Down Rodeo
Cap'n Moth of the Firehouse


2007 Oct 19 • 5404
57,583 ₧

Just like Mate de Vita said

I'm going to make a truck about it. So, SPECIAL RELATIVITY

You guys might not know a lot about this, but the question I am presenting is this: you are standing next to a barn and it is at rest relative to you. In the distance there is a stick. Previously you have measured the length of this stick while at rest relative to it and found it to be longer than the barn.

The stick is now moving towards the barn with constant velocity v which is a significant fraction of the speed of light such that relativistic effects are noticeable. From your perspective you perceive the stick to be contracted along the direction of its travel as predicted. At some point due to the stick's contracted length the barn doors are able to close entirely around the stick. Then both doors reopen and the stick flies out. At no point does the stick's velocity change.

If we now look from the stick's perspective the barn is moving toward us and therefore is contracted along its length. The stick is therefore far longer than the barn meaning at no point can the barn doors be closed around it, so my topic for discussion is: What the hell's going on? How do we resolve this paradox? I'll make a post explaining more of special relativity if you guys want. The wikipedia page might have the answer on it, but I'd like you guys to have a think about it. I give a little into the moment like I'm standing at the edge (I know)
That no-one's gonna turn me 'round
Just one more step, I could let go

Mate de Vita
Kelli

2008 Oct 4 • 2429
159 ₧

The barn is travelling with a negative velocity (if the stick is travelling with a positive one), so it's expanding, not contracting.

No, in all seriousness though, I'm afraid this level of physics is a little out of my league, so I'll just leave it to the people who actually have a clue about Relativity. ...and that's the bottom line because Mate de Vita said so.

Who controls the past, controls the future. Who controls the present, controls the past.

Down Rodeo
Cap'n Moth of the Firehouse


2007 Oct 19 • 5404
57,583 ₧

Well, it's an interesting idea, but when you derive the maths that governs the contraction, you see a term v^2, so the negative doesn't matter. How might you resolve the paradox? We're not doing the maths or anything, we are THINKING ABOUT PHYSICS (that's a phrase that needs capitals). I give a little into the moment like I'm standing at the edge (I know)
That no-one's gonna turn me 'round
Just one more step, I could let go

SRAW
Rocket Man

2007 Nov 6 • 2376
601 ₧

So the stick has eyes?

Down Rodeo
Cap'n Moth of the Firehouse


2007 Oct 19 • 5404
57,583 ₧

No, we are standing next to the stick such that we perceive it to be at rest. I give a little into the moment like I'm standing at the edge (I know)
That no-one's gonna turn me 'round
Just one more step, I could let go

Down Rodeo
Cap'n Moth of the Firehouse


2007 Oct 19 • 5404
57,583 ₧

Ok, it's been about 24 hours. Basically, the stick's viewpoint is that the shed doors open and close at different times. Each viewpoint is equally acceptable, there is no preferred rest frame. Isn't that weird and exciting?! I give a little into the moment like I'm standing at the edge (I know)
That no-one's gonna turn me 'round
Just one more step, I could let go

SolidKAYOS
Count Adelaide


2007 Jun 24 • 73
68 ₧

My head hurts... Make awkward sexual advances, not war.

NatureJay
SJA: Commander of Ruthless Abuse


2005 Mar 22 • 1532
574 ₧

Boy, wait until we start talking about clocks running faster at higher altitudes 100% natural, no antibiotics, and bloodgrass-fed

Rockbomb
Dog fucker (but in a good way now)

2009 Nov 13 • 2026

Wait, so you mean to tell me that a clock that if time were literally flying, that'd cause it to metaphorically fly?
Does this have something to do with thing at higher elevation moving faster than things closer to the core?


And DR, I think I'm just a little too tired to try comprehending your post, maybe I'll retry tomorrow

SuperJer
Websiteman

2005 Mar 20 • 3883

I think the key to the problem is that there is no such thing as "two events occurring at the same time" when they are separated by space. At least in absolute terms.

Keep in mind also for this barn example to work, the whole thing has to happen in the tiniest fraction of a second. Any information at all travelling from one barn door to the other is going to take almost as long as it takes the stick to go through.

To put it another way, by the time the light from the one momentarily-closed door gets to the other, it's already open.

Or something like that.

Down Rodeo
Cap'n Moth of the Firehouse


2007 Oct 19 • 5404
57,583 ₧

Yes! Well, kind of. Observers moving relative to one another will in general disagree about the simultaneity of events. At speeds where relativity kicks in of course.

RB, NatureJay is talking about General Relativity. Basically, masses warp both space *and* time with the result that clocks in a stronger gravitational field (or accelerating strongly) appear to tick more slowly. Sounds a bit esoteric but this result is necessary to make GPS work!

Finally this is all thought-experiment, so we're assuming that the doors work properly for our purposes and that. I'm a physicist, not a masochist.

In fact, you could kind of do it in an actual experiment by knowing the velocity of the stick in advance, then synchronising clocks at each door. You then know where the stick will be and when it will be there and can set the doors to open and close at the correct times. That way the stick will definitely "see" the doors opening and closing at different times. I give a little into the moment like I'm standing at the edge (I know)
That no-one's gonna turn me 'round
Just one more step, I could let go

SRAW
Rocket Man

2007 Nov 6 • 2376
601 ₧

This stuff isn't even proven yet, that's why we call them theories, so no point to debate on something that isn't true

SRAW
Rocket Man

2007 Nov 6 • 2376
601 ₧

This stuff isn't even proven yet, that's why we call them theories, so no point to debate on something that isn't true

SRAW
Rocket Man

2007 Nov 6 • 2376
601 ₧

Wow I doubled post... chrome fail

Mate de Vita
Kelli

2008 Oct 4 • 2429
159 ₧

Who says it isn't true? ...and that's the bottom line because Mate de Vita said so.

Who controls the past, controls the future. Who controls the present, controls the past.

sprinkles


2009 Sep 6 • 2545
10 ₧

No, but assuming you intended us to endure your big walls o' text could make you a sadist.

Down Rodeo
Cap'n Moth of the Firehouse


2007 Oct 19 • 5404
57,583 ₧

@Sprinkles: Suppose.

Ok SRAW, if you want to be like that, we could admit that there are no "theories" as such, since the definition of a Mathematical theory involves some sort of irrefutable proof based on some set of axioms. However, we can only produce hypotheses that agree with experiment, that make predictions about our world. Either the theory predicts correctly and survives another day or it is wrong and needs to be modified. So far, Special Relativity has survived about 100 years, which isn't too bad. I give a little into the moment like I'm standing at the edge (I know)
That no-one's gonna turn me 'round
Just one more step, I could let go

buq25

2008 Jul 5 • 511
95 ₧

NEAW INTRESTN DISISSUNS!

HOW IS THIS POSSIBLE?!!!


Edit: I presume that I should tell you that I knuw teh answur. Roses are red,
Violets are blue.
Shouldn't violets be violet,
and roses be rose?

Down Rodeo
Cap'n Moth of the Firehouse


2007 Oct 19 • 5404
57,583 ₧

Because the hypotenuses of both triangles are not single straight lines. Instead they deviate by a small amount; this actually equates to one square, allowing the block to be paradoxically rearranged. I give a little into the moment like I'm standing at the edge (I know)
That no-one's gonna turn me 'round
Just one more step, I could let go

phoenix_r

2009 May 13 • 810
17 ₧

Down Rodeo
Cap'n Moth of the Firehouse


2007 Oct 19 • 5404
57,583 ₧

Really? I give a little into the moment like I'm standing at the edge (I know)
That no-one's gonna turn me 'round
Just one more step, I could let go

NatureJay
SJA: Commander of Ruthless Abuse


2005 Mar 22 • 1532
574 ₧

100% natural, no antibiotics, and bloodgrass-fed

aaronjer
*****'n Admin


2005 Mar 21 • 3945
1,227 ₧

I prefer hypotenoi.

Mate de Vita
Kelli

2008 Oct 4 • 2429
159 ₧

I myself am more a fan of hypothesis. ...and that's the bottom line because Mate de Vita said so.

Who controls the past, controls the future. Who controls the present, controls the past.

adhesive



2007 Sep 13 • 79
1,301 ₧

Is the stick an inertial reference frame? I don't think it is therefore it shouldn't experience time dilation. But then again this is at the back of my physics textbook and we are only covering capacitance at the moment; there's a good chance I'm misusing or do not understand the terms.