You have a new summer job with NASA and are working on astronomical observations using electromagnetic radiation that is not in the visible range. Your supervisor has explained 21cm radiation….
estimate how long the electron and positron can exist before annihilating.
You are performing research on quantum fluctuations in empty space. In one type of fluctuation, an electron– positron pair (Section 44.2) appears in empty space. This process appears to violate the conservation of energy principle, since the rest energy of the particles has been created from nothing. According to Equation 39.24, however, this violation of conservation of energy can exist as long as the particles annihilate with each other in a time interval consistent with the energy–time version of the uncertainty principle. You employ this principle to estimate how long the electron and positron can exist before annihilating.