Two faces of time?

[phyti]

 

What is space observing?

Or: what becomes to our equations if you turn everything symmetricaly like you turn a sock inside out?

I guess space would see mass curving.

 

You have to be cautious when thinking 'ideal' symmetry. Science has been surprised many times when discovering that the 'real' universe doesn't require it.

Per GR, mass produces curves in space, or directs objects to move in a manner that makes it appear that way. It's gravity in a different dress!

 

Here's a little more to consider.

 

Distance has two components, magnitude and direction, but time has only magnitude, thus they are not equal. Mathematically distance is a vector, and time is a scalar/number. Time is also a process with an ordered sequence of events that continuously grows in one direction, and is equivalent to counting. Distance has extent and can be measured repeatedly resulting in the same values, time has no extent and its values are not reused but increase.

 

The reference to histories, graphs, Smolin, Minkowski, etc. makes another point. All mathematical constructions do not have to correspond to something physically real. The world line of an object is a superposition of its states at different times, a history, and is not observed by anyone unless you have some form of memory.

[michel123456]

I understand your point, but distance is a scalar.

 

"Distance cannot be negative. Distance is a scalar quantity, containing only a magnitude, whereas a displacement vector is a vector quantity characterized by both magnitude and direction." from http://en.wikipedia.org/wiki/Distance#Distance_versus_directed_distance_and_displacement

 

You wrote

Time is also a process with an ordered sequence of events that continuously grows in one direction

 

That is the second face of time.

Inconsciently you used terms that belong to space in order to describe time. If you stick to these words, you are not far to agree with me.

Edited March 9, 2010 by michel123456

[phyti]

I understand your point, but distance is a scalar.

 

"Distance cannot be negative. Distance is a scalar quantity, containing only a magnitude, whereas a displacement vector is a vector quantity characterized by both magnitude and direction." from http://en.wikipedia.org/wiki/Distance#Distance_versus_directed_distance_and_displacement

 

 

That is the second face of time.

Inconsciently you used terms that belong to space in order to describe time. If you stick to these words, you are not far to agree with me.

 

I think this is a question of semantics. I'm not using that scientific definition. No one has ever asked me for the displacement of a particular place, and if I just tell them how far away it is without a direction what help is that?

 

I would prefer 'length' as a scalar, independent of orientation, and distance a vector (from a to b, or its reverse, b to a, implying an order, or signed value or direction). This provides a more fundamental explanation for using negative numbers than the 'signs rule', i.e., negative numbers are actually vectors, a length rotated 180 °, a two component concept.

 

You mentioned polar coordinates, and they require direction (2 angles) and a length. The laser beam to the moon doesn't work without a direction.

Most science involving motion involves vector notation.

 

The arguments I present are intended to declassify time as a dimension in the sense of spatial dimensions. To me time is just a diary, describing the events of the day. No one moves through time because as someone else said, nobody leaves the present.

 

Thanks to the Greeks for moussaka.

[michel123456]

(...) To me time is just a diary, describing the events of the day. No one moves through time because as someone else said, nobody leaves the present.

 

Thanks to the Greeks for moussaka.

 

You're very kind. To be honest, there are more than 30.000 reasons to thank the Greeks, but that is out of topic.

 

You wrote: "No one moves through time".

I strongly believe exactly the contrary. "Τα παντα ρει", ta panta rei, Everything flows , Heraclitus of Ephesus ~535 ~475 BCE