How would the universe look without gravity? It would have no planets and no stars. Thats how it looked when it was young. When the universe was young, there was only gas and dust. From this gas and dust, everything we now see was made. How were stars and planets created from just gas and dust? The answer is gravity. The same gravity that holds you down on Earth. The same force that causes your pencil to roll off your desk. The same force that causes it to fall to the floor. The invisible force of gravity caused dust and gas particles to be pulled together. This force is what formed all the objects in our solar system. This force formed the smallest moons. It also formed our Sun. This force caused more than just our solar system to form. It caused all the other solar systems to form. It caused the formation of all the galaxies of the universe. 
What force causes pencils to roll off your desk and fall to the floor?
It's cylindrical shape