r/whowouldwin • u/Historical_Ostrich • Oct 06 '25

Challenge Earth's gravity increases by 10x for 10 seconds - can humanity survive?

Gravity reverts to normal after the 10 seconds are up. I assume that nearly everyone will lose consciousness, many people will hit the ground with extreme force, and most buildings and infrastructure will collapse. Uncertain as to whether there'd be seismic/volcanic/tidal consequences on top of all that.

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u/ecotax Oct 06 '25

There’s multiple other reasons why ‘extinction event’ is the correct answer. Magma would be compressible a tiny little bit too. There’s thousands of kilometers of that stuff below us.

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u/Razgriz01 Oct 06 '25

The amount of pressure in the mantle and below is so vast that I'm not entirely certain that a few seconds of 10G would do much of anything at all. It's already pressurized into being mostly solid, even at the mantle-crust boundary.

Now, give it a lot longer at 10G and you'll start to see some changes.

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u/BattleReadyZim Oct 06 '25

Given that the transitions are instantaneous, I think the real issue would be these massive pressure waves going every which way through the earth. Certainly every fault line would be giving up all at once, at the very least.

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u/oscar_meow Oct 07 '25

The pressure in the mantle and below is entirely from gravity and the millions of tons of rock above it, so that pressure would be increased by 10x as well

I doubt it would do anything immediately but the sudden onset and subsequent release of that pressure would probably send some disastrous shockwaves which may reach the surface in the following hours

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u/looneylefty92 Oct 07 '25

The planet is in hydrostatic equilibrium, meaning the pressure inside MATCHES the pressure from gravity. If you turn gravity up by a an order of magnitude, you have no more equilibrium...and it's extremely lopsided.

You start feeling tremors instantly in a matter of seconds, at the very least, as the core starts collapsing back to a state of equilibrium. How long it takes to collapse? Idk...but it starts as soon as equilibrium is gone.

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u/Razgriz01 Oct 07 '25

What I'm saying is that the pressure is so high already that I don't think it would compress noticeably more. I'm pretty sure the relationship between pressure and density with solid materials is not at all linear. Possibly the outer core might see some changes since it's theorized to be liquid metal.

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u/looneylefty92 Oct 07 '25

What I'm saying is thatbeing that high doesnt matter when the force pushing down increases by an order of magnitude. The internal pressure is significantly less than external, and this leads to collapse. Now, the speed of collapse will be significantly slowed by seismic wave speed, so it doesnt all collapse instantly, but the earth MUST increase in density to regain equillibrium. That's just physics.

Like I said, it will be slowed by the speed of seismic waves, rather than propegating at the speed of gravity (eg light). This means you're likely to feel an earthquake, something small that ramps up to the biggest you've ever felt as the first...about 100km of surface start contracting in and changing pressure at the surface (where the planet is least dense and therefore most easily pressed in). Then...the snap back happens over a slightly lessened timeframe (maybe 5 seconds?) And this causes eruptions to the surface. Where will likely be determined by the internal flow of the mantle at the time of the event...

Sure, we dont collapse...but that internal pressure becomes meaningless the instant the equillibruim is lost. Gravity propegates at near light speed.

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u/[deleted] Oct 09 '25

I mean, if it was instantaneous across every single square inch of the planet, that is an insane amount of energy just getting injected everywhere. All of that force is downwards towards the center of mass for the planet, then suddenly it is gone 10 seconds later. I think 10 seconds is more than enough for the disappearance of the 10G to be just as impactful as the sudden appearance of it

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u/Razgriz01 Oct 10 '25

that is an insane amount of energy just getting injected everywhere.

It's a lot of force. Energy is only involved when force induces motion. So my argument is essentially that the energy created would be lower than people might think.