adn the reason for this is that on account, if it were possible, why arnt we seeing future particles or people now?.


we may be able to fly farwards in time,

peeves
14-05-10, 16:52
Well I don't think it's possible to travel the speed of light to slow time down and to head in the future. I even saw a picture of a time diagram dimension wise. It's just science fiction not real. And i think we head into the future by gradually dealing with time.

Liara
14-05-10, 17:40
Probably in the really far future someone will stumble over a way to travel through time. I mean, we can mess around with DNA and clone stuff... I think people are smart enough to figure out time travel as well.

I don't know why, but I have a feeling that the solution will be really simple, but we can't just see it yet... Maybe we need to expand the percentage of the usability of our brains. Someone once mentioned that we only use 10% of our brain, or something like that.

Btw, hilarious avatar, Saki. :D

tranniversary119
14-05-10, 17:43
Well, I've always said: If time travel will be possible in the future, wouldn't they come back to visit us? Then again, they probably would disguise themselves if they did. So that theory doesn't necessarily work out.

I do think in the future it will be possible. When? I don't know, probably not for a long time, obviously. But with technology advancing at a very fast rate it could be sooner than we think.

Encore
14-05-10, 17:45
I believe some day it will be possible.

And if I'm still alive that day, I wanna do this.

http://i39.************/2wd0qjl.jpg

No. We will never, ever be able to time travel.

I didn't know you had a degree in Physics!

Liara
14-05-10, 17:48
If time travel will be possible in the future, wouldn't they come back to visit us? Then again, they probably would disguise themselves if they did. So that theory doesn't necessarily work out.
Maybe it's the same case like with Men in Black - there are time travelers everywhere but they don't want to panic the public or draw attention to themselves. They need to stay low-profile and make experiments or something. :D

I sure wouldn't like to know if there are time travelers everywhere - then everyone would want to use the machine for themselves or for evil purposes and all hell would brake loose. Ignorance is bliss in this case.

tranniversary119
14-05-10, 19:19
Maybe it's the same case like with Men in Black - there are time travelers everywhere but they don't want to panic the public or draw attention to themselves. They need to stay low-profile and make experiments or something. :D

I sure wouldn't like to know if there are time travelers everywhere - then everyone would want to use the machine for themselves or for evil purposes and all hell would brake loose. Ignorance is bliss in this case.

Exactly, which is definitely kind of creepy to think about-people from the future walking amongst us. And not to mention, time travel can be just as deadly as it can be useful. If someone (who wanted to use it to their advantage) went back in time to mess with history or change an important event that happened, the future itself would be messed up.

But obviously there's advantages to having time travel: Studying history, changing bad things, etc. I've also always thought, maybe the aliens we claim to see are really us from the future? Also, If you've ever watched or read about ancient cultures and aliens "visiting them" maybe that's just us from the future? :cool:

Rai
14-05-10, 19:56
But obviously there's advantages to having time travel: Studying history, changing bad things, etc. I've also always thought, maybe the aliens we claim to see are really us from the future? Also, If you've ever watched or read about ancient cultures and aliens "visiting them" maybe that's just us from the future? :cool:

I've thought about this too. Ir's an interesting theory. I once told someone I thought that 'aliens' could be us time traveling and he laughed at me :(. Oh well, his loss for lacking an imagination :p.

lara c. fan
14-05-10, 20:15
No. We will never, ever be able to time travel.

While we can't reach the speed we need to be for time travel at this moment in time, there's nothing to suggest that we couldn't in the future.

silver_wolf
14-05-10, 21:30
I suppose this all depends on the nature of time. Time as we think of it is an illusion, really. I don't believe there is a past or future, just the present. Everything happens at once. How we perceive it is over "time".

Gregori
14-05-10, 21:36
Everytime you try to time travel, you travel back to the second before you time travelled!!!!!!

Cochrane
14-05-10, 21:46
I've wondered this, can anyone dumb down to my level to explain it to me?
Easy enough: If you get close to light speed, stuff gets weird.

Surely, if you had a twin brother in space, he would age at the same time as you? You're both human, and you both age at the same rate, so surely, right?

And if you were to fly a rocket far into space, wouldn't life on earth stay exactly the same? Since it's still there, spinning in its own time, you're just further away from it, if you were then to fly back, wouldn't the earth have aged the time it took to fly away and back?

Regardless, I'm confused, so I'd probably say maybe. Hopefully. I'd like to believe I could own my own Tardis one day.
The problem here is that you assume that time runs the same everywhere, that if one second passes at point A, one second will also have passed at point B. That is a natural assumption, but as it turns out, it is completely wrong. We donít notice that normally, but depending on a number of factors, it can and does happen that when one second passes in point A, two seconds or half a second pass at point B. That has nothing to do with aging or broken clocks or anything, it is time itself that goes slower.

If a time machine were successfully invented, time travel to the past would only be possible for those from the future and only as far back to the point the first time machine became adequately operational. There's an interesting Discovery Channel clip which covers certain aspects of this.

That is one interpretation, and it certainly solves the "why isnít earth full of time travellers" issue nicely, but this is by no means the only idea.

Chocola teapot
14-05-10, 21:50
I believe some day it will be possible.

And if I'm still alive that day, I wanna do this.

http://i39.************/2wd0qjl.jpg



I didn't know you had a degree in Physics!

Shush.

xMiSsCrOfTx
14-05-10, 22:07
I suppose this all depends on the nature of time. Time as we think of it is an illusion, really. I don't believe there is a past or future, just the present. Everything happens at once. How we perceive it is over "time".

Never though of it that way... Makes sense, though.

Gregori
14-05-10, 22:10
Well, as time passes and we go on, we're traveling forward in time; in a sense, time travel is possible. I don't think it'll ever be possible to slow down or stop time/travel backwards in time.

Its possible to slow down time. There is a famous experiment with two atomic clocks. You put one on an airplane and leave another stationary on the ground.
The clock on the moving object reads as less time having passed than the one on the ground.


Its a very subtle effect though, like femto or nano seconds slower!!!!

TRfan23
14-05-10, 23:55
A guy on my college course is a science dude, and he thinks it's most likely impossible to travel back in time, since atoms forget. But there's most likely a chance to speed up time :)

@silver wolf - I said that on facebook once and got flamed by a bunch of physicists :(

aktrekker
15-05-10, 00:37
Interesting topic.
I don't believe time travel by any definition is possible.
First, travel into the future. I personally am not convinced that time is truly relative. I know some experiments have been done that seem to show that time does vary. But I tend to think it is more due to the varying effects of gravity on the measuring devices themselves. I don't think those effects have been properly accounted for. And at this time, we don't have the knowledge to account for them. We tend to think we understand gravity pretty well. But NASA's Pioneer spacecraft have deviated from their course. They still haven't figured out why. One theory is that we don't understand gravity as well as we think.
http://science.nasa.gov/science-news/science-at-nasa/2001/ast03may_1/
http://www.newscientist.com/article/dn13676-pioneer-spacecraft-mystery-may-be-laid-to-rest.html

As for travel into the past, I don't believe that is possible. My explanation can also account for perceived differences in the passage of time. Note that this is not "my" theory, it is a merging of separate theories proposed by several PhDs in astrophysics.
Starting with string theory, all matter and energy is made of strings. Strings vibrate differently, and that vibration determines what type of particle they represent. When matter and energy move through the universe, this vibration is passed from one string to the next. The speed at which a string can change from one vibration to another is what creates the speed of light limit. The strings simply can't change their vibration any faster.
Now consider the entire universe at one instant in "time". Every string will have a particular vibration. Suppose just one string (or 2 perhaps) changes its vibration. The universe is now in a different state. In reality, countless numbers of strings throughout the universe will be changing at the same time. The previous state of the universe is gone. It cannot be retrieved. There is no way to get it back.
The passage of time is simply the human attempt to organize these "state changes" of the universe. Time as an entity is an illusion. Time measuring devices are really just measuring the rate at which their own strings are changing state.
Now consider the "past". Whatever instant you want to go back to, the universe was in a particular state. All of the strings in the universe had a specific vibration. Even if you could place the universe back into that exact state, you could not go there. The original state did not include you as you are right now. If you placed yourself into that previous state of the universe, it would not be exactly the same. Events would not play out in exactly the same way because you would have altered the state of the universe just by making yourself a part of it.
Even if you reject some parts of this theory, the last paragraph still applies. The past would not be the same past you meant to visit simply because you are in it.

Kind of a layman's explanation in a nutshell. I hope everyone can understand it.

LaraLuvrrr
15-05-10, 01:26
I think it's possible but not while we are flesh and blood.

In order to time travel you have to move so fast that you would have to be broken down to some particles or something imo. I think time travel is possible after you die. Like I think our souls can somehow reincarnate in different time periods.

For all we know this current time could have already passed and we're simply consciousness at this given point in time reliving it.

silver_wolf
15-05-10, 01:48
Its possible to slow down time. There is a famous experiment with two atomic clocks. You put one on an airplane and leave another stationary on the ground.
The clock on the moving object reads as less time having passed than the one on the ground.


Its a very subtle effect though, like femto or nano seconds slower!!!!
Doesn't that have something to do with how gravity effects time? I read something similar, like a clock in space will move faster than one of the bottom of the ocean. Stuff like this makes my brain hurt.



@silver wolf - I said that on facebook once and got flamed by a bunch of physicists :(
Well, ok, for one, anyone can claim to be a physicist on facebook. And two, no one really knows, it's all just theories. The idea I posted was first proposed, as far as I know, by Edgar Cayce, a genuine...well, something. Call him a prophet or psychic if you want. The guy could diagnose any physical illness while in a trance, in the early 1900s, with no medical training.

TRfan23
15-05-10, 01:51
Well, ok, for one, anyone can claim to be a physicist on facebook. And two, no one really knows, it's all just theories. The idea I posted was first proposed, as far as I know, by Edgar Cayce, a genuine...well, something. Call him a prophet or psychic if you want. The guy could diagnose any physical illness while in a trance, in the early 1900s, with no medical training.

Well technically they're not physicists they're studying physics at Uni and one of them is my brother :/

silver_wolf
15-05-10, 01:52
ah. whoops:o
But again, with something like this, it's all theoretical. I think any idea is valid, really.

TRfan23
15-05-10, 01:53
^ True :)

Admles
15-05-10, 05:03
Time is a concept, not a physical thing.

Time travel is not possible IMHO.

Thorir
15-05-10, 05:06
Not of yet, no.

Shame you were the silver tracksuit.

silver_wolf
15-05-10, 05:16
silver tracksuit??

Dusan
17-05-10, 12:25
Anyone interested in the subject should watch a new documentary Into the Universe with Stephen Hawking (namely part 2 out of 3) where time travel is discussed in great detail.

The relative speed of time can change, depending on the speed of the moving object (coordinate system). If you travel at speeds close to the speed of light, your flow of time is slower relatively to the rest of the world/universe, therefore you age more slowly than the rest of the world. This is the principle of time travel into the future. But you have to move super fast and that is the problem...

This effect has been first discovered by Albert Einstein in his theory of relativity so it's not new.

Time travel into the past is not possible (because of issues with causality and also feedback) while time travel into the future is possible and has been actually observed with super-accelerated atomic particles.
As these particles approach the speed of light they experience slower flow of time and therefore they last longer. They 'age' about 30 times more slowly than if they didn't move. So they effectively travel in time.

GPS satellites orbiting around the Earth also have to automatically self-correct because of the different flow of time here on Earth and up on the orbit (due to the influence of the gravitational field of the Earth).

Btw, there are great university lectures online discussing all kinds of topics of physics and also relativity and time dilation here:
http://webcast.berkeley.edu/course_details.php?seriesid=1906978515

TippingWater
17-05-10, 12:31
^ :tmb:

Simochka
17-05-10, 13:26
There's one thing I learned in school I wonder. Is it true that the stars we see from earth can have exploded some thousand years ago? Like 7 000 but we won't see it from here until like 10 000 years after it happened?

It's hard to explain in english but I hope you get it :p

Alpharaider47
17-05-10, 14:47
There's one thing I learned in school I wonder. Is it true that the stars we see from earth can have exploded some thousand years ago? Like 7 000 but we won't see it from here until like 10 000 years after it happened?

It's hard to explain in english but I hope you get it :p

To my knowledge, yes that is true, because of the great distance involved, and the fact that that light has to travel that distance before we see it, which takes years at the speed of light. (correct me if I'm wrong anybody who knows more about this :p)

CerebralAssassin
17-05-10, 15:00
yar.I think it's possible.through some temporal anomaly or something like that:p

Lara's home
17-05-10, 15:15
I doubt we will ever time travel.

patriots88888
17-05-10, 15:16
There's one thing I learned in school I wonder. Is it true that the stars we see from earth can have exploded some thousand years ago? Like 7 000 but we won't see it from here until like 10 000 years after it happened?

It's hard to explain in english but I hope you get it :p

To my knowledge, yes that is true, because of the great distance involved, and the fact that that light has to travel that distance before we see it, which takes years at the speed of light. (correct me if I'm wrong anybody who knows more about this :p)

It is true. Many of the stars which we see have 'burned out' long ago because, as you have noted, the great distances it takes for the light from these stars to reach us.

When we witness a super nova explosion, we are actually looking into the past... as we are when we are fortunate enough to witness any cosmic events.

Dusan
17-05-10, 15:54
Yes, some stars are so distant that their light travels (at the speed of light) millions of years to get to us.
What we in fact see in the night sky are past images of those stars and some of them even no longer exist (but we can still see them because of the great delay).


In fact, even our own Sun is so far away from us that it takes approximately 8 minutes for the sun rays (light) to reach us.

If the Sun exploded now, we wouldn't know about it for the next 8 minutes which I always find quite remarkable :).

sandygrimm
17-05-10, 18:29
In the future YES!
Now traveling to the past, most likely not, than they said the same about flying before the airplane was invented, so who knows... MAYBE!
( but than if they could we'd see people from the future warning us now or walking among, or for that matter avoiding going back in time not to screw up the past )
Yet many think Nicolai Tesla was a man of the future but that's beside the point....

I did read in an article some time ago, another type of approach of time travel backward.

Those who believe in reincarnation tried to get in touch with their former lives, threw hypnosis. And threw that they did effectively time travel. Not physically but mentally, in another person, from the past. Many think this is how Nostradamus got his predictions. I'm not saying I believe, but it is a good possibility.

Mytly
17-05-10, 21:04
Is time travel possible? Yes, of course, the laws of physics as we currently understand them do not rule it out. Does this mean you can hop into a time machine and push a button and go back to the future? I'd say definitely not - neither now nor in the future. If it ever becomes practically feasible for human beings to travel through time, it's unlikely to be that simple - or that crude. As for travelling back to the past before the machine was built - highly unlikely, I think.

Now consider the "past". Whatever instant you want to go back to, the universe was in a particular state. All of the strings in the universe had a specific vibration. Even if you could place the universe back into that exact state, you could not go there. The original state did not include you as you are right now. If you placed yourself into that previous state of the universe, it would not be exactly the same. Events would not play out in exactly the same way because you would have altered the state of the universe just by making yourself a part of it.
Even if you reject some parts of this theory, the last paragraph still applies. The past would not be the same past you meant to visit simply because you are in it.
I do reject that theory (for lots of reasons), but you're right - the last paragraph still applies. It's a good way to show that travel into the past is not possible. Basically what you are saying is that there is only one 'timeline' and what has happened cannot be changed.

But of course, if one assumes that there are multiple timelines that can branch in the past as well as the future, then the picture changes entirely. The past can be changed with as much abandon as the future. I am not suggesting that this is true, but it is an interesting hypothesis. Since right now time travel is pretty much hypothetical anyway, it makes for some nice food for thought. :D

When we witness a super nova explosion, we are actually looking into the past... as we are when we are fortunate enough to witness any cosmic events.
Every time you look up at the night sky, you are witnessing the past - or rather lots of different pasts. Every star you see is in the state it was anywhere between 4 to 1000s of years ago, depending on how far it is from us.

aktrekker
17-05-10, 21:54
I do reject that theory (for lots of reasons), but you're right - the last paragraph still applies. It's a good way to show that travel into the past is not possible. Basically what you are saying is that there is only one 'timeline' and what has happened cannot be changed.

Like I said it's based on the work of several physicists. But it's still just theories and they are still working on them. And I'm not sure if anyone has bothered to merge the theories yet. Still, science hasn't been turned upside down......yet :D


But of course, if one assumes that there are multiple timelines that can branch in the past as well as the future, then the picture changes entirely. The past can be changed with as much abandon as the future. I am not suggesting that this is true, but it is an interesting hypothesis. Since right now time travel is pretty much hypothetical anyway, it makes for some nice food for thought. :D
Even if multiple time lines do exist, you would end up in an alternate one. You wouldn't be in the past you wanted to experience. That's really the part that makes the idea of time travel suck. The past we knew is gone and we can't go back to it or it wouldn't be the past we knew.

This kind of stuff makes your brain hurt, doesn't it? :p

Dusan
18-05-10, 04:58
Talking about branching the future etc. ...
There was an interesting BBC Horizon documentary on infinity (both as an abstract mathematical concept and whether it actually exists in the real world).

One of the main issues discussed there was whether the universe is infinite of finite. No one knows right now and to me it seems that infinity of the universe cannot by definition be tested (you'd have to go for infinitely long around it :))... on the other hand you can in principle falsify it, when you travel far enough and hit the end of it - then it clearly wouldn't be infinite :).


They argued in the documentary that if the universe is infinite, then just from the properties of infinity it directly follows that such a universe would contain not just 'our reality' but all other possible realities. In an infinite universe there would be an infinite number of copies of yourself living (in parallel) all possible different versions of your life.
In such a universe going 'far enough' (or maybe infinitely far? ... that wouldn't be feasible though) would mean that you'd stumble upon a copy of yourself.

As I said, this follows merely from the properties of infinity. In an infinite space everything, even if it's super-improbable (such as your own birth), happens all the time... :)

The main issue is, I'd say, that we don't know (yet) what the universe is and therefore what properties of it to anticipate.

Drone
18-05-10, 05:43
Its possible to slow down time. There is a famous experiment with two atomic clocks

It's possible. At some rate time always slows down. Also really heavy objects like supermassive black holes can slow down time aswel.

aktrekker
18-05-10, 06:45
They argued in the documentary that if the universe is infinite, then just from the properties of infinity it directly follows that such a universe would contain not just 'our reality' but all other possible realities. In an infinite universe there would be an infinite number of copies of yourself living (in parallel) all possible different versions of your life.
In such a universe going 'far enough' (or maybe infinitely far? ... that wouldn't be feasible though) would mean that you'd stumble upon a copy of yourself.

First, I would question how they can possibly even postulate what the properties of infinity would be.
Then I would question why those properties would be any different than the properties of a finite universe.
Finally, I challenge the idea that it would "directly follow" that an infinite universe would have multiple realities or multiple copies of anything.

Cochrane
18-05-10, 06:59
First, I would question how they can possibly even postulate what the properties of infinity would be.
Then I would question why those properties would be any different than the properties of a finite universe.
Finally, I challenge the idea that it would "directly follow" that an infinite universe would have multiple realities or multiple copies of anything.

If I got it right, it is a mathematical argument. The probability p that there is at least one copy of you or me within a radius of r light years somewhere is extremely low, but with our current level of knowledge it would be wrong to say p=0. Obviously, if we increase r then p also goes up in a cubic manner (assuming, as a simplification, a uniformly dense universe). If the universe is truly infinite, and contains an infinite amount of matter, then we can let r get arbitrarily large, and the limit of p becomes 1. The same can be said for absolutely anything.

Of course, that assumes several things about an infinite universe that may not be true. For example, matter may not be uniformly distributed — it is certainly possible that space itself is infinite, but the area actually filled with stars, galaxies and so on is limited, in which case the argument breaks down since after a certain r, p no longer increases.

aktrekker
18-05-10, 08:17
We have no ability to detect a copy of anyone, we have no reason to assume one can possibly exist, infinity notwithstanding. The idea that the probability of a copy of anyone can't be zero is an assumption. While it's a nice exercise, I think the idea is fundamentally flawed.

Cochrane
18-05-10, 09:08
Hm… yeah, I guess you’re right. The actual probability may very well be zero. We just don’t know that, so the upper bound for the probability is really what is non-zero here. If we increase the radius, that upper bound may and will rise, but the lower bound of 0 of course remains 0, with the actual probabilty being somewhere in between these bounds (inclusive).

Dusan
18-05-10, 09:36
First, I would question how they can possibly even postulate what the properties of infinity would be.
Then I would question why those properties would be any different than the properties of a finite universe.
Finally, I challenge the idea that it would "directly follow" that an infinite universe would have multiple realities or multiple copies of anything.

The explanation provided by Cochrane is correct (btw, very well done, Cochrane :wve:).

Infinity is a precisely defined mathematical concept and there is an entire branch of math studying just infinity. So the formal definition is available.

Current cosmology assumes homogeneous universe (based on all available observations), with evenly distributed matter. This implies that an infinitely large universe would contain an infinite amount of matter. This infinite matter allows for all possible combination of atoms etc. As long as something isn't plain impossible, even if its probability is super small, it will happen very often (actually, infinitely often) in an infinite universe, simply because of the infinite amount of available matter.


We have no ability to detect a copy of anyone, we have no reason to assume one can possibly exist, infinity notwithstanding. The idea that the probability of a copy of anyone can't be zero is an assumption. While it's a nice exercise, I think the idea is fundamentally flawed.

The point of the documentary was to introduce and demonstrate the strange and unintuitive properties of infinity as such.
The infinite universe being one example of such strange behavior. It does not imply that it actually exists.
But if it existed, it would be like that.

Of course there's no 'practical point' to it.

But there are many mathematical problems which are pointless from the 'practical' point of view, such as the question whether odd numbers are more numerous than even numbers or vice versa.
But that doesn't mean that it is completely useless to investigate such problems :).

Dusan
18-05-10, 09:43
.

Draco
18-05-10, 12:46
This effect was tested with the SR-71 Blackbird. One circumnavigation of the planet at top speed put the atomic clock on board 3 seconds behind the one synchronized to it on the ground.

aktrekker
18-05-10, 22:05
Infinity is a precisely defined mathematical concept and there is an entire branch of math studying just infinity. So the formal definition is available.

I understand the mathematical model. The idea that that can then be applied to an infinite universe is where I believe the flaw exists. An infinite universe is not necessarily a physical manifestation of the model. In fact I find it highly unlikely that you can map the concept of infinity to an infinite physical object.

Besides, the universe is still expanding. In fact the expansion is accelerating. If the universe is expanding it can't be infinite (yet). It has the potential to become infinite, but it will take infinitely long to happen.
In order for this multiple reality idea to work, the universe would have to create matter as it expands. This violates physics - matter cannot be created or destroyed. So I don't see how this idea could ever be a reality.

Or do I have a gap in my knowledge?

Link: The universe is flat, expanding, and "considered" infinite based on its geometry.
http://map.gsfc.nasa.gov/universe/uni_shape.html

NightWish
18-05-10, 22:11
If you have the dagger of time, it is possible :whi:


:vlol:

Draco
19-05-10, 00:03
The universe is considered infinite because there is no concept for beyond contains everything that exists, may exist, or has already existed.

Dusan
19-05-10, 05:20
I understand the mathematical model. The idea that that can then be applied to an infinite universe is where I believe the flaw exists. An infinite universe is not necessarily a physical manifestation of the model. In fact I find it highly unlikely that you can map the concept of infinity to an infinite physical object.

Besides, the universe is still expanding. In fact the expansion is accelerating. If the universe is expanding it can't be infinite (yet). It has the potential to become infinite, but it will take infinitely long to happen.
In order for this multiple reality idea to work, the universe would have to create matter as it expands. This violates physics - matter cannot be created or destroyed. So I don't see how this idea could ever be a reality.

Or do I have a gap in my knowledge?

Link: The universe is flat, expanding, and "considered" infinite based on its geometry.
http://map.gsfc.nasa.gov/universe/uni_shape.html

The concept of infinite space is simple: it just means unlimited, unbounded space, going on and on forever in all three dimensions.

The fact that the universe is expanding doesn't contradict that it is infinite (just like you can multiply infinity as well, btw).

Imagine the universe as an infinite three-dimensional grid... or maybe a two-dimensional grid in a plane will do so that it's easier to visualize. Expansion means that the scale (the "zoom") of that entire grid increases, the distances between individual cells of the grid are ever increasing.
But the grid is still infinite (unlimited in all dimensions).
So the expansion of the universe actually refers to a changing "scale" of the universe.

Don't take the expression "flat universe" too literally. It's just a two-dimensional analogy of a three-dimensional property of space.
The opposite is a "closed universe". Such a universe would mean that if we travel far enough into space, eventually we will get to the same point from where we started. This may sound weird but the same thing happens on Earth (because it has a spherical, closed surface): if we start walking (and swimming :-) forward in any direction and we travel all around the globe, we will eventually come home again even though we always moved forward...

In contrary, the so called "flat" universe isn't like this. In it, if you start flying into the universe, never changing the direction, you will always move further and further away from the initial point, never coming back.
The word "flat" only refers to a two-dimensional analogy of the same principle when walking on a flat infinite plane (and never coming back if we always walk forward).

robm_2007
19-05-10, 05:25
dont we always travel through time?

every second that goes by, it is us traveling through time.

Drone
19-05-10, 05:28
dont we always travel through time?

every second that goes by, it is us traveling through time.

everything travels in time and space. always.

Dusan
19-05-10, 05:28
dont we always travel through time?

every second that goes by, it is us traveling through time.

Yes, but by default we're travelling at a constant speed through time (one second per second :D).
This topic is about changing that speed ;).

robm_2007
19-05-10, 05:46
Yes, but by default we're travelling at a constant speed through time (one second per second :D).
This topic is about changing that speed ;).

Physically, IDTS.
figuratively, yes.

aktrekker
19-05-10, 05:47
Again, I understand the concept.
But mathematically, modifying infinity in any way still results in infinity.
The universe expanding actually changes infinity. There is more room between points that used to be closer together. Therefore, infinity is growing.
Personally I think it's just an easy way out of having to explain what is beyond the "edge of the universe".
Although there are physicists who are trying to do just that. There is an "outside" to the universe, therefore a boundary. Whether we will ever be able to detect it is a different matter.

Dusan
19-05-10, 10:20
modifying infinity in any way still results in infinity.
Yes.

The universe expanding actually changes infinity.
But it's still infinity :).
There are infinities of different magnitudes, for example there is an infinite number of whole numbers AND there is an infinite number of real numbers but clearly there are infinitely more real numbers than whole numbers because between any two whole numbers there is an infinite number of real numbers filling the gap.
So those particular two infinities are very different but nonetheless, they are both infinite :).

Personally I think it's just an easy way out of having to explain what is beyond the "edge of the universe".
I don't think it's a particularly "easy" way because it introduces more "weird stuff" than if we simply assume that the universe is finite (whatever lies "beyond").

Maybe there is such an edge, maybe there isn't, we haven't been able to observe it so far or deduce it from any other experiments. So trying to explain what's beyond that edge at this stage is absolutely pointless because we don't even know whether such an edge exists at all and if so what are the properties of that "edge".

It would be mere guessing and so (with Carl Sagan) in the absence of evidence we have to suspend our judgment for now :).

Personally I'm certainly not defending the idea of an infinite universe I'm just talking about the consequences of hypothetical existence of such a universe that I heard about in that BBC documentary which I found very thought-provoking :).

CerebralAssassin
19-05-10, 12:27
let's not forget,folks, that there are 2 kinds of infinity:countable infinity,and uncountable infinity.I believe the universe is uncountably large.

furthermore,as someone already mentioned,there's likely to be an infinity of universes,not just one.there might be a universe embedded inside something as small as a grain of sand,for instance.

Paddy
19-05-10, 12:29
let's not forget,folks, that there are 2 kinds of infinity:countable infinity,and uncountable infinity.I believe the universe is uncountably large.

furthermore,as someone already mentioned,there's likely to be an infinity of universes,not just one.there might be a universe embedded inside something as small as a grain of sand,for instance.
So if I crush a grain of sand I may have crushed a universe?
Muhahahahaha

CerebralAssassin
19-05-10, 12:35
So if I crush a grain of sand I may have crushed a universe?
Muhahahahaha

yar!!!:p you might be crushing whole civilizations without even knowing it!!
:p
I read about this concept (along with the multiple-universe theory) in one of Stephen King's books The Dark Tower I:the Gunslinger :) (good books,you should read 'em)

Cochrane
19-05-10, 13:35
let's not forget,folks, that there are 2 kinds of infinity:countable infinity,and uncountable infinity.I believe the universe is uncountably large.

furthermore,as someone already mentioned,there's likely to be an infinity of universes,not just one.there might be a universe embedded inside something as small as a grain of sand,for instance.

Why do you think that the universe is uncountable? What does that even mean, what would you count but canít? I think applying that mathematical concept here needs some more explanation.

CerebralAssassin
19-05-10, 14:28
Why do you think that the universe is uncountable? What does that even mean, what would you count but canít? I think applying that mathematical concept here needs some more explanation.

lol....was just kidding about that:p it doesn't make much sense

Catapharact
19-05-10, 14:40
Current cosmology assumes homogeneous universe (based on all available observations), with evenly distributed matter. This implies that an infinitely large universe would contain an infinite amount of matter. This infinite matter allows for all possible combination of atoms etc. As long as something isn't plain impossible, even if its probability is super small, it will happen very often (actually, infinitely often) in an infinite universe, simply because of the infinite amount of available matter.

Yet doesn't the third law of thermodynamics states that the amount of useable energy in this universe is finite and always declining. Actually the very concept of the idea is co-related with the entropic doom theory. Matter and Energy are co-related are they not? Well if useable energy is finite then by co-relation the amount of matter and reactions that cause the formation of matter is also finite because if there is such a thing as inifinite matter then it contradicts the third law of thermodynamics.

Cochrane
19-05-10, 15:06
Yet doesn't the third law of thermodynamics states that the amount of useable energy in this universe is finite and always declining. Actually the very concept of the idea is co-related with the entropic doom theory. Matter and Energy are co-related are they not? Well if useable energy is finite then by co-relation the amount of matter and reactions that cause the formation of matter is also finite because if there is such a thing as inifinite matter then it contradicts the third law of thermodynamics.

I donít see the third law of thermodynamics saying that. In fact, none of the laws of thermodynamics state anything about the universe in total, they all just make predictions for particular, closed systems.

Catapharact
19-05-10, 15:13
I don’t see the third law of thermodynamics saying that. In fact, none of the laws of thermodynamics state anything about the universe in total, they all just make predictions for particular, closed systems.

Apologies. Its actually the second law.

http://en.wikipedia.org/wiki/Second_law_of_thermodynamics

"Again roughly speaking, thermodynamic entropy is a measure of energy dispersal, and so the second law is closely connected with the concept of entropy."

It can even be stated Mathmatically:

http://upload.wikimedia.org/math/a/8/8/a88d639921a7da0ed0b7854581004163.png

Where Dt is the change in time.

I don’t see the third law of thermodynamics saying that. In fact, none of the laws of thermodynamics state anything about the universe in total, they all just make predictions for particular, closed systems.

Why can't it be applied to the universe considering that all biological and chemical reactions require an external source of heat and energy?

aktrekker
19-05-10, 18:04
Isn't the universe a closed system? Or are we back to the edge of the universe and what's beyond?


BTW, Einstein equated matter and energy. Not on any 1-to-1 basis, but still it equated matter and energy which were previously believed to be separate.
Einstein tried to find a global unification theory but was unsuccessful. What if he simply missed part of the equality?
Instead of E = M, maybe it should be E = M = Space.
In this way, matter and energy are never lost because they simply are absorbed into space. And space can become matter or energy, thus it is never created, it is only a conversion of state. It can account for particles of matter such as electrons blinking into existence apparently from nowhere and nothing (something I used to reject as impossible even though it has apparently been observed).

Cochrane
19-05-10, 19:08
Apologies. Its actually the second law.

http://en.wikipedia.org/wiki/Second_law_of_thermodynamics

"Again roughly speaking, thermodynamic entropy is a measure of energy dispersal, and so the second law is closely connected with the concept of entropy."

It can even be stated Mathmatically:

http://upload.wikimedia.org/math/a/8/8/a88d639921a7da0ed0b7854581004163.png

Where Dt is the change in time.

Why can't it be applied to the universe considering that all biological and chemical reactions require an external source of heat and energy?
You absolutely can apply it to the universe, if you assume that the universe is finite and that there is no external energy source, in short if the universe is a closed system. However, the second law of thermodynamics makes no case for or against the universe or anything in particular being a closed system, it just states how a closed system behaves if you find one. If, however, external energy is present then the second law no longer applies ó you can certainly clean up a room (decrease entropy), but energy for that has to come from somewhere and you will increase entropy elsewhere (e.g. power plant producing the electricity for a vacuum cleaner).

Would an infinite universe still be a closed system? I donít know. If total mass and energy are infinite, then the very idea of them being constant is useless, so my gut feeling is that no, it is no longer an isolated system.

Isn't the universe a closed system? Or are we back to the edge of the universe and what's beyond?
Absolutely. If we assume that the universe is a closed system, then the second law of thermodynamics applies to the universe as well. But if the universe is infinite or there is some other way of influencing it from an outside, then there is no guarantee that entropy actually increases. The second law of thermodynamics makes no statement about the universe one way or another. Granted, there is one way of stating it which explicitly says that entropy in the universe always increases, but this contains an implicit assumption that the universe is finite and closed.

BTW, Einstein equated matter and energy. Not on any 1-to-1 basis, but still it equated matter and energy which were previously believed to be separate.
Einstein tried to find a global unification theory but was unsuccessful. What if he simply missed part of the equality?
Instead of E = M, maybe it should be E = M = Space.
In this way, matter and energy are never lost because they simply are absorbed into space. And space can become matter or energy, thus it is never created, it is only a conversion of state. It can account for particles of matter such as electrons blinking into existence apparently from nowhere and nothing (something I used to reject as impossible even though it has apparently been observed).
No, I think you are confusing some things here.

The phenomena of electrons and other stuff blinking into existence has its basics in quantum physics. According to Heisenberg, we can never fully know the position and speed, or otherwise the current state and the rate this state is changing, of anything beyond a certain precision. It is simply not defined any better. Applying this concept to some scenarios leads to weird results. For example, we cannot say that a particular area of space has no particles now and that this will not change, so we have to assume that particles can randomly pop into existence. An odd idea based solely on having fun with maths, but various experiments support the idea. Notice that mass and energy actually do stay constant: The theory predicts that such particles are always formed in pairs, one of which has mass, and one of which has negative mass, a very alien, but also very interesting concept.

That is almost completely unrelated to the GUT, though. That theory deals with explaining all the four known forces in one unified way. Einstein did manage to create a very useful explanation for gravity, but applying the same method to the other forces is something he failed at, and most modern physicists believe that this is entirely the wrong way to go.

Everybody currently believes that matter and energy are constant (assuming a finite universe, but then again, all physicists currently believe that (although it is fun to think about an infinite one, as in this thread)).

Note: Although I hope I didnít, I may have gotten some things wrong here, as my Stephen Hawkings books are all elsewhere, so I couldnít look this up right now. If you are interested in that, I can only reiterate what so many others have said here: If you havenít yet, read one or more of his books.

aktrekker
19-05-10, 19:57
I've read about entangled pairs. I understand the concept. Basically. The same way I understand quantum mechanics. Basically. Trying to read a book about it tends to make my brain do cartwheels. :hea:
I just feel that using it as the (only) explanation for this phenomenon is an assumption. It's impossible to show that the detected particle became detectable due to its entanglement. It would require observation that would, itself, change the outcome.

Even if it does explain this particular phenomenon, I still think E = M = S has some merit. I wonder if anyone has even considered this very simple idea.

I also tend to be a proponent of the simplest, most obvious solution is probably the best solution. And quantum mechanics is extremely convoluted. And since it deals with uncertainty and mostly unmeasurable situations, it creates uncertainty about the theory itself. How can we ever be sure it's right if we can't measure (or even observe) anything without altering the outcome?
IOW, if we adapt the theory to what is observed, and the act of observing changes the outcome, will the theory ever be right? :p

Just wondering out loud....

Edit: And the current belief is that the universe would have to be infinite.
http://map.gsfc.nasa.gov/universe/uni_shape.html

Chocola teapot
19-05-10, 20:01
I Don't really beleive that time actually exists... in a sense.
Can someone Prove in some way that there is an actual time and not a constant event?

I Imagine time was just something man invented to measure events ect.

IMO, Everything is a constant present, You cannot harness or detect time,
Go back in it or forward because it's not actually a presence that can be detected other than with man made instruments.

Can someone prove time to me?

lara c. fan
19-05-10, 20:15
I Don't really beleive that time actually exists... in a sense.
Can someone Prove in some way that there is an actual time and not a constant event?

I Imagine time was just something man invented to measure events ect.

IMO, Everything is a constant present, You cannot harness or detect time,
Go back in it or forward because it's not actually a presence that can be detected other than with man made instruments.

Can someone prove time to me?

What about environmental change and such like? The world never stays the same, and that change is done over time.

Chocola teapot
19-05-10, 20:18
What about environmental change and such like? The world never stays the same, and that change is done over time.

What about them? The world is a very active place,
'Time' Just meaures 'How Long' It takes for specific occurences such as environmental change to happen.

the changes just happen, Time doesnt trigger or contibute to them, It just measures them.

lara c. fan
19-05-10, 20:23
What about them? The world is a very active place,
'Time' Just meaures 'How Long' It takes for specific occurences such as environmental change to happen.

the changes just happen, Time doesnty trigger or contibute to them, It just measures them.

So call it a form of measurement then. And besides, time is something like... gravity, in a obscure way. While we may not have the tools needed to harness or detect time at this point, there's nothing to suggest that it couldn't be done in the future. And besides, asking to prove time is like asking what would happen for sure when an irresistible force hits an immovable object. We may find out soon (I doubt that, it's pretty much impossible right now :p), or we may not find out at all.

Chocola teapot
19-05-10, 20:26
So call it a form of measurement then. And besides, time is something like... gravity, in a obscure way. While we may not have the tools needed to harness or detect time at this point, there's nothing to suggest that it couldn't be done in the future. And besides, asking to prove time is like asking what would happen for sure when an irresistible force hits an immovable object. We may find out soon (I doubt that, it's pretty much impossible right now :p), or we may not find out at all.

You're right, If someone actually does something to prove it's presence rather than use it to measure then... perhaps.

What gravity has that time doesn't is that it is easily noticable and in some areas (Space) it is not present. It just proves itself.

Cochrane
19-05-10, 20:32
I've read about entangled pairs. I understand the concept. Basically. The same way I understand quantum mechanics. Basically. Trying to read a book about it tends to make my brain do cartwheels. :hea:
Well, to quote Niels Bohr, if you donít get a headache from quantum mechanics, you donít understand it, so I think youíre on the right way. :D

I just feel that using it as the (only) explanation for this phenomenon is an assumption. It's impossible to show that the detected particle became detectable due to its entanglement. It would require observation that would, itself, change the outcome.

I also tend to be a proponent of the simplest, most obvious solution is probably the best solution. And quantum mechanics is extremely convoluted. And since it deals with uncertainty and mostly unmeasurable situations, it creates uncertainty about the theory itself. How can we ever be sure it's right if we can't measure (or even observe) anything without altering the outcome?
IOW, if we adapt the theory to what is observed, and the act of observing changes the outcome, will the theory ever be right? :p

Just wondering out loud....
I shuffled your text around a bit to make my reply more connected, hope you donít mind

Your objection certainly makes sense, but in short, others had it as well and havenít found a better solution yet. Given the things that can be observed, it is the simplest and most obvious solution so far. As for the observation, I think it is an issue of scale: We cannot observe what happens directly to a particle. However, we can observe on a higher level, for example what happens to a large enough group of particles, and we can observe that trying to observe a particle makes the observation result wrong.

Even if it does explain this particular phenomenon, I still think E = M = S has some merit. I wonder if anyone has even considered this very simple idea.
Iím not exactly sure what it means. What is S? Distortion of space? Space itself? What does "space itself is equal to anything" even mean? As you know, Einsteinís relativity theory states that mass and energy (same thing) do distort space, which results in what we call gravity, so there is an argument to be made that we already have E=M=S (obviously with actual maths that is way more complicated and that I certainly do not understand)

Edit: And the current belief is that the universe would have to be infinite.
http://map.gsfc.nasa.gov/universe/uni_shape.html
What that is saying that the universe never ends in temporal direction. The laws of thermodynamics absolutely allow a closed system to go on forever in terms of time, and in fact specifically say what will happen in that case. A system that is also infinite in terms of space, though, is something that does not work well with thermodynamics, and that is what I meant above.

I Don't really beleive that time actually exists... in a sense.
Can someone Prove in some way that there is an actual time and not a constant event?

I Imagine time was just something man invented to measure events ect.

IMO, Everything is a constant present, You cannot harness or detect time,
Go back in it or forward because it's not actually a presence that can be detected other than with man made instruments.

Can someone prove time to me?
Let me show you... my watch!

Now, what exactly do you mean by "there is no time"? Obviously, there is something we perceive as time, and most of our perceptions can best be explained if we assume that time is something different from the other three dimensions. You can absolutely imagine a system where one of the dimensions is swapped with time, giving different results, or look at things in a 4D way, in which case time does not really play a role, and everything is static. I am not sure what you want exactly when you ask for time to be proven to you.

Chocola teapot
19-05-10, 20:38
Let me show you... my watch!

Now, what exactly do you mean by "there is no time"? Obviously, there is something we perceive as time, and most of our perceptions can best be explained if we assume that time is something different from the other three dimensions. You can absolutely imagine a system where one of the dimensions is swapped with time, giving different results, or look at things in a 4D way, in which case time does not really play a role, and everything is static. I am not sure what you want exactly when you ask for time to be proven to you.

Why do all the intelligent people on the forum have to be so... Patronizing?

Actually, You weren't being that bad it was just the first sentence. :p

...

I'm well aware that time is used to measure ect, But my question is...

Is Time an actual proven, truely measurable, detectable force or just something mankind used to measure events?

Now, In a less patronizing manner, explain time's actual presence rather than a measurement between things, Is it a form of energy?, what is it?

CerebralAssassin
19-05-10, 20:49
Geeezus Christ....nevermind Quantum mechanics...all the above posts alone are making my head hurt!I'm assuming y'all are physicists?or do you wiki this **** all day?:p

Cochrane
19-05-10, 21:02
Why do all the intelligent people on the forum have to be so... Patronizing?
Because it is fun, you ought to try it yourself some time! :D


Actually, You weren't being that bad it was just the first sentence. :p

...

I'm well aware that time is used to measure ect, But my question is...

Is Time an actual proven, truely measurable, detectable force or just something mankind used to measure events?

Now, In a less patronizing manner, explain time's actual presence rather than a measurement between things, Is it a form of energy?, what is it?
Hm, interesting. You basically got it right: Time is not a form of energy, a force or anything similar, it is just a measurement between things. Mathematically speaking, it is identical to any one dimension of space: Height, width or length arenít forces or energies either, they are just something we use to measure. That does not mean that time does not exist: Two events (a physical event is a point in space together with a time) that have different values for time are not the same under any circumstances, just the same as how two things at the same time but at different places are clearly different things.

Mytly
19-05-10, 21:19
I'm well aware that time is used to measure ect, But my question is...

Is Time an actual proven, truely measurable, detectable force or just something mankind used to measure events?

Now, In a less patronizing manner, explain time's actual presence rather than a measurement between things, Is it a form of energy?, what is it?
The actual nature of time is hard to explain, but it is not a force nor energy. The best way to think of it is as a dimension, but even that is not good enough. The problem with trying to understand time is that there is nothing else like it in the universe, and certainly not in human experience, so it's hard to compare it to anything else.

The reality of time has nothing to do with human perception. It would still be there if we weren't. However, there are some physicists who disagree with this. For example, Julian Barbour in his book The End of Time (http://www.amazon.com/End-Time-Next-Revolution-Physics/dp/0195145925) - this is a synopsis of the book from Amazon:
Where does the time go? Independent physicist Barbour presents an unusual alternate to the standard way of viewing the four-dimensional universe (three spatial dimensions and time), beginning with how our perception of time is formed. Time, he says, does not exist apart from events: the motions of the sun and the stars, the mechanical movement of a clock. Rather than truly feeling the passing of time, we merely note changes in our surroundings, described by the author as a series of "Nows," like frames of a motion picture. Not only do Nows exist for the events that actually occur, but a large number of Nows represent alternate possibilities, inhabiting a land called Platonia. Which Nows become our perceived reality? The rule of thumb Barbour gives is, "only the probable is experienced." In the "macro" world, the author addresses determinism, Newtonian mechanics and the second law of thermodynamics as they relate to his theory of Nows. In the quantum mechanical realm, he ties his theory of time to the Schrodinger Equation in its various forms.Geeezus Christ....nevermind Quantum mechanics...all the above posts alone are making my head hurt!I'm assuming y'all are physicists?or do you wiki this **** all day?:p
Or maybe they are are just interested in this topic and read about it? I am myself obsessed with the concept of time and physics in general, and have read a lot about it (books, not Wikipedia :p). I am enjoying reading the discussion in this thread, even though I haven't contributed much.

aktrekker
19-05-10, 22:54
Here's some material for you on the topic of time.

http://discovermagazine.com/2007/jun/in-no-time
http://does-time-exist.info/
http://quantumweird.wordpress.com/2007/06/23/does-time-exist/
http://www.fqxi.org/data/essay-contest-files/Kiefer_fqx.pdf PDF examines time as it relates to quantum mechanics and relativity. Also available from the CERN website.
http://www.iep.utm.edu/time/ the philosophy of time
http://www.journaloftheoretics.com/Editorials/Vol-3/e3-1.htm
http://www.philica.com/display_article.php?article_id=188 This one has a religious slant if you're interested

Drone
20-05-10, 04:44
I Don't really beleive that time actually exists... in a sense.
Can someone Prove in some way that there is an actual time and not a constant event?

I Imagine time was just something man invented to measure events ect.

IMO, Everything is a constant present, You cannot harness or detect time,
Go back in it or forward because it's not actually a presence that can be detected other than with man made instruments.

Can someone prove time to me?


You definitely make sense with this. Time itself doesn't exist. There's space-time. If there are no existing objects around then time won't make sense at all. Just imagine that everything in the universe disappears in a blink of an eye. Then time will die too. Time is space's girlfriend and it's nothing on its own.


If things erode/fall apart it doesn't mean that time made it. It's just chemical/physical processes (but they can't happen without time).


It's like illusion. You can't measure things without changing them. That's why it's hard to reach the absolute truth.

Dusan
20-05-10, 05:19
Can someone prove time to me?

Hmmm, I don't quite understand what you mean... on one hand, it is trivial: we experience the flow of time every second, every day of our lives. Until we die as a consequence of the flow of time.

On the other hand, how do you go about proving it? How do you prove other things such as 3D space for instance? It can very well be an illusion just as the flow of time :). We don't even know how many dimensions it actually has - maybe those three that we are able to experience are just scratching the surface and maybe the full picture of space looks completely different than how we perceive it :)

Thanks for the links aktrekker, some of them were really interesting :wve:.