Invited comunication
D. Wittman
Abstract
Dark matter makes a wonderful case study in the nature of science. What should astronomers do when they see orbits that apparently conflict with the known law of gravity? Two competing explanations always arise: dark matter (unseen mass influencing the orbit according to the known law of gravity) and modified gravity. I will briefly review two historical examples—one in which dark matter turned out to be the correct explanation and one in which modified gravity turned out to be correct—to set the stage for the modern conception of dark matter. Turning to the present, I will explain how merging clusters of galaxies prove the case for dark matter despite its apparently extravagant violation of Occam’s razor. Looking to the future, I will show how the latest observations of merging clusters could tell us something surprising about dark matter.
American Association of Physics Teachers annual meeting
Sacramento, CA, USA
2016 July
