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Science Fiction > Science > Re: opposite of...
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Re: opposite of relativistic time contraction

by Erik Max Francis <max@[EMAIL PROTECTED] > Mar 16, 2008 at 08:55 PM

Tim Little wrote:

> On 2008-03-16, Erik Max Francis <max@[EMAIL PROTECTED]
> wrote:
>> This doesn't sound right to me.  Remember that geodesic
>> gravitational time dilations are actually very minor effects; the
>> maximal time dilation effect you can get from orbiting close to a
>> black hole is only about a factor of two.
> 
> It can be arbitrarily great, depending upon how close your orbit is to
> the photon sphere.

Not according to every source I could find.  Gravitational time dilation 
for an object in a circular orbit in a Schwarzschild geometry is

	tau'/tau = (1 - R/r)^(1/2),

where tau' is the proper time experienced by the orbiting clock, tau is 
the proper time experienced by a far away clock, r is the Schwarzschild 
coordinate, and R is the Schwarzschild radius.  Orbits by massive 
particles are unstable within the photon sphere (r = (3/2) R), so the 
maximum time dilation that's possible is a ratio of about 58%.

If you hover at constant radial r, rather than stay in orbit, and then 
get arbitrarily close the _event horizon_ -- not the photon sphere -- 
then you can achieve arbitrarily high time dilations.  But this requires 
  arbitrarily high thrusts.

-- 
Erik Max Francis && max@[EMAIL PROTECTED]
 && http://www.alcyone.com/max/
  San Jose, CA, USA && 37 18 N 121 57 W && AIM, Y!M erikmaxfrancis
   If you are afraid of loneliness, do not marry.
    -- Anton Chekhov
 




 45 Posts in Topic:
opposite of relativistic time contraction
Ben Crowell <crowell07  2008-03-14 14:54:25 
Re: opposite of relativistic time contraction
Tim Little <tim@[EMAIL  2008-03-15 00:25:40 
Re: opposite of relativistic time contraction
Ben Crowell <crowell07  2008-03-14 20:48:10 
Re: opposite of relativistic time contraction
Ben Crowell <crowell07  2008-03-15 12:07:17 
Re: opposite of relativistic time contraction
Tim Little <tim@[EMAIL  2008-03-16 00:57:10 
Re: opposite of relativistic time contraction
Ben Crowell <crowell07  2008-03-15 18:56:43 
Re: opposite of relativistic time contraction
Tim Little <tim@[EMAIL  2008-03-16 02:40:14 
Re: opposite of relativistic time contraction
Ben Crowell <crowell07  2008-03-16 09:35:05 
Re: opposite of relativistic time contraction
Tim Little <tim@[EMAIL  2008-03-17 01:34:10 
Re: opposite of relativistic time contraction
Ben Crowell <crowell07  2008-03-17 09:30:48 
Re: opposite of relativistic time contraction
Ben Crowell <crowell07  2008-03-17 10:30:04 
Re: opposite of relativistic time contraction
jdnicoll@[EMAIL PROTECTED  2008-03-17 17:58:15 
Re: opposite of relativistic time contraction
Tim Little <tim@[EMAIL  2008-03-18 00:18:18 
Re: opposite of relativistic time contraction
IsaacKuo <mechdan@[EMA  2008-03-17 10:00:23 
Re: opposite of relativistic time contraction
IsaacKuo <mechdan@[EMA  2008-03-17 12:25:42 
Re: opposite of relativistic time contraction
IsaacKuo <mechdan@[EMA  2008-03-17 13:49:53 
Re: opposite of relativistic time contraction
throopw@[EMAIL PROTECTED]  2008-03-15 04:26:21 
Re: opposite of relativistic time contraction
Ben Crowell <crowell07  2008-03-15 11:09:06 
Re: opposite of relativistic time contraction
Bryan Derksen <bryan.d  2008-03-15 09:42:17 
Re: opposite of relativistic time contraction
Tim Little <tim@[EMAIL  2008-03-15 13:27:54 
Re: opposite of relativistic time contraction
Bryan Derksen <bryan.d  2008-03-16 09:52:22 
Re: opposite of relativistic time contraction
Ben Crowell <crowell07  2008-03-15 11:15:29 
Re: opposite of relativistic time contraction
Erik Max Francis <max@  2008-03-16 14:25:59 
Re: opposite of relativistic time contraction
Tim Little <tim@[EMAIL  2008-03-17 01:37:46 
Re: opposite of relativistic time contraction
Erik Max Francis <max@  2008-03-16 20:55:10 
Re: opposite of relativistic time contraction
Tim Little <tim@[EMAIL  2008-03-17 08:20:44 
Re: opposite of relativistic time contraction
Greg Egan <gregegan@[E  2008-03-16 21:37:25 
Re: opposite of relativistic time contraction
Tim Little <tim@[EMAIL  2008-03-17 08:31:11 
Re: opposite of relativistic time contraction
Ben Crowell <crowell07  2008-03-17 10:10:48 
Re: opposite of relativistic time contraction
Greg Egan <gregegan@[E  2008-03-17 18:43:59 
Re: opposite of relativistic time contraction
throopw@[EMAIL PROTECTED]  2008-03-16 01:39:13 
Re: opposite of relativistic time contraction
throopw@[EMAIL PROTECTED]  2008-03-16 02:05:31 
Re: opposite of relativistic time contraction
David Mitchell <david@  2008-03-16 18:26:19 
Re: opposite of relativistic time contraction
IsaacKuo <mechdan@[EMA  2008-03-17 08:38:08 
Re: opposite of relativistic time contraction
Ben Crowell <crowell07  2008-03-17 12:09:20 
Re: opposite of relativistic time contraction
Erik Max Francis <max@  2008-03-20 23:44:07 
Re: opposite of relativistic time contraction
IsaacKuo <mechdan@[EMA  2008-03-17 12:35:02 
Re: opposite of relativistic time contraction
Bryan Derksen <bryan.d  2008-03-18 00:16:53 
Re: opposite of relativistic time contraction
throopw@[EMAIL PROTECTED]  2008-03-17 18:35:43 
Re: opposite of relativistic time contraction
Ben Crowell <crowell07  2008-03-17 12:50:17 
Re: opposite of relativistic time contraction
Bryan Derksen <bryan.d  2008-03-18 00:09:11 
Re: opposite of relativistic time contraction
throopw@[EMAIL PROTECTED]  2008-03-17 18:50:19 
Re: opposite of relativistic time contraction
throopw@[EMAIL PROTECTED]  2008-03-17 19:35:46 
Re: opposite of relativistic time contraction
throopw@[EMAIL PROTECTED]  2008-03-17 19:40:13 
Re: opposite of relativistic time contraction
Howard Brazee <howard@  2008-03-17 17:00:37 

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tan13V112 Sun Jul 6 16:06:06 CDT 2008.