Everyone on Earth has an intimate knowledge of the "force" we call Gravity. We all experience it every moment of our lives, and generally expend the vast majority of our effort working against it. We don't need a physics degree to know that it's not easy to jump more than a couple feet off the ground, and sending an object into orbit around the Earth takes an enormous amount of rocket fuel.
In fact, if you take a look at the formula for universal gravitation, you'll notice that the strength of force is dependent only on the mass of the objects involved and the distance between them. What I would like to emphasize here is that there is no limit in mass or distance. The farthest star in the Milky Way Galaxy is exerting a force on you, just as you are exerting a force on the most distant galaxy in the Universe. Granted, if you do the math you will see that the gravitational attraction between such distant objects is very weak, however, when you consider that there are approximately 300 billion stars in our Galaxy alone, and at least as many Galaxies in the Observable Universe... It quickly becomes apparent that the humongous amount of mass swirling all around us, even at great distances, has an appreciable effect on our lives.
Physicists are still struggling with their conception of Gravity and the reasons why there are observed phenomena that we don't yet understand completely, such as the accelerating expansion of the universe. While they continue to work out the math and devise experiments to explain what we experience, we know one thing is for certain - everything is affected by and therefore connected to everything else.