How come the sun floats?

Answer

The sun is one of about 100 billion stars in the galaxy. All stars, including the sun, exert gravity on the other stars. However, the force of gravity decreases with distance. The gravity of a single star at a great distance is therefore very small, but because there are so many stars, the sun (with all the planets orbiting around that sun) still “feels” the collective effect of all those stars.
The sun is surrounded by stars in all directions, so it has gravity in all directions. Because the sun is pulled about equally from all sides, the sun just stays more or less in place in the galaxy. There is no single direction in which gravity is greater, and therefore the sun has no reason to “fall” in any particular direction.
This is not entirely correct, because the gravitational force is indeed greater in the direction of the center of the galaxy because there are more stars there. But the sun itself revolves around that center in great circles, just as the earth revolves around the sun. As a result, the sun does not fall to the center of the galaxy.