does time exist?

[Einstein]

Timelord

Q may take on positive or negative values, so dt may be greater than or less than dt0. Of course, this has the obvious disadvantage of requiring nuclear reactions to slow down or speed up time. And then, I'm not sure it moves the particle(s) through time at all.

The answers wont be found in the math. Once the answer is found though, it may be described with math. I'm just pointing out that the direction mass is taking in the universe appears to be predominately downhill. If the change in mass is the primary cause for the flow of time, then it becomes evident that being able to control this flow would require the science to be able to manipulate mass.

 

[RainmanTime]

This is a great thread, BTW, and I should also say this is the kind of thread that is intended for this particular forum. Well done, gents! Let's see if my tiny grey matter can add something to the mix to keep it going.

Assuming mass remains constant, it is the volume which changes.

True, but it is the assumption that mass remains constant (with time) that is, IMO, part of the "problem" we face in seeing mass as somehow segregated from spacetime. And when taken with regard to this statement:

An object moving in time at a rate different than an observer will appear to scale in size. Funny nobody mentions this when talking about mass-energy conversions.

Yes, it is quite funny. And again, IMO this disjoint assumption of "constant mass" (or ignoring the internal mass-energy fluctuations of a body) are what contribute to ignorance of how time, or more specifically spacetime, relates to mass on cosmological and quantum scales. One can grasp the distinction in two different ways that we teach classical mechanics of energy conservation:

When I teach elementary fluid dynamics, I draw the comparison between the classical mechanical energy equation (m*g*h1 + 0.5*m*v1^2 = m*g*h2 + 0.5*m*v2^2) and Bernoulli's equation for pressure energy (P1 + rho*g*h1 + 0.5*rho*v1^2 = P2 + rho*g*h2 + 0.5*rho*v2^2). The equations are virtually identical but that one holds for solid matter and the other is applicable to fluids. Yet while they are VIRTUALLY identical, students always ask why the pressure form has P1 and P2 (static pressures) and the matter form has no equivalent. The answer is that in the mechanical/matter form we are assuming mass remains constant and therefore we ignore the internal mass-energy of the solid object that is moving from state 1 to state 2. However, the fluid dynamic treatment cannot ignore the "internal energy" represented by static pressure since it CAN and DOES change from point to point in a flowfield.

This is precisely why Einstein's "energy density" model follows (and looks an awful lot like) the fluid dynamic paradigm, because at both cosmological and quantum scales we cannot afford to "assume constant mass" nor ignore internal mass-energy. I believe it also provides a clue to how relativity and quantum theory will eventually be united.

We now know that "mass/matter" (I believe they are distinctly different entities, and have defined them as such, but most use the terms interchangeable) is only a VERY small portion of total cosmological energy (~4%), with Dark Matter (DM) and Dark Energy (DE) rounding out the remaining 96% of energy. It is my belief that normal baryonic matter (the ~4%) is not and cannot be isolated from DM and DE. They interact. In much the same way that static pressure, head pressure, and dynamic pressure interact with one another in the fluid model. And this is also part of my hunch that, at some point, we will no longer be able to treat mass/matter as a scalar quantity. To understand how baryonic matter, DM, and DE interact, we will need to adopt a vector (tensor) model for mass.... and that will eventually lead to what I call the Massive SpaceTime 3x3 Matrix.

RMT

 

[TimeLord]

The assumption of constant mass was an example of a special case in which mass does not change while an object moves through time. The purpose was simply to show that the volume of that object perceived by a temporally stationary observer would change. With constant mass, it is easy to see that density would change. Of course, mass can and does change, depending on kinetic energy, binding energy, and maybe something else too.

By the way, has anyone else noticed that (v/c)^2 = .5*m*v^2 / .5*m*c^2 = 2*U / BE, where U = kinetic energy, and BE = total mass-energy?

 

[RainmanTime]

The assumption of constant mass was an example of a special case in which mass does not change while an object moves through time. The purpose was simply to show that the volume of that object perceived by a temporally stationary observer would change.

Understood and agreed, TimeLord. I was not disputing you, only taking the discussion further.

and maybe something else too.

That's the part I am interested in. I am thoroughly convinced that mass is only perceived as a scalar, but its true nature is a vector. Another clue that tells me this is true is that there is NO conservation of mass law...only conservation of energy. Thus, mass is a degenerate (i.e. approximate...incomplete) form and measure of energy.

By the way, has anyone else noticed that (v/c)^2 = .5*m*v^2 / .5*m*c^2 = 2*U / BE, where U = kinetic energy, and BE = total mass-energy?

Interesting indeed. I've never looked at it like that. Would you say that this fact supports the idea that we live in (on!) a Brane Universe? I like to make the analogy that our limited perceptive existence (that 4% portion of witnessed energy) lives on the surface (hence the reason for squaring the Lorentz Contraction ratio) of a Hubble Bubble.

I'd appreciate your thoughts...
RMT

 

[TimeLord]

Quite alright.

I don't know about branes. My previous comment (regarding (v/c)^2) was no more than a restatement of the lorentz factor as 1/sqr(1-2U/BE). It's probably of little consequence.

As for "dark" energy and matter, I think they're only a by-product of incomplete physical models. I suspect that, in time, all shall be accounted for by "normal" matter.

Long ago, I came to the conclusion that a charged particle is defined in a plane & rotates its spin axis to be parallel to its acceleration vector. Thus, the electric field does not point equally in all directions (radially), but the alignment is so fast that we can treat such a particle as a point charge. Mass may well be similar, but I don't yet know for sure.

I have considered the slight EM attraction caused by 2 charged particles of opposite charge, such as a proton & electron, placed in very close proximity to one another (such as in an atom). Though the charges nearly cancel, there is a slight difference in the coulomb force exerted on a distant charged particle because the electron & proton are at different distances. This, combined with electrostatic induction could well induce "gravity". However, this might be yet another effect, aside from gravity. Consider the following over-simplified example:

Q = charge on distant particle
qe = electron charge
qp = proton charge = -qe
Fe = coulomb force from electron
Fp = coulomb force from proton
re = distance between distant particle & electron
rp = distance between distant particle & proton
e0 = permittivity of free space
Ra = atomic radius = rp - re (assuming the proton is further than the electron from the distant particle)
Ftot = net force exerted on atom & distant particle

Fe = qe*Q/(4*pi*e0*re^2) = (Q*qe/(4*pi*e0))*(1/re^2)
Fp = qp*Q/(4*pi*e0*rp^2) = -(Q*qe/(4*pi*e0))*(1/rp^2)
Ftot = F1 + F2 = (Q*qe/(4*pi*e0))*(1/re^2 - 1/rp^2)

The value of (1/re^2 - 1/rp^2) is incredibly small, so the force exerted is very small, but nonzero. Furthermore, Ftot will increase with increasing radius and/or total charges. The above example is for hydrogen, since it's "simple". Anyway, it's possible that I made mistakes here or overlooked something. Let me know if so.

 

[Darby]

TimeLord,

Pi is still a constant. That's the way it's defined. pi = circumference / diameter of a circle.

Another good observation and comment.

Correct. "Pi" expresses the ratio of the circumference to the diameter of a circle regardless of the curvature of spacetime. It's not a "constant" in the sense that we usually consider it to be, 3.1416... It's a variable only in the sense that the ratio itself is a variable depending on the local geometry of spacetime.

 

[Darby]

Einstein,

So it is very reasonable to assume that the mass of the entire universe is constantly decreasing.

That the sun is losing mass doesn't mean that the galaxy is losing mass on the whole. The sun's mass is given up as photons, other forms of energy and other sub-atomic particles. In that sense local conservation of mass is conserved. Measure the total mass-energy of the galaxy and it is conserved - if you take a short enough time period (whatever that really means).

But following the publication of special relativity conservation does not necessarily mean universal conservation. With the fall of absolute simultaneity absolute conservation also fell. We can't say absolutely to an arbitrary degree of certainty that the laws of conservation are universally true at all times. We can't "see" events that are relativistically distant from us. We can only see what happened in the relativistic past. We don't really know what's happening "now" in those places.

We assume that the laws of conservation hold true based on everything that we have been able to observe. We expect that when we consider orders of time that are greater than Planck's Time that conservation laws hold. But we also have an indication that given short enough periods of time they do not hold true. But that's no surprise and is considered in quantum physics.

 

[Justsomeguy]

As to the geometry of it all. No offense the cube is a bad analogy. If it were viewed from a distance in theory 3d space would be as of now a expanding irregular sphere being shaped by 4d time, and 4d time would be a equally matching expanding cone radiating from the initial point of origin to a point. Now this falls apart @ a point so a cone outside a sphere is not adequate unless you consider that all time has already taken place till the universal end and that all points intersect via 4d then you see that it's not a cone @ all but something convex such as a thick lens narrow @ the point of origin and end but wider @ it's center. Time is the largest of dimensions as it encompasses well in a nut shell everything Id love to post fancy pic's but I'm lousy with paint myself admittedly so /ttiforum/images/graemlins/smile.gif.