The Naked Scientists

The Naked Scientists Forum

Author Topic: What is special relativity?  (Read 8342 times)

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11993
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
What is special relativity?
« Reply #25 on: 24/12/2010 14:21:58 »
Jartza, were you thinking of it in terms of a black hole being 'stuck' at one place?
Even if we assume that you can still imagine a ship relative the ship at the 'black hole', and they will see each other. You need something else for it, tell me when you've got it.
==

Or will they :)
How far apart can they be before they lose 'sight' of each other?

Gravity 'bends' light right?
« Last Edit: 24/12/2010 14:25:49 by yor_on »
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11993
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
What is special relativity?
« Reply #26 on: 24/12/2010 14:27:11 »
So the 'room time geometry' at a black hole will be very 'restricted' won't it?
Defining your 'frame of reference' very clearly.
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11993
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
What is special relativity?
« Reply #27 on: 24/12/2010 15:24:06 »
And if we assume that one 'room time geometry' is equivalent to all other 'room time geometries'?

Which it should be.

What can we learn from such an example?
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11993
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
What is special relativity?
« Reply #28 on: 24/12/2010 16:07:38 »
Why do I expect it to be 'equivalent'?

Well, we do expect the other 'room time geometries' to have a relevance to ours, don't we? They are as I call it 'relations', creating the 'room time' you see in your telescope, or binoculars, or just see.
 

Offline jartza

  • Sr. Member
  • ****
  • Posts: 230
    • View Profile
What is special relativity?
« Reply #29 on: 25/12/2010 01:20:18 »
Here is a wire and a black hole. A red rod fiddles the wire. On the right is an observer, named Bob.
Bob observes that waves that arrive through the wire are kinda muffled, because waves lost their energy when climbing the uphill, or for some other reason. 





Here is a wire and an accelerating rocket. A red rod fiddles the wire. In the rocket is an observer, named Joe. We know that there is no reason why waves would lose energy when traveling through the wire. But Joe should observe that the waves are in some way muffled.

How do we solve this problem? Like this: Joe knows he is in a rocket. Joe thinks that the mass of the rocket decreases while the waves are traveling. Joe deduces that if the rocket had the same mass as it had at the time when the waves started the travel, then the waves would make the rocket shake just very slightly.
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11993
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
What is special relativity?
« Reply #30 on: 25/12/2010 14:53:28 »
I don't know what you're talking about now Jartza? :)
Better explain what you saw yourself explaining when you drew them so I can see.

Just want to clarify what I wrote about all frames of reference being equivalent.
rigorously speaking we state it as "All constant velocity frames of reference are equivalent (including frames of reference that appear to be at rest after all, a prolonged state of rest is motion with a constant speed of zero)."

And make accelerated frames a special case where the equivalence isn't as clear. For example a constantly accelerating frame of reference is according to the principle of equivalence primary equivalent with a gravity. And non-constant acceleration is not associated with anything, else than its own unique case, as I know it?

So when I spoke about all frames of reference as being the same it was in the general notion of them all describing a 'SpaceTime' for the observer, no matter what frame he is in. And that's another way to to see it, the Bekenstein bound exemplifies that view if you, like me, associate it with a description of what an observer are able to observe as his upper bound of information, in any frame thought up.

Well, it was Xmas yesterday, right:)
==
Ah western Europe, USA, and Russia too(?), have theirs today, right :)
A happy second Xmas then..
« Last Edit: 25/12/2010 16:50:50 by yor_on »
 

The Naked Scientists Forum

What is special relativity?
« Reply #30 on: 25/12/2010 14:53:28 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums