Questions for Sci-fi novel


Hello there.

I am working on the opening chapter for a novel (sic-fi; going into post apocalyptic)

I am doing a little research in order to make the story as scientifically accurate as possible.

Here are a few scenarios that I am working on.

1. If a manufactured object the size of the moon came into earths orbit, say within 1000km, what effect would it have on the planet? (i.e. oxygen deprivation, tidal effects etc.)

2. How much of Earths oceans could be removed without absolute extinction of life.

3. If Earth were suddenly to lose the said percentage of its oceans, not through evaporation but rather, it were just removed, how would this effect the planet. (i.e. visually, geologically, wether patterns, life)

Your thoughts, theories and references are much appreciated!


Patrick G Cox

Hi Leon,

An object that large coming that close would hit us, probably resulting in mutual destruction. Large objects develop some interesting interactions, and planetary bodies tug and pull one another. I suggest you do a search for information on gravitational interactons between bodies. This can be demonstrated on a small scale when you place two large ships close to one another. If untethered, they will eventually be drawn toward each other. For this reason VLCCs and ULCCs have a very large "avoidance zone" around them when being approached by other ships and is the cause of the famous "accident" involving the Titanic when she pulled several smaller ships off their moorings as she steamed past on her way out of Southampton on her first voyage.

I recall reading that if the moon were half the distance it is from the earth, the tides would be of the order of 100 feet at their mildest. That would certainly make life interesting. The forces acting on the earths crust would quite probably make the planet extremely active geologically if you moved the moon still closer.

It is unlikely anything could survive here if a body that large "grazed" us that closely. The gravitational effects on both would cause massive disruption on both surfaces and probably fatally damage our atmosphere as well.


This is news, Vincenzo, NEWS!
I'm not a physicist or nothin so I can't answer in detail. I know the mass/density has a lot to do with it. if it's hollow/empty (which a tanker would be) it could come pretty close.

it wouldn't take much loss of H2O to cause catastrophe. the real immediate effect would be climate, as rain comes from evaporation, and the watershed produces/affects wind currents.
lowering the water level might affect ocean currents too.

on the other hand, the global warming fearmongers might recommend getting rid of some water so the sea levels won't go up a la 2012. I can easily see new-age loonies welcoming aliens here to 'help' us by removing excess water and being shocked, shocked, when the aliens suck up more than they promised. cue rescue mission to blow up aliens; that close to earth the gravity well would hopefully pull the water back in.
I guess the aliens ships would have to be close as transfer the liquid (very hard to do, water is relatively dense and heavy).
you might get a good effect with a smaller ship that comes in closer.
good luck & keep us posted.


It's your sci-fi world, perhaps 'they' have a system to minimize such issues. A 'Dampening Field', or a 'Gravity Inhibitor'? For me I used an 'RMC' - 'A Relavistic Mass Compensator' to nulify some of these issues. Now when these systems fail... Thats a story all unto itself....
Good Luck and have fun writing :smiley: