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/sci/ - Science & Math

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5133342 No.5133342 [Reply] [Original]

I need some help. I can't Figure out the theory of relativity to save my life. Can any of you help explain it to me?

>> No.5133352

Anyone?

>> No.5133356

General or special?

Is it the math or the general concepts that are confusing you?

>> No.5133362

>>5133356
>special
More or Less, I'm doing an independent study on Black Holes. and the Theory of Relativity is being throw around a lot.

>> No.5133399 [DELETED] 

Consider the action functional
<div class="math">(M,\nabla)\mapsto \int_{M}\lange R\wedge e\wedge e\rangle</div>
where <span class="math">M[/spoiler] is a Lorentzian manifold, <span class="math">\nabla[/spoiler] is an <span class="math">ISO(3,1)[/spoiler] connection, <span class="math">R[/spoiler] is the 2-form component of the <span class="math">O(n)[/spoiler] part of <span class="math">ISO(3,1)[/spoiler], <span class="math">e[/spoiler] is the vielbein, and <span class="math">\langle - \rangle[/spoiler] denotes the invariant polynomial.

For SR this is the same but with vanishing <span class="math">R[/spoiler].

In all seriousness you can try the free lecture notes here - http://preposterousuniverse.com/grnotes/, but do not trust other publications from this author. He has known crackpottery.

>> No.5133407

Consider the action functional
<div class="math">(M,\nabla)\mapsto \int_{M}\langle R\wedge e\wedge e\rangle</div>
where M is a Lorentzian manifold, <span class="math">\nabla[/spoiler] is an <span class="math">ISO(3,1)[/spoiler] connection, <span class="math">R[/spoiler] is the 2-form component of the <span class="math">O(n)[/spoiler] part of <span class="math">ISO(3,1)[/spoiler], <span class="math">e[/spoiler] is the vielbein, and <span class="math">\langle - \rangle[/spoiler] denotes the invariant polynomial.

For SR this is the same but with vanishing <span class="math">R[/spoiler].

In all seriousness you can try the lecture notes here - http://preposterousuniverse.com/grnotes/, but do not trust other publications from this author. He has known crackpottery.

>> No.5133410

>>5133399
A++++ poster would read again

>> No.5133427

>>5133407
>Vielbein
>Connection
>LaTeX
I thought there was nobody left who knew about that here <span class="math">\ddot\smile[/spoiler]

>> No.5133432

>>5133427
put your trip back on josef

>> No.5133433

>>5133427
Well gentlemen thank you, I'll read over this. Now, Black Holes, how do they slow down time?

>> No.5133444

>>5133362
Black holes are pretty firmly in general relativity. Special ain't gonna help you much with that.

>> No.5133463

>>5133433
Overly simplified layman explanation: time is a measurement of change. Gravity is so strong in a black hole that it over powers normal forces to the point that atoms can no longer move around like they normally would.

Thus, from the perspective of someone/something in the black hole, time slows/stops.

>> No.5133474

>>5133433

If you watch an object fall into a black hole, it appears to slow down as it approaches the event horizon, never actually reaching it. The photons become red shifted into ridiculously long wavelengths because of the gravity of the black hole. Those are just photons though, the actual object has long since fallen in.

>> No.5133482

>>5133474
Yes yes, I understand that.
>>5133463
That makes a lot of sense thanks!

>> No.5133509

why don't you read a reliable book on it instead of trusting unverified information from random strangers on 4chan?

>> No.5133511

>>5133509
Meh, I trust you guys

>> No.5133536

>>5133511
we can make a physical sci & math center for us 4channers :D

>> No.5133546

>>5133511
Famous last words

>> No.5133905

>>5133433
Killing vectors admit shorter lengths as you get closer to a gravitating body, solve the EFEs to see this. The product of 4-momentum and some timelike Killing vector admits conservation, so you have time dilation.