Re: opposite of relativistic time contraction

In article <47de9cb8$0$17346$4c368faf@[EMAIL PROTECTED]
>,
Ben Crowell  <crowell07@[EMAIL PROTECTED]
> wrote:
>Tim Little wrote:
>> On 2008-03-16, Ben Crowell <crowell07@[EMAIL PROTECTED]
>
wrote:
>>> Mmm...I would consider diffraction to be a fundamental physical
>>> limitation, not a minor engineering problem. If the laser is
>>> at rest with respect to the galaxy, then it has to operate over
>>> distances of light-years.
>> 
>> You want to accelerate a 10^17 kg black hole at 100g over distances of
>> at least a couple of light-years?  Ouch.  The project then needs at
>> least 10^37 J of energy available.
>
>Yeah, it's a crazy amount of energy. To get it up to a gamma of 10^4,
>you need energy equivalent to 10^4 years worth of a sun's light
>output. If you only want a gamma of 10, then it's only (!) 10 years :-)
>But if you want to physically travel around a galactic civilization
>within a human lifetime, you need a gamma of more like 10^4. This
>is sort of a generic problem with any scheme for physical travel
>around a galactic civilization.
>
	At some point, it has to be simplier to send the traveller as 
a signal. I understand that this will no be acceptable to eveyone but
the ones for whom it is not can stay at home.
-- 
http://www.livejournal.com/users/james_nicoll
http://www.cafepress.com/jdnicoll
(For all your "The problem with
defending the English language [...]" T-****rt, cup and tote-bag needs)