152 replies to this topic

[Emin]

i laughed when i read spanish universities roflz

[StarMountainKid]

There's another hot and furious discussion about Time somewhere else here at UM. I wouldn't think Time were such a controversial subject!

Sepulchrave said:

To me, ``now'' only makes sense as an origin for space-time coordinates. If you and I meet today, and make plans to have lunch together at Bill's Diner in one week from ``now'', but then I decide to go on a merry 99.99999%-of-light-speed trip to Alpha Centauri tomorrow (and come back the next day), while you stay put on Earth, then ``one week from now'' will be quite different for you and me and we would both end up eating alone.

Yes, we both agree on that "now" when we make the appointment. But, while I'm sitting in Bill's Diner waiting for you to show up,  let's say I experience a "now" moment and I say "now!".  Whenever in time you reside, you experience that same "now" moment as I do, irrespective of our different rates of elapsing clocks.  You would always experience and say "now!" at the same moment as I would.

It would seem, if I say "now!" at 12:00 in my frame of reference, you would be saying "now!" at say 2:00 from my frame of reference, if I could see your clock.  So our "nows" would seem not to coincide.

However, would we not both be saying "now!" simultaneously, even though our clocks do not agree on the relative moment we say it? Can your "now" be two hours later than my "now"?

I just think "now" is the edge of time as it passes into the future, so to say. It intervenes all clocks at the same moment, irrespective of their local rates of duration in different frames of reference.

[chezarelli]

escher7, on 23 June 2012 - 01:27 PM, said:

I turn 63 this summer. My time is clearly running out.

Atleast on this site escher you will use it wisely as i am finding out

[chezarelli]

chezarelli, on 23 June 2012 - 02:59 PM, said:

Ok i give in give me the facts !! i might not respond till tomorrow

well come on i think your splitting hairs here !!

[chezarelli]

Rlyeh, on 23 June 2012 - 02:38 PM, said:

How about getting your facts straight first?

http://en.wikipedia....wiki/Phenomenon

http://dictionary.re...owse/phenomenon

have responded elsewhere (typo)
basically your splitting hairs i have used
the word in the right context

[Blizno]

DarkMatterDisturbance, on 19 June 2012 - 10:43 AM, said:

I kind of have a problem with this theory. Time only exists because we exist. Doesn't it? I mean, who's telling any kind of time if there's not someone there to count it? What would time be without someone or something to count it? Questions, questions, questions. Maybe the question should be - Does time really exist at all?

I read several similar statements in these comments that time only exists when somebody observes it.

False.
Time simply is. It needs no observer. If nobody "counts" time, time passes exactly as it would if somebody was "counting" it.

[sepulchrave]

StarMountainKid, on 23 June 2012 - 06:07 PM, said:

However, would we not both be saying "now!" simultaneously, even though our clocks do not agree on the relative moment we say it? Can your "now" be two hours later than my "now"?

Every event has an explicit space-time coordinate. However the exact position of that coordinate in space or time varies depending on the reference frame of your origin.

If you argue that events local to different reference frames can be simultaneous, then your definition of ``simultaneity'' involves connecting the two space-time events with a line of arbitrary slope.

If that definition holds, then a Pharaoh 3000 years ago saying ``now'' also coincides with you saying ``now'' earlier today and someone in the Andromeda galaxy saying ``now'' 5 000 000 years in the future (with these dates defined by my current reference frame).

In other words, it seems like your idea of the ``present'' is a surface in space-time of arbitrary shape. In that case, any space-time event can be connected to any other space-time event, and satisfy your definition of simultaneity.

In my definition, which I believe is the accepted definition in physics (I will freely admit that I am not an expert in relativity or cosmology), ``simultaneity'' is a perception based on a person's location, two people will only agree on simulaneity if they compare their observations when (however briefly) they are immediately next to each other in space-time (the closer the better).

[chezarelli]

Blizno, on 25 June 2012 - 12:23 AM, said:

I read several similar statements in these comments that time only exists when somebody observes it.

False.
Time simply is. It needs no observer. If nobody "counts" time, time passes exactly as it would if somebody was "counting" it.

Time is unique to the perspective of the observer its running at different rates all over the universe depending
where you are their is no exact passing of time unless its being counted .we could be experiencing realtime (time we measure)
compared to someone near the speed of light where it is traveling slower than our pocket we are in at exactly the same time they
are running at different rates.Meaning you only know what is relative to reality if are experiencing it time runs at different rates at the
same time!! it is not constant meaning if someone is not counting it not relative their is no standard speed limit

[Blizno]

chezarelli, on 25 June 2012 - 08:48 AM, said:

Time is unique to the perspective of the observer its running at different rates all over the universe depending
where you are their is no exact passing of time unless its being counted .we could be experiencing realtime (time we measure)
compared to someone near the speed of light where it is traveling slower than our pocket we are in at exactly the same time they
are running at different rates.Meaning you only know what is relative to reality if are experiencing it time runs at different rates at the
same time!! it is not constant meaning if someone is not counting it not relative their is no standard speed limit

"...their [sic] is no exact passing of time unless its [sic] being counted..."
False. Time passes differently in different reference frames, yes, but "counting" of time is unnecessary. Time passes more slowly on a barren rock traveling very fast away from another barren rock. Nobody is needed to observe this. It just happens.

[StarMountainKid]

Sepulchrave said:

Every event has an explicit space-time coordinate. However the exact position of that coordinate in space or time varies depending on the reference frame of your origin.

Let us imagine there are two people, A, and B, who are separated by two light hours. However, they both are located in the same space-time frame of reference, so the rate of their clocks coincide, so both of their present moments coincide as well.

Now, a person, C, who is six light hours from A, and therefore eight light hours from B, flashes a bright light.

A will observe the flash at say 12:00 according to his clock. B will observe the flash at 2:00 according to his clock.

Even though the present moment for B’s observation occurs two hours after A’s observation according to their clocks, both will still experience their present moments simultaneously, regardless of the different moments by their clocks they observe the flash.

From C’s perspective, he could either consider A and B’s discrepancy of observation as explained by the above, or that A and B reside in different relative reference frames. In the second case, for C, B’s discrepancy is caused by his clock ticking faster than A’s.

Which of C’s explanations is correct? From C’s perspective, would both of his explanations be correct?

In C’s second explanation, even though A and B appear to reside in different reference frames, their present moment still is simultaneous.

Does this example infer that the present moment is universal, and separate present moments due to relative reference frames is just a matter of perspective?

[sepulchrave]

StarMountainKid, on 25 June 2012 - 05:32 PM, said:

Even though the present moment for B’s observation occurs two hours after A’s observation according to their clocks, both will still experience their present moments simultaneously, regardless of the different moments by their clocks they observe the flash.

How can you say that they experience their ``present moments'' simultaneously?

Your argument is fine when you attribute different observers experiencing ``the present'' in relation to a singular event. What about two events?

Observer A sees a light to the left and a light to the right flash at the same time. Observer B sees these lights flash one hour apart. If I understand your logic, both observers experience the flashing of the left light ``simultaneously'', even though different amounts of time may have elapsed for each. But then both observers should experience the flashing of the right light ``simultaneously'' as well.

The difference between these two ``present moments'' is negligible for observer A, and is one hour for observer B.

StarMountainKid, on 25 June 2012 - 05:32 PM, said:

Does this example infer that the present moment is universal, and separate present moments due to relative reference frames is just a matter of perspective?

No, because in the example above the way the ``present moment'' advances through space-time has arbitrary curvature for different points. By your logic every single event that ever happened or ever will happen exists in the same present moment, because one can always connect any arbitrary set of events with a curved space-time surface.

[chezarelli]

StarMountainKid, on 25 June 2012 - 05:32 PM, said:

Let us imagine there are two people, A, and B, who are separated by two light hours. However, they both are located in the same space-time frame of reference, so the rate of their clocks coincide, so both of their present moments coincide as well.

Now, a person, C, who is six light hours from A, and therefore eight light hours from B, flashes a bright light.

A will observe the flash at say 12:00 according to his clock. B will observe the flash at 2:00 according to his clock.

Even though the present moment for B’s observation occurs two hours after A’s observation according to their clocks, both will still experience their present moments simultaneously, regardless of the different moments by their clocks they observe the flash.

From C’s perspective, he could either consider A and B’s discrepancy of observation as explained by the above, or that A and B reside in different relative reference frames. In the second case, for C, B’s discrepancy is caused by his clock ticking faster than A’s.

Which of C’s explanations is correct? From C’s perspective, would both of his explanations be correct?

In C’s second explanation, even though A and B appear to reside in different reference frames, their present moment still is simultaneous.

Does this example infer that the present moment is universal, and separate present moments due to relative reference frames is just a matter of perspective?

yes

[StarMountainKid]

I keep forgetting to add this:
"Disclaimer! I am a semi-scientifically-literate person who usually completely misinterprets the meaning of quantum mechanics, The Theory of Relativity and all other scientific theories, have little knowledge of the advanced mathematics which properly describe these theories, and am presenting the following poorly conceived personal hypothesis off the top of my head, realizing it is a complete fabrication of my own and bears no resemblance to how the universe in fact actually operates."

Edited by StarMountainKid, 25 June 2012 - 11:10 PM.

[chezarelli]

StarMountainKid, on 25 June 2012 - 11:09 PM, said:

I keep forgetting to add this:
"Disclaimer! I am a semi-scientifically-literate person who usually completely misinterprets the meaning of quantum mechanics, The Theory of Relativity and all other scientific theories, have little knowledge of the advanced mathematics which properly describe these theories, and am presenting the following poorly conceived personal hypothesis off the top of my head, realizing it is a complete fabrication of my own and bears no resemblance to how the universe in fact actually operates."

you know how the universe actually operates and is all mathematic but you know your wrong but you actually don't understand all
the principals behind it that they have not even discovered yet but you know their wrong as well ?

[Blizno]

chezarelli, on 26 June 2012 - 07:49 AM, said:

you know how the universe actually operates and is all mathematic but you know your wrong but you actually don't understand all
the principals behind it that they have not even discovered yet but you know their wrong as well ?

Alas, you don't know that "your" IS NOT "you are" and that "their" IS NOT "they are", sigh.

You are = you're.
They are = they're.