On Feb 19, 10:47 pm, Eric Gisse wrote:
On Feb 19, 9:15 pm, Koobee Wublee wrote:

Kinetic energy is observer dependent, and so is the momentum. This is
also true for the observed mass.

Always the "observed" qualifier, eh?

Do you not agree that the kinetic energy is observer dependent?

The weasel words are one of the
many annoying aspects of you.

What weasel words? Do you not understand the meaning of the word
'observed'?

When asked to calculate the surface area
of a sphere of constant radius at a specific slice of time, you weasel
out of the simple calculation by whining about "observed" radius.

I did give you a straight answer. You were the one who chose to
weasel your way out ignoring my answer. shrug

Thus, the energy-momentum tensor
must be observer dependent as well.

False logic leading to a wrong conclusion from someone who doesn't
know any better.

How can it be false logic if the kinetic energy is observer dependent?

The stress-energy tensor for a lone particle isn't
made out of the particle's 3-momentum OR its' kinetic energy.

Then, you disagree with Professor Roberts. You two need to make up.
shrug

1) Its' a tensor, but we both know multilinear objects are beyond your
grasp but not your reach so understanding is not expected of you.

We know the tensor is merely a matrix. shrug

2) The STRESS-ENERGY tensor is not a function of observer dependent
quantities. Go look up a few.

According to Professor Roberts, it consists of the kinetic energy and
the momentum. shrug

Since it is the energy-momentum
tensor that equates with the Einstein tensor, the field equations
allow an observer dependent quantity to shape the curvature of
spacetime that is supposed to be observer independent or invariant.

...and when asked "what is a tensor", will you finally provide an
answer that DOESN'T talk about matrices?

Please give me a date when you personally will be in peace with this
particular self-inconsistency.

Please give us a date when you will sit your ass down and start
learning the theories which you routinely criticize.

I have already done so. When are you getting your BS degree? You
have missed your promise date in several occasions so far, Mr. super-
super-super-super senior.

Properly identified according to Hilbert's Lagrangian that satisfies
as an density to the Einstein-Hilbert action, the energy-momentum
tensor is described as follows.

Please stop talking about Lagrangians and actions until you actually
understand the concepts and mathematics relating to the concepts.

Well, I have understood about Lagrangians and the calculus of
variations. This means I have the right to use the Euler-Lagrange
equation in a timely situation where the Lagrangian actually satisfies
the mathematical constraints according to the Lagrangian method.

T_ij oc rho g_ij

You pulled this straight out of your ass.

Well, since Hilbert did pull out that Lagrangian out of his ass, and
the above is merely a derivation from it, so technically you are
correct, but so. shrug

Plus it has the added
stupidity of not only being written wrong, but is also deliberately
non tensorial by the *******ized inclusion of the metric.

The plot gets more intrigued. I thought you believe in the divine
tensority of the metric.

Where

** g_ij = Elements of the metric, the matrix

The metric is not a matrix you ignorant ****.

The metric is merely matrix. shrug

** rho = mass density

So, where did you get that energy-momentum tensor?

Pragmatic reason? The number of rank two tensors that you can build
out of a particle's four-velocity is rather limited. Kinetic energy is
not frame invariant and momentum is a function of its' four-velocity,
so you don't have any choices.

Foaming in the mouth without any answer but excuses, I see. shrug

Technical reason?

The definition of the stress-energy tensor for a single particle is
T^uv = m U^u U^v. Test the definition for simple cases. It easily
generalizes to a density.

Hey, why stuff the field equations with definitions after Hilbert
derived them?

Try U^i = (c,0,0,0) - the particle is at rest. So the only nonzero
component of the tensor is T^00 = mc^2. Remember SR?

And, the joke continues. shrug

The verdict depends on how you pull out that energy-momentum tensor
from. shrug

Why do you care? It isn't as if you can use this knowledge, or even
repeat what you are told without butchering it.

You are correct. I do not care about bullsh*t. shrug

This still does not make much sense. It still has nothing to do with
the field equations that Hilbert derived before 1916.

YAWN.

Yes, it is getting late.

This is explained in every relativity textbook that has the
Lagrangian derivation of the field equations - there is a specific
component that is simply labeled the stress-energy tensor.

It sounds like you need to fabricate toilet papers with all these
books that are so wrong. shrug

It is less contradictory if you allow an invariant quantity to decide
how spacetime should be curved. shrug

Covariant, dumb****. COVARIANT.

There is no more excuse. It is less contradictory if you allow an
invariant quantity to decide how spacetime should be curved.