Whats the Energy Density of the Vacuum?
John Baez August 25, 1999 People talk a lot about “vacuum energy” or “zero-point energy” – that is, the energy density of empty space. In cosmology, people also call this quantity the “cosmological constant”, or “dark energy”. Sometimes kooky people get really excited about the idea that if we could only use this energy somehow, all our problems would be solved. But first things first! Does this energy really exist? And if so, how much of it is there? Once upon a time, someone named Amw wrote: >I have heard widely varying numbers for so called “zero point >energy”, some as low as practically zero and some as high as >astronomical. It gets to the point I am not sure what to think. To which I replied: Yes, one hears lots of conflicting stuff about this. However, you’ve come to the right place to get to the bottom of it all. Here’s the deal. We have two fundamental theories of physics: quantum field theory and general relativity. Quantum field theory takes quantum mechanics and special re
