Help me understand globers

For those of you who believe that the world is a globe, can someone please explain how our atmosphere stays around our planet without getting sucked into the vacuum of space? In every experiment you do to try and recreate the Earths atmosphere, the gases get sucked right into the vacuum. You can’t recreate our atmosphere on a smaller scale. If “gravity” gets less strong the further out you go, how is it strong enough to contain gases that are less dense than a human without there being some sort of container? And for that matter, if gravity is strong enough to keep us in orbit around the sun, why wouldn’t astronauts/spaceships be forced back to Earth as soon as they start to leave the atmosphere? How could we leave at all?