Why bother with tentative research?

Our astronomer ponders the state of the science in the middle of the last century, when things were so different and difficult.

Our astronomer recently had occasion to refer to a textbook on statistics for astronomers published in 1951.  Not because somehow older is better, but different authors have different ways of approaching a subject, and sometimes a chance comment can be illuminating.  Also, this is a “classic” text, which means it’s hard to learn from but is likely to have a full development of aspects that others only refer to.

Much of the book is concerned with working out the motions of stars near us in the Milky Way.  “Near us” means within about 50 parsecs, which is a tiny bubble compared to the rest of the Galaxy, but beyond that they simply did not have the data.  Even within that distance there was not very much.  Those were the days when each star had to be painstakingly measured by hand.  The authors admit from the start that they don’t have good figures for enough stars to reach reliable conclusions, and can only give some tentative results.

Some forty years later, a satellite was placed in orbit to gather the kind of data these authors needed.  In fact it measured over a thousand times as many stars as our authors had available, and to almost a hundred times better precision.  The tentative conclusions of mid-century were replaced with confident answers.

So would it not have been better just to wait until enough progress had been made to enable a good job?  Granted, a high-precision satellite in orbit was not something one would predict in 1951, but astronomers were gathering more data all the time, and eventually there would be enough to answer the questions.  Why spend all the time and effort to do something that was at best tentative?

We can think of several reasons.  First, even starting the analysis will tell you what additional data you need, and thus guides your observing program.  Second, even a tentative conclusion allows you to rule some things out and to suggest a new set of questions.  A small amount of progress is still progress.

Third, the various fields of astronomy are all related.  A tentative insight into stellar motions has a direct bearing on the formation and evolution of the Milky Way, as well as on the internal workings of individual stars.  The science has to fit together as a whole, so several results in different parts that all point in the same direction inspire confidence, even though each may not be very reliable in itself.  Conversely, if there is no consensus it may mean some rethinking or reworking is in order.

Not all progress in science is revolutionary.  Sometimes a tentative conclusion is all you can get.  At least it allows you to move on.