Gravity always attracts a mass toward the center of the Earth.
If you were to dive into a tunnel through the center of the Earth and stretch your
arms out like Superman as you descended, then the force of gravity would point
in the direction of your fingers until you reached the center, and in the direction of
your toes after that. So you might say that the direction of the force had switched
around when you passed the center.
But if you knew enough Physics to dive into such a tunnel in the first place, then
you would know that the force is always directed toward the center of the Earth,
and that "down" means different directions in different places, and you would not
interpret it as a 'switcheroo'.
Since the atmosphere is more or less symmetric, its center of mass (center of gravity) gravity must be quite close to Earth's center.
center of earth
center of earth
that is gravity
Yes. At least, the gravity resulting from planet Earth.
in the core
No. Earth's gravity is a result of its mass. Every bit of mater on and within Earth contributes to its gravity.
No. At the centre of the earth the acceleration due to gravity is ZERO
That all depends on the shape of the object and how its mass is distributed. The center of gravity of a solid sphere is at the center of the solid sphere. The center of gravity of a solid cube is at the center of the solid cube. The Earth's center of gravity is at the center of the Earth, and there's certainly plenty of mass there. But the center of gravity of a ring is at the center of the ring ... an open space where the finger goes.
Roughly 3,960 miles from the center of the earth.
The Earth. Actually, technically, the Moon and Earth revolve around a common center of gravity, but that center of gravity falls within the earth itself.
Gravity, which is a function of the earth's mass, is a constant force toward the center of the earth.