In Praise of Ernest Marsden

Tomorrow would be the 122nd anniversary of the birth of Ernest Marsden, the man who discovered the nucleus for the man who discovered the nucleus. As an undergraduate at the University of Manchester studying physics, Marsden became a laboratory assistant for Ernest Rutherford, who like Marsden hailed from New Zealand, but had found his way into the scientific circles of early 20th century England. Rutherford was loud, brash, and, compared to his contemporaries at Cambridge, shockingly uncouth. But that is what endeared him to J.J. Thompson, discoverer of the electron and the most powerful scientist in the country.

Having discovered the electron, tiny particles of negativity in the atom, Thompson had proposed the "plum pudding model" in which these electrons swam in a soup of positivity making an electrically neutral atom. Rutherford, along with his assistant Hans Geiger, was testing whether such a model fit observation. So they devised an experiment wherein they would fire alpha particles -- large projectiles from an atomic point of view, at very thin foil of gold. Most would go through, some would deflect. They would need statistics on the angle of deflection. This meant sitting in an incredibly dark basement staring for tiny flashes and meticulously recording them for hours upon hours upon hours. Rutherford was brilliant, but had little patience and so the job was given to Marsden.

He did what an undergrad research assistant is supposed to do -- the crapwork. And he was careful noting all of the scintillations for hour after long hour. Even some that reflected at very large angles, something that should not have happened. He could have waved it off as his eyes playing tricks. But he didn't. He recorded it and looked for it, such flashes not happening often. But he told Geiger and Rutherford about it.

Rutherford took Marsden very seriously despite their difference in social position and thought about what would cause such radical changes in direction. It had to be something hard. And thus was discovered the structure of the atom, something for which Rutherford received the Nobel Prize.

But behind every great advance, there are people quietly who do the hard work. We rarely give these folks the credit they deserve, but they are always there. The world is full of gaffers and gophers, secretaries and offensive linemen, ghost writers and joke writers, TAs and RAs, people who don't get the glory or adoration, but whose dedication is paramount in making things work. Happy birthday Ernest Marsden and thanks to all the Ernest Marsdens out there.