IT’S WONDERFUL TO IMAGINE HOW EXCITING IT MUST have been. Just picture yourself as a passenger on one of the trains that rolled past Thomas Edison’s workshops on summer nights in 1879. The newspapers were full of stories about the Wizard of Menlo Park and his latest project, an audacious plan to create a practical electric light and use it in vast numbers to illuminate all of downtown Manhattan. As the trains went by Edison’s labs, passengers could plainly see bright light coming from inside the buildings — light that obviously didn’t come from candles, lanterns, or gas lamps. Those riders must have felt they were looking into the future.

Few moments in the history of technology have engaged the imagination of ordinary people as did Edison’s invention of the incandescent light. On October 22,1879, Edison’s search for an affordable filament material led him to carbonized thread, and it glowed for an astonishing 14Vi hours on one of the first tries.

My own plans include a toast to Edison on another big anniversary of the light bulb, New Year’s Eve. His Wizardness isn’t usually remembered as a party animal, but he threw an unforgettable bash on December 31, 1879. At least 3,000 partygoers accepted an invitation to come to Menlo Park in New Jersey to see in the year 1880 by the light of incandescent bulbs both inside the buildings and along the paths connecting them.

It is fitting that the light bulb stands out in the popular mind as Edison’s best-known accomplishment. He pursued it especially doggedly. He is justifiably remembered for being able to focus enormous amounts of time, effort, and money on his work, logging long hours and maintaining goals for months and years, but the light project was special even by his standards.

He began talking about the invention—bragging, really—long before he’d done much work on it. He enjoyed public attention as much as reporters loved giving it to him, and he provided headlines about how he intended to make gaslight obsolete. On September 16, 1878, more than a year before building the first practical bulb, he was quoted in the New York Sun : “I can light the entire lower part of New York City, using a 500 horse power engine.” He added that manufacturing his bulbs would be simple. “I can produce a thousand, aye, ten thousand lights from one machine.”

If you know anything at all about Edison’s work on the light bulb, you know that his biggest breakthrough was his discovery that a suitable filament could be made from carbonized thread. Carbon was a much more affordable material than platinum, which he used in his first experiments. What’s missing from most popular accounts of the story is that the development of a practical light bulb was really just the beginning of the project. Edison’s laboratory bulbs ran on batteries or small generators, but he had to develop an improved generator to supply consumers. He had to design and manufacture systems of wires, connectors, regulators, fuses, insulators, fixtures, switches—everything needed to safely conduct power from his generators to the private homes and businesses of his customers. By the beginning of 1880 he had built the work force at Menlo Park to 60 men constituting a modern-looking research-and-development project.

In retrospect, the most remarkable fact about Edison’s incandescent lamp may be how little it has changed in 125 years. Modern tungsten filaments burn longer and brighter than Edison’s carbon, but there’s little else to distinguish the bulbs we use today from those he produced more than a century ago. And a growing number of experts argue that consumers are overdue for a better, more innovative bulb.

The problem involves efficiency. More than 90 percent of the energy consumed by an incandescent bulb produces heat instead of light. Twenty percent of the world’s electricity provides lighting. This means that a huge amount of electricity is wasted in the production of lighting. Clearly, better efficiency could provide enormous savings and reduce the emissions of toxic waste and greenhouse gases produced by power plants.

A partial solution came during the 1920s, when H. M. Edmund Germer invented a practical fluorescent lamp; Germer joined Edison in the National Inventors Hall of Fame in 1996 (Edison was the very first inductee, in 1973). Fluorescent lights are four times as efficient as incandescents, which is why most commercial and industrial buildings use them. But most home lighting fixtures are still designed to accept incandescent bulbs. In the 1990s the U.S. Department of Energy became sufficiently concerned about this to direct its Pacific Northwest National Laboratory to run a program to encourage manufacturers to produce compact fluorescent lights, or CFLs, for incandescent fixtures. As a result of the program, consumers can now buy a wide selection of strange-looking lights with twisted, spiral bulbs; CFLs account for 3 percent of the residential lighting market.

Perhaps the biggest irony in the story of the electric light is the unintended consequence known as light pollution. If you haven’t heard that term, visit the Web site of the International Dark-Sky Association, www.darksky.org . There you’ll find a vast archive of information about the downside of artificial illumination.

The main idea espoused by the IDA is that the wasteful use of lights is bad for the environment, the economy, and especially astronomers. The association estimates that at least two billion dollars’ worth of electricity is wasted annually in the United States by outdoor fixtures that send light skyward, where it isn’t needed or wanted. The glare is so overpowering that half of all Americans have never seen the Milky Way, a glorious natural spectacle known to everyone before Edison came along.

The IDA proposes several remedies. One is improved light fixtures that direct all their output downward. The amber light of highly efficient low-pressure sodium fixtures is considered a better choice than most alternatives, especially Edison-style incandescents. Lamps activated by motion detectors are recommended to replace outdoor fixtures that blaze unattended all night. Owners of retail centers are asked to reconsider the wisdom of lighting parking lots all night for stores that aren’t open. The IDA is especially critical of Edison’s bulb. An IDA press release from 2002 said: “The American home-owning public needs to give up its love affair with incandescent lighting. As familiar as it may be, it’s extraordinarily expensive and wasteful.”

If all this sounds a bit weird, consider the case of Tucson, Arizona, where the International Dark-Sky Association is strongest. There, astronomy is a local industry because the city is only 56 miles from the cluster of large telescopes affiliated with the National Optical Astronomy Observatory on Kitt Peak. The scientists, engineers, and support staff at the observatory make a significant contribution to the local economy, and locals take pride in the fact that the University of Arizona’s Tucson campus hosts one of the most advanced astronomy departments in the world. But Tucson is a fast-growing city, and the increased glare threatens to force the astronomers to move somewhere darker. As a matter of self-interest, Tucson officials have committed to a program that includes replacing streetlamps, discouraging glare, and promoting an awareness of the problem of light pollution.

Last year I saw the results first-hand, during a vacation trip to Arizona. Tucson is a strikingly beautiful city at night. There are plenty of streetlights, billboards, and illuminated retail areas, but they tend to do a better job of directing the light where it does the most good. “Full cut-off” streetlights feature shaded bulbs that don’t produce glare. Instead of being dazzled by the unshaded blue brilliance of mercury vapor lamps, nighttime drivers in Tucson travel through glowing golden corridors of light directed down to the street instead of into their eyes. This is the result of a desire to both help the astronomers and save on energy bills, but the most noticeable effect may be that Tucson looks much better than other cities.

Like many of you, I grew up in a house ruled by a father who opposed wasting electricity. Anytime one of us kids left a light on in a vacant room, Dad gave us a lecture about the high cost of energy. It turns out Dad was right.