David Schramm: The Astrophysicist Who Weighed the Universe and Predicted Dark Matter

On October twenty-fifth, nineteen forty-five, David Norman Schramm was born in St. Louis, Missouri, USA. He was a theoretical astrophysicist, and his academic field was cosmology and particle astrophysics.

Schramm was a central figure during the golden age of modern cosmology in the nineteen-seventies and eighties. His groundbreaking work connected the smallest particles of particle physics with the universe's largest structures. Together with his colleagues, he used the Big Bang model to predict the number of different types of neutrinos and to calculate the amount of ordinary, baryonic matter in the universe. A crucial finding was that this calculated amount of ordinary matter was not sufficient to explain the gravitational forces holding galaxies and galaxy clusters together. This was one of the strongest early scientific arguments for the existence of dark matter – an invisible form of matter that makes up most of the universe's mass. Schramm was also a leading voice in research on Big Bang nucleosynthesis, which explains the formation of the light elements. His career was tragically cut short by a plane crash in nineteen ninety-seven, but his legacy as a charismatic force who shaped the field of particle cosmology endures.