The Great Dane would leave a legacy that few would even dream of rivaling. Niels Bohr was a quiet and shy man, whose contribution to 20th century physics is so fundamental that, without it, the whole edifice would only be half built. His brilliant insights into physical problems not only gave solutions, but also taught the world a new way of thinking of a physical problem – think of only what can be explained and what can be observed, leaving all your philosophical baggage behind. Bohr, the great, celebrates his birthday today and Google honours him with a doodle.
Bohr’s great insight
If you asked me to judge the doodle, I would just give it passing grades; Google could’ve easily been more imaginative. The doodle shows an atom, given by the Bohr’s atomic model (well, not quite, but more on that in a bit) and a photon (particle of light) being emitted having exactly the right frequency. This frequency times the Planck’s constant gives the energy of the photon. It turns out that the transition of an electron from a higher energy level to a lower one would involve the emission of a photon with energy equal to exactly the difference between the levels and this was Bohr’s great insight.
So what problem was I referring to about the Bohr’s Atomic Model? Well, Bohr’s Atomic Model doesn’t involve elliptic orbits*. It just involves electrons going around the nucleus in circular orbits. So just a bit mistaken there! (*See corrigendum below)
Bohr happened to be on the Manhattan Project too. His escape out of Nazi occupied Denmark is the stuff of folklore. Apparently, he received a permit letter, allowing him to leave Copenhagen when Denmark was being captured by the Nazi power in the 2nd World War. This special permit came probably from Heisenberg who was holding a high position in the department of science in Nazi establishment. Niels Bohr was then smuggled out of Denmark and given a safe haven in America.
More than just a scientist
So Bohr! More than being a brilliant physicist, he was also a pioneer. He was one of the founding fathers of CERN, 1954. Where we would be without the Great Dane. And of course, the Copenhagen Institute which housed the great minds of the 20th century at a time was co-founded by Niels Bohr.
An atom wouldn’t be the same without you! Happy Birthday Niels Bohr.
Corrigendum from the author: A good friend of mine and a regular reader of the blog, Joe Phillips Ninan, research scholar at TIFR, Mumbai, wrote to me pointing out that my conclusion of the orbits not being circular is incorrect. He says that they are circles oriented in 3D planes and thus just look like ellipses, but are not actually ellipses. This is what he wrote to me in an email:
I carefully checked the pixel position of the nucleus in the Google Doodle image. They lie exactly at the center of line connecting the diameter. Hence they are not elliptical orbits with nucleus at one of the foci. They have drawn only perfect circles, oriented in different planes in 3D.
Good point Joe and it’s gracefully accepted. The hasty error on my part is regretted.