Since ancient times, we have been curious to knowthe origin and the nature of the universe. Numerous ancient philosophers and scientists have tried to answer these fundamental questions. It is only at the present time of the twentieth millennium that we can provide a partial answer to these questions, as some significant progress has been accomplished in both particle physics and astrophysics, which are two areas of research in two apparently opposite scale directions (see Fig. 1.1).

On the one hand, this progress is due to our ability to explore the heart of matter, with powerful accelerators (where the accelerated particle has a velocity near to the velocity of light), which reveal their infinitely small, deepest structure (see Fig. 1.2).

As an example, we show in Figs. 1.3 and 1.4, the large electron-positron (LEP) accelerator and the reaction inside the detector after the collision of the electron and the anti-electron (positron). Notice that at LEP, the energy of the electron is in the range of 90-180 GeV which is about (5–10)×106 times the energy of our home TV screen. On the other hand, powerful telescopes (see Fig. 1.5) explore the enormous structure of the universe, and may reach the time of its origin.