It was a major fail. There I was, a naive undergraduate, waiting in my professor’s office as he spoke with an older student about some theoretical problem that wasn’t working out. After the student left I boldly asked him: “Couldn’t you just redefine everything to make it come out OK?” The withering look that followed told me all I needed to know about how really stupid my suggestion had been. Rewriting X as Y in all the equations wasn’t going to help anything.
But what are the options when a scientist faces a problem with no obvious solution?
That is the dilemma astronomers have faced over the last few decades as they took a census of cosmic matter and motion. Mapping the beautiful pinwheel arcs of spiral galaxies, they found the constituent stars moving far too fast to be explained by the galaxies’ known mass. All matter produces a gravitational force that tugs surrounding material into motion. But summing up all the matter they could see in the pinwheels left astronomers with far too small a reserve to explain how fast the galaxies were spinning. -Adam Frank (Photo credit: M.J. Jee and A. Mahdavi/NASA/ESA/CFHT/CXO)