If Earth's gravity instantly increased by 50 percent?

Question

Would humans be able to cope? What would the effects of the gravity have on our infrastructure, and would animal life be able cope with the increase of gravity?

Hello, Stephanie. I think this question is a little broad, as there are may aspects which would have to be explored. For example, impact on infrastructure and thus civilization, impact on biology and thus society, etc. Maybe you should try asking separate questions, although the short answer is that *we would all probably die*. — AndreiROM, Apr 06 '16 at 16:10
Possible duplicate of If Earth's gravity suddenly became stronger, how would we cope? — Schwern, Apr 06 '16 at 17:17

score 1 · Answer 1 · edited Apr 06 '16 at 16:32

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Infrastructure would not cope. Structures are engineered to be as strong as needed, so would not in general handle it long term.

Plants are only strong enough, so trees would fall, stems would bend over, etc.

Animals likewise: elephants would be crippled; ants would not carry the loads they need to, bugs could not fly, etc.

The atmosphere would be compressed down. Now the air sliding down the mountains can give Los Angeles summer-like weather at Christmas. So compressing all air on Earth by such an amount would turn the surface into an oven, rendering the other points moot.

edited Apr 06 '16 at 16:32

The Anathema

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answered Apr 06 '16 at 16:13

JDługosz

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Actually, I'm confident most infrastructure would be fine. A safety factor of 1.5 is quite low for large structures like buildings or bridges. As for biology, it certainly would have an impact, but all walking animals wouldn't all of a sudden be crippled. Ants can already lift many times their own body weight - cut that in half, and it's still many times their body weight. I think you're also overestimating the thermal effect of increased air pressure by far. – Nuclear Hoagie Apr 06 '16 at 16:20
@Matt but now the things the ants have to lift are also more heavy. – Cort Ammon Apr 06 '16 at 16:27
@Matt I believe you're oversimplifying it. The ants still have to use up energy to keep themselves upright, and the things they're lifting are also heavier. And all it takes is one failure point in a physical structure. Who's to say that you won't find many more occurrences of that happening across the planet? – The Anathema Apr 06 '16 at 16:34
"bugs could not fly" - Really? Yes, they would be 1.5 times heavier, but the atmosphere would also be higher pressure and therefore more buoyant so wouldn't the two cancel out? – komodosp Apr 06 '16 at 16:40
The boyancy is insignificant. – JDługosz Apr 06 '16 at 16:51
Really? I thought it was directly proportional to g which itself is directly proportional to the gravitational force. – komodosp Apr 06 '16 at 17:05
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@colmde The buoyant force on a bug is far smaller than g, so a proportional increase in both will affect g more and make it harder to fly. Let's give the buoyant force a number, doesn't matter what it is so long as it's less than g (bugs don't float in air), say b is 4. And g is 9.8. A bug has to overcome g - b or 5.8 m/s^2 to fly. If we increase both by 1.5 it will have a greater effect on g. b is now 6, but g is now 14.7. A bug now has to overcome 8.7 m/s^2 to fly. – Schwern Apr 06 '16 at 17:22
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Safety factor of 1.5: I'm not saying that bridges will fall down promptly. But now the safety factor is gone and weather and other variations will now exceed the strength. It was presumably designed for reasonable (not expensive overkill) excursions from baseline strength. With the change, everyday (or once-per-year) stresses will be too much. I alluded to this "in general, long term" but did not elaborate. – JDługosz Apr 06 '16 at 17:33
@Schwern The buoyancy isn't the main benefit: it's that the wings sweep through an area that now has more mass (because increased pressure). If the bug is strong enough to move the wings at the same speed, then it will be able to fly in this new environment. – Lacklub Apr 07 '16 at 13:07
Also, to add to this answer: as the air collapses and compresses, a ton of energy (probably in heat, but maybe in shockwaves) will be generated. While this is happening, there is a decent chance all planes in the air would crash (increased gravity + this air collapse). Also, most satellite would drop out of orbit (the NEO ones would crash, geosynchronous would probably be fine). – Lacklub Apr 07 '16 at 13:10

score 1 · Answer 2 · answered Apr 06 '16 at 16:29

I would expect an increase in gravity by 50% to herald in a round of seismic activity like the world has never seen. Expect basically every coastal city to be wiped out by tsunamis in the first week.

Also, expanding on JDlugosz's comment about infrastructure and Matt's counter, while infrastructure typically has a safety factor, its typically evaluated in a steady state situation. You have the most dynamic environment possible: an instantanious increase in forces. More buildings would collapse than one might expect.

If Earth's gravity instantly increased by 50 percent?

2 Answers2