Recent content by Slinkey

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    How to calculate apparent size of an object based on distance

    No, it will be like using it on the same monitor. The monitor has not changed size.
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    Dark Matter Clumping: Unanswered Questions

    Maybe I'm missing something here (which is quite possible I might add) but we have inferred the existence of dark matter due to the velocities of stars at the edges of galaxies being too fast. We see this in contrast to the velocities we see in the solar system, for example, where the velocity...
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    Stuck on Algebra in Time Dilation Problem.

    If you want me to run through the procedure that I used to get the new equation in v then I'd be happy to run through it for you.
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    Can you measure the proper length of a rope when dangling it into a black hole?

    I accept that. This is what I was trying to get round with my scenario in that we know the length of the rope (made of unobtainium, I guess) prior to lowering it down towards the EH of a BH with a known mass. So, I could modify my thought experiment by, for example, attaching a mirror to the...
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    Stuck on Algebra in Time Dilation Problem.

    This is the basic equation that you have written out. \frac{d}{v} = \frac{t}{\sqrt{1- \frac{v^2}{c^2}}} Solving for v gives: v = \frac{cd}{\sqrt{d^2+c^2t^2}} where c = speed of light constant d = distance in metres t = time (on spaceship) in seconds v = velocity in m/s At least by my reckoning!
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    Can you measure the proper length of a rope when dangling it into a black hole?

    Well, my head exploded trying to understand that! :bugeye: That's beyond my abilities at present to wrap my head around, but thanks for the reference. Going back to my OP and the scenario I depicted, does that mean the rope will not reach the the EH, because the rope experiences a contraction...
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    Can you measure the proper length of a rope when dangling it into a black hole?

    Is there a direction to this length contraction like in SR?
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    Can you measure the proper length of a rope when dangling it into a black hole?

    I know of the precession of the perihelion of Mercury but I'm not au fait with precisely why that happens. Is it because the distance that it travels has been reduced and thus it takes a tighter orbit than it would if there was no relativistic effect?
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    How Does Time Dilation Affect Subjective Travel Times in Space?

    I found this one rather useful. http://johanw.home.xs4all.nl/PhysFAQ/Relativity/SR/rocket.html Although not a calculator it gives you the math to work it out.
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    Can you measure the proper length of a rope when dangling it into a black hole?

    Yoron, thanks for your input. So does this apply to rules as well in that if I pass a 12 inch rule to my friend in the stronger gravitational field then from my perspective the rule will be shorter in the direction of the gravitational source (assuming enough difference in potential to be able...
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    Can you measure the proper length of a rope when dangling it into a black hole?

    Hmm, I'm surprised at that, but if there isn't then there isn't. Thanks guys.
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    Can you measure the proper length of a rope when dangling it into a black hole?

    I'll try to be as specific as possible with my question. From my reading of SR I understand that an object that is moving relative to me will be contracted in the direction of its motion. I have no issue with that and I accept it as a fact. Would I be right in thinking that there is also length...
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    How does gravitational acceleration change near an event horizon?

    Correct. I will be doing differential and integral calculus later on my current course so will be taking my first steps into understanding it, but I'm thinking that when we are talking about the curved space around a black hole the path you take is very important? As opposed to say calculating a...
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    How does gravitational acceleration change near an event horizon?

    Cough... correction. 10 solar mass black hole has 1.521*10^12 m/s^2 and 20 solar mass has 7.607*10^11 m/s^2 at their respective event horizons.
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    Simultaneity is directional while time dilation is not?

    I was thinking about this earlier this evening and I think we, that is gh and me, have actually been arguing past each other here. I think where we diverged was on the definition of synchronisation. I was taking it in the common everyday sense where clocks are visually seen as showing the same...
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