Gravity glues our universe together. Without it, neither we nor any life could exist. The Earth spins at just over 1,000 miles per hour at the equator. Without gravity, anything loose on the surface like water, cars, picnic tables, and people would immediately fly off into space. Without gravity, Earth couldn’t keep an atmosphere. As soon as it drifted free from the surface, the fierce solar wind would blast it away. Without gravity the Sun itself would expand, dissipating in a fine, cold mist of dust and gas.