What is the Zero Point Energy?

A brief layman's summary

The common perception of a ‘vacuum’ has to do with a void, or emptiness, or ‘nothingness.’  However, during the 20th century, our knowledge of what comprises a vacuum, especially the vacuum of space, took a considerable leap forward.  The old idea of a vacuum is now referred to as a ‘bare vacuum.’  But, as science has learned more about the properties of space, a new description has become necessary, one which physicists call the ‘physical vacuum.’

To understand the difference between these two definitions, imagine you have a perfectly sealed container. First remove all solids and liquids and gases from it so that no atoms or molecules remain. There is now a bare vacuum in the container. This 17th century concept gave rise to the definition of a vacuum as a totally empty volume of space. It was later discovered that this vacuum would not transmit sound but would transmit light and all other wavelengths of the electromagnetic spectrum ranging from the very short wavelength gamma rays, down to radio and longer wavelengths.

Late in the 19th century, it was realized that the vacuum could still contain heat or thermal radiation. If our container with the vacuum is then perfectly insulated so no heat can get in or out, and if it is cooled to absolute zero, or minus 273o C, all thermal radiation has been removed. It might be expected that a complete vacuum now exists within the container. However, both theory and experiment show this vacuum, the physical vacuum, still contains measurable energy. This energy is called the Zero-Point Energy (ZPE) because it exists even at absolute zero. The ZPE was discovered to be a universal phenomenon, uniform, all-pervasive, and penetrating every atomic structure throughout the cosmos. The existence of the ZPE was not suspected until the early 20th  century for the same reason that we are unaware of the atmospheric pressure of 15 pounds per square inch that is imposed upon our bodies. There is a perfect balance within us and without. Similarly, the radiation pressures of the ZPE are everywhere balanced in our bodies and measuring devices.

The origin of the ZPE may be traced to the initial expansion of the cosmos. In the same way that energy is put into the fabric of a rubber band when it is stretched, or into the fabric of a balloon when it is inflated, the fabric of space also had energy invested into it at its original expansion. The process whereby the potential energy of the stretching is changed into the kinetic energy of the ZPE is explained in this paper. This process does not occur instantaneously but takes time to accomplish in the same way that a pan of food in the oven takes time to heat. As a consequence, the strength of the ZPE has built up with time. The form of the energy in the ZPE has been demonstrated to be primarily electromagnetic fields and/or waves of all wavelengths.

There is evidence that the universe expanded out to a maximum size and then became relatively static. Narliker and Arp demonstrated that a static cosmos was stable against collapse, but would oscillate slightly about its average position. As a consequence the energy per unit volume or energy density of the ZPE will oscillate about an average value once its maximum has been attained. This occurs because the ZPE energy per unit volume is slightly greater when the cosmos was at its minimum size, and slightly less at the cosmos maximum.

To give some kind of comprehension of the vast strength of the Zero Point Energy, consider this:  Our lights in our homes are rated at about 50-150 watts per bulb. That's the energy the bulbs give out. Our sun shines with the brightness of about 3,000,000,000,000,000,000 light bulbs. Our galaxy is comprised of about 150,000,000,000 suns something like ours. If all these suns were shining for 10,000,000,000 years, that would still be less energy expended than the Zero Point Energy packs into one cubic centimeter of space! This is in each of us and everything around us and throughout the universe.

The matter in the universe, then, is almost insignificant compared to the sea of energy in which it is immersed! For this reason, the Zero Point Energy is not reduced by its interaction with matter. Thus, its strength remains fairly constant in our time.