Empty space is never truly empty.

In quantum mechanics, the concept of a vacuum differs significantly from the classical idea of 'nothingness.' According to the Heisenberg Uncertainty Principle, formulated by Werner Heisenberg in 1927, there is a fundamental limit to how precisely we can know certain pairs of physical properties. This principle implies that energy and time have a similar relationship, meaning energy can never be exactly zero for any period of time.This fluctuation results in the constant creation and destruction of virtual particles, such as electron-positron pairs. These particles emerge from the vacuum, exist for an incredibly brief moment, and then annihilate each other. Physicist John Wheeler coined the term 'quantum foam' in 1955 to describe this turbulent, microscopic structure of spacetime at the Planck scale, which is approximately 1.6 x 10^-35 meters.Evidence for this phenomenon was famously demonstrated by the Casimir effect in 1948. Dutch physicist Hendrik Casimir predicted that two uncharged conductive plates placed micrometers apart in a vacuum would be pushed together by the pressure of these virtual particles. Experimental verification in 1997 by Steve Lamoreaux at Los Alamos National Laboratory confirmed that the vacuum does indeed exert a measurable force.This zero-point energy suggests that even at absolute zero temperature, space contains a residual amount of energy. Modern cosmology also links these vacuum fluctuations to the expansion of the universe and the cosmic microwave background radiation. Understanding this 'nothingness' remains one of the greatest challenges in unifying general relativity with quantum field theory.