# Why two mass attracts each other?

Discussion in 'Physics & Math' started by hansda, Mar 19, 2013.

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1. ### hansdaValued Senior Member

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To understand your above questions, you have to read the papaer. Here is their final conclusion from the paper:
From this conclusion we can say that "time reversal" is not possible.

3. ### hansdaValued Senior Member

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I told you "real time" corresponds to 'arrow of time', which is proven in this experiment.

Existence of what?

5. ### hansdaValued Senior Member

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FLRW equations can be seen here.

7. ### ash64449Registered Senior Member

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Ok. If 'real time' really exists,how do we measure it?

8. ### hansdaValued Senior Member

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"Real Time" can be known from the sequence of events ie 'cause' will happen before 'effect' and not other way.

9. ### ash64449Registered Senior Member

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it appears as if your 'real' time is same as Proper time..

Proper Time is invariant.. it can never change..

Time dilation effect is related to a coordinate system and is a coordinate effect..

So,there is no other thing that is.. Proper time is what you mean by 'real' time.

10. ### hansdaValued Senior Member

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My idea of "Real Time" is actually 'arrow of time'. If you think "Proper Time" corresponds to 'arrow of time', it can be that also.

That is basically corresponds to "time measured by a local clock" in a co-ordinate system.

May be, if that corresponds to 'arrow of time'.

11. ### UndefinedBannedBanned

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Just to make it clear for my naive understanding of your position re handsa's "real time" conception/opinion, what do you, ash64449, mean when you say "Proper Time is invariant.. it can never change"? Are you referring to the rate of counting/ticking off increments of standard seconds etc, or do you refer to some "absolute universal" increment of time that does not vary according to what "standard increments" we human scientists choose and conventionally agree on to use for "timing" processes?

12. ### rr6BannedBanned

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.."we cannot return to the womb"...(Fuller) aka as handsa's "arrow-of-time" in one direction only, however, that direction is not to be confused with three other cosmic directions( fuller again );

1) out.....<>

2) around...()

3) in...><

So the arrow-of-time is more likened to hawkings explanation that all time is going/flowing from south to north or vice versa, east to west or vice versa.

This has to do with what others have mention in regards to our understanding of entropy says that cup falls off the table breaks and all particles come apart eventually and we are left with a "heat death" Universe--- aka very large flat photon ---.

Hawking had one scenario where at that at some terminal end point of Universe, the time reverses itself and entropy will mean the opposite of what it means now, i.e. the a broken cup will fall higher and rebuild itself before it lands on the table.

r6

13. ### brucepValued Senior Member

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Under normal conditions gravity is always attractive. Under certain circumstances it can be repulsive. Alan Guth and Andrei Linde [behind the iron curtain] came up with an idea to see what could happen to a soliton, in a quantum scalar field, if the solitons local gravitational field reflected the circumstance where the pressure term dominates over all other energy components of the metric [or the SEM tensor]. From there they evaluated what components of this event could lead to an inflation signature in the CMBR. Following with theoretical predictions for the signatures. The birth of cosmology as a predictive science. Good job following the derivation. It was well done. The following is a relativistic version

v = at/[1+(at)^2]^1/2

A fairly easy to read paper on Eternal Inflation.
http://arxiv.org/abs/hep-th/0702178

Last edited: May 21, 2013
14. ### ash64449Registered Senior Member

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I mean the invariant interval between the two events.

15. ### ash64449Registered Senior Member

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yes. Thank you for the information... Though i think handsa mean normal conditions...

16. ### Farsight

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Use two parallel-mirror light-clocks coincident at event1, and no matter how you transport one clock as opposed to the other before bringing both clocks back together for event2, the light-path lengths for those two clocks are the same. It is invariant.

17. ### TachBannedBanned

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The above is manifestly false, John. Ever heard of the twins paradox?

18. ### Beer w/StrawTranscendental Ignorance!Valued Senior Member

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I still haven't ruled out you suffer from some childhood trauma, Farsight.

19. ### pmbBannedBanned

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Hi Farsight,

I found you again. I was staying away from most forums for the usual obvious reasons. How's this place for posting?

20. ### UndefinedBannedBanned

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In my naive understandings it seems you are referring to the clock/counter "comparative counts" in the twin paradox scenario (when they meet again and compare), which naturally differ. But Farsight seems to be referring instead only to the "tick rates" and "light paths" themselves, which will be back "in synch" again when the twins clocks are again meet and co-moving once more. The "cumulative counts" will differ, but the "rates" and the light paths will agree again after return and comparison in co-moving frame once more. Can you please naively explain fully and clearly what you meant to "explain" or "correct" by invoking the "twins paradox" in your seemingly confused comment on Farsight's actual point, Tach? Please, fair warning: play no games in your reply on this, or you will be reported. Thankyou.

21. ### UndefinedBannedBanned

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Please read my post to Tach regarding Farsight's post. It questions Tach's relevance when saying "false" re Farsight's statement. So your above personal comment seems premature and anyway is against site rules about flaming and trolling (especially in this instance). Please do this forum and yourself the favor of retracting or deleting your own objectionable science-empty and personal attack post. Thankyou.

22. ### Farsight

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It isn't false at all, Tach. The twins "paradox" is where you and I are passing one another at some relativistic speed, and I say your parallel-mirror light-clock is going slower than mine because its light-path is zigzagging, and you say mine is going slower than yours and its light-path is zigzagging. People think this is amazing but it isn't. It's no more amazing than when we're separated by distance, and I say you look smaller than me whilst you say I look smaller than you.

As for those light-path lengths, assume you and I synchronise our parallel-mirror light-clocks at event1, then you set off on an out-and-back trip. My light path is repeatedly straight up and down like this ||, one up-and-down segment of the light-path representing one tick of my clock. I say your light path is zigzagging, like this /\/\/\/\/\, and again zigzagging when you turn round and come back. The out-and-back turnaround breaks the symmetry of the passing twins, such that we end up agreeing that it was you doing the moving, and it was your light zigzagging rather than mine. When we meet up at event2 a year later, your clock reading is lower than mine, and you have experienced 11 months of time. But the separation between event1 and event2 is the same for both of us. We don't miss each other by a month. And when we work out the total light-path-lengths in our respective clocks, we find that they're both one light year.

See the simple inference of time dilation where we use Pythagoras's theorem to work out the Lorentz factor. We then apply a reciprocal to distinguish time dilation from length contraction. It's all very simple stuff.

23. ### Farsight

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Hi pmb, I hope you are well.

This place is struggling I'm afraid, for the usual reasons. It's now less active than my place. I don't like to refer to the latter because it would be improper, I have my reputation to think about. I saw you at the naked place the other day. You're flogging a dead horse there I'm afraid. They're like custodians of ignorance for kids.