Stardate 20020427.1403

(On Screen): Chris Kerstiens notes that astronomers have set the age of the universe at a bit over 13 billion years, and he wonders why anyone should care.

It's not as useless as he might think (though his characterization of it as being "based on a picture" is not really correct). What was going on here was to resolve an apparent paradox. There were stars in certain globular cluster whose ages could be calculated, and they gave a minimum age for the universe (since the universe can't be younger than what it contains). The other way of dating the age of the universe was based on what's known as the "Hubble Constant", a value which is probably going to be very important. It's a measurement of the rate at which the universe is expanding, and using it and extrapolating backward you can figure out where the beginning was.

The Hubble Constant has been calculated progressively more closely by measuring the redshift of extremely distant galaxies and using independent means of measuring their distances. (Measuring astronomical distances is a fascinating subject but too complicated to go into here.) For a while, calculations based on the Hubble Constant gave an age of the universe quite a lot younger than the age of some of its oldest stars, which was a problem. Now it's been resolved, much to the relief of astronomers.

This is not futile. It's not just of intellectual interest. This is basic research into a field known as cosmology. Cosmology has greater scope than any other field of science of which I know because it concentrates on scales all the way from sub-atomic particles up to the overall size of the universe. Astronomical observations give us information about how atoms are put together, and study of atoms gives clues to the astronomers.

What will the information be used for? It's difficult to say right now. All I can do is to give historical examples.

In the 19th century, scientific orthodoxy was that light was a wave, which meant it had to pass through some sort of medium. That became known as the luminiferous ether, and in the 1880's it occurred to an American scientist that it should be possible to measure the speed at which the Earth moved through it. The math is a bit complicated, but if the ether had existed, he really would have measured that velocity. The reason is that he would find a different speed of light in the direction of motion than he would find laterally to it.

The only problem was that even using the best equipment available at the time (and it was very good) every measurement he could take said that his apparatus was standing still, or rather that the speed of light in all directions was always the same. It didn't matter what time of day, or when in the year it was, his apparatus couldn't measure any movement. That simply didn't make sense.

So what were the outcomes of the Michelson-Morley experiment? Among other things, nuclear weapons and semiconductors. How could making very precise measurements of the speed of light lead to that? In 1887, it surely couldn't have been predicted. But his experiment led directly to the Theory of Relativity and to the development of Quantum Mechanics. (QM was required to explain how light could be a wave without a medium through which to travel. The Michelson-Morley experiment is generally accepted as proving that there was no ether. Relativity, on the other hand, was needed to explain why it was that the speed of light is always a constant, which the Michelson-Morley experiment directly proved was the case.)

By the same token, the reason cosmology may have radically important results is that it is basic research into how the universe is constructed and how it was put together. One thing they're trying to do is to explain how the four forces were created and why they have the strengths they do. Another thing is to try to figure out what matter really is. (We can point to it, but we can't yet explain it. In particular, we can't yet really explain why matter and energy are interchangeable, though we know it's true.)

Working out the age of the universe is important partly because it helps to solidify our measurements of the Hubble constant. It's also necessary in order to evaluate different proposed models of the first few hundred years (let alone the first few hundred nanoseconds) of the life of the universe, and those theories could conceivably have extremely dramatic effects on our ability to understand and manipulate the universe.

What might come out of this? Anti-gravity, for one thing. No, I don't know how to do it. But Michelson didn't know how to set off a nuclear bomb in 1887, or how to build a computer either. I think antigravity is a long shot, but it's not inconceivable. A much more likely outcome would be controlled conversion of mass into energy without using such crude and indirect approaches as fission or fusion. If we really know what mass is, and how mass/energy conversions take place, we might well come up with something completely new which makes that much more efficient and effective.

Once we really understand where the four forces come from and why their strengths are what they are, we might figure out how to change them locally. That opens endless possibilities.

Measuring the Hubble Constant is a piece in a large puzzle. Once that large puzzle is solved, the practical uses of it will be as dramatic as were those of quantum mechanics and relativit