Science Follows Dark Path Trying to Explain the Observed Universe
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.
Soon, the same problem appeared in other cosmic quarters. Giant clusters of galaxies showed the same kind of mass deficit. Even data from cosmology — the study of the universe as a whole — pointed to some mismatch between what we can see and what’s out there. Something else, it appeared, was going on and astronomers were on the hook to come up with an explanation.