Recent content by johnconner

It's more of a question really. Since I don't understand it very well I need guidance to understand it. I constantly think about things I learn and this is currently bugging me that I can't figure out. I would appreciate it if you help me with this.

For explaining Delayed-choice quantum eraser experiment, what if I change the Copenhagen interpretation a little. When the experiment is concluded, we observe one detector (the first detector with the shortest path) has detected the pattern long before the wavefunction is collapsed (before the...

thank you. then what is dilation? when we can use that? if we consider time as the fourth dimension, then can we say expansion in time is a dilation?

Hello. If a closed ball is expanding in time would we say it's expanding or dilating in Riemannian geometry? better saying is I don't know which is which? and what is the function that explains the changes of coordinates of an arbitrary point on the sphere of the ball?

No I'm certain it has peculiar velocity. because the whole point was to generalize what I said in #10. the point with one directional motion in 2-D becomes a sphere in 3-D space without center. it is comoving before expansion of its own. which means that it's comoving with the Hubble flow in our...

the points on the surface won't have zero peculiar velocity. they are moving away from the center. and peculiar velocity is any velocity that is not comoving. this is not comoving. this is exactly the opposite of comoving.

the center yes. it has zero peculiar velocity but the surface has outward velocity which in magnitude is equal to rate of expansion.

Is that the scale factor? If you consider it for two seconds apart would it actually be different? if that ##a## is scale factor that remains the same. for one second separating the ##t## from ##t_{0}## scale factor won't change. And why should we change what I suggested? is it wrong to say a...

it's just a hypothetical sphere. and it's expanding with the rate of expansion in small scales like meter or less.

Ok if all the problem is finding a physical system for this scenario you can consider a system of entangled atoms which are expanding on the shell of the sphere. although achieving the constant rate of expansion is a tricky thing to do (I'm not familiar with the practical experiments so it might...

first one.

I said it in #22: a simple geometrical 3-D shape. a hypothetical sphere. you can consider it the Hubble flow itself but not in cosmological scale. one meter in diameter, less, even nanometer if you want. the only thing to remember is it shouldn't be affected by the scale factor so it's not in...

All right. How do I measure the spatial change for this sphere in the Milne universe?

Is it comprehensible in a space with center?

Because I have no idea how to do the math. I already wrote two things in math and created enough mess. I need someone to put me in the right direction. because I do get how things work. But I'm not qualified in math. even putting me in the right direction would do it. because right now, I don't...