There were enough evidences to prove that the radius of electrons is very small. In fact, this radius reflects the very small charge radius of electrons. After all, if the charge radius of an electron is large enough, our existing technology can certainly measure it. The problem now is that if the charge radius of the electron is very small, then the energy of the electrostatic energy possessed by the electron will be very large, at least much larger than the mass of the electron itself. However, in various calculation processes, we had ignored this electrostatic energy of electrons. For example, when calculating the energy level of hydrogen atoms, we only needed to consider the mass of electron, not the energy possessed by the electrostatic field of electrons. So where did the static electricity of this part go? This article believed that this part of the electrostatic energy distribution corresponded to the so-called "space-time" concept, and it was probably an important part of what we called "dark energy". This article made some estimates of the distribution of electrostatic energy, and estimated the distribution of electrostatic energy for the electron, the earth, and the Milky Way based on the assumed distribution of electrostatic energy in the solar system.