Special Relativity, Relativity of Simultaneity etc.

[burdenofbeing]

Hi everyone.
I wanted to make a hopefully interesting talking topic.
It's about relativity of simultaneity, time as the 4th dimension and such.
Nothing too new, but I'm sure there are many who are not familiar with this, or didn't ponder much over the issue.

What is relative simultaneity:

According to the famous scientist Minkowski's spacetime theory, in special relativity, events that are simultaneous for one observer are not simultaneous for another observer in relative motion. If one observer sets up a line of clocks that are all synchronised so they all read the same time, then another observer who is moving along the line at high speed will see the clocks all reading different times. This was proven by empirical experiments as well.

So, the time being the fourth dimension is an very established and accepted scientific concept.

Now our "positioning" and perspective in this dimension is related to our speed. Here's an excerpt from wikipedia:



"Events A, B, and C occur in different order depending on the motion of the observer. The white line represents a plane of simultaneity being moved from the past to the future."
edit: that v means velocity and c means lightspeed, if it wasn't obvious.
----------------

So what? So this, for example. Even though we, ourselves have uncertainty about future, and move slowly through the time dimension, a hypothetical ultrafast entity, that resides above this dimension can see past future and now simultaneously, as causes and effects blend into each other.

interesting isn't it?

[burdenofbeing]

not as interesting as I though I guess

[Whatsthepoint]

Give it some time, by tuesday this thread will be swarming with aspiring theoretical physicists.

[burdenofbeing]

last bump before tuesday :P

[GreyKode]

Hi burden,
I am interested but just gimme some time cause I am not very familiar with the stuff.
I noticed youre an associate professor, I am an electrical engineering T.A., working on my phd, so not very familiar with physics but if its math then I'm on it.

[GreyKode]

So what the movie means is :
If youre stationary then the three events A,B and C happening at different points in space will seem simultaneous. But if youre moving then they wont appear silmultanous.

[GreyKode]

Ok so this means we can never measure absolute time?

[burdenofbeing]

^Somewhat. The point is, their simultaneity changes. So, if they aren't simultaneous when you are stationary, they may be simultaneous for you, when you are moving.

More importantly, this is about what now is. Our now, or present may be -and as far as we know, are- very different from others. As in containing different information.

There is an interesting and easy to understand example named the Andromeda Paradox. Let me see if I can find it. Ok:

"Two people walking past each other in the street could have very different present moments. If one of the people were walking towards the Andromeda Galaxy then events in this galaxy might be hours or even days advanced of the events on Andromeda for the person walking in the other direction. If this occurs, it would have dramatic effects on our understanding of time. Penrose highlighted the consequences by discussing a potential invasion of Earth by aliens living in the Andromeda galaxy. On Earth, one person might live in a universe where the Andromedeans have not yet decided to invade, whilst someone passing them in the street could live in a universe where alien spaceships are underway."

I put this here, mainly to show how both being uncertain about future, and having the free will to shape it can hypothetically coexist with an entity who already knows what's going to happen.

[GreyKode]

So, if they aren't simultaneous when you are stationary, they may be simultaneous for you, when you are moving.

So what this means is that by moving through space you can reveal future events?
Like a series of snapshots spread across space...somewhat?

[burdenofbeing]

hm. again somewhat. your present moment will include the information of somebody elses future. but series of snapshots spread across space is an apt description, to understand time as the 4th dimension. snapshots act as the 2d papersheets, to a stack of papers in 3d dimension.

[Chuck]

cool illustration

[~Raynn~]

Right, ...The details are a little confusing, but I think I understand what you mean by how this could be interpreted...

...how both being uncertain about future, and having the free will to shape it can hypothetically coexist with an entity who already knows what's going to happen.

[GreyKode]

Penrose highlighted the consequences by discussing a potential invasion of Earth by aliens living in the Andromeda galaxy. On Earth, one person might live in a universe where the Andromedeans have not yet decided to invade, whilst someone passing them in the street could live in a universe where alien spaceships are underway

Got it.

(A)--->
(B)<---

For Person A andromedeans have already decided to invade.
For Person B not yet decided.

But is it possible that for B Andromedeans would somehow reject the idea of invading?

[YusufNoor]

just a quick note. remember that equations like e=mc squared ARE considered shirk by some. Allah, SWT, can do ANYTHING he wants to. that equation is for humans.

may sound odd, but it actually makes sense.

[aamirsaab]

I think my head just exploded. Interesting stuff anyhow.