Yesterday I introduced R B Harkess and his new book to this blog and as you will have gathered I commented on some sections of its earlier manuscript. There was a scene where he really played around artificial gravity in a serious way, but instinct told me that it was somehow inconsistent. yes, I did say INSTINCT and yes there is such a thing as engineering instinct.
End result was I asked the Harkess person to let me think about the whole scene and how the artifical gravity could be made to work…
One good general rule of engineering is keep things simple. Amongst other things it makes the devices easy to build and easy to repair. It has other advantages for science fiction writers… it makes things easy to explain and as Harkess says, helps with the flow of writing.
The main problem with gravity is that it radiates outwards in all directions. This can lead to an overspill in that force where the author does not want it. So we need a material that can block gravity going in certain directions. We also of course need a gravity generation mechanism. And this is really all that is needed in terms of invention… the rest can be engineered… seriously.
I’m going to take the rest of this by simple steps so as to make it easy to understand and apologise immediately for what might appear to be baby-speak.
If you have a gravity generating substance, lets call it gragen (for want of inventing a name) sitting at the bottom of a long test tube made of the gravity blocking material (lets call this substance gravbloc), where would you experience gravity outside the test tube from the gragen? The answer is only when you have line of sight to the gragen i.e. directly over the test tube mouth and a smidgen off the main line of the test tube. The gravbloc has to be a gravity absorber (as opposed to gravity reflector) as otherwise you will get gravity reflected at various angles off the gravbloc near the top of the test tube, which in turn will cause spillage in many directions.
Now what happens when you put a set of test tubes next to each other with their open ends all pointing in the same direction? You get an area above the test tubes that experience gravity and a quickly diminishing field at the edges.
Let’s now miniaturise the test tubes into a layer of carpet say… You have the gravity immediately above you and not to the sides, except for a small overspill. Even that overspill can be reduced by adding small ‘winglets’ of gravbloc rising up out of the sides of the path.
The difficulties with this is that gravity goes on into distance above the carpet. However, if this carpet is inside a building all that is needed is to have this gravity absorbing material in the ceiling facing the carpet. If it is in open air, then by the time the gravity reaches other structures, it will be very much weaker and therefore barely noticeable. Remember gravity is proportional to one over the distance squared.
As for where the energy of absorbing gravity goes to – well given that the crack is open to the atmosphere, you might like the underfloor heating from the path!
Simples as the meerkats would say… (for those not familiar we have a series of adverts in the UK using cute meerkat puppets).
Rosie Oliver 