Werner Heisenberg and Wolfgang Pauli Paul Dirac

Wolfgang Pauli

We now come to the crucial question for the whole new theory Is it able to account for the properties of the hydrogen atom In the 1960s, physicists were asked to identify the greatest physicist who ever lived. Competing for the top spot were Isaac Newton and Albert Einstein. Coming up third was a scientist who lived in the third century bc, Archimedes. For many reasons, Newton and Einstein qualify for this honor. Newton essentially brought heaven and Earth together by demonstrating convincingly...

William Prout

Hydrogen seems almost aware of its illustrious history, for the atom behaves in a regal fashion. All of us, from infant to most senior, are aware of the world around us. The breadth and depth of this awareness varies dramatically from person to person, but the same world is there for all to observe. When we look not only with our eyes, but also with our minds and souls, we can see very different worlds. For example, we might interpret the world as diverse each face in a throng of people is...

Paul Dirac

With relativity and quantum mechanics, antimatter was part of the general framework . . . of modern physics. The reputation of a physicist can be built upon a body of work so important that it defines a field of research and influences all other investigators in the field. Or a physicist may write one paper that is so prominent in a domain of research that the identity of the physicist becomes linked to that epochal paper. Although the British physicist P. A. M. Dirac wrote many important...

Willis Lamb

Images Hydrogen Atom Splitting

The spectrum of the hydrogen atom has proved to be the Rosetta stone of modern physics. Theodor W. Hansch, Arthur L. Schawlow, and George W Series Hundreds of physics conferences have been held since World War II, but with little doubt, the most influential conference of them all occurred on June 2, 3, and 4, 1947 on Shelter Island at the eastern end of Long Island. This conference occurred soon after physicists had returned from their wartime work designing the atomic bomb in Los Alamos,...

The Rydberg Constant A Fundamental Constant

Johannes Robert Rydberg, 1890 Theodor W. Hansch, 1992 The Rydberg constant is one of the most important constants of atomic physics because of its connection with the fundamental atomic constants e, h, me, c and because of the high accuracy with which it can be determined. The Rydberg constant first appeared in the literature of physics in 1890. Today, more than a century later, this constant still challenges physicists as they carefully design experiments with state-of-the-art instruments to...

Rabi

You felt if you were measuring the properties of hydrogen, the most fundamental nucleus, you just measure it and do it as well as you can. When Isidor Isaac Rabi was a graduate student at Columbia University in the mid-1920s, his eye was on Europe, where intellectual fireworks were illuminating the minds of physicists, animating their discussions, and entertaining their ambitions. This was not the situation at Columbia University, where only a sputtering roman candle occasionally lit the...

Notes

Evidence does suggest the presence of dark matter, whose nature is yet unknown. 2. John S. Rigden, H Stands for Hydrogen . . . and Humility, American Journal of Physics 50, 299 1982 . 1. For a wonderful account of the early moments of the universe, read Steven Weinberg's The First Three Minutes A Modern View of the Origin of the Universe New York Basic Books, 1977 . 2. Hydrogen and the Unity of Matter 1. William Prout, Annals of Philosophy 6, 321-330 1815 1, 111-113 1816 . 2. Quoted in...

Harold Urey

Because of its unique properties, the distribution of deuterium in the universe constitutes a powerful clue to the history of the development of matter. David N. Schramm and Robert V. Wagoner Nearly all the chemical elements that make up our material world occur in different isotopic forms. Every breath we inhale brings into the lungs oxygen in three isotopic forms O16, O17, and O18. Each of these oxygen atoms has eight electrons around a nucleus with eight protons. In addition, O16 has eight...

Johann Jakob Balmer

Historically, the simple and regular Balmer spectrum has inspired . . . pathbreaking discoveries. From 1859 until his death at age seventy-three, Johann Jakob Balmer 1825-1898 was a high-school teacher at a girls' school in Basel, Switzerland. His primary academic interest was geometry, but in the mid-1880s he became fascinated with four numbers 6,562.10, 4,860.74, 4,340.1, and 4,101.2. These are not pretty numbers, but for the mathematician Balmer, they became an intriguing puzzle Was there a...

Erwin Schrodinger

Schrodinger Model Electron

In its special role as the simplest of all atoms, hydrogen has starred in some great episodes in the history of science. Numbers are so important in physics that real numbers alone are not enough imaginary numbers are also used and often appear in the equations of physics. Physicists are enamored with numbers, so imaginary numbers are not that surprising however, it is a bit surprising that an imaginary cat appears in the lore of physics. The cat belongs to Erwin Schrodinger. This imaginary cat...

Niels Bohr

Niels Bohr Model The Hydrogen Atom

The Bohr model scored a stunning success in accounting for major features of the observed spectrum of the hydrogen atom. Bretislav Friedrich and Dudley Herschbach As soon as I saw Balmer's formula, the whole thing was immediately clear to me. How logically neat it would be if Balmer's simple formula had, out of the blue, led Bohr directly to his model of the hydrogen atom. Unfortunately, neat logic must give way to the reality of events as they occurred. Bohr did see Balmer's formula, he did...

Edward M Purcell and Felix Bloch

Purcell Nmr

I remember, in the winter of our first experiments, just seven years ago, looking at snow . . . around my doorstep great heaps of protons quietly precessing in the earth's magnetic field. The United States formally declared war on Italy and Germany on December 8, 1941. Long before the United States entered World War II, however, many American physicists were restive. Nuclear fission was discovered in Germany in late December 1938. Niels Bohr learned about this momentous event on January 3,...

Edward M Purcell and Harold Ewen

Milky Way Hydrogen Map

It was certainly apparent to Jan Oort right away . . . right away he saw it as a tool for learning something about the structure of the Galaxy. Sometimes the most brilliant people can be short-sighted. Sometimes they can even be wrong. For example, consider two mathematicians who were contemporaries 200 years ago. One of them, the German Carl Friedrich Gauss 1777-1855 , is universally regarded as one of the greatest mathematicians of all time. The other, Friedrich Wilhelm Bessel 1784-1846 ,...

David N Schramm

The last parameter of big bang nucleosynthesis . . . is being pinned down by measurements of the deuterium abundance in high-redshift hydrogen clouds. David N. Schramm and Michael S. Turner In the era of the Hubble Space Telescope it is a common experience to be both intellectually and emotionally stunned by the detailed beauty of images from space. Cosmic clouds, light years in their dimensions, are observed where fetal stars are moving toward birth and delicate nebula mark the graves of...

The Hydrogen Maser A High Precision Clock Norman F Ramsey and Daniel Kleppner

This is about the stillness in moving things, In running water, also in the sleep Of winter seeds, where time to come has tensed Itself, enciphering a script so fine Only the hourglass can magnify it, only The years unfold its sentence to the root. Time mystifies it goads the imagination, and always has. The earliest records of human existence document that even our distant ancestors were aware of the passage of time. Ancient frescos on the walls of caves in France, dating from approximately...

Otto Stern

When Otto Stern measured the proton moment in the early 1930s, he was advised not to bother elementary theory proved the result would be one nuclear magneton. Fortunately, Stern had a healthy disregard for elementary theory. The name of Otto Stern is identified with one of the most bizarre and influential experiments in quantum physics. The Stern-Gerlach experiment was carried out prior to the creation of quantum mechanics and for some physicists, this experiment, more than any other,...

Arnold Sommerfeld

There's a reason physicists are so successful with what they do, and that is they study the hydrogen atom and the helium ion and then they stop. The quantum idea Bohr used in his model of the hydrogen atom was born in 1900. In that year Max Planck 1858-1947 , the leading physicist at the University of Berlin, described the universal constant h, called Planck's constant. This constant establishes the scale of quantum phenomena. The extreme smallness of h explains why quantum effects are masked...