About Paul Halpern

Paul Halpern is Professor of Physics at the University of the Sciences in Philadelphia. He is the author of twelve popular science books and dozens of research articles, exploring various topics in theoretical physics and the history of science. He is the recipient of a Guggenheim Fellowship, a Fulbright Scholarship and an Athenaeum Literary Award. Halpern’s most recent book is Collider: The Search for the World’s Smallest Particles. More information can be found on his website: phalpern.com.

Emmy Noether’s Grave, Philadelphia

Emmy Noether’s grave, the Cloisters, Bryn Mawr

Emmy Noether’s grave, the Cloisters, Bryn Mawr

One of the great intellectual heroes of the 20th century was German-Jewish mathematician Emmy Noether. Born in 1882, she was remarkable in that her accomplishments in the field of abstract algebra emerged despite considerable prejudice against her, first because of being a woman, and second because of her ethnic background. She taught in the 1920s and early 1930s at the University of Goettingen. Then in 1933, with the rise of the Nazi regime, an act was passed “The Law of the Restoration of the Civil Service” forbidding those of Jewish background to teach in Germany, unless they had been World War I veterans (a concession made to placate Hindenburg). Noether fled Germany and obtained a position at Bryn Mawr College in the US. She died two years later.

Einstein wrote a beautiful obituary about her in the New York Times:

“In the judgment of the most competent living mathematicians, Fräulein Noether was the most significant creative mathematical genius thus far produced since the higher education of women began. In the realm of algebra, in which the most gifted mathematicians have been busy for centuries, she discovered methods which have proved of enormous importance in the development of the present-day younger generation of mathematicians. Pure mathematics is, in its way, the poetry of logical ideas.”
-Albert Einstein, New York Times, May 1, 1935.

Emmy Noether’s grave is in a quiet, monastery-like part of Bryn Mawr campus, known as The Cloisters.

Emmy Noether’s simple grave marker

Emmy Noether’s simple grave marker

The grave marker, with her initials and years of birth and death only, is very plain and right in the pavement.

Map location (Emmy Noether’s grave, Bryn Mawr College): 101 N Merion Ave, Bryn Mawr, PA, USA

This article is adopted from a piece posted on the Philadelphia Area Center for the History of Science (PACHS) blog. Photos by Aden Halpern.

Related link: Emmy’s Noether’s birthplace in Germany by Thony Christie

David Rittenhouse in Philadelphia

Ask Philadelphians what is the fanciest address in the city and they are likely to say Rittenhouse Square. Located at the intersection of Walnut Street and 19th Street, Rittenhouse Square houses many posh hotels and restaurants. Few locals know, however, that the prime location is named after astronomer and mathematician David Rittenhouse.

David Rittenhouse was born in 1732 in an early industrial community, set on a stream, that was then outside the boundaries of Philadelphia. Later incorporated into the city, the enclave is now called Historic RittenhouseTown.

Circa 1702 Mill, photographed in 1890

Circa 1702 Mill, photographed in 1890, courtesy of Historic RittenhouseTown.

The story of RittenhouseTown dates back to the 17th century, when German-born papermaker William Rittenhouse emigrated from Holland to Philadelphia and established the first paper mill in the Colonies. Because of its success, a second mill and bakehouse were constructed, along with the Rittenhouse Homestead. Generations of papermakers, weavers, and other industrial workers lived in the community supplying important products for the colonies.

Historic RittenhouseTown is open for tours. Surrounded by parkland, it is located at 206 Lincoln Drive in the northwest part of Philadelphia. It is open summer weekends from 12:00 pm to 4:00 pm. It is also open on weekdays, if arranged in advance, for groups of 10 or more.

Rittenhouse Homestead, photographed in 2006

Rittenhouse Homestead, photographed in 2006, courtesy of Historic RittenhouseTown.

The great-grandson of William, young David demonstrated great mathematical and scientific prowess, studying Newton’s Principia on his own. He became adept at building mechanical devices and established his own clock-making and instrument-making business.

Combining his scientific interests, particularly in astronomy, with his mechanical skills and craftsmanship, Rittenhouse set out in 1767 to build an orrery: a machine replicating the motions of the planets and moons in the Solar System using Kepler’s laws as a guide. He also constructed a modified refracting telescope to record the transit of Venus.

In 1786, politician Francis Hopkinson, a friend of Rittenhouse, sent him an intriguing question, “why… when he looked through a fine silk handkerchief at a light source, did he see a grid of dark lines which did not move at all, even though he moved the handkerchief back and forth?” (Hindle, p. 276)

After repeating Hopkinson’s experiment, Rittenhouse decided to resolve the issue by developing what became the first diffraction grating. By placing fine hairs parallel to each other, he constructed a grating with about 250 lines per inch. He then turned to the subject of precision timekeeping and astronomical measurement, constructing the first collimating telescope.

Rittenhouse was honoured much in his life. In the 1780s he was appointed the University of Pennsylvania’s first Professor of Astronomy and Vice-Provost. In 1791, one year after the death of Franklin, Rittenhouse was elected to be the second president of the American Philosophical Society. Rittenhouse held that position five years, until his own death. In 1825, Philadelphia renamed what was previously called Southwest Square after him, and Rittenhouse Square soon became known as one of the fanciest locations in the city. The physics and mathematics building at the University of Pennsylvania is named David Rittenhouse Laboratory in his honour.

Map location (Historic RittenhouseTown): 206 Lincoln Drive, Philadelphia, PA 19144, USA


I thank Chris Owens, Director of Historic RittenhouseTown, for his help and for supplying the photos for this article.

Parts of this article are adopted from “Philadelphia: Life, Liberty, and the Pursuit of Physics,” by Paul Halpern, published in Physics in Perspective.


  1. Brooke Hindle, David Rittenhouse, (Princeton,: Princeton University Press, 1964)
  2. Paul Halpern, “Philadelphia: Life, Liberty, and the Pursuit of Physics,” Physics in Perspective 11, No. 2, (2009), pp. 209-227.
  3. Historical RittenhouseTown website: http://www.rittenhousetown.org

The Franklin Institute and Other Sites in Philadelphia Related to Benjamin Franklin, USA

In honour of Benjamin Franklin’s 306th birthday (this article was published on 17 January 2012) and the upcoming 2012 Three Societies’ Meeting in Philadelphia, we have a special BSHS Travel Guide entry on sites relating to Benjamin Franklin in Philadelphia written by Paul Halpern, Professor of Physics at the University of the Sciences in Philadelphia.

Benjamin Franklin, inventor, scientist, and statesman, lived in Philadelphia from 1723 until his death in 1790 (aside from multiyear stays in London and Paris). His contributions to the study of electricity capped an impressive career dedicated to public service. In Philadelphia numerous places and institutions carry his name. The Franklin Institute, funded in part through funds set aside from Franklin’s will, is one of many sites honouring Franklin in the city.

Located on Logan Square, at 20th Street and the Benjamin Franklin Parkway, in the heart of Philadelphia’s museum district, the Franklin Institute is a large, classically-styled building with a columned façade. It houses one of the leading hands-on science museums in the United States, a collection of Franklin artifacts, and the Benjamin Franklin National Memorial.

Benjamin Franklin National Memorial

Benjamin Franklin National Memorial

With a spacious rotunda designed by noted architect John Torrey Windrim and modelled after the Pantheon in Rome, the Memorial serves as the Institute’s main entrance. It is the only section of the Institute building that is free to the public; the science museum has an entrance fee. In the center of the Memorial is a six-metre high statue of Franklin, sculpted by James Earle Fraser. Beyond the Memorial is the science museum, which features numerous exhibits including a 26-metre Foucault pendulum, and a large steam train built in 1926. Outside the museum building is a Grumman Lunar Module, built for the Apollo program.

Another Philadelphia museum dedicated to Franklin is Franklin Court, the site of his former home and print shop, located near the corner of Market Street (Philadelphia’s high street) and Third Street. Although the original building had been demolished, in 1976, during the bicentennial of American independence, the ruins of the house’s cellar and foundations were excavated, and new structures were built to offer a sense of how it looked. An underground museum, free to the public, showcases Franklin’s achievements.

Bolt of Lightning sculpture

Bolt of Lightning sculpture

Several streets away from Franklin Court are other notable sites related to Franklin. Franklin’s grave is located in Christ Church cemetery near the corner of Fifth Street and Arch Street. It is a tradition to toss pennies on his grave marker for good luck. At Fifth and Vine Street is the entrance to the Benjamin Franklin Bridge. Within its entrance plaza stands a metal sculpture commemorating Franklin’s reported ‘kite and key’ electrical experiment. Designed by Japanese-American artist Isamu Noguchi to depict a kite and a lightning bolt, it is called Bolt of Lightning and was erected in 1984.

Franklin Wall Plaque at the corner of Fourth and Arch Streets, Philadelphia

Franklin Wall Plaque at the corner of Fourth and Arch Streets, Philadelphia

Franklin was the founder of many organisations and scholarly institutions, including the American Philosophical Society and the University of Pennsylvania. The original site of the latter, the corner of Fourth and Arch Streets, is commemorated by a wall plaque.

The current site of the University of Pennsylvania is in the western part of Philadelphia. There stands yet another Franklin memorial, a bronze statue of a seated Franklin created by John J. Boyle in 1899.

Bronze statue of a seated Franklin created by John J. Boyle in 1899.

Bronze statue of a seated Franklin created by John J. Boyle in 1899.

Further information

Address: Franklin Institute, 222 North 20th Street, Philadelphia, PA 19103


  1. Paul Halpern, “Philadelphia: Life, Liberty, and the Pursuit of Physics,” Physics in Perspective 11, No. 2, (2009), pp. 209-227.
  2. The Franklin Institute website: http://www.fi.edu

Albert Einstein Memorial, Washington D.C.

Einstein statue, Washington DC

Einstein statue, Washington DC

The Albert Einstein Memorial, located just off the National Mall in Washington, D.C. near the corner of 21st Street northwest and Constitution Avenue, is the official monument to Einstein in the United States. Free to the public, it is situated in a shady grove of trees in front of the headquarters of the National Academy of Sciences (NAS) . Einstein was elected a foreign associate of the NAS in 1922 and a full member in 1942.

The Einstein Memorial features a 12 foot bronze statue of Einstein that weighs about 4 tonnes. The sculptor, Robert Berks (1922- ), modeled it after a bust he had made from a portrait sitting with Einstein in 1953. Consequently, it portrays the founder of relativity in his final years.

Einstein is depicted sitting on a three-step granite bench reading a paper with a set of equations. These equations summarize the results of three of Einstein’s most important contributions to physics: the photoelectric effect, the general theory of relativity and the famous relationship between energy and mass.

Einstein statue detail

Einstein statue detail showing a set of Einstein's most famous equations

Engraved in the bench are three different quotations attributed to Einstein:

As long as I have any choice in the matter, I shall live only in a country where civil liberty, tolerance, and equality of all citizens before the law prevail.

Joy and amazement of the beauty and grandeur of this world of which man can just form a faint notion …

The right to search for truth implies also a duty; one must not conceal any part of what one has recognized to be true.

At the base of the statue is a granite field speckled with over 2700 metal studs. These represent the position of the celestial objects in the sky at the time the memorial was dedicated, as ascertained by astronomers at the US Naval Observatory. The unveiling took place on April 22, 1979, during a meeting of the NAS that honoured Einstein’s centennial year.

The stately NAS building, just a few steps from the Memorial, stands as an emblem of the dedication of astrophysicist George Ellery Hale (1868-1938) to construct suitably elegant quarters for the esteemed organisation. A pioneer in the field of solar spectroscopy, inventor of the spectrohelioscope and founder of Mt. Wilson Observatory, Hale was elected to the NAS in 1902. Almost immediately, he set out to reform the organisation and transform it into an active force for the promotion of science. An 1863 act of the U.S. Congress had established the NAS as an honorific society but didn’t provide it with dedicated quarters. Hale pushed for the founding of an arm of the NAS, called the National Research Council (NRC), to enable scientists to help guide government policy. With the establishment of the NRC in 1916, Hale argued that the NAS required a proper headquarters. He personally sought out noted architect Bertram Grosvenor Goodhue, led a fundraising campaign for the building, oversaw its design and even contributed the motto inscribed in the dome of its Great Hall. Hale wrote:

To science, pilot of industry, conqueror of disease, multiplier of the harvest, explorer of the universe, revealer of nature’s laws, eternal guide to truth.

National Academy of Sciences (NAS) headquarters

National Academy of Sciences (NAS) headquarters

Location: 2101 Constitution avenue northwest, Washington, DC

Parts of this description are excerpted from my article “Washington: A DC Circuit Tour.”


  1. Paul Halpern, “Washington: A DC Circuit Tour,” Physics in Perspective 12, No. 4, (2010), pp. 443-466
  2. “The Einstein Memorial,” National Academy of Sciences, http://www.nasonline.org