Remember these scenes from the first Star Wars movie? It has since become the fourth Star Wars movie, of course. But it has been long said that those two suns in the skies of the planet Tatooine are too close together. In principle, a binary star system like that would be gravitationally too unstable to support planets.

So beautiful scenes of double sunset are probably quite common in the universe. So much beauty gone to waste with no one to observe them.

What we learn from this is that much of what we think we know depends on principles that come from a fairly limited body of evidence. It is another example of how science is not just self-correcting, but of how careful observation — evidence — is vital to better understanding and, in this case, of understanding where principles don't apply in the way we thought. This is — or ought to be — true when it comes to everything that we think we know, not just what we think we know about objective reality, which is science.

In astronomy, "the n-body problem" is that of determining the motions of a number — "n" — of bodies given their masses, positions and velocities at a point in time. Believe it or not, very little is known about how to solve such problems when n is greater than 2 and especially when n is greater than 3. The math just gets too complicated. This is how such a discrepancy between expectations and reality arises in the case of planets around binary star systems.

Evidence is vital even when we think we know what it "should" be. And, yes, bumble bees do fly even though an overly-simplistic — which is to say, wrong — aerodynamic analysis says they can't.