We picture the asteroid belt as a dense field of tumbling rock, but the spaces between its objects are so vast that spacecraft can fly straight through it, with the chance of hitting anything almost nil.

We picture the asteroid belt as a dense field of tumbling rock, but the spaces between its objects are so vast that spacecraft can fly straight through it, with the chance of hitting anything almost nil.

The asteroid belt of the films is a wall of tumbling rock, the kind a pilot has to weave through at speed while boulders close in from every side. The real belt between Mars and Jupiter holds more than a million sizeable objects, and a spacecraft can fly straight through it without steering around a single one. The chance of striking anything on a given crossing is close to nil. The two pictures are hard to reconcile until you look at the volume…