(urth) Travelling North aka miscellaneous thoughts on Wolfe

[Jack Smith]

On Thu, Jun 10, 2010 at 8:50 AM, Gerry Quinn <gerryq at indigo.ie> wrote:

>
> From: "Jeff Wilson" <jwilson at io.com>
>
>  On 6/9/2010 10:38 AM, Gerry Quinn wrote:
>>
>
>  Secondly, the 'tacking' method of travelling faster than the wind works
>>> for sailboats. But the analogy between wind and light radiation doesn't
>>> hold up because light does not exert pressure in directions orthogonal
>>> to its direction of travel, as moving air does.
>>>
>>
>> That's not entirely correct; if the light is reflected at an angle, it
>> imparts momentum at an angle normal to the reflecting surface. For example
>> if light traveling due north strikes a mirror facing SW and is reflected to
>> the west, the mirror is pushed NE. This sort of thing really happens, and
>> produces a measureable effect on natural and artificial satellites
>> _over_a_period_of_years_.
>>
>
> Yes, but this is different from the 'airfoil' mechanism that can propel a
> boat faster than the wind, and which is not available in the case of light.
> That said, I think I was wrong to place so much store in this, as light also
> has comensating advantages - unlike air, it will not necessarily resist
> objects that are already in motion relative to it
>
> There still is the issue of accelerating *past* the speed of light,
> however, which applies to all similar FTL mechanisms.
>
> - Gerry Quinn
> .
>
>
> It is also not clear that moving faster than the speed of light would allow
> you to go backward in time.   If the mathematics of the relativity equations
> correctly describes reality, then a velocity greater than the speed of light
> puts you not into negative time but into imaginary time.
>

Maybe SF should just rely on old-fashioned hyperspace.

>
>
>
>
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-- 
Best wishes,
Jack
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