At the climax of my story, most of the people on the planet have the way they interact with gravity magically altered. Until a week passes or they die (whichever comes first), instead of being pulled towards the planet, they get pushed perpendicular to it, falling west instead of down, while everything else on the planet is affected by gravity like normal.

I'm trying to find out what exactly would happen to anyone unfortunate enough to fall from a high height into this bizarre horizontal abyss, as I'm thinking that's going to happen a lot in this story, and I'm going to have to discuss the morbid fate of these people and their corpses, which I suspect might be a frequent sight for the survivors, a least in the cities.

One thing that immediately stuck out to me from what I remember of physics is that, with no force pulling them back to Earth, but the centrifugal force of constantly being pushed perpendicular to it pushing them away, eventually, if they lived long enough, they would start "falling" into a higher and higher "orbit" around the planet until they were out in space. However, the issue is that they stop falling sideways when they die, and I'm not entirely sure when that would be. I've heard conflicting accounts as to when, or even if, the act of being in free-fall alone would be lethal.

Suppose, in this situation, that someone fell sideways out of an open/broken window on the 80th floor of the Empire State Building. At what point would they die, what would kill them, and what would then happen to the body?

  • $\begingroup$ West is concept which is valid only locally. In space there is no West. $\endgroup$
    – L.Dutch
    Jul 1, 2019 at 19:43
  • $\begingroup$ @L.Dutch Yes, but as long as you're in the Earth's gravitational pull, there is always exactly one "west" relative to where you are, isn't there? $\endgroup$ Jul 1, 2019 at 19:46
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    $\begingroup$ Earth's gravity doesn't define "west" though - it's rotation does. I suppose there will be a very (very!) faint frame dragging due to the interaction of rotation and gravity that could locally define west. Then again magic, so magic :) $\endgroup$
    – Gene
    Jul 2, 2019 at 16:31

2 Answers 2


they get pushed perpendicular to it, falling west instead of down

If I get this to the letter, it implies that they get to move in a pseudo circular orbit following a given parallel, because as soon as they wouldn't do it, they would be moving "west and up".

Since you mention that they would keep accelerating, I deduce that they will, rather soon, reach limit velocity in air, about 200 km/h. After that they would probably impact some hill on their westward motion, probably in Pennsylvania, but surely they won't reach the West Coast.

Regardless of the location, hitting an obstacle at 200 km/h with no protection other that their clothes it means they are going to die pretty soon. Then their smashed bodies will drop to ground following the good old gravity.

  • $\begingroup$ You are correct. It becomes an orbit, as the direction they fall in constantly changes relative to where on earth they are, much like how gravity works normally. That's interesting. I didn't realize there were so many hills in Pennsylvania that were that tall. $\endgroup$ Jul 1, 2019 at 19:53
  • $\begingroup$ A circular orbit involves acceleration towards the center (specifically, the acceleration vector is along the inverse of the position vector). Acceleration perpendicular to the position vector will result in an escape trajectory (though, as suggested in the answer, terrain features will likely prevent actual escape). $\endgroup$
    – manveti
    Jul 1, 2019 at 21:31
  • $\begingroup$ @CraigMeier Ah yes, sorry, I may have misunderstood Dutch's interpretation. Gravity continuously pulls them west, but it doesn't cancel the centrifugal momentum they previously had, so yes, like you said, they would be in an escape trajectory. That is what I meant. $\endgroup$ Jul 2, 2019 at 2:35
  • $\begingroup$ Follow-up question: what would happen if they were too high up to crash into mountains? When would they die in the process of orbit-falling? $\endgroup$ Jul 2, 2019 at 23:41
  • $\begingroup$ @JasonClyde, if that's a follow up question, ask it as such $\endgroup$
    – L.Dutch
    Jul 3, 2019 at 4:19

Your questions may be better aimed as geography related.

My take on this:

Everyone not inside AND only a few meters eastward from some sturdy wall or with good reflexes with something to grab, will die. Total decimation of the population.

  1. Inside cities they die by hitting other high rise buildings or simply by falling tens of meters inside their spacious apartments.
  2. If they survive the city by fast thinking and good sky-diving skills, they die by meeting a mountain. 2 weeks are 336 hours. 200 km/h traveling speed. 67200 km traveled. The Earth's circumference 40075 km. Unless they are so much above sea level when they start out, that they above ALL mountains in their westward fall, they will die.

Death by OTHER ways than hitting mountains in high velocity:

Good thinking people (or those who read this question and answer) with good sky-diving skills, may figure out their impending doom by mountain and navigate in a way to rise in altitude. This will most likely result only a different, more painful death.

  1. Unless properly clothed, the constant wind and high altitude will quickly freeze them to death. It is cold up there. To avoid mountains you will have to be pretty high.
  2. Any injury suffered at the start of the fall will only get worse. No medical help coming, so broken bones, bleeding, etc. will lead to death if hypothermia doesn't kill the poor soul first.
  3. Hunger and Thirst. Unless wearing a backpack full of supplies, without stable footing, you can't even try to loot nearby shops. Rain and clouds MAY elevate thirst, but catching birds why you fall... well... Good luck, have fun!

Slim options for survival, I can think of:

(So you can have brave heroes who endured the most horrible your apocalypse can throw at them)

  1. Have the above mentioned skills, warm clothing, backpack with water and food which they can ration out and suffers no injury at the start of the event
  2. Number 1, without backpack. Slim chance but they can near ground above large bodies of water and use the water to slow down. It will most likely cost them an arm, but once "safely" in water, they can just "sink" westward "climb" on the ground westward until they find a strong wall or something to rest. Humans are capable of amazing things for survival. This one or maybe two would be the real heroes of the event.
  3. Already has a parachute on their back. It can leverage the parachute to break his fall in a region where they can try a somewhat safe landing.
  4. Flying airplanes MAY be safe. If the pilots can quickly adapt without falling out of their chairs, figure out only humans are affected and compensate for the screwed up pull the mass of humans add to the plane and can land safely without the help of ground control.

Some closing thoughts: Any babies, children or old people without immediate and constant attention and care are dead. Very very few people will survive. People with wall and mountain climbing experience (and gear near them) will be heroes inside cities. They will be able to "safely" move around and transport supplies. No stairs or lift westward. You will have to climb and climb on artificial surfaces without foothold. Ropes or rope like things will be used. Good physical condition will be key to survival, otherwise you are imprisoned and may not even reach your own fridge or sink to drink.

  • $\begingroup$ I appreciate the big picture advice. Though due to a bunch of stuff that I left out due to it not being relevant to the specific question, it's not quite that devastating. Still, I appreciate the information. $\endgroup$ Jul 1, 2019 at 20:47
  • $\begingroup$ @JasonClyde No problem, halfway through answering I had started having lots of fun imagining the various ways people will die and struggle to survive and how your event would unfold. My answer should help with how and if free-fall is fatal. Also, when you finish your story, please give me a link or some way to read it! :) $\endgroup$
    – Lupus
    Jul 1, 2019 at 20:49
  • $\begingroup$ I'll see what I can do :) $\endgroup$ Jul 1, 2019 at 20:56
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    $\begingroup$ @Lupus The idea of someone trying to kill themself, by jumping off a bridge (on the east side) just prior to it happening, to then land face first on the side of the bridge and not die anyway is a bit funny to think about :) $\endgroup$ Jul 2, 2019 at 9:08
  • $\begingroup$ @MichaelMortensen, that's hilarious $\endgroup$
    – user62562
    Jul 2, 2019 at 15:53

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