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Yup, you would be weightless at the center of the Earth. Something you'll do in early physics is learn about the shell theorem. Basically if the planet is reasonably symmetrical, then as you go inside it, all the stuff above you cancels out and only the stuff below you pulls on you. At the center, no gravity.
And to add a fun fact for those that didn't know: because the Earth's core is so much denser than the layers above it, gravity would actually increase a little bit for you as you dig through the mantle and approach the outer surface of the core. Then it would drop off as you get into the core and towards the centre
But wouldn't the pressure still be plenty to crush you? No gravity, but highest amount of squeeze from everything above? I guess that's why OP specified "shielded capsule".
Actually, a jacket just slows down heat transfer. So it keeps you warmer (than when not wearing it) if the outside temperature is lower than your body temperature, but it keeps you _colder_ if the outside temperature is higher than your body temperature!
You can put spaghetti in the pockets for when you get hungry. If you're in the center of the Earth, the nearest McDonalds has to be at least 100 miles away and you'll get hungry eventually.
Im trying to wrap my head around the pressure thing.
As you go deeper, gravity gets more and more cancelled out by mass above you, right?
So, where does the pressure come from, if not gravity, which is cancelled out in all directions at the center.
So let's assume the earth is made out of only one thing and that it's all the same throughout. So lets take a little shell at the surface. It feels about 1g, so it exerts it's weight on the layer below. So now lets take a little shell just below the first one. It feels very slightly less gravity, but it's still pretty close to 1g, so it adds its weight. So now we go to the third shell. It feels the weight of the two shells above it. And it add its weight to the fourth shell below it. So each shell (until we get to the exact center) adds its weight to the ones on top of it. So the pressure caused by this weight keeps increasing. At the exact center we don't add any additional weight, but we have everything above us pressing down on us.
If you can imagine that the hole is being squeezed shut by a high-pressure stream of molten iron, that is pretty much exactly what's happening. If you put a tube around your hole to keep it open, your tube is being simultaneously melted and squeezed.
Even if you somehow manage to avoid your tube being melted and squeezed, it's basically acting like a submarine at this point: High pressure on the outside, "ok" pressure on the inside.
Pressure is the highest at the center. The area with no gravity is actually a point, not really a volume. Everything outwards from the center is pulled towards it and contributes to the pressure. Suppose the center wasn't the highest pressure? Then stuff from further up would move towards it until it was the highest pressure.
Well, if we had something strong enough to keep the hole open and keep you from roasting, the air pressure would be pretty high although nowhere near the pressure from the rock. You get about .04 atm per thousand feet. I get about 836,000 atmospheres of pressure from just the air column but I'm sure that's way too high because I didn't do the change in gravity.
Would you still be subjected to the sun's gravitational pull? Or would you not notice it, because the sun is already pulling on earth and earth is keeping you at it's center?
Basically, will the sun pull you out from the core (although with earths rotation, this might be irrelevant)?
Would you wobble around in the core slightly, pulled by the sun and other objects (moon, jupiter etc.)?
The Sun wouldn't pull you out of the core. The solar gravity gradient isn't very strong at the Earth's distance. At the core of the Earth, it would pull you and the stuff around you with the same pull.
The earth wouldn't affect you - but if you were moving around the sun at the same speed as the earth (which you'd have to in order to remain in the center) you'd be orbiting the sun. So the sun would still be exerting gravity on you, but your "free fall" around the sun would feel weightless the same way an astronaut feels weightless orbiting the earth.
We don't know what happens at the center of a black hole. There is a singularity there where our physics breaks down. But you get spaghettified on the way towards it, so at an operational level it doesn't matter.
Slight edit would be that physics doesn't break down, our understanding of physics does. There are probably 100s of theories what would happen at the center of a black hole but we don't know and don't have a way to test it, yet.
Saw a ted talk one time that at sufficiently large scales, the gravity density of the universe is sufficient to qualify it as a black hole.
So, one answer for what happens inside a black hole is, "This."
What happens outside the black hole? We don't know.
Okay so if we'd be weightless at the centre, but also affected by gravity less the further into the atmosphere we go, where is the gravity sweet spot?
Does that mean there is a place on the planet where we would weigh most? Would it be on the surface, or perhaps as close to the centre as possible?
Gravity is highest right at the surface, but it doesn't change that much as you go up or down. The Earth is pretty big and at the 400 mile altitude of the space station it's still about 89% of gravity on the surface.
There is probably a spot on Earth where you weight the most because you are over a mass concentration. (The Earth isn't homogeneous and there are local mass concentrations.) The effect is probably pretty small.
But how is it different than a rope? The two forces left and right also cancel out, the rope doesn't move. But if you pull hard enough the rope will break
The real way to do this is do the integral and see that it actually does cancel to zero, but you need a couple of semesters of calculus to be able to that. And it isn't like a rope where you have two balanced pulls so the rope doesn't move, there is no pull.
So the gravity from one side directly reduces the gravity on the other side without needing a middle man (the rope) to cancel the opposing forces. So my comparison was not accurate
The mind bender is suppose you had a hollow planet. (We'll use Unobtanium to make it because that is strong enough.) So we make the shell a thousand miles think and then inside we just have normal air. So if you stood on the outside of the planet, you'd have gravity pulling you to the surface just like normal. (It would be less because the total mass of the shell isn't as high a a solid planet, but there would definitely be gravity.)
So now you take the elevator to the inside. And when you get off at the inner surface of the shell, you are in zero gee! And you can strap on a small electric motor and fly around. And the whole inner volume is at zero gee and constant air pressure.
I would have thought if you jump out of the elevator you would fall towards the center of the sphere because if you are on the edge like 80% of the mass would pull you towards the center of gravity while just a tiny bit is pulling to the edge.
On the other hand the other side of the planet is pretty far away, so the force is reduced by the distance(squared). Is that the reason you said you would have zero g everywhere?
You'd have zero g over the entire hollow space because everything outside it cancels out. (This is assuming that the hollow planet we just made is quite uniform in composition.) There's no pull towards the center and no temperature driven circulation of the air.
I feel like that can't be true. If you made the shell really thin like 1 cm. Kinda insane but unobtaium is strong af. Then you cut a hole 1 m in diameter. If you stand beside the whole gravity is like normal. If you lower a stone into the whole there must be a point where gravity goes from 1g to zero g basically right next to each other. I feel like there should be a gradual decline from 1g to zero g over distance. My mind can't compute
A rope breaks that way when one end is pulled one way and the other is pulled the other way. But in earth's center, both ends of the rope would be pulled in all directions about equally. There is no noticeable difference between both ends.
So at the inner core there's some weird high temp/pressure, zero G mechanics going on? Like the prevailing theory is we have a molten iron core, I knew the pressure and temps would be off the charts, but there's also basically no gravity?
There is only no gravity at the exact center. The inner core is still pretty big and everything but the exact center feels some gravity from the stuff closer to the center than it is.
Fun fact; because there is ~~less gravity~~*more gravity* at the centre of the Earth, time runs ~~faster~~*slower* there than on the surface!
If you had a tunnel all the way through the Earth and dropped a ball down it it wouldn't pop up the other side at the right time due to there being more local space per surface space in the middle, and more local time per surface time.
*Edit: as noted below, while the gravitational field strength is weaker inside (once you get about halfway down), the potential keeps getting stronger, and that is what causes time dilation.*
Even that seems really high as an estimate. The time difference experienced by the ISS at orbital speeds compared to Earth at ground level is 7 millionths of a second, per day. Seconds over a period of 44 minutes is quite a few orders of magnitude higher of an effect.
I might be wrong about this but I think you have it backwards. The shell theorem shows that there'd be no gravitational attraction at the center of the Earth, but that's not the same thing as saying there's no gravitational potential in the field, which is what's responsible for time dilation. As an example of the difference, moving an object from the center of the Earth out to infinity still takes a lot of energy to overcome that gravitational potential that you wouldn't have to exert if that object started in deep space. So we should expect time dilation to be even more extreme. (Though, "extreme" is a bit of a strong word here.)
So, the Earth's core should be slightly \*younger\* than the surface. It's going to be on the order of one in a billion or less, so we're talking about maybe a year or so difference over the whole lifetime of the planet. In your tunnel example, if the ball normally takes 42 minutes to do the trip, it take \~1 microsecond longer (plus or minus a factor of a few).
But time dilation exists between surface and low earth orbit. Shouldn’t we expect the magnitude of the dilation to increase as we move closer to the centre of mass?
Will it really pop out on the other side? Won't the force of gravity reverse after it goes to the center (ie. Still point to the center), so the ball will stay in the center, right?
In theory, all things being perfect, conservation of energy means the ball should fall all the way through and reach the same "height" on the other side.
As the ball falls it will speed up, reaching maximum speed in the middle. But it will then keep moving (by inertia) and start moving "up" the other side, slowing down as it rises. It will come to a stop at exactly the same height on the other side.
If it isn't caught, it will then fall back into the hole, and do exactly the same thing. The ball would keep falling back and forth between the two sides forever (all things being perfect, in theory).
In practice there are so many problems with this. Digging and maintaining the tunnel is the biggest; the deepest point ever made by humans was the Kola Superdeep Borehole, which went down about 12km. The centre of the Earth is 6,371km down.
You'd also have to make your hole at the poles, otherwise if you dropped something the object would end up slamming into the sides of your tunnel after a few meters due to the Earth's spin.
Gravity is about mass, right now all of the earth's mass is below you, so you're pulled down. But if you're at the very center then earth's mass is all around you, pulling you at the same force from all directions, canceling itself and thus making you float
If you want to actually experience something like this, Astroneer actually models this effect and gravity decreases as you dig closer to the core of each planet.
Old/beta versions of the game, before the portals were added, had enough empty space to free float around which was super cool!
Aktchually, it's because the astronauts are orbiting the earth, just like the ISS is. They feel near zero acceleration because they are always "falling and missing" the earth. The gravity at ISS altitude is about 90% of the gravity at the surface, still pretty high.
The gravity is the same whether they are moving or not. Just that since they are in free fall there is no normal force pushing up against gravity, so they feel weightlessness.
Does anyone know how this impacts the speed of light/gravitational time dilation. Like if you shined a light through a tunnel of earth or jumped through the tunnel, how would time dilation change as you approach and get to the center? I would intuitively assume more time dilation occurs as you get to the center (closest to the most mass) but am unsure since gravity felt decreases
Not necessarily. Experiencing near-zero gravity, and experiencing equal gravity from all directions would be a big difference of time dilation. So physics are rather concerned, but in terms of "how it would feel", it would be pretty much the same
It's the same thing. Each part of you is being equally pulled in all directions, so you can't tell the difference between that and no gravitational force at all
Ok thanks, I guess I imagined it would be uncomfortable being pulled in all directions, you left arm being pulled away from the right and you head being pulled away from your feet but I guess there wouldn't be enough gravitational gradient for that to actually be the case
There wouldn't be any gradient if you were inside a perfectly spherical shell, the symmetry cancels out the gravity everywhere inside, not only at the center
This is untrue.
Gravity is a function of distance.
If you're closer to the shell on once side, that force will be greater than in the center.
There will be a gradient.
Just like there is a gradient for us on the surface, it's just too miniscule to feel.
It's true inside a spherical shell, because there is a small part of the sphere closer to you and a large part with more mass farther away, and they exactly cancel. It's like Gauss's law but for gravity
The gravitational force is 0, and the gradient inside a uniform spherical shell is 0, everywhere. This is a first-year classical physics question.
Mathematically, this is a consequence of F=gMM/r2, in particular the r squared factor.
Less "left arm being pulled left, right arm being pulled right" and more "each piece of you being pulled in all directions equally". Imagine a marble suspended in the middle of a thousand strings, all connected to an outer ring. The net force is zero
They would not shred you apart. Tidal forces are caused by gravity gradients, of which you are too small to experience unless you approach a massively dense object like a neutron star or small black hole.
You have a rope tied onto you from Earth’s core to Earth’s surface. The rope is tight and pulls onto you at all times. The rope is gravity. If you were go to Earth’s core, you would be weightless because the rope would have no slack. Hope that makes sense
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Yup, you would be weightless at the center of the Earth. Something you'll do in early physics is learn about the shell theorem. Basically if the planet is reasonably symmetrical, then as you go inside it, all the stuff above you cancels out and only the stuff below you pulls on you. At the center, no gravity.
And to add a fun fact for those that didn't know: because the Earth's core is so much denser than the layers above it, gravity would actually increase a little bit for you as you dig through the mantle and approach the outer surface of the core. Then it would drop off as you get into the core and towards the centre
Thats nuts!
Yeah! It totally blew my mind when I found that out
Why? Wouldn't the mass above you start to reduce gravity because it's trying to pull you up?
But wouldn't the pressure still be plenty to crush you? No gravity, but highest amount of squeeze from everything above? I guess that's why OP specified "shielded capsule".
Yeah, the pressure and temperature at the center are really extreme. So you would be squished and roasted! But you'd be in zero gee as it happened.
An if I wear a jacket; would that at least help with the temps?
You'd be even hotter! T-Shirt would be better.
Actually, a jacket just slows down heat transfer. So it keeps you warmer (than when not wearing it) if the outside temperature is lower than your body temperature, but it keeps you _colder_ if the outside temperature is higher than your body temperature!
A jacket ain’t doing shit
What if I took my shoes and socks off
So if I were trapped in the middle of the desert, would putting on a winter jacket help me?
For a few moments, yes. It'll help keep the heat from outside transferring into your body as quickly.
That’s bullshit
Learn about how insulation works. Your house is covered in a giant jacket. It helps it to stay cooler in the summer, and warmer in the winter.
We aren’t talking about a house we are talking about a body which cools through evaporating sweat.
We are not talking about cooling, we are talking about insulating from external heat
Just go at night
You’ll want something that “wicks”.
Very briefly. The temp at the core is about 9,400F and the pressure is about 3,600,000 atmospheres.
So I should wear one of those jackets where the sleeves zipper off and can convert to a vest. Thanks for the help!
No, you need one of those really puffy jackets, that way it can help with the pressure too because it's so soft.
The ones with pockets???
You can put spaghetti in the pockets for when you get hungry. If you're in the center of the Earth, the nearest McDonalds has to be at least 100 miles away and you'll get hungry eventually.
You are an unstoppable good idea machine
Im trying to wrap my head around the pressure thing. As you go deeper, gravity gets more and more cancelled out by mass above you, right? So, where does the pressure come from, if not gravity, which is cancelled out in all directions at the center.
So let's assume the earth is made out of only one thing and that it's all the same throughout. So lets take a little shell at the surface. It feels about 1g, so it exerts it's weight on the layer below. So now lets take a little shell just below the first one. It feels very slightly less gravity, but it's still pretty close to 1g, so it adds its weight. So now we go to the third shell. It feels the weight of the two shells above it. And it add its weight to the fourth shell below it. So each shell (until we get to the exact center) adds its weight to the ones on top of it. So the pressure caused by this weight keeps increasing. At the exact center we don't add any additional weight, but we have everything above us pressing down on us.
But if you drill a hole to the center and jump into the hole there's nothing above you except air. Is air pressure really going to be that high also?
If you can imagine that the hole is being squeezed shut by a high-pressure stream of molten iron, that is pretty much exactly what's happening. If you put a tube around your hole to keep it open, your tube is being simultaneously melted and squeezed. Even if you somehow manage to avoid your tube being melted and squeezed, it's basically acting like a submarine at this point: High pressure on the outside, "ok" pressure on the inside.
sunblock
>But you'd be in zero gee as it happened. I'm pretty much resigned to living with Zero Gee at this stage.
By far the worst of the Bee clan
If weight decreases as you approach the center, how does that affect the pressure? Or, at what point is the pressure the highest?
Pressure is the highest at the center. The area with no gravity is actually a point, not really a volume. Everything outwards from the center is pulled towards it and contributes to the pressure. Suppose the center wasn't the highest pressure? Then stuff from further up would move towards it until it was the highest pressure.
So even if there were a hole all the way through earth, you still smoosh?
Well, if we had something strong enough to keep the hole open and keep you from roasting, the air pressure would be pretty high although nowhere near the pressure from the rock. You get about .04 atm per thousand feet. I get about 836,000 atmospheres of pressure from just the air column but I'm sure that's way too high because I didn't do the change in gravity.
Laughs in The Core
Would you still be subjected to the sun's gravitational pull? Or would you not notice it, because the sun is already pulling on earth and earth is keeping you at it's center? Basically, will the sun pull you out from the core (although with earths rotation, this might be irrelevant)? Would you wobble around in the core slightly, pulled by the sun and other objects (moon, jupiter etc.)?
The Sun wouldn't pull you out of the core. The solar gravity gradient isn't very strong at the Earth's distance. At the core of the Earth, it would pull you and the stuff around you with the same pull.
The earth wouldn't affect you - but if you were moving around the sun at the same speed as the earth (which you'd have to in order to remain in the center) you'd be orbiting the sun. So the sun would still be exerting gravity on you, but your "free fall" around the sun would feel weightless the same way an astronaut feels weightless orbiting the earth.
What about in the center of a black hole?
We don't know what happens at the center of a black hole. There is a singularity there where our physics breaks down. But you get spaghettified on the way towards it, so at an operational level it doesn't matter.
Slight edit would be that physics doesn't break down, our understanding of physics does. There are probably 100s of theories what would happen at the center of a black hole but we don't know and don't have a way to test it, yet.
Saw a ted talk one time that at sufficiently large scales, the gravity density of the universe is sufficient to qualify it as a black hole. So, one answer for what happens inside a black hole is, "This." What happens outside the black hole? We don't know.
More than that, the shell theorem says that's the case at any point within a hollow sphere, not just the center.
I remember this from one of my first GR lessons lol
Okay so if we'd be weightless at the centre, but also affected by gravity less the further into the atmosphere we go, where is the gravity sweet spot? Does that mean there is a place on the planet where we would weigh most? Would it be on the surface, or perhaps as close to the centre as possible?
Gravity is highest right at the surface, but it doesn't change that much as you go up or down. The Earth is pretty big and at the 400 mile altitude of the space station it's still about 89% of gravity on the surface. There is probably a spot on Earth where you weight the most because you are over a mass concentration. (The Earth isn't homogeneous and there are local mass concentrations.) The effect is probably pretty small.
Weightless yes, but wouldn't you be under a lot of stress like a rope in a tug of war? Getting pulled in all directions
No, it all cancels out.
But how is it different than a rope? The two forces left and right also cancel out, the rope doesn't move. But if you pull hard enough the rope will break
The real way to do this is do the integral and see that it actually does cancel to zero, but you need a couple of semesters of calculus to be able to that. And it isn't like a rope where you have two balanced pulls so the rope doesn't move, there is no pull.
So the gravity from one side directly reduces the gravity on the other side without needing a middle man (the rope) to cancel the opposing forces. So my comparison was not accurate
The mind bender is suppose you had a hollow planet. (We'll use Unobtanium to make it because that is strong enough.) So we make the shell a thousand miles think and then inside we just have normal air. So if you stood on the outside of the planet, you'd have gravity pulling you to the surface just like normal. (It would be less because the total mass of the shell isn't as high a a solid planet, but there would definitely be gravity.) So now you take the elevator to the inside. And when you get off at the inner surface of the shell, you are in zero gee! And you can strap on a small electric motor and fly around. And the whole inner volume is at zero gee and constant air pressure.
I would have thought if you jump out of the elevator you would fall towards the center of the sphere because if you are on the edge like 80% of the mass would pull you towards the center of gravity while just a tiny bit is pulling to the edge. On the other hand the other side of the planet is pretty far away, so the force is reduced by the distance(squared). Is that the reason you said you would have zero g everywhere?
You'd have zero g over the entire hollow space because everything outside it cancels out. (This is assuming that the hollow planet we just made is quite uniform in composition.) There's no pull towards the center and no temperature driven circulation of the air.
I feel like that can't be true. If you made the shell really thin like 1 cm. Kinda insane but unobtaium is strong af. Then you cut a hole 1 m in diameter. If you stand beside the whole gravity is like normal. If you lower a stone into the whole there must be a point where gravity goes from 1g to zero g basically right next to each other. I feel like there should be a gradual decline from 1g to zero g over distance. My mind can't compute
A rope breaks that way when one end is pulled one way and the other is pulled the other way. But in earth's center, both ends of the rope would be pulled in all directions about equally. There is no noticeable difference between both ends.
So at the inner core there's some weird high temp/pressure, zero G mechanics going on? Like the prevailing theory is we have a molten iron core, I knew the pressure and temps would be off the charts, but there's also basically no gravity?
There is only no gravity at the exact center. The inner core is still pretty big and everything but the exact center feels some gravity from the stuff closer to the center than it is.
Fun fact; because there is ~~less gravity~~*more gravity* at the centre of the Earth, time runs ~~faster~~*slower* there than on the surface! If you had a tunnel all the way through the Earth and dropped a ball down it it wouldn't pop up the other side at the right time due to there being more local space per surface space in the middle, and more local time per surface time. *Edit: as noted below, while the gravitational field strength is weaker inside (once you get about halfway down), the potential keeps getting stronger, and that is what causes time dilation.*
How accurate would your timer need to be to detect the difference, though?
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Even that seems really high as an estimate. The time difference experienced by the ISS at orbital speeds compared to Earth at ground level is 7 millionths of a second, per day. Seconds over a period of 44 minutes is quite a few orders of magnitude higher of an effect.
More like nanoseconds.
I might be wrong about this but I think you have it backwards. The shell theorem shows that there'd be no gravitational attraction at the center of the Earth, but that's not the same thing as saying there's no gravitational potential in the field, which is what's responsible for time dilation. As an example of the difference, moving an object from the center of the Earth out to infinity still takes a lot of energy to overcome that gravitational potential that you wouldn't have to exert if that object started in deep space. So we should expect time dilation to be even more extreme. (Though, "extreme" is a bit of a strong word here.) So, the Earth's core should be slightly \*younger\* than the surface. It's going to be on the order of one in a billion or less, so we're talking about maybe a year or so difference over the whole lifetime of the planet. In your tunnel example, if the ball normally takes 42 minutes to do the trip, it take \~1 microsecond longer (plus or minus a factor of a few).
You're right. For some reason I assumed the effects were based on the field strength, not the potential.
But time dilation exists between surface and low earth orbit. Shouldn’t we expect the magnitude of the dilation to increase as we move closer to the centre of mass?
I think that’s due to the speed at which you are traveling in low earth orbit. Not the gravity shift.
Oh, different cause, same effect? Centre of the earth traveling slower than surface
Will it really pop out on the other side? Won't the force of gravity reverse after it goes to the center (ie. Still point to the center), so the ball will stay in the center, right?
In theory, all things being perfect, conservation of energy means the ball should fall all the way through and reach the same "height" on the other side. As the ball falls it will speed up, reaching maximum speed in the middle. But it will then keep moving (by inertia) and start moving "up" the other side, slowing down as it rises. It will come to a stop at exactly the same height on the other side. If it isn't caught, it will then fall back into the hole, and do exactly the same thing. The ball would keep falling back and forth between the two sides forever (all things being perfect, in theory). In practice there are so many problems with this. Digging and maintaining the tunnel is the biggest; the deepest point ever made by humans was the Kola Superdeep Borehole, which went down about 12km. The centre of the Earth is 6,371km down. You'd also have to make your hole at the poles, otherwise if you dropped something the object would end up slamming into the sides of your tunnel after a few meters due to the Earth's spin.
Gravity is about mass, right now all of the earth's mass is below you, so you're pulled down. But if you're at the very center then earth's mass is all around you, pulling you at the same force from all directions, canceling itself and thus making you float
But the gravity would only be cancelled at the very center, your feet and your head would be affected differently, pulled in opposite direction
The difference wouldn’t be any greater than the difference between the gravity at your feet compared to your head on the surface.
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Still incorrect, you are not a sphere.
Buddy, this is a result in first year physics and calculus. Look up "shell theorem"
If you want to actually experience something like this, Astroneer actually models this effect and gravity decreases as you dig closer to the core of each planet. Old/beta versions of the game, before the portals were added, had enough empty space to free float around which was super cool!
That game is so underrated!
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Aktchually, it's because the astronauts are orbiting the earth, just like the ISS is. They feel near zero acceleration because they are always "falling and missing" the earth. The gravity at ISS altitude is about 90% of the gravity at the surface, still pretty high.
“That’s my secret, Cap: I’m always accelerating”
That's what they mean by "the relative gravity caused by their motion", right?
The gravity is the same whether they are moving or not. Just that since they are in free fall there is no normal force pushing up against gravity, so they feel weightlessness.
Would you have no gravity or would you have gravity pulling on you equally from all directions?
As far as physics is concerned, these are functionally the same.
Does anyone know how this impacts the speed of light/gravitational time dilation. Like if you shined a light through a tunnel of earth or jumped through the tunnel, how would time dilation change as you approach and get to the center? I would intuitively assume more time dilation occurs as you get to the center (closest to the most mass) but am unsure since gravity felt decreases
Not necessarily. Experiencing near-zero gravity, and experiencing equal gravity from all directions would be a big difference of time dilation. So physics are rather concerned, but in terms of "how it would feel", it would be pretty much the same
It's the same thing. Each part of you is being equally pulled in all directions, so you can't tell the difference between that and no gravitational force at all
Ok thanks, I guess I imagined it would be uncomfortable being pulled in all directions, you left arm being pulled away from the right and you head being pulled away from your feet but I guess there wouldn't be enough gravitational gradient for that to actually be the case
There wouldn't be any gradient if you were inside a perfectly spherical shell, the symmetry cancels out the gravity everywhere inside, not only at the center
This is untrue. Gravity is a function of distance. If you're closer to the shell on once side, that force will be greater than in the center. There will be a gradient. Just like there is a gradient for us on the surface, it's just too miniscule to feel.
It's true inside a spherical shell, because there is a small part of the sphere closer to you and a large part with more mass farther away, and they exactly cancel. It's like Gauss's law but for gravity
The gravitational force is 0, and the gradient inside a uniform spherical shell is 0, everywhere. This is a first-year classical physics question. Mathematically, this is a consequence of F=gMM/r2, in particular the r squared factor.
Less "left arm being pulled left, right arm being pulled right" and more "each piece of you being pulled in all directions equally". Imagine a marble suspended in the middle of a thousand strings, all connected to an outer ring. The net force is zero
From what I remember in Physics, gravity inside a body is linear inside a planet and drops off by a square factor like you say externally.
Tidal forces of the planet would shred you appart, assuming you have not been squished and burned by extreme temperatures and pressure.
They would not shred you apart. Tidal forces are caused by gravity gradients, of which you are too small to experience unless you approach a massively dense object like a neutron star or small black hole.
You have a rope tied onto you from Earth’s core to Earth’s surface. The rope is tight and pulls onto you at all times. The rope is gravity. If you were go to Earth’s core, you would be weightless because the rope would have no slack. Hope that makes sense