July 30, 2004

Small Solar Systems

While passing by the Smithsonian Aerospace Museum yesterday, I noticed the solar system scale model along the sidewalk of Jefferson avenue. A gilded sphere about ~15 cm across was the sun, and along the next few 600 meters plates (on Star Trekesque stands) marked the planets and gave information about them. Each planet was a tiny dot on an oval glass screen.

Such scale models are fairly common. One of the largest is the Swedish Solar System scale model (once officially completed, it will likely become the largest). Here the spherical Globen arena in Stockholm is used as the sun, placing more human-sized planet sculptures across a good part of Sweden. Pluto ends up in Delsbo (about 300 kilometers away), and the Sun's terminal shock in Kiruna (950 km). The Venus model is near me at the Royal Institute, and it is pretty neat, a meter sized sphere with inscriptions reminding of its properties (such as H2SO4 for the sulpuric acid). Several of the sculptures of other planets seem to be rather nice too, like the tomb-like monument around the Pluto model or the little gold model of Eros.

Which system model is the best? The Smithsonian one is sized to get an impression of the width of the system. One can walk along it with reasonable exertion. But the planets are dissapointing tiny dots. The Swedish one has SCALE - knowing the sheer size of everything involved really brings home how large the system is. But one can never see the other planets; there will not even be a line of sight between the Moon and Earth models.

In a sense all attempts of showing the scale fails because there are two very different size scales that one wishes to show, the scale of the orbits and entire system and the scale and features of the planets themselves. But since they are so different that cannot be showed at the same time: either the system becomes graspable but the planets become meaningless dots, or the planets become plausible worlds but then the system becomes unmanageably large.

It is of course possible to cheat by using different scales for orbits and planets or a logarithmic approach, but that is misleading or confusing. Far too much bad science illustrations and science fiction gives the impression that space is crammed with planets. Similarly, the vast difference in size between Jupiter and Earth is often hidden. These misconceptions should not be perpetuated.

In the end it might be that the only good way of getting a simultaneous feeling of the planets themselves and their distances is 3D astronomy programs like Celestia that allows you to fly between the planets. Simulations instead of models, removing us from some of the limitations of street space. But until the simulations gives us a strong sense of presence the solidity of these walkable models still has something important to contribute.

Posted by Anders2 at July 30, 2004 05:12 PM

"I may kid around about drugs, but really, I take them seriously."
- Doctor Graper

Posted by: fioricet at August 16, 2004 07:59 AM