09 Feb 10
Originally posted by menace71Facts are hard to put forward in this.
This is a frustrating thread 🙂 A given real world application (GPS satellites) of time and Relativity and yet no comprehension or a dismissal of given facts. Still Good thread.
Manny
My question about time changing or our ablility to measure is still standing as far
as I'm concern.
If all I get is measuring devices are different, why is it time that is thought of as
having been changed and not the device that under went the stress of gravity?
All I am asking for are the reasons for this?
For me if all things share the moment of now, than time is a constant and we are
looking at it all wrong.
Kelly
09 Feb 10
Originally posted by amolv06Thank you for this, if you can point me to any book on this that addresses my
[b]I'm interested in the reasons behind the answers, the root causes, the
whys. Simply saying this is true is not enough, simply saying go read
a book is not an opinion either.
You will not get a sufficient answer on a forum. This matter really is entrenched in deep physics and mathematics. This is not something that can easily be shown on a forum ...[text shortened]... nd reading a fraction of the plethora of papers and books that exist dealing with this subject.[/b]
question directly I'll aquire it.
Kelly
09 Feb 10
Originally posted by twhiteheadTime or perspectives are relative?
Time is relative.
However, your question cannot truly be answered unless we can define time - and understand that definition and its implications.
Although as humans we imaging some sort of flow of time and can imagine it going faster or slower or being constant with only our measuring devices changing, the truth of the matter is that what we call time ...[text shortened]... o call 'time', then as far as science is concerned it is not measurable and is irrelevant.
If time is constant and our ability to measure it during certain stresses like gravity,
than knowning that would change the way we viewed things would it not, wouldn't
it alter how it is all viewed?
If time isn't a constant but can be altered speeding up or slowing down, exactly
how can we know how old everything is since we acknowledge all that we are
looking at may have been affected by some stress that caused it all to speed up
or slow down?
Kelly
09 Feb 10
2 edits
Get it straight, I am free to question nearly 100 years of established science if
that is not true, you are no longer dealing with science but religion.
Kelly
Of course you should be able to question established science! But your questions seem to be stemming from incredulity, rather than a cogent challenge to the theory of relativity. To me, that by itself is a weak reason to be questioning well-established science. But as I said earlier, you are free to your beliefs.
So if a snap shot has everything sharing the same moment why isn't time
a constant again?
This misunderstanding between us may be as simple as we're using one word to describe two separate things. How do you define "constant."
Thank you for this, if you can point me to any book on this that addresses my
question directly I'll aquire it.
Kelly
Any book covering basic relativity should suffice. One book I might recommend is Introduction to Special Relativity by Robert Resnick. This book is an introductory level book to relativity, and lays out the theory without the use of advanced mathematics. That said, it has been written as a textbook, so do expect quite a bit of math there, but there is nothing more advanced than basic calculus -- it does not really go into the geometry of flat spacetime except in the appendix. It may help to be acquainted with some classical electrodynamics to understand an important motivating factor for the development of the theory of relativity. My recommendation here would be Introuction to Electrodynamics by Griffiths. This book makes heavy use of vector calculus, so be aware.
If you're looking for a more advanced treatise on relativity, I recommend Gravitation by Misner, Wheeler and Thorne. This book is on general relativity, but is a good book to truly understand the geometry of spacetime. This book requires knowledge of vector calculus, and some basic concepts from linear algebra. It takes you through all of the differential geometry you need to know.
I think if you truly want to satisfy your curiosity, you would consult those books, or similar ones. A simpler answer, as twhitehead explained quite nicely in my opinion, is that time "slows down" in certain situations because it is defined this way. Why is it defined this way? Because such a definition is useful in making predictions, calculations, etc.
10 Feb 10
Originally posted by KellyJayThere is a popular scientific book by Feynman on the subject:
Thank you for this, if you can point me to any book on this that addresses my
question directly I'll aquire it.
Kelly
Six Not So Easy Pieces: Einstein’s Relativity, Symmetry and Space-Time, Addison Wesley, 1997, ISBN 0-201-15026-3
Haven't read this one in particular, but I've read some of his other work and he explains things very well, also to the layman. However it turns out that you need some elementary calculus knowledge to grasp this, so if you are really interested in this matter you can grab a calculus book and enter the world of physics and mathematics.
14 Feb 10
Originally posted by amolv06"Of course you should be able to question established science! But your questions seem to be stemming from incredulity, rather than a cogent challenge to the theory of relativity. To me, that by itself is a weak reason to be questioning well-established science. But as I said earlier, you are free to your beliefs. "
[b]Get it straight, I am free to question nearly 100 years of established science if
that is not true, you are no longer dealing with science but religion.
Kelly
Of course you should be able to question established science! But your questions seem to be stemming from incredulity, rather than a cogent challenge to the theory of relativity. To me, t ...[text shortened]... this way? Because such a definition is useful in making predictions, calculations, etc.[/b]
Established science should be questioned as everything else should be in my
opinion. My question boils down does everything share the same moment right
now? If that is false, then if we were stop all things at once those things which
we seem to share the universe with at the moment would disappear, because they
are either moving to fast or to slow to be in the same moment of time as the rest.
If everything shared the same moment in time, then all things would still be in the
moment and paused with the rest. Simply because the math works out does not
mean anything other than the math works out, we can come up with formulas that
describe things quite nicely, but with various and sundry conditions not so practical.
Kelly
15 Feb 10
Originally posted by KellyJayIt is a lot more than measuring devices that are affected. It is the very laws of physics - which is of course what the measuring devices work under.
If all I get is measuring devices are different, why is it time that is thought of as
having been changed and not the device that under went the stress of gravity?
All I am asking for are the reasons for this?
Because it is simpler mathematically. Our mathematical models of the universe (laws of physics) are not the only way to look at things or calculate things, we simply try to find the simplest way of describing things.
For example, any point on the Cartesian plane can be described with either Cartesian co-ordinates or polar co-ordinates. Neither is wrong, but one is more useful than the other for a given set of circumstances.
If it was more useful to see time as constant and the physics changing, then maybe we would do it that way, but for most intents and purposes it is easier to look at it as if time is changing.
For me if all things share the moment of now, than time is a constant and we are
looking at it all wrong.
Kelly
But what do you mean by 'share the moment'? Due to the limit on the speed of light, one can never know whether they share the moment with anything else.
...and we are looking at it all wrong.
That depends on what you mean by 'wrong'. Science is all about utility. If the equations work, use them. Newtonian mechanics doesn't always work, but for situations where it does, we use it. Relativity as far as I know, always works, so we use it. Quantum mechanics always works - so we use it. You seem to be saying we should stop using what works because you don't find it aesthetically pleasing.
In reality, you probably want to make the change because you think it will solve some problem where science conflicts with your religion, but sorry to say, it wont help. Whichever way you choose to look at time, if the equations work under relativity, then looking at it differently wont make them stop working.
15 Feb 10
3 edits
Originally posted by twhiteheadThe devices are simply part and parcel of what we have to measure things with,
It is a lot more than measuring devices that are affected. It is the very laws of physics - which is of course what the measuring devices work under.
[b]All I am asking for are the reasons for this?
Because it is simpler mathematically. Our mathematical models of the universe (laws of physics) are not the only way to look at things or calculate th uations work under relativity, then looking at it differently wont make them stop working.[/b]
and we know that we can cause many of our devices to not behave the same way
when we do certain things to do them while we use them.
The laws of phyiscs are just our understanding of how the universe works, if we
are getting it wrong than that means there will be things that simply do not fit as
we look at a broader picture of the universe, and you know as well as I that we
do not have a clear understanding of how it all works together at this time. Reality
could really be operating differently than how we currently view it, even if we call
something a law, does not mean we "got it right", but where we are very sure that
we have got it right we should operate as if that were true until we are shown
we are wrong.
What I mean by, "time being a constant" is that it does not change any where at
any time, but all things move through it at the same time. Having said that I am
not saying that all things move through the universe are not affected differently,
but all things share the same moment at all times.
"You seem to be saying we should stop using what works because you don't find it
aesthetically pleasing. In reality, you probably want to make the change because
you think it will solve some problem where science conflicts with your religion, but
sorry to say, it wont help."
Do you feel the need to bring in my religion when I ask questions on science, you
really just cannot talk to me without doing that? Come on! Stick to the topic I'm
not bringing in religion into this discussion why are you?
Kelly
15 Feb 10
Originally posted by KellyJayThere is two views how time is going relative space, and vice versa.
What I mean by, "time being a constant" is that it does not change any where at
any time, but all things move through it at the same time. Having said that I am
not saying that all things move through the universe are not affected differently,
but all things share the same moment at all times.
(1) That time flows and the universe stands still. Like you stand on a rock in the middle of a river and see the water (the time) flows around you.
(2) The universe moves but the time is still. Like you stand on a rock inte middle of a river (the now) and see the water (the universe) passes you.
In (1) all times, present as well as the future exist simultaneously. But it's only 'now' that you can experience. The universe does not change, only time changes.
In (2) there is no future, nor past, only an eternal 'now'. The time does not change, only universe changes.
These two ways is fundamentally different. In one you can actually predict future. The other you cannot. In one the free will exist, in the other not. In one prophecies and foretelling is a possibility, but no free will. In the other the future is closed for us untill we are there in time as 'now' changes.
One is religiously appealing, the other is not. Is this the reason for discrepances between the Kelly way of seeing things, and other way of seeing things?
15 Feb 10
Originally posted by FabianFnasI wonder if we will live long enough for viable evidence for one V the other?
There is two views how time is going relative space, and vice versa.
(1) That time flows and the universe stands still. Like you stand on a rock in the middle of a river and see the water (the time) flows around you.
(2) The universe moves but the time is still. Like you stand on a rock inte middle of a river (the now) and see the water (the univers ...[text shortened]... for discrepances between the Kelly way of seeing things, and other way of seeing things?
Personally, I can't even envision an experiment that could elucidate the issue.
For instance, we know we can predict the weather to a certain extent, so the universe does things in a predictable way but that is not proof.
15 Feb 10
KellyJay,
How does one define a moment? I would be interested in your definition.
In special relativity, one of the topics I find most interesting is that of simultaneity. For instance, one could use two simultaneous events to define a moment (i.e. a laser hitting two photo-detectors at the same instant). This is a precise moment in time. Relativity does away with the concept of universal simultaneity (i.e. if one oberver observes two events happening simultaneously, in general an observer in a different inertial reference frame does not). In this sense, a moment in time is not the same throughout the universe. This was first predicted theoretically, and experimental data supports this view.
Is this what you mean by "moment?" If not, please clarify.
P.S. These ideas are clearly explained in the books I have mentioned. Have you gotten a chance to check any of them out? They really are great books, and well-worth the read.
16 Feb 10
Originally posted by FabianFnasFabianFnas, could you explain some more, or provide a link? I honestly can not see the difference between the two. To me, it appears that both are stating the same thing in different ways.
There is two views how time is going relative space, and vice versa.
(1) That time flows and the universe stands still. Like you stand on a rock in the middle of a river and see the water (the time) flows around you.
(2) The universe moves but the time is still. Like you stand on a rock inte middle of a river (the now) and see the water (the univers ...[text shortened]... for discrepances between the Kelly way of seeing things, and other way of seeing things?
16 Feb 10
Originally posted by FabianFnasI am not sure if I understand the difference between your two views.
There is two views how time is going relative space, and vice versa.
(1) That time flows and the universe stands still. Like you stand on a rock in the middle of a river and see the water (the time) flows around you.
(2) The universe moves but the time is still. Like you stand on a rock inte middle of a river (the now) and see the water (the univers ...[text shortened]... for discrepances between the Kelly way of seeing things, and other way of seeing things?
My view is that neither the past nor future are fully knowable, but we can know more about the past than the future due to a curious effect of thermodynamics. If we cant know some thing, then does it exist? I don't know. I think quantum mechanics implies that when we can't know something then it is every possible thing except what we know it isn't. This applies to both past and future, it is just that the past is far more constrained than the future and thus it appears to us that the past is fixed and the future is flexible and this is what produces the illusion of time flowing.
16 Feb 10
1 edit
Originally posted by sonhouseWhen we predict things, it's not more than a statistical guessing. Like weather forecast, like future demografics, etc.
I wonder if we will live long enough for viable evidence for one V the other?
Personally, I can't even envision an experiment that could elucidate the issue.
For instance, we know we can predict the weather to a certain extent, so the universe does things in a predictable way but that is not proof.
If our statistical guessing is wrong, there is always a reason for that that we haven't, or couldn't, know about. That's why weather predicitons sometimes fail.
Those who belive religiously that prophecies are true, they can easily prove that they are right, by make predictions and compare with the outcome. If repeated predicions is better than any guessing, then even I will change my mind. Experiments has been conducted, but always failed.
It's impossible to predict the future more than statistically. We have a free will. These two statements hold hands.
16 Feb 10
Originally posted by KellyJayOur measuring devices follow the laws of physics just like the rest of the universe. Many of our measuring devices have very specific very well known laws. For example, some of the most accurate clocks rely on the properties of atoms.
The devices are simply part and parcel of what we have to measure things with,
and we know that we can cause many of our devices to not behave the same way
when we do certain things to do them while we use them.
But there are many different ways to measure time, and different ways use different laws. If you move a whole bunch of clocks that all use different methods from one environment to another and they all appear to run faster at exactly the same rate, and you check the known laws that govern their time keeping and find that the only factor they have in common is time, then surely the correct conclusion is that what has changed is time.
The laws of phyiscs are just our understanding of how the universe works, if we
are getting it wrong than that means there will be things that simply do not fit as
we look at a broader picture of the universe, and you know as well as I that we
do not have a clear understanding of how it all works together at this time.
I agree. However, that doesn't make what we know 'wrong' is merely makes it inaccurate in certain circumstances. For example, although Newtons laws were replaced by relativity, his laws were not 'wrong' and they are still just as a applicable today. They just have a certain range in which they are accurate and useful. If something never violated Newtons laws 100 years ago, it still wont violate them today, and it won't violate them 100 years from now whatever we may discover or whatever new understanding we may have.
What I mean by, "time being a constant" is that it does not change any where at
any time, but all things move through it at the same time. Having said that I am
not saying that all things move through the universe are not affected differently,
but all things share the same moment at all times.
But that is all a mater of perspective and relies on fiddling with the definition of 'time' in order to achieve a preferred scenario.
But it doesn't really mater. What matters is what we are able to conclude or not conclude from what you are saying. If time is as you say it is, are there any implications? If not, then who cares? If there are, can any predictions be made and tested?
A large part of this discussion is really about definitions, not about reality. It is rather like our previous discussions about circles being straight lines in lower dimensions. You may not like it, but using strict mathematical definitions a circle is a straight line in a lower dimension and flat surface may fold back on itself and be finite in a higher dimension.
The current definition of time, is based on the 't' we put in the equations of motion and other laws of physics and it is decidedly not constant under relativity. If you want a constant time, you must invent a new definition and if possible discover what the relationship between your new time 't1' and the standard time of physics 't' is.
Do you feel the need to bring in my religion when I ask questions on science, you
really just cannot talk to me without doing that? Come on! Stick to the topic I'm
not bringing in religion into this discussion why are you?
Kelly
My apologies. I was engaging in some totally unnecessary mind reading.