One of the oddest but most pleasing aspects of science is that we can measure exactly what goes in, in terms of money and effort, but we are never sure what will come out. Invest in one area, and valuable results are apt to pop up in a totally unrelated field.

To take one famous example, if you had polled the world's leading physicians in 1895 and asked them which recent discovery was most important to the future of medical science, answers might have varied from surgical methods to anesthetics to new medications. I am willing to bet that not one of them would have pointed to the curious experiments then being conducted on evacuated tubes by a man named Wilhelm Roentgen; yet his discovery of X-rays transformed the exploration of inner disease by offering an alternative to risky surgery.

In the same way, in the 1830's Michael Faraday had been fiddling about (in an inspired way - he is one of the great experimenters in history) with iron filings, magnets, rotating copper disks, hollow metal cans, and what must have seemed to many like an assortment of random rubbish. His contemporaries would have laughed at the idea that his work would transform the world. Yet I invite you to sit down and list the number of devices that you depend on every day and which rely on electricity. I started with alarm clock, lights, kettle, toaster, watch, telephone, radio, and car, and then gave up because I could not decide if I really relied on traffic lights.

One more: imagine you could consult the authorities on postal services, back in 1946, concerning the invention of that period which would by the year 2000 most affect Post Office operations. No one, I feel sure, would have pointed to the primitive electronic computer then being developed at the Moore School of Engineering in Philadelphia; yet today I and my friends rarely send letters to each other on paper, and these columns never to my knowledge see the inside of a Post Office.

These examples are all surprising. Today, however, I want to describe a piece of scientific work which intrigues me even more. Over time, from a very improbable origin, it gave an answer to a question that a century ago probably seemed forever beyond our knowledge: How old is the universe?

We begin in an unlikely place, with comet hunting. This is a rather odd hobby, practiced with zeal by a few but regarded as eccentric by the rest of us. In the 1770s, a dedicated comet hunter named Charles Messier became annoyed at the way that certain permanent hazy patches in the sky could easily be confused with his highly desirable comets. He plotted out the fuzzy patch locations, so as not to be bothered by them. This resulted in the Messier Catalog, the first and inadvertent catalog of nebulas and galaxies.

There is no evidence that Messier particularly cared what those fuzzy glows might be. He merely wanted them out of the way. However, others became interested. Over time the suspicion grew that a large fraction of these hazy patches might be galaxies composed of stars, just as our own Milky Way is made up of stars.

As telescope power increased, so did the number of galaxies, until today the number known is more than a hundred billion. Galaxies, fainter and fainter yet more and numerous as their distance increases, are seen as far as our telescopes can probe. In most respects, the distant ones looked little different from the nearest ones. But there proved to be one crucial difference. It was suggested by Carl Wirtz in 1924, and confirmed by Edwin Hubble in 1929, that more distant galaxies appear redder than nearer ones. To be more specific, particular wavelengths of light have been shifted towards longer wavelengths in the fainter (and therefore presumably more distant) galaxies. The question was, what could cause such a shift?

The most plausible mechanism, to a physicist, is called the Doppler Effect. According to this effect, light from a receding object will be shifted to longer (redder) wavelengths; light from an approaching object will be shifted to shorter (bluer) wavelengths. Exactly the same thing works for sound, which is why a speeding police car's siren seems to drop in pitch as it passes by.

Accept the Doppler effect as the cause of the reddened appearance of the galaxies, and we are led (as was Hubble) to a bizarre idea: the whole universe must be expanding, at a close to constant rate, because the red shift of the galaxies corresponds to their faintness, and therefore to their distance.

>From the recession of the galaxies we can draw another conclusion. If the expansion proceeded in the past as it does today, there must have been a time when everything in the whole universe was drawn together to a single point. It is logical to call the period since, the age of the universe. The Hubble galactic redshift allows us to calculate that length of time. The universe seems to be between ten and twenty billion years old.

This is a most remarkable result: observation of the faint agglomerations of stars first mapped by Charles Messier leads us, directly and cleanly, to the conclusion that we live in a universe of finite and determinable age. You may ask, is that of any practical use? In fact, it is. As a natural by-product, we have limits on the age of the Earth and the Sun, and every physical process. Any scientific theory which requires longer time scales for any part of it must be rejected.

Everything so far is well-documented history. Unfortunately, this same history is in many ways the bane of science. How can you ask financial support from people interested in the area of your research, when all the evidence shows that discoveries, if they are made, are likely to be most useful in unrelated areas? Worse yet, the more basic the discovery, the less likely its final uses seem to be the starting-point of the investigations.

The only method I can suggest sounds more like a game of chance than a scientific procedure: Spread the national science budget thinly, supporting as many different topics and groups as possible. One or more of them will surely hit the scientific jackpot. But if you can predict which ones, you will probably find it easier to gain fame and fortune at Las Vegas.

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