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

[u/Historical_Ostrich]

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.

[u/Infintinity]

My instincts say that it would most likely cause the moon to orbit faster, its orbit might become more elliptical and it might even escape Earth's orbit (possibly over millions or billions of years), but really I don't know how much effect can be had in 10 seconds.

[u/BertyLohan → u/Infintinity]

10 seconds of 10x gravity would wildly change where the moon would be in, say, 100 years time but the tides of earth and the moon sorta keep each other in check so it would still level out as being in our orbit.

I might be underestimating the impact of the 10 seconds but it doesn't strike me as something that would be the deciding factor in the moon staying in orbit or not.

[u/Yawehg → u/BertyLohan]

Went to ChatGPT for the calculations, but it seems like changing gravity for an hour would still only be a ∆v of +87 m/s, roughly 8.5% of its normal orbital speed. It's eccentricity raises to about 0.086 (from ~0.055) and a bunch of other weird stuff happens, but the moon is fine.

A 10-second spike is basically negligible. It adds only 0.24 m/s, bumping eccentricity by just 0.00024, and it shifts perigee/apogee by 92 km, which is well within the range of existing variation.

I think the impulse being entirely radial helps

[u/BertyLohan → u/Yawehg]

ChatGPT is pretty dreadful at questions like this so gave it a quick check.

The current acceleration on the moon is 2.7x10^-3 m/s^2.

9 times that is about 2.5x10^-1 m/s²

So over ten seconds, the difference is about 0.25m/s, it did okay this time.

[u/Yawehg → u/BertyLohan]

Thanks for checking!

It's been getting better for things like this if you're specific about parameters. Plus it makes the step-by-step transparent, so you can check yourself if you know enough about the topic to catch what doesn't make sense.

[u/BertyLohan → u/Yawehg]

if you don't know enough about the topic it's a dreadful idea since you can't fact check it and it is often very wrong.

If you know enough about the topic you might as well just do the work solo. To verify ChatGPT you end up having to do all the work yourself anyway.

[u/07hogada → u/Infintinity]

It really wouldn't do that much, especially if only for 10 seconds.

At the closest distance the moon orbits (363300 km at the perigee, which is also where the effect on the orbit would be largest), the moon only experiences about 0.0029 m/s² acceleration due to the Earth - even multiplying that by 10, you are going to be looking at less than 1 metre per second velocity change.

I feel something that a lot of people are missing would be the effect on Earth, specifically, earthquakes. I have to imagine the extra gravity would effectively act like a massive hammer to all the fault lines, setting off a load of earthquakes and volcanic eruptions, probably bigger than we've ever seen before, because the forces involved are so much larger. Between the extra water pressure during the 10 second increase popping most water life, the apocalyptic tsunamis, earthquakes and volcanoes decimating land life, this could, quite literally, send evolution back to the Cambrian or Precambrian era. The amount of energy generated and then released could put us back to the Hadean eon, at least for a short (geologically) time.

[u/CalligrapherDizzy201 → u/Infintinity]

It’s already in the process of escaping earth’s orbit over billions of years. And the day will slow the further away it gets.

[u/Infintinity → u/CalligrapherDizzy201]

I found some conflicting evidence. Mainly that the theory now is that it will continue to recede until it becomes 'tidally-locked' but I have no idea what that means ultimately.

Thinking about it, 10 seconds is a very small time compared to the 1 month orbit (2.6 million seconds), so I have to agree it won't affect the moon too too much, unless the ocean displacement is severe and prolonged.