Masses warp the spacetime. As a result, the shortest distance between two points in spacetime is not a straight line. Spacetime is curved and warped. Bodies follow the path of less resistance, i.e., these short paths in spacetime. When the Earth moves around the Sun, it follows this short path.
Wormholes shortcut spacetime.
This effect shows that the light consists of particles, the photons, whose energy is proportional to the frequency of the light. A light beam shines on the anode of a photocell. We can measure the kinetic energy of the emitted electrons by reversing the voltage and measuring the potential that stops the current. The kinetic energy of the emitted electrons is equal to the electron charge times the stopping voltage. We observe that there is no current flowing for small frequencies of light.