Creating artificial worlds to explain real ones

These days, most movies use computer animation and computer graphics.  Artificial creatures and realities are concocted so well, and spliced so seamlessly into more everyday scenes that our brains just accept everything we see. It can sometimes be very hard to determine where our reality and computer-generated realities meet. We don’t need model spaceships hanging on strings, or stop-motion animation anymore. Now our home computers have enough power for us to create computer worlds and simulations ourselves. It’s obvious how these technical advantages revolutionize entertainment and art, but it might be surprising how big an impact they are having on science, including astronomy.

Science starts with observations. The next step is to formulate a theory that accounts for those observations and also raises questions that can be addressed through further observations and research. Theories that do not raise new questions or new ways to test them are on the whole useless.

Theories that predict simple things, like, say the position of the Moon in the sky at 8 p.m. next Thursday are reasonably easy to test. However, if you are trying to understand something more complex, such as the collapse of a cosmic cloud of gas and dust to form new stars and planets, then examining columns of numbers to see how well your new theory explains the observations is not the most convenient way to proceed. When it really gets down to it, we prefer to see a picture.

For many years this luxurious way of seeing how a theory performs was not even a dream. Now it is the standard way to test models. We can simulate a little piece of the universe in a computer or supercomputer, plug in our theory as sets of relationships, and then let the program run to see what happens. Does what we see look like what we observed? Are there suggestions of additional things that we can go back to the telescope and look for? What happens if we change some of the numbers we put in? Our new tools for simulation and visualization are proving as valuable as the telescopes we use to make the observations. What we see gets us modelling, and what we learn from that sends us back to the telescopes.

A revelation from these computer applications is that you don’t need complicated rules to explain complex things.  A few simple rules are all you need to create the wisps, streaks and blobs in a collapsing cloud of cosmic material, and to “see” planets and stars forming. The puzzle is how those rules work together in that particular situation.

In addition to being scientifically useful, the images we get are often beautiful. Look at some of the star formation images available on the web, or other astronomical simulations. In addition to the images from telescopes, there are pictures and movies produced by theories and computer visualization. This realization that simple sets of rules can do such complex and beautiful things is attracting the attention of both artists and mathematicians.

Jupiter, Mars, Venus and Mercury are all clustered just to the west of the Sun at the moment, and lost in the sunrise glare. The only bright planet available is Saturn, which rises about 5 p.m. and is well up in the eastern sky by dark. Look for a moderately bright, yellowish “star”. The Moon will reach First Quarter on the 10th and will be full on the 17th.

Ken Tapping is an astronomer with the National Research Council’s Herzberg Institute of Astrophysics, and is based at the Dominion Radio Astrophysical Observatory, Penticton, E-mail: ken.tapping@nrc-cnrc.gc.ca.