Atomic clocks are the basis upon which a second is defined. But there is a new kid on the block, the optical clock, which ...

The great Russian physicist and Nobel laureate Lev Landau once remarked that "cosmologists are often in error, but never in doubt." In studying the history of the universe itself, there is always a ...

THIS compact little volume contains a vast array of chemical and physical constants. Since the first publication in 1914 it has passed through eight editions in the United States—a sufficient ...