Saturday, July 16, 2011

A Physics Walking Tour of Washington D.C.

A Physics Walking Tour of Washington, DC
By Paul Halpern

Excerpted from “Washington: A DC Circuit Tour,” P. Halpern, Physics in Perspective 12, No. 4, (2010), pp. 443-466. All photos by Aden Halpern and Paul Halpern, except for the photo of the historic Van de Graaff generator at the Department of Terrestrial Magnetism, used by permission of the Carnegie Institution of Washington.

Stop 1: Joseph Henry Statue
We start our walk at the statue of Joseph Henry located in the National Mall directly in front of the “castle” housing the headquarters of the Smithsonian Institution (Smithsonian Metro Station). Designed by William Wetmore Story, the statue was dedicated in 1883. A widely accomplished physicist, Henry served as the first Secretary of the Smithsonian Institution.

Stop 2: The Smithsonian Building
We now walk from the Henry statue to the castle-like edifice behind it, the Smithsonian Building, completed in 1855. On the south side of the Smithsonian Building is an area known as the South Yard where, from 1890 to 1955, a shed housed the Smithsonian Astrophysical Observatory, one of the first centers in the world for astrophysical research.

Stop 3: U.S. Department of Energy
Across Independence Avenue from the Smithsonian’s South Yard is the Forrestal Building, which was built in 1970 and today houses the U.S. Department of Energy.

Stop 4: The Continuum Sculpture and the National Air and Space Museum
Going east along Independence Aveue and crossing 7th Street SW, we see on our left the National Air and Space Museum. Directly in front of its entrance is the modern sculpture Continuum, which was commissioned in 1976 and designed by artist Charles O. Perry to represent a distorted region of spacetime in the vicinity of a black hole.

Stop 5: Koshland Science Museum
Crossing the National Mall and walking due north several blocks along 6th Street NW, we arrive at the corner of E Street and find ourselves at the entrance of the Marion Koshland Science Museum of the National Academy of Sciences, which specializes in contemporary scientific issues.

Stop 6: National Museum of American History
Walking six blocks west along E Street, and then the equivalent of three blocks south along 12th Street NW, we arrive at Constitution Avenue and see on the other side of it the entrance to the National Museum of American History (Federal Triangle Metro Station). Long a part of the Smithsonian, it has two significant collections on physics: the Physical Sciences Collection and the Modern Physics Collection.

Stop 7: Albert Einstein Memorial and the National Academy of Sciences
We exit the National Museum of American History and walk eight blocks west on Constitution Avenue, cross 21st Street NW, and see the Albert Einstein Memorial in a shady grove in front of the National Academy of Sciences. It features a 12-foot bronze statue of Einstein, weighing about 4 tons, that was sculpted by Robert Berks to depict the founder of relativity in his later years.

Stop 8: Corcoran Hall: George Washington University
We now stroll the equivalent of about four blocks north on 21st Street NW, cross G Street, and reach Corcoran Hall, home of the Department of Physics of George Washington University since 1924.. GWU’s Department of Physics rose to prominence internationally with the appointment of Russian physicist George Gamow in 1934 and of Hungarian physicist Edward Teller in 1935. Plaques honoring Gamow and Teller, along with the Fifth Washington Conference on Theoretical Physics are featured on the wall facing 21st Street. At that conference, which took place at GWU in 1939, Niels Bohr announced to the astonished participants the discovery of nuclear fission in Germany.

Stop 9: Carnegie Institution of Washington
We now leave GWU and stroll seven blocks north along 21st Street NW to P Street. Then we turn right and go five blocks east to the corner of 16th Street NW and P Street where the Carnegie Institution of Washington (also known as the Carnegie Institution for Science) is situated (Dupont Circle Metro Station). Its three divisions with the deepest connections to physics are the Observatories Department (originally just Mount Wilson Observatory), the Department of Terrestrial Magnetism, and the Geophysical Laboratory.

The Carnegie Institution’s Department of Terrestrial Magnetism, founded in 1904 under the directorship of American physicist Louis Agricola Bauer, is housed in separate quarters at 5241 Broad Branch Road NW in the leafy northwestern corner of the District. It includes a pioneering Van de Graaff accelerator, completed in 1933 by physicist Merle Tuve, and used to explore the realm of the nucleus.

The Geophysical Laboratory was founded in 1905 and was located on Upton Street NW before it was relocated to the Broad Branch Road campus near the DTM in 1990. (Mt. Wilson Observatory is in California and not included on this walking tour except for the very athletic.)

Stop 10: Oak Hill Cemetery in Georgetown
From the main headquarters of the Carnegie Institution on the corner of 16th Street NW and P Street, we go two blocks north to Q Street and then the equivalent of eight blocks west, crossing the bridge over Rock Creek, to reach Oak Hill Cemetery in venerable Georgetown. Among the notables buried there is Joseph Henry whose grave is prominently located in the section called “Henry Crescent” near the East Gate.

Stop 11: American Center for Physics in College Park
Visiting the American Center for Physics, the final stop on our tour, requires a trip by Metro to the College Park Metro Station and a brief walk. Established in 1993 under the leadership of Kenneth W. Ford, the American Center for Physics houses the American Institute of Physics, the American Physical Society, the American Association of Physics Teachers, the American Association of Physicists in Medicine, and the Society of Physics Students. The ACP also houses the AIP Center for History of Physics with its Niels Bohr Library and Archives and the Emilio Segrè Visual Archives.

Thanks to Roger Stuewer for suggesting and editing the article on which this guide is based, to Greg Good for helpful suggestions, and to Shaun Hardy for suggesting that I post a web version of my guide.

Wednesday, February 16, 2011

The Discreet Charm of the Discrete

I've just written a new essay and submitted it to the FQXi Essay Contest: "Is Reality Digital or Analog?"

Here is a link to my essay, entitled:

The Discreet Charm of the Discrete