Monday, April 29, 2013

Bart Bok

Bartholomeus Jan Bok was born on April 18, 1906 in Hoorn, Netherlands. His father was a sergeant major in the Dutch army and he was born on a military base, that later became a monument. After World War I, Bok's family moved to The Hague, were he went to high school. Also while living there Bok joined the Boy Scouts and he attributed his early interest in astronomy to an astronomy test given to him by a scoutmaster. Bok failed the test and afterward made an effort to study astronomy. After graduating high school he won a scholarship to study at Leiden University where he earned his bachelors, and then when to the University of Gronigen, where he earned his doctorate in astronomy. Bok then took a job working for Harlow Shapely at the Harvard Observatory. Bok worked at Harvard Observatory from 1929 to 1957. In 1957 Bok moved to Australia where he served as director of the Mount Stromlo Observatory until 1966, when he moved to the University of Arizona and the directorship of the Steward Observatory.

Bok's research at Harvard involved mapping stars of the Milky Way galaxy. He also was involved with radio astronomy, and turned Harvard into a center for radio astronomy with the installation of Agassiz Station, which he engineered. Bok worked with his wife, Priscilla, who was also an astronomer. The pair wrote a popular book about the Milky Way that went through six printings. Bok is probably best remembered for his study of dark globular clouds. These globular clouds composed of hydrogen and dust range in mass between 2 and 50 solar masses and are light years across. Bok theorized that these clouds could be the site of stellar formation. Star formation occurs when gravity collapses a cloud of hydrogen gas so compactly that a fusion reaction begins, converting hydrogen into helium and releasing energy. Bok's prediction has been proven to be correct and consequently these dark globular clouds are called Bok globules.

Awards won by Bok during his career include the Bruce Medal, from Astronomical Society of the Pacific. Bok served as president of the American Astronomical Society from 1972-74. He and his wife also have a lunar crater and an asteroid named after them.

Bok died on August 5, 1983 of a heart attack.


Graham, J.A., Wade, C.M, and Price, R.M.; "Bart J. Bok: 1906-1983"; in Biographical Memiors; National Academy Press; 1994

Lada, C.J.; "Obituaries: Bart Bok"; Quarterly Journal of the Royal Astronomical Society (1987)28:539

Interview of Bart J. Bok by David Devorkin on May 15, 1878; Retrieved from

Wednesday, April 24, 2013

Sir Harold Jefferys

Harold Jeffrys was born April 21, 1891 in the village of Fatfield, near the city Sunderland, England, where his father was a schoolmaster and his mother a school teacher at the village school. He attended school in Fatfield and he was awarded a scholarship to study at Rutherford University in Newcastle-upon-Tyne. In 1907 he went to Armstrong College, also in Newcastle graduating in 1910 with distinction in mathematics. He then went to St. John's College, Cambridge earning on of four mathematical scholarships. He became a fellow at St. John's in 1914 and remained there throughout his career.

Jefferys' studies encompass many related fields, including astronomy, pure mathematics, and geophysics. He was particularly interested in seismology and using the records of earthquakes to discern information about the structure of the Earth. By studying the rates at which seismic waves travel through the Earth's crust he was able to determine that it is composed of at least two layers and that the Earth has a molten core. We now know that the Earth's core has molten outer core and a solid inner core. Although his studies advanced our knowledge of the structure of the Earth he remained skeptical of the theory of plate tectonics, the currently accepted theory of movements of the Earth's crust. Much of Jeffrey's work was completed before the advent of artificial satellites and deep ocean drilling used to do geophysical research today.

Jeffery's work in astronomy focused on the planets Neptune and Uranus. In 1923 he proposed that these planets would have surface temperatures of the order of -120 Celsius. This was disputed at the time, but has been proven accurate. He also published a book on probability theory that was influential in that field. Honors won by Jeffry's include election to the Royal Society in 1925, a Gold Medal from the Royal Astronomical Society in 1937 and the Copely Medal from the Royal Society in 1961. He was knighted in 1953.

Jeffrys died on March 18, 1989.


O'Connor, J.J. and Robertson, E. F.; "Harold Jeffrys"; retrieved from

Mumford, George S.; "Jeffrys, Harold"; in Biographical Encyclopedia of Astronomers; Springer; 2007

Harold Jeffrys Wikipedia Entry

Sunday, April 14, 2013

Alan MacDiarmid

Alan Graham MacDiarmid was born in Masterton, New Zealand on April 14, 1927. His was one of five children. His family was poor and his father, an engineer was unemployed during the great depression of the 1930s. The family moved to Lower Hutt, closer to Wellington where work was believed to be more plentiful. MacDiamid became interested in chemistry as a child from reading his father's chemistry text and books he checked out from a local library. During a Guy Fawkes Day celebration he produced his own fireworks. After attending Hutt Valley High School, he entered Victoria University in Wellington in 1943. He took work there as a lab boy and finished his BSc in 1947. He remained at Victoria University as a graduate student, finishing his MSc. He attended the University of Wisconsin Madison on a Fullbright Fellowship, earning a MS in 1952 and a PhD in 1953. He earned a second PhD from Sidney Sussex College, Cambridge in 1955. After finishing his second doctorate he was a member of the junior faculty for a year at the University of St. Andrews and then became a professor at the University of Pennsylvania, were he remained for the majority of his career. In 2002 he joined the faculty at the University of Texas, Dallas.

MacDiarmid's research focused on the chemistry of silicon and non-metallic conductors. Metals (elements in the metallic region of the periodic table) are good conductors of electricity. Non-metallic elements, such as carbon, do not conduct electricity. (see here for an blog post on metal and non-metal elements) Mac Diarmid's lab developed carbon polymers that were able to conduct electricity. They developed polyacetylene, a carbon polymer, that was able to conduct electricity.  They determined that the reason the normally non-conductive carbon polymer was able to conduct electricity  were due to impurities, such as the catalyst used to create the polymer. They learned to "dope" the polymers they created, creating polymers that had widely ranging electrical conductivities. Since their discovery conductive polymers have been developed and used to make electrical capacitors that could be used as environmentally friendly batteries. For his work discovering conductive polymers, MacDiamid shared the 2000 Nobel Prize in chemistry with Alan Heeger and Hideki Shirakawa.

Other honors won by MacDiamid include the Rutherford Medal from the Royal Society of New Zealand, the American Chemical Society's materials award, and the Order of New Zealand.

MacDiamid died on Febrary 7, 2007.


Callaghan, Paul: "MacDiamid, Alan Graham: 1927-2007"; in the Dictionary of New Zealand Biography retrieved from

MacDiamid, Alan; Nobel Autobiography

Alan MacDiamid Wikipedia entry

Monday, April 8, 2013

Edwin G. Krebs

Edwin Gerhard Krebs was born on June 6, 1918 in Lansing, Iowa. He was the son of a Presbyterian minister, William Carl Krebs, and Louise Helen (Stegman) Krebs, who was a schoolteacher before she married. Krebs' family moved many times during his youth as his father took different ministry positions. Krebs' father died when he was sixteen and a freshman in high school. After his father's death the family moved to Urbana, Illinois, where Krebs attended the University of Illinois majoring in chemistry. He earned a scholarship to Washington University in St. Louis, Missouri, where he studied medicine. After completing a 18 month residency and serving as a medical officer in the U.S. Navy, Krebs was unable to find a clinical position. Instead he took a postdoctoral research position working in the laboratory of Carl and Gerty Cori at Washington University. In 1948 Krebs was appointed assistant professor of biochemistry at the University of Washington, where he remained until 1968. In 1968 he moved to the University of California Davis, where he served as the founding chairman of the department of biological chemistry. Krebs returned to the University of Washington in 1977.

Krebs' research involved enzymes, the protein molecules that catalyze biochemical reactions. While at the University of Washington, Krebs worked with Edmond Fisher and the pair discovered the reversible phosphorylation of glycogen phosphorylase which serves to activate the enzyme. Glycogen phosphorylase is the enzyme that removes monosacharides from glycogen (the polysacharide used to store glucose for future use) so that they can be broken down into energy. Glycogen phosphorylase exists in two forms A and B. The Cori's had found that form B is inactive unless it is in the presence of adenosine monophosphate (AMP) and that form A is active without AMP. They also knew from the experiments of the Cori's that the active A form degrades into the inactive B form. Krebs and Fischer discovered that the B form is reversibly phosphorylated (phosphate is added to the protein molecule) converting it into the A form, which causes it to be activated so that it can break down glycogen. This was the first discovery of reversible phosphorylation which is a ubiquitous mechanism that serves as a means of activating many enzymes and transducing biochemical signals. For their discovery of the regulation of glycogen phosphorylase by phosphorylzation Krebs and Fischer were awarded the 1992 Nobel Prize in medicine and physiology.

Krebs died on December 9, 2009.


Fischer, Edmond H.; "Edwin G. Krebs (1918-2009)"; in Biographical Memoirs; 2010; National Academy Press

Krebs, Edwin G.; "Nobel Autobiography"

Edwin G. Krebs Wikipedia Entry