weight
It was gravity.
First of all, the atmosphere is the air. Secondly, air is matter, all matter is affected by gravity. Imagine this: the sea is liquid, it lies on the earth, pulled by gravity. the atmosphere is also like this except it is a "sea" of air, it lies on the earth, pulled by gravity.
gravity
the force of gravity.
Gravity is NOT matter, it is a force that effects matter.
everything is pulled by gravity. solids, liquids, everything...
There is no definite boundary for matter not being pulled toward a black hole. At large distances the effects of a black hole's gravity are not different from that of a different object of the same mass. How far out a black hole's gravity is dominant depends on that black hole's mass and its proximity to other massive objects.
Gravity pulled it in.
Gravity.
gravity
gravity
Objects are pulled towards the center of the Earth due to gravity.