message 0558

• How do the spaceship drives work? And what about the underlying 'Jump mechanics'?

>From: Jo Jaquinta <jaymin@maths.tcd.ie>
>Subject: CherryhList/ Dragging things into jump
>Date: Tue, 21 Sep 93 8:37:53 BST

Item: Ships can drag small nearby objects with them through jump.

Item: Ships need to jump between massive objects, except:

Item: There is a technique for short jumping

Postulation: The jump effect is sensitive to the curvature of space.

Exposition:
	Can everyone remember those colourful demonstrations of
relativity or black holes? All those green grid lines on black that
dimpled into cusps around massive objects?
	Imagine you have a heavy object sitting in space. It posesses
a gravatational attraction. This is inversely proportional to the
square of the distance you are from it. I.e. the attraction is very
strong near the object but quickly tapers off. If we represent space
as a horizontal line and the gravitational attraction as the slope at
each point we get something like this:

**********************                          *****************************
*****************************            ************************************
*******************************        **************************************
*******************************        **************************************
*********************************    ****************************************
*****************************************************************************

We can then quite intuitively see that another object will be attracted
to the massive object and roll down the slope toward it. I can remember
some BBC show with a sort of distorted billiard table on it with balls
rolling about the place.
	The above represents a one-dimensional space, a two-d space can
be seen on a billiard table but in the full 3-d you can't show the
"gravitaional slope" by vertical displacement. 2-d is enough for 
demonstrating most things.
	Lets say we have a ship as the object in the centre. Nearby
object will each have their own little dimples around the ship. Clearly
since ships can jump small objects near them the jump effect is not
limited to the superstructure of the hull. By my above postulation we
can theorise that it will cover the surroundings to a certain 
gravitiational gradient. On our billiard table we are effectively
filling the dimple with water up to a certain level. Any object nearby
will also be covered with the water. This corelates Item 1.
	Lets look again at our diagram but instead imagine that this time
in the centre of space our object is a star. This creates rather a massive
dimple in the area. We know that ships have to travel some distance
away from the central mass to enter into jump. Our postulation fits by
assuming that the jump drive can only activate in a region with a
gentle slope. That gives a fixed radius around each start that jumps
can be entered.
	Lets further imagine that when a ship enters jump-space it
actually peirces the surface of our model and continues along translated
into an orthoganal dimension "beneath" the "surface". When we approach
another large mass the gravitational gradient bends below the surface
we are traveling at we we "pop" back into normal space. This corelates
with Item 2. We will be at the fringes of the system where the gradient
is similar to where we left.
	If you have your navigation wrong and miss the destination mass
you could travel for some time before you hit another mass. If more rugged
jump drives (e.g. military ones) can jump lower down the gradient they
will come out deeper on the far end. (They might also travel faster
through jump space) Of course if they jump too deep and don't target a
massive enough exit-point they may miss altogether...
	So far we have been only talking about breaching the interface
more or less paralell to the generally assumed flat norm. If we breached
at a slightly lower angle then our "exit gradient" would slowly increase
as we travelled making exit more difficult. If we breached at a slightly
higher angle our "exit gradient" would decrease. It the angle was 
sufficiently high we might reach "zero gradient" and precipitate us back
in flat inter-stellar space. I.e. we've just done a short jump. That
corelates Item 3.

	It this model it looks like species like t'ca and knnn have
mastered the ability to change their vector while "beneath the surface".

			Jo Grant