Please help me understand:Time and Space

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tighabhinn

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Please help me understand:Time and Space
« on: 05/09/2014 12:36:46 »
I've read that TIME and SPACE are inter-connected in a similar way to MASS and ENERGY. Is there a sense in which it's possible to argue that TIME is an illusion. That the history of the Universe EXISTS NOW somewhere in Space:  that the future and the past are only human constructs to help us make sense of our restricted view of reality.
I hope this question isn't too naive. Any patient respondents out there?

evan_au

• Neilep Level Member
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Re: Please help me understand:Time and Space
« Reply #1 on: 05/09/2014 14:12:57 »
You could imagine a viewpoint which sees all of time and space laid out before you as a complex 4-dimensional shape. In fact, Einstein did imagine the universe from this viewpoint. However, he could only really see the past and the present (and extrapolate a short way into the future).

Our brains and bodies work by turning chemical energy into electrical and heat energy, increasing the entropy of the universe, and propelling it faster towards its ultimate heat death.

Unfortunately, entropy only goes in one direction - a smashed glass does not magically unsmash, and a scrambled egg does not magically get unscrambled; and unfortunately, we don't get any younger.

So the forward progression of time is very real and inevitable for a macroscopic chemical-driven being such as ourselves.

In theory, you could alter the experience of time by traveling near the speed of light, or zooming close to a black hole; by freezing yourself in liquid nitrogen, or by reducing your universe to just 2 interacting subatomic particles. Unfortunately, you would not survive the attempt with our current state of technology.

tighabhinn

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Re: Please help me understand:Time and Space
« Reply #2 on: 07/09/2014 18:59:34 »
Thank you Evan I'm very grateful for your full answer. I don't understand it very well but I'm going to give it some serious thought thanks  KC

PmbPhy

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• 2784
Re: Please help me understand:Time and Space
« Reply #3 on: 07/09/2014 21:12:46 »
Quote from: tighabhinn
I've read that TIME and SPACE are inter-connected in a similar way to MASS and ENERGY. Is there a sense in which it's possible to argue that TIME is an illusion. That the history of the Universe EXISTS NOW somewhere in Space:  that the future and the past are only human constructs to help us make sense of our restricted view of reality.
I hope this question isn't too naive. Any patient respondents out there?
Actually there's a better way to look at it. Mass and energy are said to be equivalent meaning that increase in one means an increase in the other. However this does not mean that they're the same thing since energy is a quantity which is not defined but its main meaning is that its total is conserved while mass is the quantity which determines momentum.

Now we can turn to mass and momentum. The relationship here is that time is related to mass and space is related to momentum. By this I mean

Definitions:
r = $$(x^1, x^2, x^3)$$ = 3-Position Vector of Particle
m = Proper mass
M = Inertial mass
$$M = \gamma m$$
p = Mv
U = 4-Velocity of Particle
P = 4-Momentum of Particle

Spacetime event: $$(cx^0, x^1, x^2, x^3)$$ = (ct, r)
4-Momentum: $$P = (cp^0, M v^1, M v^2, M v^3)$$ = (cM, p)

Do you notice the symmetry between time and inertial mass and momentum and position? If not then notice the following

Spacetime event:
X = (ct, x, y, z)
x0 = t
r = (x, y, z)

4-Momentum:
P = mU = (cM, Mv)
p0 = M
p = Mv

This viewpoint was presented in Concepts of Mass in Contemporary Physics and Philosophy by Max Jammer, (2000).

PmbPhy

• Neilep Level Member
• 2784
Re: Please help me understand:Time and Space
« Reply #4 on: 07/09/2014 21:14:41 »
I've read that TIME and SPACE are inter-connected in a similar way to MASS and ENERGY. Is there a sense in which it's possible to argue that TIME is an illusion.
While I don't agree with the people who present those articles they do exist. E.g. see
http://www.scientificamerican.com/article/is-time-an-illusion/

I'm with the fella who wrote
http://www.pitt.edu/~jdnorton/Goodies/passage/
Quote
A common belief among philosophers of physics is that the passage of time of ordinary experience is merely an illusion. The idea is seductive since it explains away the awkward fact that our best physical theories of space and time have yet to capture this passage. I urge that we should resist the idea.
Underline is mine.

lightarrow

• Neilep Level Member
• 4586
Re: Please help me understand:Time and Space
« Reply #5 on: 08/09/2014 15:42:42 »
Quote from: PmbPhy link=topic=52250.msg440299#msg440299 date=14
[quote author=PmbPhy link=topic=52250.msg440299#msg440299 date=1410120766
Actually there's a better way to look at it. Mass and energy are said to be equivalent meaning that increase in one means an increase in the other. However this does not mean that they're the same thing since energy is a quantity which is not defined but its main meaning is that its total is conserved while mass is the quantity which determines momentum.

Now we can turn to mass and momentum. The relationship here is that time is related to mass and space is related to momentum. By this I mean

Definitions:
r = $$(x^1, x^2, x^3)$$ = 3-Position Vector of Particle
m = Proper mass
M = Inertial mass
$$M = \gamma m$$
p = Mv
U = 4-Velocity of Particle
P = 4-Momentum of Particle

Spacetime event: $$(cx^0, x^1, x^2, x^3)$$ = (ct, r)
4-Momentum: $$P = (cp^0, M v^1, M v^2, M v^3)$$ = (cM, p)

Do you notice the symmetry between time and inertial mass and momentum and position? If not then notice the following

Spacetime event:
X = (ct, x, y, z)
x0 = t
r = (x, y, z)

4-Momentum:
P = mU = (cM, Mv)
p0 = M
p = Mv

This viewpoint was presented in Concepts of Mass in Contemporary Physics and Philosophy by Max Jammer, (2000).

I noticed this by myself long ago. But you probably should also have mentioned that time/energy and space/momentum are conjugated variables in QM.

--
lightarrow

PmbPhy

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• 2784
Re: Please help me understand:Time and Space
« Reply #6 on: 08/09/2014 17:35:42 »
Quote from: lightarrow
I noticed this by myself long ago. But you probably should also have mentioned that time/energy and space/momentum are conjugated variables in QM.
I would have if I could see any significance that it has in relativity. All I could say at this point is that its a coincidence an
I don't like that idea.