...The Times started its science section in 1978. A year later the same folks who publish Penthouse brought forth Omni, a mix of science and speculation. In rapid succession the American Association for the Advancement of Science, publisher of the journal Science, started Science79; Time Inc. started Discover; and Science Digest expanded to a full-size glossy magazine. The New York Academy of Sciences published The Sciences.

This profusion led to a hiring frenzy for science journalists, who, for a golden while anyway, had a blast producing magazines on scales of time and money that seem unworldly today.

A decade later most were gone or struggling for lack of advertising, despite circulations in the range of half a million and despite the growing importance of science in an age of climate change, energy crises and AIDS. The lone survivor of that golden era, Discover, has been sold four times. A more recent arrival, Seed, noted for its edginess, exists only online.

The audience has fragmented among stalwarts like National Geographic and Scientific American; blogs; and new-media adventures like the TED talks, the World Science Festival and Edge.org, the online salon, and Simons Science News, a new effort by the mathematician and philanthropist James H. Simons. ...