I'm reading A Universe From Nothing by Lawrence M. Krauss, and I encountered a paragraph that I found confusing:
The source of the infinity is easy to describe. When we consider all possible virtual particles that can appear, the Heisenberg Uncertainty Principle implies that particles carrying ever more energy can appear spontaneously out of nothing as long as they then disappear in ever-shorter times. In principles, particles can therefore carry almost infinite energy as long as they disappear in almost infinitesimally short times.
- I don't understand what this means by ever-shorter times. How can something disappear faster than it appears if it appears in an instant?
- I was under the impression that there are no physical phenomena which are infinite (indeed, such a phenomenon would be impossible to measure) -- this paragraph seems to be suggesting otherwise?