heavens has in some way been resolved, with the knowledge that 13.7 billion years have passed since the primordial fireball let loose its power. Like exacting surveyors, we have scoped out the shape of visible space. In a wry twist on the legacy of Columbus, we can finally proclaim that the universe is flat—at least in three dimensions and possibly in five dimensions. Cosmology has ample reason to glow in triumph.

In the particle realm, scientists similarly have much cause for celebration. Two of the four forces of nature are united as the electroweak theory, a highly successful physical model with astonishing predictive powers. As for the strong interaction, quantum chromodynamics remains widely accepted. It is more difficult to work with than the other models but nevertheless seems to serve well. With regard to gravity, true, there’s no quantum theory as of yet. But at least it is well described by Einstein’s remarkable theory. So far, all known measurements of general relativity appear to verify its validity. Optimism abounds in the superstring community that a “theory of everything” will soon be forthcoming.

Many times in the history of knowledge, various thinkers have proclaimed the imminent end of science. Practically all there is to know, they’ve asserted at such moments, has already been discovered. For example, in the late 19th century, physicists considered Newtonian physics a perfect description of mechanics and Maxwell’s equations a complete model of electromagnetism and light. Though these theories harbored mutual contradictions, many scientists believed that the existence of aether could help explain these. Physics seemed virtually complete. Only a few “minor mysteries,” such as the reason for discrete spectral lines and the origins of radioactivity (discovered in 1895), appeared to remain. Nevertheless, it was those very conundrums that opened up the floodgates, ushering in waves of new scientific activity.

Today cosmology has arrived at a concordance model—one that meshes well with all known data. Probes of distant supernovas,



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