Life at the Cutting Edge
Physicists often refer to the theories of relativity and quantum physics as “modem physics, to distinguish them from the theories of Newtonian mechanics and Maxwellian electromagnetism, which are lumped together as “classical physics. As the years go by, the word “modem” seems less and less appropriate for theories whose foundations were laid down in the opening years of the twentieth century. Nevertheless, the label hangs on.In this closing chapter we consider two lines of investigation that are truly modem but at the same time have the most ancient of roots. They center around two deceptively simple questions:
What is the universe made of?
How did the universe come 10 be the way it is?
Progress in answering these questions has been rapid in the last few decades. Many new insights are based on experiments carried out with large particle accelerators. However, as physicists bang particles together at higher and higher energies using larger and larger accelerators, they come to realize that no conceivableEarth-bound accelerator can generate particles with energies great enough to test • their ultimate theories. There has been only one source of particles with these energies, and that was the universe itself within the first millisecond of its existence. In this chapter you will encounter a host of new terms and a veritable flood of particles will the names that you should not try to remember. If you are temporarily bewildered, you are sharing the bewilderment of the physicists who lived through these developments and who at times saw nothing but increasing complexity with little hope of understanding. If you stick with it, however, you will come to share the excitement physicists felt as marvelous new accelerators poured out new results, as the theorists put forth ideas each more daring than the last, and as clarity finally sprang from obscurity.