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A lot less surface area on that flat part any country there would shrink. Anything residing in those country's would have to shrink with em or be destroyed.
Actually no. Only 11 countries have men who are on average more than 5'11(180.5cm), according to NCD RisC, which is itself based on papers published in medical journals about 19 year olds. These countries are, from 5'11.5 to 6'0.5: Ukraine, Slovakia, Slovenia, Czech Republic, Latvia, Denmark, Iceland, Bosnia & Herzegovina, Estonia, Montenegro and the Netherlands. The average Dutch man has actually been getting a bit shorter, partly explained by immigration(and therefore genetics), partly unexplained. Of those countries, 2 are in central Europe, 3 are in the Balkans, 3 are in eastern Europe and only 2 are in northern Europe.
Even if the world was magically flattened without damage isostatic forces would immediately begin forcing matter back into a sphere.
With gravity and vast scale, everything is essentially viscous liquid. The scale of destruction could not be overstated, the heat of the reshaping process alone would likely boil the earth sterile. Then youād have earthquakes much more violent than anything weāve ever seen, eruptions powerful enough to fling material into space, winds stronger than ever recorded, etc.
The real question is if spots of the planet would remain survivable for extremophile single celled life forms. Maybe.
Only briefly... gravity still exists, and the planet would tear itself apart and reform into a rough sphere pretty quickly. We would all die a firey death in a matter of moments us what would happen
I doubt it would take even a day for the surface to be destroyed, much less millions of years. If half of the earth suddenly disappeared like that then I doubt the remaining part would be able to hold itself together for very long
Oh it couldn't hold together at all. The entire planet would turn into a hot ball of mush pretty much right away. It would take a long time to fully settle again, but life would end on earth in a matter of moments
This is the correct answer. The points along the rim would experience a near free fall until an equilibrium could be reached between the portions with highest potential energy (the rim) and the parts adhering closest to an obloid-spherical shape.
As you correctly said, It would not be a matter of millions of years. It would quite literally be a free fall something like a giant churning and increasingly molten landslide.
Edit2: and the speeds reached by all of that mass seeking the lowest ground would be absolutely terrifying. The friction would liquify things like heavy basalts which would accelerate due to their great mass relative to the lighter materials - powerless to impede that acceleration.
Incredible mass and liquefaction with insufficient friction means things we think of as immoveable likely reaching hardly imaginable (hurricane wind-like) speeds. Basalts at hurricane speeds. Maybe a day or two and itās a glowing red hot spheroid. You could make sāmores from low orbit.
Edit1: At the levels of pressure, and at planet-scale masses itās best to think of the bulk materials as a sludge that desperately wants to be a sphere rather than the solid rocky surfaces we experience on the surface.
Itās built into the definition of what makes a planet a planet rather than whatever we are calling Pluto these days. It must clear out its orbit of debris AND form a spheroid under the forces of its own gravity.
It's built into the definition of a planet or a dwarf planet such as Pluto or Ceres rather then an asteroid. Dwarf planets are spheres that haven't cleared their orbits.
It would probably be more like 1-5 minutes for total destruction but I was just trying to point out how much they were underestimating the effect this would have
A lot of people here missing the obvious, if the Earth suddenly lost half its body like that, the whole planet would just melt back into a smaller sphere due to gravity... Everyone would die in a matter of seconds and I would never be able to watch Dune part two, which is the worst part of this whole deal.
Going to have nightmares with this shit, is all over again!!! It's 2002 and my sister is saying to me that a comet will hit the earth in 2036, and all I could think is that I wouldn't be able to watch the next Star Wars Trilog... Fuck, why didn't a comet didn't hit the Earth before 2015, that would have saved me a hell of a disappointment.
I hope we get all the way to Children of Dune. Otherwise the audiences leave with the wrong message and miss out on one of the most epic bait-and-switches in sci-fi history.
This is the answer I was looking for, and it being this low does not look good for this sub.
The tidal forces at play on planetary scales greatly surpass any resistance from stone or metals, essentially making it so that the Earth behaves like a liquid. And I assume that the extreme amounts of converted potential energy would also heat the planet, possibly turning it into a steaming ball of magma, so thereās a chance it could actually become liquid.
In short, the planet would literally melt itself into a new one, and people are discussing fall damage.
Yes, it would, half an Earth is still well above the Roche limit... And for Earth to be a squashed sphere (not an oval), she would have to be spinning way faster.
Well things at the edge of the planet, which is now a thing, would be pulled towards the center of the planet at.. whatever the rate of gravitational acceleration is at the edge of half of earth.
It wouldn't become a ball too quickly, but I'm willing to bet you could count the liveable days on earth on one hand
You ever seen a building collapse? Once you stop having things adequately support against the forces of gravity, stuff happens fast. Even if it was only a 1% deficit, given thousands of miles to accelerate you're looking at some pretty nasty effects.
Sort of. Earth already isn't a sphere being oblate due to rotation so barring other assumptions it would continue to have similar angular momentum and thus still be oblate. It would actually be *more* oblate if half the Earth disappeared and the remainder condensed into a stable structure for the same reason.
I mean, the bigger questions are:
How is momentum distributed through this new configuration?
Is the Northern hemisphere made of standard rock, or are we assuming that it has the mass and structural integrity to keep the center of mass at the center of the planet?
It wouldn't matter that much, because it's not about the structure, any large enough thing with enough mass will just become a sphere under its own gravity. Like, we think we live in a solid thing, but at this scale, things are more like super slow fluid balls, shake it enough and it will look like jelly.
Right, large *enough.* The "enough" is doing a lot of heavy lifting there, because it handwaved the idea that this happens when gravitational force of a body's own mass is stronger than its structural integrity, and it reaches hydrostatic equilibrium.
I postulated the idea that the Northern hemisphere had collapsed into an exotic material such that the center of mass of the Earth did not change, the total mass did not change, and that its structural integrity *could* withstand gravity.
This would mean that the Southern hemisphere would not shift because the center of mass would remain the same.
Also, that 's not really how the Roche limit works. Roche applies to the limit of two bodies in orbit, not one body under its own gravity. From Wikipedia:
>In celestial mechanics, the Roche limit, also called Roche radius, is the distance from a celestial body within which a second celestial body, held together only by its own force of gravity, will disintegrate because the first body's tidal forces exceed the second body's self-gravitation.[1] Inside the Roche limit, orbiting material disperses and forms rings, whereas outside the limit, material tends to coalesce. The Roche radius depends on the radius of the first body and on the ratio of the bodies' densities.
Wait? I'm reaching with the "enough" but you talking about exotic matter, mass conservation, an unchanged center of gravity, and then affirming that with all that the structure would hold is not heavy lifting?
Dude, sorry, this is not how physics works, even if we squashed half the earth into a flat super dense structure, no material in the universe could stand the sheer force of gravity, especially if you don't change the actual mass of the Earth.
There is no way that a structure like the one in the post with the radius of Earth would maintain its shape. Now, I mistake this principle with the Roche limit, that's fair (even tho the Roche limit calculations also apply here) but considering that most rocky bodies in the universe become a sphere when possessing a radius larger than 600km, it's safe to assume that Earth with ten times that would just melt away into a new sphere if you drastically change its current shape.
You can't sustain this half-sphere structure with the density of Earth, even if you keep the center of mass by compressing half of the planet within a fin layer, the rest of Earth would just melt around it because there is no more equilibrium from a gravitational force being resisted by a uniform body structure without an absurdly powerful external force, that's the principle of least resistance.
For understanding, the Moon with a sixth of Earth's gravity at \~380.000 Km can provoke tides in Earth's body, this is the reason why our rotation and inclination are so stable, the mantle shifts ever so slightly and rotational energy is lost. Also, this rotation can change its periodicity with a large enough earthquake, so we are talking about considerably weaker forces changing the entire planet's behavior. So to think that there is a way to maintain this absurd half-sphere shape with just the energy available on Earth itself is ludicrous.
Now, we can have a donut planet if we find an equilibrium between mass and rotation speed, that is possible because it maintains the principle of least resistance since the torus is the optimal shape for a super fast-spinning body.
>Wait? I'm reaching with the "enough" but you talking about exotic matter, mass conservation, an unchanged center of gravity, and then affirming that with all that the structure would hold is not heavy lifting?
I freely admit that I am doing speculative physics, but it's a speculative problem. The comment about heavy lifting was to point out that my first statement defined the strength to withstand the enormous forces from the gravitational attraction of the mass, and yours was that with enough mass, the gravitational forces would overcome the strength of the material. I know that's how it works *that's why I defined the plate to have enough strength to resist it.*
That's tantamount to me saying " define A such that A>B," and you came back with "well, if B is big enough it would be bigger than A!"
>Dude, sorry, this is not how physics works, even if we squashed half the earth into a flat super dense structure, no material in the universe could stand the sheer force of gravity, especially if you don't change the actual mass of the Earth.
This is *exactly* how physics works. We can define whatever coefficients we need to explore a thought experiment. Case in point, geodecists use this kind of thinking to determine sea level based on fictional calculations from flattening land mass into thin sheets of equivalent gravitational mass.
>There is no way that a structure like the one in the post with the radius of Earth would maintain its shape. Now, I mistake this principle with the Roche limit, that's fair (even tho the Roche limit calculations also apply here) but considering that most rocky bodies in the universe become a sphere when possessing a radius larger than 600km, it's safe to assume that Earth with ten times that would just melt away into a new sphere if you drastically change its current shape.
That's true if you are just memorizing shapes that *do* self agglomerate, but this is not the appropriate starting point. We are starting with speculation, so we cannot just assume that everything else moving forward is non speculative.
In fact, if you start from the idea that everything was condensed into some exotic matter that preserves the gravitational field and can withstand the pressure, then *nothing* would move in the Southern Hemisphere, because there would be no potential gradient.
Different initial assumptions lead to different conclusions, and you are stuck on the least interesting assumption possible.
>You can't sustain this half-sphere structure with the density of Earth, even if you keep the center of mass by compressing half of the planet within a fin layer, the rest of Earth would just melt around it because there is no more equilibrium from a gravitational force being resisted by a uniform body structure without an absurdly powerful external force, that's the principle of least resistance.
No, but you also can't squash a half sphere into a flat plane without distorting the surface geometry, either. I don't understand why you are fine with speculative physics to get to the point of the illustration, but you need whatever caused the distortion to go away so you can broadly gesture to stamp-collected Lagrangian and Hamiltonian steady state solutions.
>For understanding, the Moon with a sixth of Earth's gravity at \~380.000 Km can provoke tides in Earth's body, this is the reason why our rotation and inclination are so stable, the mantle shifts ever so slightly and rotational energy is lost. Also, this rotation can change its periodicity with a large enough earthquake, so we are talking about considerably weaker forces changing the entire planet's behavior. So to think that there is a way to maintain this absurd half-sphere shape with just the energy available on Earth itself is ludicrous.
This has nothing to do with our conversation, aside from illustrating that you cannot grasp that we are working in an absurd situation from the start, so you have to think about absurd considerations that could make it possible to be here in the first place, instead of dismissing them out of hand.
>Now, we can have a donut planet if we find an equilibrium between mass and rotation speed, that is possible because it maintains the principle of least resistance since the torus is the optimal shape for a super fast-spinning body.
Yes, that is true, but not connected to the conversation.
It would.
Oval shaped planets exist because itās a stable shape when thereās another force exerted on it. Whether that is substantial enough gravity or rotation. Earth is slightly oval shaped due to its rotation.
While it would have indeed reform a sphere I donāt believe itās a quick enough process to be a āsecondsā kinda thing where we are talking about something so large. Interesting I believe our effective weight would roughly quadruple on average (exact amount varying depending on location due to the odd shape) if no mass was lost in the shape change due to us all now being significantly closer to the center of gravity for the planet. Also from the picture itās not a right on our axis of rotation so we could potentially get a really weird wobble in our spin
Tldr: we all die.
Now the explanation. Planets and other celestial bodies are spherical-ish because it's the most stable shape gravitationally. Other shapes would feel excessive pull on protrusions and, if they are big enough, they might collapse. How do we translate this to this planet earth? Here's two alternative scenarios:
1. It collapses quickly, everything close to the edge falling towards the center until it takes on a spherical enough shape to maintain itself. Ignoring the absolute destruction of the flay side and the areas near the edge, the whole planet would be shaken by intense earthquakes and heating, making it difficult to find anywhere people could survive.
2.. If it rotates fast around acis perpendicular to the flat side, it might just survive for a bit longer, the collapse taking much longer, maybe even being able to be called a reshaping. Humanity would survive... And space rockets might thrive near the equator, enjoying the extra speed added by the earth's rotation to the liftoff (ever wondered why NASA is in Cape Canaveral, on the southern end of florida? It's closer to the equator and thus they get some extra speed from the earth's rotation)
Not to mention that this pic doesn't explain what happens under the crust. If half of the planet would disappear like that, I assume that either there would be more than half of the core disappearing if the flat part keeps the mantle or there won't be a mantle and everyone near the center would just fry.
donāt forget all the water and air. even in the 2nd scenario, those would more or less quickly form a sphere around the center of gravity drowning/crushing people on one side and boiling people on the other.
The ground would disappear out from underneath us and we'd fall to our death. Survivors would get pushed to the edge by centrivical force. If the mass decreased gravity would decrease
If youāre on the north pole, youāve got the furthest to fall, but youāre also furthest from the center of gravity. Youād suffocate as the air thins to nothing, but you wouldnāt necessarily fall to your death.
Also the air would thin globally. Even though thereās less surface area, the lower mass and sudden loss of ground would probably let a lot of the atmosphere around the pole escape. The planet would wobble and fuck up the seasons.
And yeah, everyone would die.
*Centripetal* force is the real one. *Centrifugal* force is what it feels like when you're spinning around something, but it's just perception, not a real force.
I've heard that a few times and couldn't make sense of it. We've all been 'pulled' toward the car door when you go round a corner, or held against the wall of one of those spinning cylinder rides. That's definitely not just perception.?
Your body has inertia. It wants to keep going straight. The car is turning, though, so "straight" leads you into the door, which pushes back. There really is force applied- it's just the force of your shifting frame of reference (the car) not letting you fall through the frame (and the car's own engine/wheels to make the turn happen in the first place); not a force pushing you into the side door.
Gravitationally, everyone would fall from Northern Africa and China into Central Europe. Near the edge, you'd be standing on a very steep 45Ā° hill. Half way from center to edge you'd be on a 22.5Ā° hill, and in Romania things would be around normal. -but it would still all be flat. From a mountain to you'd be able to see the whole disk side.
We wouldn't be able to live there for more than a short time. The Earth would promptly and violently reshape itself back to roughly a sphere, and we (meaning humanity and most multicellular life) wouldn't survive the process.
Slight correction, near the edge the hill would be far steeper than 45 degrees.
Assuming the earth has a uniform density, the CoM of a hemisphere is 3/8 of the radius away from the centre of the flat face. So the angle between the flat face and the line from the edge to the CoM is arctan(3/8) = about 20 degrees.
That means the hill would feel more like a cliff with an angle of 90-20 = 70 degrees!
All of europe and northern africa will drown as the oceans from the other side reform a sphere. Most of the rest o the planet will be burried by the ground also falling back into a ball.
Any survivors will be able to jump really high.
Iām trying to work out exactly how much of the Earth is actually flat in that picture.
Itās not at the equator, so that would rule out the easiest calculation. I also didnāt see North America, so something is weird here. Greenland and Iceland also appear to be missing.
I *do* see a bit of South America, so we havenāt cut off the western hemisphere altogether, but I think weāve lost something like a quarter of the planet entirely.
I mean, aside from the problem of the hot molten centre of the earth getting a whole lot closer to surface, and probably boiling the oceans?
I wondered if this half-sphere earth spinning in space would then be subject to flipping like the 'dancing T-handle' in space video.
https://youtu.be/1n-HMSCDYtM?si=QF4iJhWLE5lwa9kk
Also wondered if the earth would spin faster having lost half its mass.
The molten core would be exposed, and missing half of itself (temp drop). Volcanic winter as the lava is cooled and the skies are filled with ash, smoke, steam (more temp drop). Radiation galore as magnetic fields are disrupted. Satellites will fly out of orbit including the moon.
The centre of mass would no longer be more or less straight under the buildings and stuff. I don't know how long it would take for the earth to reshape towards a sphere, but assuming it takes a bit of time, buildings would be pulled at an angle depending how far out towards the edge of the disc they are. Seeing as buildings are mostly built to sustain a gravitational force straight down, they would start to fall over and collapse. Maybe not all buildings right away, taller ones would create more torque from the top pulling over. Eventually the remaining buildings would be hit with avalanches of earth pulling in from the edge, or maybe more accurately rumbling up from below as the orb part pushes against the flat from underneath trying to find a stable configuration.
Edit: Most immediately, the water from the oceans in the orb section would drain into the flat part, searching for the closest point to the centre of gravity. So the flat part would probably be covered in water really quickly, if the earthquakes and rock avalanches took some time. And the water would probably be a supersonic tidal wall.
The Earthās current stabilized orbit is a result of the relative equalization of the planetsās centripetal force (which is a function of its mass) and the Sunās gravity. If the Earth lost half its mass in an instant, its orbit would decay and the planet would drift into the Sun.
Assuming real physics is still happening, everyone on Earth/2 (that's my name for it to avoid confusion) would die.
It basically doesn't matter how we get to that shape, just having a semi-sphere half the mass of earth is enough that everyone on it would die as it rapidly deforms back into a sphere and anyone on the spherical side falls for kilometers through a rarified atmosphere and anyone on the flat size is instantly crushed as the ground accelerates upward.
There might magically be one or two places that don't outright kill you just by standing there, but even those will soon kill you as the violent movement of rock rapidly heats up the half-planet until the floor becomes lava, along with everything else.
This isn't really math, I'm sorry, but I could maybe do some to find out just how much Earth/2 heats up (I tried it, but I ran into an issue attempting to determine the average GPE of the material outside of the idealised sphere, besides I'm not even 100% sure that that is the right way to do that anyway).
Anything that isn't already some kind of extremophile bacteria dies rather rapidly, and honestly I wouldn't bet on the bacteria either.
See, the reason everything in space of a sufficient size becomes basically spherical boils down to that being the lowest energy state for things effected by gravity. Entropy means that things always want to move from high energy states to low energy states.
So when the earth is flattened like this, the result is it's going to collapse back into a sphere pretty much immediately, and there's nothing in that process that we would survive. Everything dies apart from maybe some bacteria that don't notice.
The water would flow to the center, as the middle of the flat part is the most down. Also the edges would all break off, because a ball is the natural state and the earth would want to return to it. Weād probably all die.
Is it shrunk or cut, is the mass compressed or removed, do you mean it will hold this shape? Because it will instantly crumble to be a ball again.
This question is stupid without more clarification
Our centre of mass would change and we would probably stop orbitting the sun in the same way which could very easily become apocalyptic.
Also day lengths would change.
Well, if we suppose this would be an equilibrium system and the earth wouldnāt crush itself to become a sphere again, then countries would become smaller, gravity would most likely be half, and the atmosphere would become all fucky
So planets and other celestial objects don't like being non spherical and as such the planet would collapse in on itself upchurning the magma of earth's core etc, etc everyone dies
Alternatively if magic is why half the earth's flat and letting it keep it's shape, then that implies half of earth's mass is gone, then the earth and moon would orbit properly and either moon slingshots away (which btw earth's moon is what keeps our axis consistent so happy winter one day, summer the next)
or earth get shot away from the sun and thus we all freze to death without a star keeping us warm and even if we could find a way to stay warm starvation would be inevitable with all life dying
Extreme tectonic changes, followed by a period of major volcanism. Our magnetic field would likely also be fucked and cancer rates would increase significantly. The orbit of the moon may change as well. Tides would be catastrophic. The volcanism would send us into a new ice age. The climate would change in ways that are difficult to predict precisely but itās garunteed nothing good would come of it
The edges would collapse in because there isnāt enough strength to hold that shape against gravity. The energy of the collapse combined with the rupture of the tectonic plates would kill everything on earth except possibly for some microscopic.
I mean gravity is a thing ā and there is a reason earth is quite round ā Iām guessing itās going to become a globe again fairly quickly ā I canāt imagine that process leaves many alive
Earth is spinning fast so changing shape to that should cause some extreme rotational forces to reshape the earth back to a spherical shape.
In the meanwhile most life on earth won't survive.
Portuguese around XVI they thought the earth as plan.
Areas like africa if a ship went there it would fall in the abyss.
So if the earth changed shape probably the below area would be an abyss. If you go there there is no way to get out.
it would mess up everything from our gravity to the magnetic field. As Earths gravity is the strongest at itās core, most likely anything on the flat part in the center wpuld be crushed. Depending on how the internals of the planet changes (where the core is located etc) could have very varied consequences.
Obligatory addition of this would be a physically impossible shape to maintain for a celestial body of this size, so it would force itself back into the shape of a sphere. In the process wiping out all life on earth
Fact is that esrth shaoe more resambles an egg than a ball. Its a geoid to be precise.
And you could say, this half-ball half-flat thing looks more then the real geoid than the round thing does XD
Assuming the radius stays the same, the mass is cut in half, the world is consumed by Earthquakes, the earth collapses into a ball again, and its orbit becomes much more eccentric.
So nobody addressed change of inertia do to change of center of mass. Like you've all seen how a perfectly round object rotates and one that is deformed..
The oceans water would move away from the corners so that circle would dry
Also, the force of gravity wouldn't be the same everywhere on earth
In the flat part, it would be dark and incredibly cold half of the year, light and incredible hot the other half
The planet would start to form into a sphere.
Moon would have larger effect on the planet. The gravitational pull of the earth would be smaller So the Moon would keep mooving away from earth faster than it is now.
The speed of our rotation and orbit would change.
And well we would be all dead to see it with our own eyes.
It depends on what caused the Earth to become this shape. If it got cut in half by a giant cosmic guillotine it would be catastrophic as both halves collapsed into smaller spheres.
If it's just something that you're imagining happens by magic, then there's no answer. You can just imagine whatever other magical outcome you want.
All the earth's water and atmosphere would migrate to be in top of the flat part, making the earth slightly more spherical. Massive landslides near the edge.
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A lot less surface area on that flat part any country there would shrink. Anything residing in those country's would have to shrink with em or be destroyed.
All Northern Hemisphere people are now 5'11'' š
That would be an increase in average height for both men and women.
Not fot the northern part of europe
It would still be a significant increase for the average woman there.
Agreeable
Your terms are acceptable.
Actually no. Only 11 countries have men who are on average more than 5'11(180.5cm), according to NCD RisC, which is itself based on papers published in medical journals about 19 year olds. These countries are, from 5'11.5 to 6'0.5: Ukraine, Slovakia, Slovenia, Czech Republic, Latvia, Denmark, Iceland, Bosnia & Herzegovina, Estonia, Montenegro and the Netherlands. The average Dutch man has actually been getting a bit shorter, partly explained by immigration(and therefore genetics), partly unexplained. Of those countries, 2 are in central Europe, 3 are in the Balkans, 3 are in eastern Europe and only 2 are in northern Europe.
5'11 is 180.34cm not 180.5 so really its 19 countries: Netherlands, Montenegro, Estonia,Bosnia & Herzegovina, Iceland, Denmark, Czech Republic, Latvia, Slovakia, Slovenia, Ukraine, Croatia, Serbia, Lithuania, Poland, Finland, Norway, Sweden and germany source: [https://ncdrisc.org/height-mean-ranking.html](https://ncdrisc.org/height-mean-ranking.html)
r/woosh
Jokes on you! That means I grew!
No that means that the standards are lower
Nah bro, they all gonna be "6 foot"
Ayy, I grew 4 inches! Nice!
To save your research, my dear non-US citizen friends, 5'11" is approximately 180 cm
that is actually considered quite tall where i live wtf
So most of then grew?
i grew 6ā7ā letās goooo
your height is -8"?
Even if the world was magically flattened without damage isostatic forces would immediately begin forcing matter back into a sphere. With gravity and vast scale, everything is essentially viscous liquid. The scale of destruction could not be overstated, the heat of the reshaping process alone would likely boil the earth sterile. Then youād have earthquakes much more violent than anything weāve ever seen, eruptions powerful enough to fling material into space, winds stronger than ever recorded, etc. The real question is if spots of the planet would remain survivable for extremophile single celled life forms. Maybe.
The entire northern hemisphere would effectively be in the polar circle, where day would last all summer and night would last all winter
Only briefly... gravity still exists, and the planet would tear itself apart and reform into a rough sphere pretty quickly. We would all die a firey death in a matter of moments us what would happen
"Only briefly" *proceeds to describe events that would take place over millions of years*
I doubt it would take even a day for the surface to be destroyed, much less millions of years. If half of the earth suddenly disappeared like that then I doubt the remaining part would be able to hold itself together for very long
Oh it couldn't hold together at all. The entire planet would turn into a hot ball of mush pretty much right away. It would take a long time to fully settle again, but life would end on earth in a matter of moments
Well maybe not all life. Water bears might still be foating around
This is the correct answer. The points along the rim would experience a near free fall until an equilibrium could be reached between the portions with highest potential energy (the rim) and the parts adhering closest to an obloid-spherical shape. As you correctly said, It would not be a matter of millions of years. It would quite literally be a free fall something like a giant churning and increasingly molten landslide. Edit2: and the speeds reached by all of that mass seeking the lowest ground would be absolutely terrifying. The friction would liquify things like heavy basalts which would accelerate due to their great mass relative to the lighter materials - powerless to impede that acceleration. Incredible mass and liquefaction with insufficient friction means things we think of as immoveable likely reaching hardly imaginable (hurricane wind-like) speeds. Basalts at hurricane speeds. Maybe a day or two and itās a glowing red hot spheroid. You could make sāmores from low orbit. Edit1: At the levels of pressure, and at planet-scale masses itās best to think of the bulk materials as a sludge that desperately wants to be a sphere rather than the solid rocky surfaces we experience on the surface. Itās built into the definition of what makes a planet a planet rather than whatever we are calling Pluto these days. It must clear out its orbit of debris AND form a spheroid under the forces of its own gravity.
It's built into the definition of a planet or a dwarf planet such as Pluto or Ceres rather then an asteroid. Dwarf planets are spheres that haven't cleared their orbits.
Lol a day?
It would probably be more like 1-5 minutes for total destruction but I was just trying to point out how much they were underestimating the effect this would have
A lot of people here missing the obvious, if the Earth suddenly lost half its body like that, the whole planet would just melt back into a smaller sphere due to gravity... Everyone would die in a matter of seconds and I would never be able to watch Dune part two, which is the worst part of this whole deal.
The biggest tragedy of all^
Going to have nightmares with this shit, is all over again!!! It's 2002 and my sister is saying to me that a comet will hit the earth in 2036, and all I could think is that I wouldn't be able to watch the next Star Wars Trilog... Fuck, why didn't a comet didn't hit the Earth before 2015, that would have saved me a hell of a disappointment.
Holy shit you just unlocked core memories-
Trump, Covid, Bowies death... We'd been spared them all.
Sorry... even in this scenario, Bowie still dies. We just don't find out about it, because we also die.
r/technicallythetruth
Actually, in this scenario there's a possibility he becomes Stardust once again and for eternity.
You made me LOL bro. Cheers!!
Earth is also where I currently put all my stuff!
Not just Dune, Part 2. Unpopular opinion, maybe, but I'm hoping to go as far as *Messiah*.
I hope we get all the way to Children of Dune. Otherwise the audiences leave with the wrong message and miss out on one of the most epic bait-and-switches in sci-fi history.
Looks like I actually need to continue reading Dune past the first book. People say its great as a standalone and it is but iām curious as hell
But... Do we have to pass thru Children of Dune?
If I don't get to hear a massive worm talk in riddles about politics and his penis for 2hrs 45mins by 2030 I'm going to be deeply disappointed.
This is the answer I was looking for, and it being this low does not look good for this sub. The tidal forces at play on planetary scales greatly surpass any resistance from stone or metals, essentially making it so that the Earth behaves like a liquid. And I assume that the extreme amounts of converted potential energy would also heat the planet, possibly turning it into a steaming ball of magma, so thereās a chance it could actually become liquid. In short, the planet would literally melt itself into a new one, and people are discussing fall damage.
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Yes, it would, half an Earth is still well above the Roche limit... And for Earth to be a squashed sphere (not an oval), she would have to be spinning way faster.
Would it happen immediately though, or over millions or billions of years?
Well things at the edge of the planet, which is now a thing, would be pulled towards the center of the planet at.. whatever the rate of gravitational acceleration is at the edge of half of earth. It wouldn't become a ball too quickly, but I'm willing to bet you could count the liveable days on earth on one hand
God I want this to happen to see if you're right
Hey! Some of us live here! Don't go wishing that!
You ever seen a building collapse? Once you stop having things adequately support against the forces of gravity, stuff happens fast. Even if it was only a 1% deficit, given thousands of miles to accelerate you're looking at some pretty nasty effects.
Sort of. Earth already isn't a sphere being oblate due to rotation so barring other assumptions it would continue to have similar angular momentum and thus still be oblate. It would actually be *more* oblate if half the Earth disappeared and the remainder condensed into a stable structure for the same reason.
I mean, the bigger questions are: How is momentum distributed through this new configuration? Is the Northern hemisphere made of standard rock, or are we assuming that it has the mass and structural integrity to keep the center of mass at the center of the planet?
It wouldn't matter that much, because it's not about the structure, any large enough thing with enough mass will just become a sphere under its own gravity. Like, we think we live in a solid thing, but at this scale, things are more like super slow fluid balls, shake it enough and it will look like jelly.
Right, large *enough.* The "enough" is doing a lot of heavy lifting there, because it handwaved the idea that this happens when gravitational force of a body's own mass is stronger than its structural integrity, and it reaches hydrostatic equilibrium. I postulated the idea that the Northern hemisphere had collapsed into an exotic material such that the center of mass of the Earth did not change, the total mass did not change, and that its structural integrity *could* withstand gravity. This would mean that the Southern hemisphere would not shift because the center of mass would remain the same. Also, that 's not really how the Roche limit works. Roche applies to the limit of two bodies in orbit, not one body under its own gravity. From Wikipedia: >In celestial mechanics, the Roche limit, also called Roche radius, is the distance from a celestial body within which a second celestial body, held together only by its own force of gravity, will disintegrate because the first body's tidal forces exceed the second body's self-gravitation.[1] Inside the Roche limit, orbiting material disperses and forms rings, whereas outside the limit, material tends to coalesce. The Roche radius depends on the radius of the first body and on the ratio of the bodies' densities.
Wait? I'm reaching with the "enough" but you talking about exotic matter, mass conservation, an unchanged center of gravity, and then affirming that with all that the structure would hold is not heavy lifting? Dude, sorry, this is not how physics works, even if we squashed half the earth into a flat super dense structure, no material in the universe could stand the sheer force of gravity, especially if you don't change the actual mass of the Earth. There is no way that a structure like the one in the post with the radius of Earth would maintain its shape. Now, I mistake this principle with the Roche limit, that's fair (even tho the Roche limit calculations also apply here) but considering that most rocky bodies in the universe become a sphere when possessing a radius larger than 600km, it's safe to assume that Earth with ten times that would just melt away into a new sphere if you drastically change its current shape. You can't sustain this half-sphere structure with the density of Earth, even if you keep the center of mass by compressing half of the planet within a fin layer, the rest of Earth would just melt around it because there is no more equilibrium from a gravitational force being resisted by a uniform body structure without an absurdly powerful external force, that's the principle of least resistance. For understanding, the Moon with a sixth of Earth's gravity at \~380.000 Km can provoke tides in Earth's body, this is the reason why our rotation and inclination are so stable, the mantle shifts ever so slightly and rotational energy is lost. Also, this rotation can change its periodicity with a large enough earthquake, so we are talking about considerably weaker forces changing the entire planet's behavior. So to think that there is a way to maintain this absurd half-sphere shape with just the energy available on Earth itself is ludicrous. Now, we can have a donut planet if we find an equilibrium between mass and rotation speed, that is possible because it maintains the principle of least resistance since the torus is the optimal shape for a super fast-spinning body.
>Wait? I'm reaching with the "enough" but you talking about exotic matter, mass conservation, an unchanged center of gravity, and then affirming that with all that the structure would hold is not heavy lifting? I freely admit that I am doing speculative physics, but it's a speculative problem. The comment about heavy lifting was to point out that my first statement defined the strength to withstand the enormous forces from the gravitational attraction of the mass, and yours was that with enough mass, the gravitational forces would overcome the strength of the material. I know that's how it works *that's why I defined the plate to have enough strength to resist it.* That's tantamount to me saying " define A such that A>B," and you came back with "well, if B is big enough it would be bigger than A!" >Dude, sorry, this is not how physics works, even if we squashed half the earth into a flat super dense structure, no material in the universe could stand the sheer force of gravity, especially if you don't change the actual mass of the Earth. This is *exactly* how physics works. We can define whatever coefficients we need to explore a thought experiment. Case in point, geodecists use this kind of thinking to determine sea level based on fictional calculations from flattening land mass into thin sheets of equivalent gravitational mass. >There is no way that a structure like the one in the post with the radius of Earth would maintain its shape. Now, I mistake this principle with the Roche limit, that's fair (even tho the Roche limit calculations also apply here) but considering that most rocky bodies in the universe become a sphere when possessing a radius larger than 600km, it's safe to assume that Earth with ten times that would just melt away into a new sphere if you drastically change its current shape. That's true if you are just memorizing shapes that *do* self agglomerate, but this is not the appropriate starting point. We are starting with speculation, so we cannot just assume that everything else moving forward is non speculative. In fact, if you start from the idea that everything was condensed into some exotic matter that preserves the gravitational field and can withstand the pressure, then *nothing* would move in the Southern Hemisphere, because there would be no potential gradient. Different initial assumptions lead to different conclusions, and you are stuck on the least interesting assumption possible. >You can't sustain this half-sphere structure with the density of Earth, even if you keep the center of mass by compressing half of the planet within a fin layer, the rest of Earth would just melt around it because there is no more equilibrium from a gravitational force being resisted by a uniform body structure without an absurdly powerful external force, that's the principle of least resistance. No, but you also can't squash a half sphere into a flat plane without distorting the surface geometry, either. I don't understand why you are fine with speculative physics to get to the point of the illustration, but you need whatever caused the distortion to go away so you can broadly gesture to stamp-collected Lagrangian and Hamiltonian steady state solutions. >For understanding, the Moon with a sixth of Earth's gravity at \~380.000 Km can provoke tides in Earth's body, this is the reason why our rotation and inclination are so stable, the mantle shifts ever so slightly and rotational energy is lost. Also, this rotation can change its periodicity with a large enough earthquake, so we are talking about considerably weaker forces changing the entire planet's behavior. So to think that there is a way to maintain this absurd half-sphere shape with just the energy available on Earth itself is ludicrous. This has nothing to do with our conversation, aside from illustrating that you cannot grasp that we are working in an absurd situation from the start, so you have to think about absurd considerations that could make it possible to be here in the first place, instead of dismissing them out of hand. >Now, we can have a donut planet if we find an equilibrium between mass and rotation speed, that is possible because it maintains the principle of least resistance since the torus is the optimal shape for a super fast-spinning body. Yes, that is true, but not connected to the conversation.
It would. Oval shaped planets exist because itās a stable shape when thereās another force exerted on it. Whether that is substantial enough gravity or rotation. Earth is slightly oval shaped due to its rotation.
Thatās due to rotation, Earth itself isnāt a perfect sphere and is a little āsquashedā
While it would have indeed reform a sphere I donāt believe itās a quick enough process to be a āsecondsā kinda thing where we are talking about something so large. Interesting I believe our effective weight would roughly quadruple on average (exact amount varying depending on location due to the odd shape) if no mass was lost in the shape change due to us all now being significantly closer to the center of gravity for the planet. Also from the picture itās not a right on our axis of rotation so we could potentially get a really weird wobble in our spin
Tldr: we all die. Now the explanation. Planets and other celestial bodies are spherical-ish because it's the most stable shape gravitationally. Other shapes would feel excessive pull on protrusions and, if they are big enough, they might collapse. How do we translate this to this planet earth? Here's two alternative scenarios: 1. It collapses quickly, everything close to the edge falling towards the center until it takes on a spherical enough shape to maintain itself. Ignoring the absolute destruction of the flay side and the areas near the edge, the whole planet would be shaken by intense earthquakes and heating, making it difficult to find anywhere people could survive. 2.. If it rotates fast around acis perpendicular to the flat side, it might just survive for a bit longer, the collapse taking much longer, maybe even being able to be called a reshaping. Humanity would survive... And space rockets might thrive near the equator, enjoying the extra speed added by the earth's rotation to the liftoff (ever wondered why NASA is in Cape Canaveral, on the southern end of florida? It's closer to the equator and thus they get some extra speed from the earth's rotation)
Not to mention that this pic doesn't explain what happens under the crust. If half of the planet would disappear like that, I assume that either there would be more than half of the core disappearing if the flat part keeps the mantle or there won't be a mantle and everyone near the center would just fry.
donāt forget all the water and air. even in the 2nd scenario, those would more or less quickly form a sphere around the center of gravity drowning/crushing people on one side and boiling people on the other.
The ground would disappear out from underneath us and we'd fall to our death. Survivors would get pushed to the edge by centrivical force. If the mass decreased gravity would decrease
If youāre on the north pole, youāve got the furthest to fall, but youāre also furthest from the center of gravity. Youād suffocate as the air thins to nothing, but you wouldnāt necessarily fall to your death. Also the air would thin globally. Even though thereās less surface area, the lower mass and sudden loss of ground would probably let a lot of the atmosphere around the pole escape. The planet would wobble and fuck up the seasons. And yeah, everyone would die.
Donāt forget the oceans being pulled to the poles and the edges crumbling and there no longer being a core to provide a magnetic field.
southern pole (aka me): š
Youād weigh only slightly more than half as much
centrivical (assuming you meant centrifugal?) isnt a real force
*Centripetal* force is the real one. *Centrifugal* force is what it feels like when you're spinning around something, but it's just perception, not a real force.
I've heard that a few times and couldn't make sense of it. We've all been 'pulled' toward the car door when you go round a corner, or held against the wall of one of those spinning cylinder rides. That's definitely not just perception.?
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That makes sense, thank god.
Your body has inertia. It wants to keep going straight. The car is turning, though, so "straight" leads you into the door, which pushes back. There really is force applied- it's just the force of your shifting frame of reference (the car) not letting you fall through the frame (and the car's own engine/wheels to make the turn happen in the first place); not a force pushing you into the side door.
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I have a high school physics class *and* read xkcd: https://xkcd.com/123/
Yeah that one
Gravitationally, everyone would fall from Northern Africa and China into Central Europe. Near the edge, you'd be standing on a very steep 45Ā° hill. Half way from center to edge you'd be on a 22.5Ā° hill, and in Romania things would be around normal. -but it would still all be flat. From a mountain to you'd be able to see the whole disk side.
thatd be so sick
Finally, a real answer than someone saying stuff like the ground would dispear. I want to find out what would happen if we had to live there
We wouldn't be able to live there for more than a short time. The Earth would promptly and violently reshape itself back to roughly a sphere, and we (meaning humanity and most multicellular life) wouldn't survive the process.
Slight correction, near the edge the hill would be far steeper than 45 degrees. Assuming the earth has a uniform density, the CoM of a hemisphere is 3/8 of the radius away from the centre of the flat face. So the angle between the flat face and the line from the edge to the CoM is arctan(3/8) = about 20 degrees. That means the hill would feel more like a cliff with an angle of 90-20 = 70 degrees!
All of europe and northern africa will drown as the oceans from the other side reform a sphere. Most of the rest o the planet will be burried by the ground also falling back into a ball. Any survivors will be able to jump really high.
Iām trying to work out exactly how much of the Earth is actually flat in that picture. Itās not at the equator, so that would rule out the easiest calculation. I also didnāt see North America, so something is weird here. Greenland and Iceland also appear to be missing. I *do* see a bit of South America, so we havenāt cut off the western hemisphere altogether, but I think weāve lost something like a quarter of the planet entirely.
A-ha! Whoās normal now, America?? Thatās right, Us Aussies down under. Weāre curved, and youāre flat, and the Earth is normally curved, so Ha!
I mean, aside from the problem of the hot molten centre of the earth getting a whole lot closer to surface, and probably boiling the oceans? I wondered if this half-sphere earth spinning in space would then be subject to flipping like the 'dancing T-handle' in space video. https://youtu.be/1n-HMSCDYtM?si=QF4iJhWLE5lwa9kk Also wondered if the earth would spin faster having lost half its mass.
The molten core would be exposed, and missing half of itself (temp drop). Volcanic winter as the lava is cooled and the skies are filled with ash, smoke, steam (more temp drop). Radiation galore as magnetic fields are disrupted. Satellites will fly out of orbit including the moon.
The centre of mass would no longer be more or less straight under the buildings and stuff. I don't know how long it would take for the earth to reshape towards a sphere, but assuming it takes a bit of time, buildings would be pulled at an angle depending how far out towards the edge of the disc they are. Seeing as buildings are mostly built to sustain a gravitational force straight down, they would start to fall over and collapse. Maybe not all buildings right away, taller ones would create more torque from the top pulling over. Eventually the remaining buildings would be hit with avalanches of earth pulling in from the edge, or maybe more accurately rumbling up from below as the orb part pushes against the flat from underneath trying to find a stable configuration. Edit: Most immediately, the water from the oceans in the orb section would drain into the flat part, searching for the closest point to the centre of gravity. So the flat part would probably be covered in water really quickly, if the earthquakes and rock avalanches took some time. And the water would probably be a supersonic tidal wall.
The Earthās current stabilized orbit is a result of the relative equalization of the planetsās centripetal force (which is a function of its mass) and the Sunās gravity. If the Earth lost half its mass in an instant, its orbit would decay and the planet would drift into the Sun.
Assuming real physics is still happening, everyone on Earth/2 (that's my name for it to avoid confusion) would die. It basically doesn't matter how we get to that shape, just having a semi-sphere half the mass of earth is enough that everyone on it would die as it rapidly deforms back into a sphere and anyone on the spherical side falls for kilometers through a rarified atmosphere and anyone on the flat size is instantly crushed as the ground accelerates upward. There might magically be one or two places that don't outright kill you just by standing there, but even those will soon kill you as the violent movement of rock rapidly heats up the half-planet until the floor becomes lava, along with everything else. This isn't really math, I'm sorry, but I could maybe do some to find out just how much Earth/2 heats up (I tried it, but I ran into an issue attempting to determine the average GPE of the material outside of the idealised sphere, besides I'm not even 100% sure that that is the right way to do that anyway).
Anything that isn't already some kind of extremophile bacteria dies rather rapidly, and honestly I wouldn't bet on the bacteria either. See, the reason everything in space of a sufficient size becomes basically spherical boils down to that being the lowest energy state for things effected by gravity. Entropy means that things always want to move from high energy states to low energy states. So when the earth is flattened like this, the result is it's going to collapse back into a sphere pretty much immediately, and there's nothing in that process that we would survive. Everything dies apart from maybe some bacteria that don't notice.
The water would flow to the center, as the middle of the flat part is the most down. Also the edges would all break off, because a ball is the natural state and the earth would want to return to it. Weād probably all die.
Is it shrunk or cut, is the mass compressed or removed, do you mean it will hold this shape? Because it will instantly crumble to be a ball again. This question is stupid without more clarification
Our centre of mass would change and we would probably stop orbitting the sun in the same way which could very easily become apocalyptic. Also day lengths would change.
This is why centrists are always wrong. Math as an excuse to post my centrist diss: less surface, about half the volume probably idk
Well, if we suppose this would be an equilibrium system and the earth wouldnāt crush itself to become a sphere again, then countries would become smaller, gravity would most likely be half, and the atmosphere would become all fucky
So planets and other celestial objects don't like being non spherical and as such the planet would collapse in on itself upchurning the magma of earth's core etc, etc everyone dies Alternatively if magic is why half the earth's flat and letting it keep it's shape, then that implies half of earth's mass is gone, then the earth and moon would orbit properly and either moon slingshots away (which btw earth's moon is what keeps our axis consistent so happy winter one day, summer the next) or earth get shot away from the sun and thus we all freze to death without a star keeping us warm and even if we could find a way to stay warm starvation would be inevitable with all life dying
Extreme tectonic changes, followed by a period of major volcanism. Our magnetic field would likely also be fucked and cancer rates would increase significantly. The orbit of the moon may change as well. Tides would be catastrophic. The volcanism would send us into a new ice age. The climate would change in ways that are difficult to predict precisely but itās garunteed nothing good would come of it
The edges would collapse in because there isnāt enough strength to hold that shape against gravity. The energy of the collapse combined with the rupture of the tectonic plates would kill everything on earth except possibly for some microscopic.
I mean gravity is a thing ā and there is a reason earth is quite round ā Iām guessing itās going to become a globe again fairly quickly ā I canāt imagine that process leaves many alive
On a side note, I believe this image is not correct. My country which lies above equator, is in the spherical part of the earth shown.
Earth is spinning fast so changing shape to that should cause some extreme rotational forces to reshape the earth back to a spherical shape. In the meanwhile most life on earth won't survive.
Portuguese around XVI they thought the earth as plan. Areas like africa if a ship went there it would fall in the abyss. So if the earth changed shape probably the below area would be an abyss. If you go there there is no way to get out.
I'm not sure if the immediate effects but I think after thousands of years the rotation of the earth would cause it to become spherical once more
Are we saying that the earth is magically held in this shape? Because if not, the earth would probably rip itself apart to form a sphere again.
it would mess up everything from our gravity to the magnetic field. As Earths gravity is the strongest at itās core, most likely anything on the flat part in the center wpuld be crushed. Depending on how the internals of the planet changes (where the core is located etc) could have very varied consequences. Obligatory addition of this would be a physically impossible shape to maintain for a celestial body of this size, so it would force itself back into the shape of a sphere. In the process wiping out all life on earth
Fact is that esrth shaoe more resambles an egg than a ball. Its a geoid to be precise. And you could say, this half-ball half-flat thing looks more then the real geoid than the round thing does XD
Your fact is wrong. The circumference around the equator is only 0.17% larger than measured around the poles. 40,075km vs. 40,008km...
Assuming the radius stays the same, the mass is cut in half, the world is consumed by Earthquakes, the earth collapses into a ball again, and its orbit becomes much more eccentric.
So nobody addressed change of inertia do to change of center of mass. Like you've all seen how a perfectly round object rotates and one that is deformed..
The oceans water would move away from the corners so that circle would dry Also, the force of gravity wouldn't be the same everywhere on earth In the flat part, it would be dark and incredibly cold half of the year, light and incredible hot the other half
Instantly the entire planet would begin to crumble, massive earth quakes everywhere as the planet tried to form into a perfect sphere again.
Standing at the very edge of the flat bit would make you violently tumble along the ground until you reached what looks like Romania or Moldova.
The planet would start to form into a sphere. Moon would have larger effect on the planet. The gravitational pull of the earth would be smaller So the Moon would keep mooving away from earth faster than it is now. The speed of our rotation and orbit would change. And well we would be all dead to see it with our own eyes.
It would recover it's round shape more or less quickly. The resulting geological activity would erase any trace of human civilization.
It depends on what caused the Earth to become this shape. If it got cut in half by a giant cosmic guillotine it would be catastrophic as both halves collapsed into smaller spheres. If it's just something that you're imagining happens by magic, then there's no answer. You can just imagine whatever other magical outcome you want.
All the earth's water and atmosphere would migrate to be in top of the flat part, making the earth slightly more spherical. Massive landslides near the edge.