The benefit of accident and coincidence in radioactivity

coincidence = [noun] a chance occurrence of events remarkable either for being simultaneous or for apparently being connected. Synonyms: accident, luck, fate

 First medical X-ray by Wilhelm Roentgen, of his wife Anna Bertha Ludwig's hand. When she saw her skeleton, Anna is said to have uttered, "I have seen my death". By Wilhelm Röntgen (public domain).During a non-accidental* wander through the Pacific Science Center’s online calendar of scientific events, I noticed one of those divine coincidences that is probably only exciting to me and maybe a few other calendar/science nerds out there.

Not that this is going to stop me sharing—it’s about radioactivity and accidents. Interested? Here goes: Marie Curie’s birthday—that’s today—is the day before the anniversary of Wilhelm Roentgen‘s discovery of X-rays.

Ahem. Maybe I should come clean about this fascinating coincidence of scientific chronology. Curie was born November 7, 1867, and Roentgen made his astonishing discovery on November 8, 1895.

What really killed the passenger pigeon?

Passenger pigeonJessica Stanton is a detective investigating a trail that’s been cold for over 100 years. She wants to know what really killed the passenger pigeon—and she’s not taking anyone else’s word for it.

Stanton, a Ph.D. student at Stony Brook University, presented last week at the Ecological Society of America’s annual meeting in Portland, Oregon, USA. Her research focuses on questions like how long it takes a species to go extinct, and how, and how much, we can help it once it’s on that path. Stanton wanted to look at a case study where we knew the outcome, so she could model the phases of decline and extinction. The passenger pigeon was especially fascinating because it was abundant and wide-ranging, which usually means a species isn’t at much risk for extinction. Yet its numbers went from billions to zero in less than 100 years.

She used a standard, matrix-based mathematical population model. She had to put in some baseline variables: fecundity (number of chicks per pigeon per year), survival (number of chicks that survive to breed), and