(urth) Travelling North aka miscellaneous thoughts on Wolfe

[Jeff Wilson]

On 6/10/2010 7:50 AM, Gerry Quinn 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

That's true, but it is still tacking in the sense of rigging the sails 
at similar angles to get transverse propulsion - and since the speakers 
are originally  educated as wet sailors rather than physicists, 
"tacking" is the most accurate word they have for it. And The Ship does 
end up going faster than light, just like a surface vessel tacking 
against the wind can make better than windspeed, so again "tacking" is 
the metaphorically most correct word a simple sailor can use.

> There still is the issue of accelerating *past* the speed of light,
> however, which applies to all similar FTL mechanisms.

The Ship going FTL can be attributed to it traveling into that unseen 
direction that Juturna points into and the direction F B & O's saucer 
takes when it leaves Baldanders' castle, the conceit being that 
relativity doesn't cover that fifth dimension with the same constraints 
as our familiar four.

There is a mathematical comcept analagous to this called surreal 
numbers, invented about 1976 and covered in some popular science 
literature, and the notation employed used a metaphor similar to Zeno's 
paradox, of traveling an infinite distance in one direction, then one 
step more, and mapping this additional distance to the side, and 
repeating that ad infinitum, producing not just a new dimension but all 
kinds of mathematical structures with suggestive names like transfinite 
ordered fields that could easily be an influence on the imagery of Yesod.

-- 
Jeff Wilson - jwilson at io.com
IEEE Student Chapter Blog at
< http://ieeetamut.org >