There would be no net gravitational force at the center of the Earth (due to the Earth alone), if the Earth were perfectly spherical and made up "shells" of material of uniform density.
In fact, the "real" Earth is pretty close to those "ideal" requirements.
You can use the "related link" below, to confirm these details.
Of course, actually reaching the Earth's center is impossible with present technology. We haven't even drilled very far down yet.
Molten lava could disintegrate you long before you ever reached the center.
In fact, the center of the Earth is reckoned to be at about the same temperature as the surface of the Sun!
Also, there are huge pressures inside the Earth.
Another answer:
Imagine a hole that is drilled straight through the center of the earth from one side to the other. This hole is big enough to jump into. I jump in *crazy thing to do*; at that point I am falling.
As I approach the center of the earth, the question is, do the gravitational forces increase, or do they cancel.
If gravity increases, than I have the potential of exceeding my muscular-skeletal capacity to sustain me. (Try to forget the molten core for just a few minutes.)
If gravity cancels, than I have the potential of hanging around for quite sometime.
Through observation, we know that as an object goes further from the Earth, it feels less of Earth's gravity. If it goes far enough away from the Earth, it will not be affected by Earth's gravity. As objects get closer to Earth, gravity increases. But in all of those observations, the mass of the whole planet has always been to one side of the object that is being attracted. For example, when a plane is in flight, the mass of the whole planet is pulling the plane downward.
I do not know of any observational models that clearly demonstrate the concept of a larger mass (one with appreciable gravity) surrounding a smaller mass (one with negligible gravity). I would suggest, however, that since mass is directly proportional to gravitational attraction, and, at the center of the earth all of the mass is outward, toward the surface in all directions, that if I were in the center of the earth, I would be attracted outward, evenly in all directions. It would feel as if I were in a non gravity environment.
Hypothesis: In the center of the earth, gravitation forces, acting evenly outward in all directions, create a limited spherical zone where gravity is canceled.
So I believe the first answer is right.
Questions not figured into this hypothesis include: In the canceled gravity zone would I become aware of the effects of the Moon's gravity, or the gravity of the Sun?
NOTE on celestial body gravity. Their effects would be there, but about on the same order that astronauts feel when they are in orbit. Not enough for human senses to really pick up. While in orbit, you technically experience microgravity, not zero gravity.
Take the example of drilling a hole all the way through the Earth (ignoring the molten outer core and other problems).
You would indeed encounter effectively zero gravity at the center of the Earth.
I say effectively, because people are not points - so there would be microgravity effects that are felt most at your extremities.
An object dropped into that theoretical hole drilled through the Earth would accelerate towards the center of the Earth.
At the center of the Earth its speed would reach its maximum.
The object would continue to move, but would start getting slowed by the increasing net gravity pulling it back towards the center.
The object should just reach the surface on the other side of the Earth, ignoring frictional forces and other complications. Then it would start to fall again.
But even barring lava, I doubt you'd survive in a hole drilled through. And this is because the air pressure would crush you. The net effective force of gravity at the center is zero, but that air column will have a lot of pressure, most of that air is not at the center, is encountering the effects of gravity and is crushing you.
A second note on a person not being a point: If your center of mass was positioned exactly on the center of mass for the Earth, you would actually encounter a slight gravitational force PULLING you apart. I suspect it would be negligible and no more noticeable than the Sun's pull. If someone wants to do the integral calculus for a human shape in a sphere we could figure out the effective gravitational pull.
Yes, Mecca is "centre" of Earth. It is scientifically proved.
It is not scientifically proven yet, but the Muslims believe that Mecca should be the centre of the Earth!
Another Answer: The centre of the Earth is a very hot place and is under very high pressure. You wouldn't like to be there. It is about 4000 miles below the surface.
If gravity were somehow "turned off," all planets and stars would explode outwards due to high pressure within their cores. There would be no attraction between masses, and solar systems and galaxies would break apart. The Universe would go back to being a dense soup of matter.
Without gravity, the earth's atmosphere could not be retained, so there would be no breathable air at the surface, an likely no life forms as we know them. The climate would also be quite different because we rely on the greenhouse effect to maintain the earth's temperature. Without an atmosphere temperatures would be extremely warm during the day and extremely cold in the night. Think of the moon as an example. However, without gravity, the earth would not be rotating in an orbit around the sun, so it is hard to say what the earth would be like, or the entire universe, for that matter.
As you deep towards the center of the earth, the distance decreases but mass remains the same and gravity is based on both mass and distance from the surface
Additional answer
Basically, gravity as the attraction by any part of the Earth. If you are in the middle, the attraction of each side of you cancels out.
There is no place on the surface of the earth where there is no gravity.
However, if you are sky-diving or in a special plane, roller coaster, or other device that can allow you to experience free fall, you will not feel the pull of gravity, although you are still responding to it.
You get to pick one. Either you can fall, or there can be no gravity. If you're going to set out two contradictory conditions, then what happens is purple monkey dishwasher; it's pointless to even try to speculate how things would work in a universe where you could fall despite there being no gravity.
So: let's keep gravity, and let's assume there's a hole that goes ... well, let's make it go all the way through the earth, we're going to need some braking room on the other side. The hole is lined with something that doesn't melt at the 6000 K or so temperatures in the center of the Earth.
Now: you jump in.
What happens is you fall. For now let's neglect air resistance (we've pumped all the air out of the tunnel, and you're in a space suit so you can breathe). You fall faster and faster as time goes on, but if you were to very carefully measure, you'd notice that your acceleration was decreasing... you're still falling faster each second than you did the last, but not as much faster as the difference between last second and the one before that.
Long before you get to the center of the Earth, you die from bursting into flame. 6000 K, remember? So let's say the tube protects you from that somehow too.
Now, when you reach the center, your acceleration drops to zero. But you're moving extremely fast already, so you zip right past it and notice that your acceleration is now negative ... you're slowing down. This will continue until you JUST reach the surface on the opposite end of the tunnel and come out in China (or whereever ... actually, if you started on land, you'll probably come out in the middle of an ocean).
At this point you start falling back into the hole. This continues forever.
Well, except that you need to start at either the North or South pole, because the Earth is turning, and if you're free falling you're going to smash against the side of the tunnel. So let's say you do that.
Now let's let air back into the tunnel. It's a relief to get out of that space suit.
What happens now is that your speed reaches a maximum at some point due to air resistance, and you won't come out the other end, you won't get even close. Instead you'll slow to a stop somewhere on the other side (but not at the other end) and start falling back toward the center. You'll keep oscillating line this as friction (air resistance) damps your motion more and more, until you finally come to a stop in the center.
all the planets will fly off to space.
more likely, the sun, planets, stars, galaxies, etc. would never have even formed to begin with.
If the earth had no gravity it follows that gravity would be absent from any mass. In the absence of gravity life would not exist.
with out it we would be floating around gravity pulls everything down to the center of the earth
If the Earth would be a perfect sphere, you would experience no gravity in the center because all the mass around you would pull at you with the same strength in all directions, netting you a zero total force.
Your weight is the result of the force of gravity. Without gravity you would be weightless and would float away. This does not happen on the top of mountains. Because you are farther from the center of the Earth, your weight is slightly less on top of a mountain, but compared to the diameter of the Earth, mountains are quite small, and the difference in weight is very slight, and would not even be noticed. So yes, you feel gravity on top of a mountain.
At the center of the Earth there would be no effective gravity; a pendulum wouldn't work as a pendulum.
If the earth had no gravity it follows that gravity would be absent from any mass. In the absence of gravity life would not exist.
It will never happen because the earth's gravity is caused by it's mass and it's density.
we would be heavy
There would be less gravity on earth.
with out it we would be floating around gravity pulls everything down to the center of the earth
As you go down below the surface, the force of gravity would decrease, because now part of the Earth is attracting you from above, and less from below. At the center of the Earth, gravity would be zero.
we can fly
The earth would become a black hole.
It would be impossible NOT to have gravity, on planet earth atleast. But if we were to have no gravity, we would just float around unable to stay in one spot for atleast a minute. That includes everything else, trees, water ect. would not stay in place. This would NOT be a suitable place for humans to inhabit. Gravity is the force that pulls everything towards the center of the earth. (Thank you gravity. :D)
All the objects will float if there will be no gravity. Gravity is the earth's pull on objects.
It would get bigger
If the Earth would be a perfect sphere, you would experience no gravity in the center because all the mass around you would pull at you with the same strength in all directions, netting you a zero total force.