Yin Wu

A galaxy is like a cosmic highway where stars, like cars, race along circular orbits. Their speed is set by the invisible "cargo" of mass enclosed within the orbit: the more massive the central region, the faster the stars at the periphery.

A ship with hundreds of passengers is caught in a storm, and the captain hands out life rings. Some people need a ring, while for others it will only get in the way. Oncology faces the same challenge: after surgery to remove a breast tumor, doctors prescribe chemotherapy, but it is not clear in advance which patients will benefit and which will only get side effects with no gain.