| Topic: |
Religions > Atheism |
| User: |
"" |
| Date: |
02 Feb 2008 07:33:25 PM |
| Object: |
OT Physics Question |
I'm reading a book on Einstein and his theories and I'm having trouble
with the idea that time is relative.
The example used is two poles placed at a distance apart, a stationary
observer watching from the middle with a mirror so that he can see
both poles and another observer on a moving train, also with a mirror
for the same purpose.
The lightening hits both poles simultaneously and the stationary
observer sees it as such but the one on the train when he reaches the
middle point of course sees the strike on the pole he is traveling
toward first and then what appears to be a second strike on the second
pole to his rear.
The suggestion is that each observer is at least experiencing time
differently but even more, that time is actually different for them.
Can anyone explain?
Also if a person is facing west looking at a light source is the light
approaching him in a wave lying north and south or a wave or particle
beam lying west to east?
Any book suggestions for the layman?
atheist@home#1554
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| User: "Fred Stone" |
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| Title: Re: OT Physics Question |
02 Feb 2008 09:18:47 PM |
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wrote in news:5t4aq3pf6rc2q0ctnqvrf3pt1itc6q3vo6@
4ax.com:
I'm reading a book on Einstein and his theories and I'm having trouble
with the idea that time is relative.
The example used is two poles placed at a distance apart, a stationary
observer watching from the middle with a mirror so that he can see
both poles and another observer on a moving train, also with a mirror
for the same purpose.
The lightening hits both poles simultaneously and the stationary
observer sees it as such but the one on the train when he reaches the
middle point of course sees the strike on the pole he is traveling
toward first and then what appears to be a second strike on the second
pole to his rear.
The suggestion is that each observer is at least experiencing time
differently but even more, that time is actually different for them.
Can anyone explain?
http://en.wikibooks.org/wiki/Special_Relativity/Simultaneity,
_time_dilation_and_length_contraction
http://math.ucr.edu/home/baez/physics/Relativity/SR/barn_pole.html
Also if a person is facing west looking at a light source is the light
approaching him in a wave lying north and south or a wave or particle
beam lying west to east?
Any book suggestions for the layman?
atheist@home#1554
Might as well go right to The Man Himself:
http://tinyurl.com/2c3bc3
"Relativity: The Special and the General Theory--A Clear Explanation that
Anyone Can Understand" by Albert Einstein.
I have an old copy of that book, it's very readable if you've got a fair
understanding of college-level algebra.
--
Fred Stone
aa# 1369
People who think with their epidermis or their genitalia or their clan
are the problem to begin with.
C. Hitchens
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| User: "" |
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| Title: Re: OT Physics Question |
03 Feb 2008 09:23:24 PM |
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On 03 Feb 2008 03:18:47 GMT, Fred Stone <fstone69@earthling.com>
wrote:
atheist@home.com wrote in news:5t4aq3pf6rc2q0ctnqvrf3pt1itc6q3vo6@
4ax.com:
I'm reading a book on Einstein and his theories and I'm having trouble
with the idea that time is relative.
The example used is two poles placed at a distance apart, a stationary
observer watching from the middle with a mirror so that he can see
both poles and another observer on a moving train, also with a mirror
for the same purpose.
The lightening hits both poles simultaneously and the stationary
observer sees it as such but the one on the train when he reaches the
middle point of course sees the strike on the pole he is traveling
toward first and then what appears to be a second strike on the second
pole to his rear.
The suggestion is that each observer is at least experiencing time
differently but even more, that time is actually different for them.
Can anyone explain?
http://en.wikibooks.org/wiki/Special_Relativity/Simultaneity,
_time_dilation_and_length_contraction
http://math.ucr.edu/home/baez/physics/Relativity/SR/barn_pole.html
Also if a person is facing west looking at a light source is the light
approaching him in a wave lying north and south or a wave or particle
beam lying west to east?
Any book suggestions for the layman?
atheist@home#1554
Might as well go right to The Man Himself:
http://tinyurl.com/2c3bc3
I have that but haven't read it yet.
"Relativity: The Special and the General Theory--A Clear Explanation that
Anyone Can Understand" by Albert Einstein.
I have an old copy of that book, it's very readable if you've got a fair
understanding of college-level algebra.
<sigh.
Fourth grade math here.
I got tired of teachers responding to my question of why math worked
with "You don't need to know why, just that it does," so I sort of
gave up on it.
A few years ago however I did start working with it a bit and realized
that we can in fact know why it works.
But then typical of my monkey like and stupidly undisciplined manner I
saw something else shinning off in the distance and got distracted by
that.
I do have some books on basic and advanced math and plan to hit them
pretty hard during the next few months.
Believe it or not this whole thing started with my desire to learn to
program computers and a search for which field would make the
programming most interesting.
I decided on physics and now I'm stuck with this damned thing and
drinking so much coffee to stay awake studying it that I'm starting to
sound like a chipmunk on speed when I talk to people.
I appreciate your response :)
atheist@home#1554
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| User: "Richo" |
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| Title: Re: OT Physics Question |
03 Feb 2008 11:45:10 PM |
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On Feb 3, 12:33 pm, wrote:
I'm reading a book on Einstein and his theories and I'm having trouble
with the idea that time is relative.
It is counter intuitive.
The logic of it is undeniable.
Also keep in mind that "time" is at least two different things.
Time is a marker a "position" on the timeline.
That is we say its 3:20 pm Feb 4th 2008.
The other meaning of time is interval - that two events were 2.3456
seconds apart.
Both of these conceptions of time need to be modified after Einstein.
The example used is two poles placed at a distance apart, a stationary
observer watching from the middle with a mirror so that he can see
both poles and another observer on a moving train, also with a mirror
for the same purpose.
The lightening hits both poles simultaneously and the stationary
observer sees it as such but the one on the train when he reaches the
middle point of course sees the strike on the pole he is traveling
toward first and then what appears to be a second strike on the second
pole to his rear.
The suggestion is that each observer is at least experiencing time
differently but even more, that time is actually different for them.
Can anyone explain?
This is showing that simultaneity is not an absolute - whether or not
two events were simultaneous depends on your relative motion.
Neither observer has the "true" picture in any meaningful sense.
The events (lightning strikes) were simultaneous and not simultaneous
- just for different observers.
Notice you were saying "stationary observer"?
There is no absolute stillness or motion - there is only stillness or
motion *relative* to something else.
I am traveling at 0m/s relative to my computer and its traveling at 0m/
s relative to the surface of the earth - yet the surface of the earth
is moving (the earth is rotating) - and the earth as a whole is moving
relative to the sun - and the sun and the entire solar system is
orbiting the center of the milky way galaxy.
( In star trek you often hear Captain Picard order the ship to halt
or travel at some speed - but he never says relative to what? The
writers of star trek instinctively (and wrongly) believe that motion
or stillness has some absolute meaning in empty space - and this is
completely false. Galileo and Newton understood this.)
So the idea of the relativity of motion is old hat.
What is new with Einstein is that the speed of light is a constant for
all observers.
The only way that can stay true (and it is true) is for time to be
dependent on relative motion.
The beauty is that once you understand how relative motion effects
measurement - you can say the events were 2.546 seconds apart on my
clock so they were exactly 1.456789... seconds apart for that observer
that just zoomed past in the rocket ship.
And these days we really do have incredibly accurate atomic clocks
wizzing about over our heads - and without Einstein - we would get the
wrong answers.
8-)
Cheers, Mark.
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| User: "" |
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| Title: Re: OT Physics Question |
05 Feb 2008 01:24:49 PM |
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On Sun, 3 Feb 2008 21:45:10 -0800 (PST), Richo
<m.richardson61@gmail.com> wrote:
On Feb 3, 12:33 pm, wrote:
I'm reading a book on Einstein and his theories and I'm having trouble
with the idea that time is relative.
It is counter intuitive.
The logic of it is undeniable.
I deny it ;)
Beautiful stuff isn't it?.
Also keep in mind that "time" is at least two different things.
Time is a marker a "position" on the timeline.
That is we say its 3:20 pm Feb 4th 2008.
The other meaning of time is interval - that two events were 2.3456
seconds apart.
Both of these conceptions of time need to be modified after Einstein.
The example used is two poles placed at a distance apart, a stationary
observer watching from the middle with a mirror so that he can see
both poles and another observer on a moving train, also with a mirror
for the same purpose.
The lightening hits both poles simultaneously and the stationary
observer sees it as such but the one on the train when he reaches the
middle point of course sees the strike on the pole he is traveling
toward first and then what appears to be a second strike on the second
pole to his rear.
The suggestion is that each observer is at least experiencing time
differently but even more, that time is actually different for them.
Can anyone explain?
This is showing that simultaneity is not an absolute - whether or not
two events were simultaneous depends on your relative motion.
Neither observer has the "true" picture in any meaningful sense.
The events (lightning strikes) were simultaneous and not simultaneous
- just for different observers.
Notice you were saying "stationary observer"?
There is no absolute stillness or motion - there is only stillness or
motion *relative* to something else.
I am traveling at 0m/s relative to my computer and its traveling at 0m/
s relative to the surface of the earth - yet the surface of the earth
is moving (the earth is rotating) - and the earth as a whole is moving
relative to the sun - and the sun and the entire solar system is
orbiting the center of the milky way galaxy.
( In star trek you often hear Captain Picard order the ship to halt
or travel at some speed - but he never says relative to what? The
writers of star trek instinctively (and wrongly) believe that motion
or stillness has some absolute meaning in empty space - and this is
completely false. Galileo and Newton understood this.)
Actually I believe the reference was supposed to be a fixed point
somewhere in the center of the galaxy.
But there wouldn't be an absolute fixed point in the truest sense
would there?
Except in relation to the ship at any given moment.
So the idea of the relativity of motion is old hat.
What is new with Einstein is that the speed of light is a constant for
all observers.
I believe I'm beginning to understand it.
The only way that can stay true (and it is true) is for time to be
dependent on relative motion.
The beauty is that once you understand how relative motion effects
measurement - you can say the events were 2.546 seconds apart on my
clock so they were exactly 1.456789... seconds apart for that observer
that just zoomed past in the rocket ship.
And these days we really do have incredibly accurate atomic clocks
wizzing about over our heads - and without Einstein - we would get the
wrong answers.
8-)
I guess the primary problem I'm having is with the clocks and the
bodies of those traveling at higher speeds.
The body for instance has it's own internal clock and cells decay and
reproduce at certain rates and we age in part because of it.
I can understand different observers perceiving time differently from
different positions but apparently its more than perception and is
very real.
Its all absolutely fascinating.
Thanks.
atheist@home#1554
Cheers, Mark.
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| User: "Michael Gray" |
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| Title: Re: OT Physics Question |
05 Feb 2008 09:07:34 PM |
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On Tue, 05 Feb 2008 13:24:49 -0600, wrote:
On Sun, 3 Feb 2008 21:45:10 -0800 (PST), Richo
<m.richardson61@gmail.com> wrote:
On Feb 3, 12:33 pm, wrote:
I'm reading a book on Einstein and his theories and I'm having trouble
with the idea that time is relative.
It is counter intuitive.
The logic of it is undeniable.
I deny it ;)
Beautiful stuff isn't it?.
Also keep in mind that "time" is at least two different things.
Time is a marker a "position" on the timeline.
That is we say its 3:20 pm Feb 4th 2008.
The other meaning of time is interval - that two events were 2.3456
seconds apart.
Both of these conceptions of time need to be modified after Einstein.
The example used is two poles placed at a distance apart, a stationary
observer watching from the middle with a mirror so that he can see
both poles and another observer on a moving train, also with a mirror
for the same purpose.
The lightening hits both poles simultaneously and the stationary
observer sees it as such but the one on the train when he reaches the
middle point of course sees the strike on the pole he is traveling
toward first and then what appears to be a second strike on the second
pole to his rear.
The suggestion is that each observer is at least experiencing time
differently but even more, that time is actually different for them.
Can anyone explain?
This is showing that simultaneity is not an absolute - whether or not
two events were simultaneous depends on your relative motion.
Neither observer has the "true" picture in any meaningful sense.
The events (lightning strikes) were simultaneous and not simultaneous
- just for different observers.
Notice you were saying "stationary observer"?
There is no absolute stillness or motion - there is only stillness or
motion *relative* to something else.
I am traveling at 0m/s relative to my computer and its traveling at 0m/
s relative to the surface of the earth - yet the surface of the earth
is moving (the earth is rotating) - and the earth as a whole is moving
relative to the sun - and the sun and the entire solar system is
orbiting the center of the milky way galaxy.
( In star trek you often hear Captain Picard order the ship to halt
or travel at some speed - but he never says relative to what? The
writers of star trek instinctively (and wrongly) believe that motion
or stillness has some absolute meaning in empty space - and this is
completely false. Galileo and Newton understood this.)
Actually I believe the reference was supposed to be a fixed point
somewhere in the center of the galaxy.
But there wouldn't be an absolute fixed point in the truest sense
would there?
Except in relation to the ship at any given moment.
So the idea of the relativity of motion is old hat.
What is new with Einstein is that the speed of light is a constant for
all observers.
I believe I'm beginning to understand it.
The only way that can stay true (and it is true) is for time to be
dependent on relative motion.
The beauty is that once you understand how relative motion effects
measurement - you can say the events were 2.546 seconds apart on my
clock so they were exactly 1.456789... seconds apart for that observer
that just zoomed past in the rocket ship.
And these days we really do have incredibly accurate atomic clocks
wizzing about over our heads - and without Einstein - we would get the
wrong answers.
8-)
I guess the primary problem I'm having is with the clocks and the
bodies of those traveling at higher speeds.
The body for instance has it's own internal clock and cells decay and
reproduce at certain rates and we age in part because of it.
Body clocks and external clocks are all affected equally by time
dilation.
They MUST be according to special relativity (for very good reasons).
I can understand different observers perceiving time differently from
different positions but apparently its more than perception and is
very real.
It is very very real!
Its all absolutely fascinating.
Thanks.
atheist@home#1554
Cheers, Mark.
.
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| User: "Michael Gray" |
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| Title: Re: OT Physics Question |
02 Feb 2008 08:20:20 PM |
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On Sat, 02 Feb 2008 19:33:25 -0600, wrote:
I'm reading a book on Einstein and his theories and I'm having trouble
with the idea that time is relative.
Don't worry: So did Albert!
The example used is two poles placed at a distance apart, a stationary
observer watching from the middle with a mirror so that he can see
both poles and another observer on a moving train, also with a mirror
for the same purpose.
The lightening hits both poles simultaneously and the stationary
Woa there!
"simultaneity* has zero meaning without a "frame of reference" being
specified.
There is no such thing as absolute simultaneity.
This is the very crux of the concept.
If you skip that, then you are guaranteed to be confused!
observer sees it as such but the one on the train when he reaches the
middle point of course sees the strike on the pole he is traveling
toward first and then what appears to be a second strike on the second
pole to his rear.
The suggestion is that each observer is at least experiencing time
differently but even more, that time is actually different for them.
The two events appear to be simultaneous to the first observer, but
not the second.
Neither has a "privileged" point of view, and BOTH observers are
equally correct in their descriptions of the two events.
Another way of stating the crux of special relativity is that for all
observers not experiencing acceleration, their viewpoints are EQUALLY
valid, despite them not agreeing on the relative timing of separate
events.
Can anyone explain?
Not in a single short response, I expect.
Also if a person is facing west looking at a light source is the light
approaching him in a wave lying north and south or a wave or particle
beam lying west to east?
I do not understand this question.
Where is the light source located?
To the west?
Can you make this a little clearer please?
Any book suggestions for the layman?
Not a book as such, but audio lectures.
Quite the best I have heard for your purpose, and i have reveiewed
much lame junk on the subject of getting relativity across to the
newbie! ;)
By the Teaching Company:
http://www.teach12.com/ttcx/coursedesclong2.aspx?cid=153&
"It doesn't take an Einstein to understand modern physics," says
Professor Richard Wolfson at the outset of this course on what may be
the most important subject in the universe.
Relativity and quantum physics touch the very basis of physical
reality, altering our commonsense notions of space and time, cause and
effect. Both have reputations for complexity. But the basic ideas
behind relativity and quantum physics are, in fact, simple and
comprehensible by anyone. As Professor Wolfson points out, the essence
of relativity can be summed up in a single sentence: The laws of
physics are the same for all observers in uniform motion.
The same goes for quantum theory, which is based on the principle that
the "stuff " of the universe—matter and energy—is not infinitely
divisible but comes in discrete chunks called "quanta."
Profound ... Beautiful ... Relevant
Why should you care about these landmark theories? Because relativity
and quantum physics are not only profound and beautiful ideas in their
own right, they are also the gateway to understanding many of the
latest science stories in the media. These are the stories about time
travel, string theory, black holes, space telescopes, particle
accelerators, and other cutting-edge developments...."
.
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| User: "" |
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| Title: Re: OT Physics Question |
03 Feb 2008 08:53:27 PM |
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On Sun, 03 Feb 2008 12:50:20 +1030, Michael Gray
<mikegray@newsguy.com> wrote:
On Sat, 02 Feb 2008 19:33:25 -0600, wrote:
I'm reading a book on Einstein and his theories and I'm having trouble
with the idea that time is relative.
Don't worry: So did Albert!
Does anybody actually understand it?
The example used is two poles placed at a distance apart, a stationary
observer watching from the middle with a mirror so that he can see
both poles and another observer on a moving train, also with a mirror
for the same purpose.
The lightening hits both poles simultaneously and the stationary
Woa there!
"simultaneity* has zero meaning without a "frame of reference" being
specified.
There is no such thing as absolute simultaneity.
This is the very crux of the concept.
If you skip that, then you are guaranteed to be confused!
I knew that absolute simultaneity isn't likely but understood the need
for an example.
And even with that I may be thinking that something I believe is in
error.
observer sees it as such but the one on the train when he reaches the
middle point of course sees the strike on the pole he is traveling
toward first and then what appears to be a second strike on the second
pole to his rear.
The suggestion is that each observer is at least experiencing time
differently but even more, that time is actually different for them.
The two events appear to be simultaneous to the first observer, but
not the second.
Neither has a "privileged" point of view, and BOTH observers are
equally correct in their descriptions of the two events.
Ok, and I may be expecting far too much of myself regarding the issue,
<And very strongly suspect I am> but if the two events did in fact
occur at the same moment how could the actual events occur in a real
and different time for other observers?
If they occured at exactly 7:00pm I can understand that other
observers in different circumstances due to the time it takes for
light to travel certain distances might believe it happened at 7:01
<And I know that's an extreme length of time because of the speed of
light> but still, didn't it happen at 7:00 regardless of the position
and status of the other observers?
Internal and external time are easy enough concepts but is there a
different definition of time that I am unaware of?
Another way of stating the crux of special relativity is that for all
observers not experiencing acceleration, their viewpoints are EQUALLY
valid, despite them not agreeing on the relative timing of separate
events.
Can anyone explain?
Not in a single short response, I expect.
I understand.
Also if a person is facing west looking at a light source is the light
approaching him in a wave lying north and south or a wave or particle
beam lying west to east?
I do not understand this question.
Where is the light source located?
To the west?
Can you make this a little clearer please?
Source to the west.
Is the light coming at me in this fashion in solid
waves -------------------
/\
or this as individual particles in waves; llllll
llllll
llllll
/\
Any book suggestions for the layman?
Not a book as such, but audio lectures.
Quite the best I have heard for your purpose, and i have reveiewed
much lame junk on the subject of getting relativity across to the
newbie! ;)
I've seen some in the past.
And last night I checked out some stuff on YouTube and while watching
what apparently was originally a very good and legitimate educational
program on string theory, I was somewhat annoyed by a crawler that the
christian who posted the thing had added explaining that alternate
universes are Heaven, that's where God and angels reside and string
theory proves it.
Odd minds they have.
For them the science doesn't explain the universe and how it works but
proves that the Bible and it's childish absurdities are true.
Sort of spooky in a sense.
By the Teaching Company:
http://www.teach12.com/ttcx/coursedesclong2.aspx?cid=153&
"It doesn't take an Einstein to understand modern physics," says
Professor Richard Wolfson at the outset of this course on what may be
the most important subject in the universe.
Relativity and quantum physics touch the very basis of physical
reality, altering our commonsense notions of space and time, cause and
effect. Both have reputations for complexity. But the basic ideas
behind relativity and quantum physics are, in fact, simple and
comprehensible by anyone. As Professor Wolfson points out, the essence
of relativity can be summed up in a single sentence: The laws of
physics are the same for all observers in uniform motion.
The same goes for quantum theory, which is based on the principle that
the "stuff " of the universe—matter and energy—is not infinitely
divisible but comes in discrete chunks called "quanta."
Profound ... Beautiful ... Relevant
Why should you care about these landmark theories? Because relativity
and quantum physics are not only profound and beautiful ideas in their
own right, they are also the gateway to understanding many of the
latest science stories in the media. These are the stories about time
travel, string theory, black holes, space telescopes, particle
accelerators, and other cutting-edge developments...."
Thanks.
I checked the site and will probably be ordering the DVD soon.
atheist@home#1554
.
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| User: "Michael Gray" |
|
| Title: Re: OT Physics Question |
03 Feb 2008 10:17:14 PM |
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|
On Sun, 03 Feb 2008 20:53:27 -0600, wrote:
On Sun, 03 Feb 2008 12:50:20 +1030, Michael Gray
<mikegray@newsguy.com> wrote:
On Sat, 02 Feb 2008 19:33:25 -0600, wrote:
I'm reading a book on Einstein and his theories and I'm having trouble
with the idea that time is relative.
Don't worry: So did Albert!
Does anybody actually understand it?
Yes, plenty of math & physics graduates.
The example used is two poles placed at a distance apart, a stationary
observer watching from the middle with a mirror so that he can see
both poles and another observer on a moving train, also with a mirror
for the same purpose.
The lightening hits both poles simultaneously and the stationary
Woa there!
"simultaneity* has zero meaning without a "frame of reference" being
specified.
There is no such thing as absolute simultaneity.
This is the very crux of the concept.
If you skip that, then you are guaranteed to be confused!
I knew that absolute simultaneity isn't likely but understood the need
for an example.
"absolute simultaneity" not only isn't "likely", Einstein showed that
it is profoundly meaningless and impossible!
And even with that I may be thinking that something I believe is in
error.
I have read ahaed, and think that I have put my finger on the source
of your confusion.
observer sees it as such but the one on the train when he reaches the
middle point of course sees the strike on the pole he is traveling
toward first and then what appears to be a second strike on the second
pole to his rear.
The suggestion is that each observer is at least experiencing time
differently but even more, that time is actually different for them.
The two events appear to be simultaneous to the first observer, but
not the second.
Neither has a "privileged" point of view, and BOTH observers are
equally correct in their descriptions of the two events.
Ok, and I may be expecting far too much of myself regarding the issue,
<And very strongly suspect I am> but if the two events did in fact
occur at the same moment how could the actual events occur in a real
and different time for other observers?
And this is the primary source of your puzzlement:
The various statements such as "occur at the same moment", "both
occured at exactly 7:00pm" are completely meaningless, according to
Special Relativity.
To say that, implies an observer with a privileged point of view from
the others, and Einstein explicitly rendered that concept impossible.
There is no "real time" or "different time".
Times are relative to the observer's frame of reference, and no
observer has a "correct" view of time.
All non-accelerating observer's views of the timing of events are
equally valid.
Often people assume that the guy standing on the platform has a more
real take on matters than the guy in the train.
But this is not so.
According to the guy in the train, the platform and the two poles are
moving, and he is staying still.
This is just as valid a view.
According to an observer in the Space Station, both guys are
travelling at 1,000 miles an hour!
If they occured at exactly 7:00pm I can understand that other
observers in different circumstances due to the time it takes for
light to travel certain distances might believe it happened at 7:01
<And I know that's an extreme length of time because of the speed of
light> but still, didn't it happen at 7:00 regardless of the position
and status of the other observers?
With respect to what frame of reference?
And why that frame particularly?
From the frame of reference of the train?
The platform?
What's to choose between them?
Internal and external time are easy enough concepts but is there a
different definition of time that I am unaware of?
I do not know what you mean by 'internal and external' time.
I have never heard these terms before.
Another way of stating the crux of special relativity is that for all
observers not experiencing acceleration, their viewpoints are EQUALLY
valid, despite them not agreeing on the relative timing of separate
events.
Can anyone explain?
Not in a single short response, I expect.
I understand.
Also if a person is facing west looking at a light source is the light
approaching him in a wave lying north and south or a wave or particle
beam lying west to east?
I do not understand this question.
Where is the light source located?
To the west?
Can you make this a little clearer please?
Source to the west.
Is the light coming at me in this fashion in solid
waves -------------------
/\
or this as individual particles in waves; llllll
llllll
llllll
/\
Oh, I see.
As Feynman was wont to stress, light is most definitely particles, not
a wave.
Falsely considering it as a wave make much of mathematical optics
easier, buy renders bits of it contrary to evidence.
No, light is most assuredly composed of photons, or packets, or
particles.
It is the only way that every optics experiment can be adequately
explained.
It comes to the observer as particles.
This is why Einstein got his Nobel Prize, incidentally, not for
relativity.
He nutted out the Photoelectric Effect by assuming that light came in
quanta (Latin for bundles), not waves as had been previously thought.
Prof Wolfson also tackles this in my recommendation below!
Any book suggestions for the layman?
Not a book as such, but audio lectures.
Quite the best I have heard for your purpose, and i have reveiewed
much lame junk on the subject of getting relativity across to the
newbie! ;)
I've seen some in the past.
And last night I checked out some stuff on YouTube and while watching
what apparently was originally a very good and legitimate educational
program on string theory, I was somewhat annoyed by a crawler that the
christian who posted the thing had added explaining that alternate
universes are Heaven, that's where God and angels reside and string
theory proves it.
Odd minds they have.
For them the science doesn't explain the universe and how it works but
proves that the Bible and it's childish absurdities are true.
Sort of spooky in a sense.
Scary, I think...
By the Teaching Company:
http://www.teach12.com/ttcx/coursedesclong2.aspx?cid=153&
"It doesn't take an Einstein to understand modern physics," says
Professor Richard Wolfson at the outset of this course on what may be
the most important subject in the universe.
Relativity and quantum physics touch the very basis of physical
reality, altering our commonsense notions of space and time, cause and
effect. Both have reputations for complexity. But the basic ideas
behind relativity and quantum physics are, in fact, simple and
comprehensible by anyone. As Professor Wolfson points out, the essence
of relativity can be summed up in a single sentence: The laws of
physics are the same for all observers in uniform motion.
The same goes for quantum theory, which is based on the principle that
the "stuff " of the universe—matter and energy—is not infinitely
divisible but comes in discrete chunks called "quanta."
Profound ... Beautiful ... Relevant
Why should you care about these landmark theories? Because relativity
and quantum physics are not only profound and beautiful ideas in their
own right, they are also the gateway to understanding many of the
latest science stories in the media. These are the stories about time
travel, string theory, black holes, space telescopes, particle
accelerators, and other cutting-edge developments...."
Thanks.
I checked the site and will probably be ordering the DVD soon.
He also put out a Teaching Company thing called "Time Travel,
Tunnelling, Tennis & Tea", but it doesn't look like that is avaible
any more.
If you can lay your hands on this one, then it is so absolutely
perfect for your requirements as it is hours of explanations on solely
what you have queried, aimed at the non-graduate.
If you do not have any luck then email me with a postal address
please.
.
|
|
|
| User: "Smiler" |
|
| Title: Re: OT Physics Question |
04 Feb 2008 11:19:24 PM |
|
|
"Michael Gray" <mikegray@newsguy.com> wrote in message
news:c54dq3d2qe2eipqou3bjsio1at1i2ecd49@4ax.com...
On Sun, 03 Feb 2008 20:53:27 -0600, wrote:
On Sun, 03 Feb 2008 12:50:20 +1030, Michael Gray
<mikegray@newsguy.com> wrote:
On Sat, 02 Feb 2008 19:33:25 -0600, wrote:
I'm reading a book on Einstein and his theories and I'm having trouble
with the idea that time is relative.
Don't worry: So did Albert!
Does anybody actually understand it?
Yes, plenty of math & physics graduates.
The example used is two poles placed at a distance apart, a stationary
observer watching from the middle with a mirror so that he can see
both poles and another observer on a moving train, also with a mirror
for the same purpose.
The lightening hits both poles simultaneously and the stationary
Woa there!
"simultaneity* has zero meaning without a "frame of reference" being
specified.
There is no such thing as absolute simultaneity.
This is the very crux of the concept.
If you skip that, then you are guaranteed to be confused!
I knew that absolute simultaneity isn't likely but understood the need
for an example.
"absolute simultaneity" not only isn't "likely", Einstein showed that
it is profoundly meaningless and impossible!
And even with that I may be thinking that something I believe is in
error.
I have read ahaed, and think that I have put my finger on the source
of your confusion.
observer sees it as such but the one on the train when he reaches the
middle point of course sees the strike on the pole he is traveling
toward first and then what appears to be a second strike on the second
pole to his rear.
The suggestion is that each observer is at least experiencing time
differently but even more, that time is actually different for them.
The two events appear to be simultaneous to the first observer, but
not the second.
Neither has a "privileged" point of view, and BOTH observers are
equally correct in their descriptions of the two events.
Ok, and I may be expecting far too much of myself regarding the issue,
<And very strongly suspect I am> but if the two events did in fact
occur at the same moment how could the actual events occur in a real
and different time for other observers?
And this is the primary source of your puzzlement:
The various statements such as "occur at the same moment", "both
occured at exactly 7:00pm" are completely meaningless, according to
Special Relativity.
To say that, implies an observer with a privileged point of view from
the others, and Einstein explicitly rendered that concept impossible.
There is no "real time" or "different time".
Times are relative to the observer's frame of reference, and no
observer has a "correct" view of time.
All non-accelerating observer's views of the timing of events are
equally valid.
Often people assume that the guy standing on the platform has a more
real take on matters than the guy in the train.
But this is not so.
According to the guy in the train, the platform and the two poles are
moving, and he is staying still.
This is just as valid a view.
According to an observer in the Space Station, both guys are
travelling at 1,000 miles an hour!
If they occured at exactly 7:00pm I can understand that other
observers in different circumstances due to the time it takes for
light to travel certain distances might believe it happened at 7:01
<And I know that's an extreme length of time because of the speed of
light> but still, didn't it happen at 7:00 regardless of the position
and status of the other observers?
With respect to what frame of reference?
And why that frame particularly?
From the frame of reference of the train?
The platform?
What's to choose between them?
Internal and external time are easy enough concepts but is there a
different definition of time that I am unaware of?
I do not know what you mean by 'internal and external' time.
I have never heard these terms before.
Another way of stating the crux of special relativity is that for all
observers not experiencing acceleration, their viewpoints are EQUALLY
valid, despite them not agreeing on the relative timing of separate
events.
Can anyone explain?
Not in a single short response, I expect.
I understand.
Also if a person is facing west looking at a light source is the light
approaching him in a wave lying north and south or a wave or particle
beam lying west to east?
I do not understand this question.
Where is the light source located?
To the west?
Can you make this a little clearer please?
Source to the west.
Is the light coming at me in this fashion in solid
waves -------------------
/\
or this as individual particles in waves; llllll
llllll
llllll
/\
Oh, I see.
As Feynman was wont to stress, light is most definitely particles, not
a wave.
Falsely considering it as a wave make much of mathematical optics
easier, buy renders bits of it contrary to evidence.
No, light is most assuredly composed of photons, or packets, or
particles.
It is the only way that every optics experiment can be adequately
explained.
Not arguing, just curious.
Please explain in simple terms as I had my science education over 40 years
ago!
Do photons oscillate at right angles to their direction of travel (IOW,
their paths are wave-like)?
If that's correct, then I can understand the basic mechanics.
If it's incorrect, how does quantum theory explain polarisation of light?
Smiler,
The godless one
a.a.# 2279
.
|
|
|
| User: "Michael Gray" |
|
| Title: Re: OT Physics Question |
05 Feb 2008 01:55:45 AM |
|
|
On Tue, 05 Feb 2008 05:19:24 GMT, "Smiler" <Smiler@Joe.King.com>
wrote:
:
Not arguing, just curious.
Please explain in simple terms as I had my science education over 40 years
ago!
Do photons oscillate at right angles to their direction of travel (IOW,
their paths are wave-like)?
No-one actually "knows", and so it remains (for the while) a moot
question.
The various fictional models that we contrive are for the convenience
of calculation only.
The model that has stood the test of time is that photons comprise
tiny "packets" of electric oscillations and magnetic oscillations that
are at some predermined angle to each other.
The concept is nearly impossible to get across in text form!
(But you are essentially correct in your proposition that the electic
and magnetic "fields" oscillate at right angles to each other
deviating sinusoidally from the axis of forward movement.
BUT!!! This is JUST A MODEL to make thinking about it easier.
It is probably not "like" that at all, in fact vary, vary far from it.
As far as we can tell the photon has no actual path, and takes every
single possible one!)
And Feynman showed that they do NOT have a path as such, but sort of
"sniff out" every possible route from the source to the observer!
This is so counter-intuitive as to boggle the mind to an alarming
extent, but the model explains ALL of electromagnetism, the behiour of
light, and the operation of the weak nuclear force, all in the one
sweep.
(So it may not be far from "reality")
Richard Feynman battled constantly with how to distill this concept
for a lay audience, and eventually trimmed it down to four lectures,
each lasting over an hour or so.
He devised this very theory or model, and he was a brilliant lecturer,
so if he could not shrink to under 5 hours of interaqctive lectures,
then I have no hope of explaining it in a few text messages!!
He tried it out on a New Zealand audience of guinea pigs, (so that if
he bombed out, it was on the opposite side of the planet to his home!)
I saw the series of 4 lectures on Youtube.
I can't find it again after a cursory inspection. Bugger!
Perhaps someone else can help to locate it?
I found an excert from the series:
<http://www.youtube.com/watch?v=5VMu14mBXAs>
(Very poor quality)
If that's correct, then I can understand the basic mechanics.
If it's incorrect, how does quantum theory explain polarisation of light?
It *doesn't* explain it!
It just describes its effects.
You are right to be puzzled.
Feynman also famously said:
"If you think you understand Quantum Electrodynamics, the you DON'T
understand it!"
.
|
|
|
| User: "Smiler" |
|
| Title: Re: OT Physics Question |
05 Feb 2008 07:38:31 PM |
|
|
"Michael Gray" <mikegray@newsguy.com> wrote in message
news:p35gq3huu7hnboqs6sliia6gq46iof6ac0@4ax.com...
On Tue, 05 Feb 2008 05:19:24 GMT, "Smiler" <Smiler@Joe.King.com>
wrote:
:
Not arguing, just curious.
Please explain in simple terms as I had my science education over 40 years
ago!
Do photons oscillate at right angles to their direction of travel (IOW,
their paths are wave-like)?
No-one actually "knows", and so it remains (for the while) a moot
question.
The various fictional models that we contrive are for the convenience
of calculation only.
The model that has stood the test of time is that photons comprise
tiny "packets" of electric oscillations and magnetic oscillations that
are at some predermined angle to each other.
The concept is nearly impossible to get across in text form!
(But you are essentially correct in your proposition that the electic
and magnetic "fields" oscillate at right angles to each other
deviating sinusoidally from the axis of forward movement.
BUT!!! This is JUST A MODEL to make thinking about it easier.
It is probably not "like" that at all, in fact vary, vary far from it.
As far as we can tell the photon has no actual path, and takes every
single possible one!)
And Feynman showed that they do NOT have a path as such, but sort of
"sniff out" every possible route from the source to the observer!
This is so counter-intuitive as to boggle the mind to an alarming
extent, but the model explains ALL of electromagnetism, the behiour of
light, and the operation of the weak nuclear force, all in the one
sweep.
(So it may not be far from "reality")
Richard Feynman battled constantly with how to distill this concept
for a lay audience, and eventually trimmed it down to four lectures,
each lasting over an hour or so.
He devised this very theory or model, and he was a brilliant lecturer,
so if he could not shrink to under 5 hours of interaqctive lectures,
then I have no hope of explaining it in a few text messages!!
He tried it out on a New Zealand audience of guinea pigs, (so that if
he bombed out, it was on the opposite side of the planet to his home!)
I saw the series of 4 lectures on Youtube.
I can't find it again after a cursory inspection. Bugger!
Perhaps someone else can help to locate it?
I found an excert from the series:
<http://www.youtube.com/watch?v=5VMu14mBXAs>
(Very poor quality)
If that's correct, then I can understand the basic mechanics.
If it's incorrect, how does quantum theory explain polarisation of light?
It *doesn't* explain it!
It just describes its effects.
You are right to be puzzled.
Feynman also famously said:
"If you think you understand Quantum Electrodynamics, the you DON'T
understand it!"
You wrote:
No, light is most assuredly composed of photons, or packets, or
particles.
It is the only way that ***every*** optics experiment can be adequately
explained.
[My emphasis]
I hereby claim my Nobel Prize for devising an optics experiment that cannot
be adequately explained by the Quantum Theory, namely, the polarisation of
light :-)
Smiler,
The godless one
a.a.# 2279
.
|
|
|
| User: "Michael Gray" |
|
| Title: Re: OT Physics Question |
05 Feb 2008 08:57:11 PM |
|
|
On Wed, 06 Feb 2008 01:38:31 GMT, "Smiler" <Smiler@Joe.King.com>
wrote:
"Michael Gray" <mikegray@newsguy.com> wrote in message
news:p35gq3huu7hnboqs6sliia6gq46iof6ac0@4ax.com...
On Tue, 05 Feb 2008 05:19:24 GMT, "Smiler" <Smiler@Joe.King.com>
wrote:
:
Not arguing, just curious.
Please explain in simple terms as I had my science education over 40 years
ago!
Do photons oscillate at right angles to their direction of travel (IOW,
their paths are wave-like)?
No-one actually "knows", and so it remains (for the while) a moot
question.
The various fictional models that we contrive are for the convenience
of calculation only.
The model that has stood the test of time is that photons comprise
tiny "packets" of electric oscillations and magnetic oscillations that
are at some predermined angle to each other.
The concept is nearly impossible to get across in text form!
(But you are essentially correct in your proposition that the electic
and magnetic "fields" oscillate at right angles to each other
deviating sinusoidally from the axis of forward movement.
BUT!!! This is JUST A MODEL to make thinking about it easier.
It is probably not "like" that at all, in fact vary, vary far from it.
As far as we can tell the photon has no actual path, and takes every
single possible one!)
And Feynman showed that they do NOT have a path as such, but sort of
"sniff out" every possible route from the source to the observer!
This is so counter-intuitive as to boggle the mind to an alarming
extent, but the model explains ALL of electromagnetism, the behiour of
light, and the operation of the weak nuclear force, all in the one
sweep.
(So it may not be far from "reality")
Richard Feynman battled constantly with how to distill this concept
for a lay audience, and eventually trimmed it down to four lectures,
each lasting over an hour or so.
He devised this very theory or model, and he was a brilliant lecturer,
so if he could not shrink to under 5 hours of interaqctive lectures,
then I have no hope of explaining it in a few text messages!!
He tried it out on a New Zealand audience of guinea pigs, (so that if
he bombed out, it was on the opposite side of the planet to his home!)
I saw the series of 4 lectures on Youtube.
I can't find it again after a cursory inspection. Bugger!
Perhaps someone else can help to locate it?
I found an excert from the series:
<http://www.youtube.com/watch?v=5VMu14mBXAs>
(Very poor quality)
If that's correct, then I can understand the basic mechanics.
If it's incorrect, how does quantum theory explain polarisation of light?
It *doesn't* explain it!
It just describes its effects.
You are right to be puzzled.
Feynman also famously said:
"If you think you understand Quantum Electrodynamics, the you DON'T
understand it!"
You wrote:
No, light is most assuredly composed of photons, or packets, or
particles.
It is the only way that ***every*** optics experiment can be adequately
explained.
[My emphasis]
I hereby claim my Nobel Prize for devising an optics experiment that cannot
be adequately explained by the Quantum Theory, namely, the polarisation of
light :-)
How so?
Quantum electrodynamics describes this perfectly well.
I am keen to see your experiment.
.
|
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|
|
|
|
|
| User: "Michael Gray" |
|
| Title: Re: OT Physics Question |
05 Feb 2008 01:12:20 AM |
|
|
A recent "newbie freindly" edition of the podcast from The Skeptics'
Guide to the Universe dealt partly with this very topic:
<http://media.libsyn.com/media/skepticsguide/skepticast2008-01-23.mp3>
.
|
|
|
|
| User: "" |
|
| Title: Re: OT Physics Question |
05 Feb 2008 03:37:53 PM |
|
|
On Mon, 04 Feb 2008 14:47:14 +1030, Michael Gray
<mikegray@newsguy.com> wrote:
On Sun, 03 Feb 2008 20:53:27 -0600, wrote:
On Sun, 03 Feb 2008 12:50:20 +1030, Michael Gray
<mikegray@newsguy.com> wrote:
On Sat, 02 Feb 2008 19:33:25 -0600, wrote:
I'm reading a book on Einstein and his theories and I'm having trouble
with the idea that time is relative.
Don't worry: So did Albert!
Does anybody actually understand it?
Yes, plenty of math & physics graduates.
<snip>
Ok, and I may be expecting far too much of myself regarding the issue,
<And very strongly suspect I am> but if the two events did in fact
occur at the same moment how could the actual events occur in a real
and different time for other observers?
And this is the primary source of your puzzlement:
The various statements such as "occur at the same moment", "both
occured at exactly 7:00pm" are completely meaningless, according to
Special Relativity.
To say that, implies an observer with a privileged point of view from
the others, and Einstein explicitly rendered that concept impossible.
There is no "real time" or "different time".
Times are relative to the observer's frame of reference, and no
observer has a "correct" view of time.
All non-accelerating observer's views of the timing of events are
equally valid.
I'm beginning to get it.
Often people assume that the guy standing on the platform has a more
real take on matters than the guy in the train.
But this is not so.
According to the guy in the train, the platform and the two poles are
moving, and he is staying still.
This is just as valid a view.
According to an observer in the Space Station, both guys are
travelling at 1,000 miles an hour!
If they occured at exactly 7:00pm I can understand that other
observers in different circumstances due to the time it takes for
light to travel certain distances might believe it happened at 7:01
<And I know that's an extreme length of time because of the speed of
light> but still, didn't it happen at 7:00 regardless of the position
and status of the other observers?
With respect to what frame of reference?
And why that frame particularly?
From the frame of reference of the train?
The platform?
What's to choose between them?
Lol!
Wonderful :)
Internal and external time are easy enough concepts but is there a
different definition of time that I am unaware of?
I do not know what you mean by 'internal and external' time.
I have never heard these terms before.
Internal time being the way we and our bodies measure time and
external being clocks and other things that keep us aware of the
passage of time.
Another way of stating the crux of special relativity is that for all
observers not experiencing acceleration, their viewpoints are EQUALLY
valid, despite them not agreeing on the relative timing of separate
events.
Can anyone explain?
Not in a single short response, I expect.
I understand.
Also if a person is facing west looking at a light source is the light
approaching him in a wave lying north and south or a wave or particle
beam lying west to east?
I do not understand this question.
Where is the light source located?
To the west?
Can you make this a little clearer please?
Source to the west.
Is the light coming at me in this fashion in solid
waves -------------------
/\
or this as individual particles in waves; llllll
llllll
llllll
/\
Oh, I see.
As Feynman was wont to stress, light is most definitely particles, not
a wave.
Falsely considering it as a wave make much of mathematical optics
easier, buy renders bits of it contrary to evidence.
No, light is most assuredly composed of photons, or packets, or
particles.
It is the only way that every optics experiment can be adequately
explained.
Ah...
It comes to the observer as particles.
This is why Einstein got his Nobel Prize, incidentally, not for
relativity.
He nutted out the Photoelectric Effect by assuming that light came in
quanta (Latin for bundles), not waves as had been previously thought.
Prof Wolfson also tackles this in my recommendation below!
Any book suggestions for the layman?
Not a book as such, but audio lectures.
Quite the best I have heard for your purpose, and i have reveiewed
much lame junk on the subject of getting relativity across to the
newbie! ;)
I've seen some in the past.
And last night I checked out some stuff on YouTube and while watching
what apparently was originally a very good and legitimate educational
program on string theory, I was somewhat annoyed by a crawler that the
christian who posted the thing had added explaining that alternate
universes are Heaven, that's where God and angels reside and string
theory proves it.
Odd minds they have.
For them the science doesn't explain the universe and how it works but
proves that the Bible and it's childish absurdities are true.
Sort of spooky in a sense.
Scary, I think...
I'm afraid I've lost my former tolerance for it.
I still feel that if it takes religion to help some people survive or
live productive lives its worth it but in many cases thats not the
case.
Its the mental and emotional distortions that irritate me.
And of course the smug arrogance of so many believers.
By the Teaching Company:
http://www.teach12.com/ttcx/coursedesclong2.aspx?cid=153&
"It doesn't take an Einstein to understand modern physics," says
Professor Richard Wolfson at the outset of this course on what may be
the most important subject in the universe.
Relativity and quantum physics touch the very basis of physical
reality, altering our commonsense notions of space and time, cause and
effect. Both have reputations for complexity. But the basic ideas
behind relativity and quantum physics are, in fact, simple and
comprehensible by anyone. As Professor Wolfson points out, the essence
of relativity can be summed up in a single sentence: The laws of
physics are the same for all observers in uniform motion.
The same goes for quantum theory, which is based on the principle that
the "stuff " of the universe—matter and energy—is not infinitely
divisible but comes in discrete chunks called "quanta."
Profound ... Beautiful ... Relevant
Why should you care about these landmark theories? Because relativity
and quantum physics are not only profound and beautiful ideas in their
own right, they are also the gateway to understanding many of the
latest science stories in the media. These are the stories about time
travel, string theory, black holes, space telescopes, particle
accelerators, and other cutting-edge developments...."
Thanks.
I checked the site and will probably be ordering the DVD soon.
He also put out a Teaching Company thing called "Time Travel,
Tunnelling, Tennis & Tea", but it doesn't look like that is avaible
any more.
If you can lay your hands on this one, then it is so absolutely
perfect for your requirements as it is hours of explanations on solely
what you have queried, aimed at the non-graduate.
If you do not have any luck then email me with a postal address
please.
Sent an e-mail.
Thanks.
atheist@home#1554
.
|
|
|
| User: "Michael Gray" |
|
| Title: Re: OT Physics Question |
05 Feb 2008 09:05:26 PM |
|
|
On Tue, 05 Feb 2008 15:37:53 -0600, wrote:
On Mon, 04 Feb 2008 14:47:14 +1030, Michael Gray
<mikegray@newsguy.com> wrote:
On Sun, 03 Feb 2008 20:53:27 -0600, wrote:
:
Internal and external time are easy enough concepts but is there a
different definition of time that I am unaware of?
I do not know what you mean by 'internal and external' time.
I have never heard these terms before.
Internal time being the way we and our bodies measure time and
external being clocks and other things that keep us aware of the
passage of time.
Ah, thanks.
:
If you do not have any luck then email me with a postal address
please.
Sent an e-mail.
Thanks.
Oops!
I checked my account that is described in my address, and it was
clogged to the gills, and so your message would not fit!
I have cleared it out, and ask that you resend your message to it
please.
Sorry.
.
|
|
|
|
|
|
|
|
| User: "MarkA" |
|
| Title: Re: OT Physics Question |
04 Feb 2008 07:18:21 AM |
|
|
On Sat, 02 Feb 2008 19:33:25 -0600, atheist wrote:
I'm reading a book on Einstein and his theories and I'm having trouble
with the idea that time is relative.
The example used is two poles placed at a distance apart, a stationary
observer watching from the middle with a mirror so that he can see
both poles and another observer on a moving train, also with a mirror
for the same purpose.
The lightening hits both poles simultaneously and the stationary
observer sees it as such but the one on the train when he reaches the
middle point of course sees the strike on the pole he is traveling
toward first and then what appears to be a second strike on the second
pole to his rear.
The suggestion is that each observer is at least experiencing time
differently but even more, that time is actually different for them.
Can anyone explain?
Also if a person is facing west looking at a light source is the light
approaching him in a wave lying north and south or a wave or particle
beam lying west to east?
Any book suggestions for the layman?
atheist@home#1554
I find the most intuitive way to think about time dilation is the example
of two people on motorcycles, riding parallel to each other. An observer
is watching them from above. When the riders are stationary WRT the
observer, one sends a photon to the other, and the speed is measured, by
the riders and the observer. Now, put the motorcyclists in motion. They
are still at rest WRT each other, but are moving WRT the observer. Now,
when a photon is sent, the observer sees it travel a diagonal path, which
is longer than a straight path between the two riders. The riders
see it as following a straight path between them. However, they must all
agree that the speed of the photon is 'c', ergo, time must be slower for
the riders than the observer. Simple, no?
--
MarkA
(My OTHER sig line is clever)
.
|
|
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| User: "Richo" |
|
| Title: Re: OT Physics Question |
04 Feb 2008 05:12:52 PM |
|
|
On Feb 5, 12:18=A0am, MarkA <t...@nowhere.com> wrote:
On Sat, 02 Feb 2008 19:33:25 -0600, atheist wrote:
I'm reading a book on Einstein and his theories and I'm having trouble
with the idea that time is relative.
atheist@home#1554
I find the most intuitive way to think about time dilation is the example
of two people on motorcycles, riding parallel to each other. =A0An observe=
r
is watching them from above. =A0When the riders are stationary WRT the
observer, one sends a photon to the other, and the speed is measured, by
the riders and the observer. =A0Now, put the motorcyclists in motion. =A0T=
hey
are still at rest WRT each other, but are moving WRT the observer. =A0Now,=
when a photon is sent, the observer sees it travel a diagonal path, which
is longer than a straight path between the two riders. =A0The riders
see it as following a straight path between them. =A0However, they must al=
l
agree that the speed of the photon is 'c', ergo, time must be slower for
the riders than the observer. Simple, no?
--
MarkA
Nice work Mark.
Cheers, Richo.
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| User: "" |
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| Title: Re: OT Physics Question |
05 Feb 2008 02:17:11 PM |
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On Mon, 04 Feb 2008 08:18:21 -0500, MarkA <toor@nowhere.com> wrote:
On Sat, 02 Feb 2008 19:33:25 -0600, atheist wrote:
I'm reading a book on Einstein and his theories and I'm having trouble
with the idea that time is relative.
The example used is two poles placed at a distance apart, a stationary
observer watching from the middle with a mirror so that he can see
both poles and another observer on a moving train, also with a mirror
for the same purpose.
The lightening hits both poles simultaneously and the stationary
observer sees it as such but the one on the train when he reaches the
middle point of course sees the strike on the pole he is traveling
toward first and then what appears to be a second strike on the second
pole to his rear.
The suggestion is that each observer is at least experiencing time
differently but even more, that time is actually different for them.
Can anyone explain?
Also if a person is facing west looking at a light source is the light
approaching him in a wave lying north and south or a wave or particle
beam lying west to east?
Any book suggestions for the layman?
atheist@home#1554
I find the most intuitive way to think about time dilation is the example
of two people on motorcycles, riding parallel to each other. An observer
is watching them from above. When the riders are stationary WRT the
observer, one sends a photon to the other, and the speed is measured, by
the riders and the observer. Now, put the motorcyclists in motion. They
are still at rest WRT each other, but are moving WRT the observer. Now,
when a photon is sent, the observer sees it travel a diagonal path, which
is longer than a straight path between the two riders. The riders
see it as following a straight path between them. However, they must all
agree that the speed of the photon is 'c', ergo, time must be slower for
the riders than the observer. Simple, no?
Got it.
But here's a question and it may seem stupid but I'm trying to
visualize it all.
If we had a straight train track ten miles in length, a flatbed car
500 feet in length traveling west at 60mph with a laser and from the
opposite direction another car carrying a wall and traveling at twenty
mph <we could really have fun we could change that to ships in space
at near light speeds but I can't find anybody who can set it up> and
each with an observer fixed in relation to their respective cars with
electronic measuring equipment and we fire the laser at the wall and
had an observer on land with the proper equipment also measure the
time it takes for the laser to hit the wall would the time interval
register the same for each piece of equpiment?
I'm having trouble phrasing the question and hope it makes some sort
of sense in expressing the thing I am looking for.
Does the question make any sense at all?
atheist@home#1554
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