September 9 – Today In Science History – First Computer Bug


The first computer bug was discovered on September 9, 1947.

Grace Hopper was working on the Mark II Aiken Relay Calculator computer during testing at Harvard University. She was attempting to trace a hardware problem that was most likely a short circuit in one of the machine’s many relays. The problem was eventually traced to a moth that had wedged itself in Relay #70 on Panel F and causing the short. Hopper logged the fix in the logbook and taped the moth corpse to the page with the annotation “The first actual case of bug being found”.

First Computer Bug

Copy of the Log Book page showing the first computer bug. Credit: US Navy Naval Surface Warfare Center

“Bugs” have been known to engineers for a long time. Thomas Edison called problems that arose in the engineering process as bugs back in 1878. Debugging is the process of removing these problems. Many sources list this as the origin of the term ‘debugging’ a problem in a computer. Computer operators have been debugging computers probably as long as there have been computers, but Grace’s moth is the first ‘actual’ bug found.

Some sources, the US Navy’s Naval Surface Warfare Center museum included listed the date of the first bug on September 9, 1945. Grace Hopper wasn’t part of the Mark II program until after that date. The correct date is 1947.

Another misconception about the moth legend was where the logbook was displayed. Many sources listed the logbook to be at an exhibit at the Smithsonian. The log was actually at the Naval Surface Warfare Center. It turned out the Navy attempted to donate the logbook to the Smithsonian but the offer was rejected. In 1991, The History of American Technology Museum section of the Smithsonian found out about the original offer by the Navy and asked if they could still get the log. Today, the logbook is on display at this museum.

Grace Hopper admits she was not present when the moth was found. She enjoyed telling the story during lectures.

Notable Science Events for September 9

2003 – Edward Teller died.

Edward Teller

Edward Teller (1908 – 2003)
Lawrence Livermore National Laboratory

Teller was a Hungarian-American physicist who was a central figure in the United States nuclear weapons program. During the Manhattan Project, he led the Los Alamos theoretical physics department. After the Soviets detonated their atomic bomb, his designs were used to build the hydrogen or thermonuclear bomb.

He continued his strong defense policies as the director of the Lawrence Livermore Laboratory and was an outspoken proponent of the antiballistic missile programs.

1985 – Paul John Flory died.

Flory was an American physical chemist who was a pioneer in the chemistry of polymers and macromolecules. He investigated the kinetics of polymer reactions in solutions and wrote the standard textbook on polymer chemistry, Principles of Polymer Chemistry. He was awarded the 1974 Nobel Prize in Chemistry in honor of his theoretical and experimental achievements in polymer and macromolecular chemistry.

1947 – First computer bug discovered.

1941 – Hans Spemann died.

Hans Spemann

Hans Spemann (1869 – 1941)
Nobel Foundation

Spemann was a German embryologist who was awarded the 1935 Nobel Prize in Medicine for the discovery of embryonic induction. Embryonic induction is what directs parts of an embryo to develop groups of cells into particular tissues and organs.

Spemann was one of the first to transfer the nucleus of one cell to another cell in amphibian cells. This was one of the first steps to the study of cloning.

1923 – Daniel Carleton Gajdusek was born.

Daniel Carleton Gajdusek

Daniel Carleton Gajdusek (1923 – 2008)

Gajdusek was an American physician and virologist who shares the 1976 Nobel Prize in Medicine with Baruch Blumberg for their discoveries into the origins and dissemination of infectious diseases. He investigated a neurological disease called kuru that was prevalent in New Guinea tribesmen. It was later determined this disease was the first human prion disease.

1922 – Hans Georg Dehmelt was born.

Dehmelt is a German physicist who shares half the 1989 Nobel Prize in Physics with Wolfgang Paul for the development of the ion trap. The ion trap is a device that uses electric and magnetic fields to capture ions in a particular quantum state. These ions could be contained for extended periods of time for further detailed study.

1789 – William Cranch Bond was born.

William Cranch Bond

William Cranch Bond (1789 – 1859)

William Bond was an American astronomer who together with his son, George Bond discovered Saturn’s eighth moon, Hyperion and Saturn’s inner ring named Crepe Ring. He was also one of the first astronomers to catalog stars through photography.

Harvard University sent Bond to Europe in 1815 to learn about European observatories. In 1836, Bond moved his personal collection of astronomy equipment to the University grounds and served as Astronomical Observer to the University. He raised funds to purchase one of the largest telescopes in the world for Harvard. This telescope is still functional to this day.

1737 – Luigi Galvani was born.

Luigi Galvani

Luigi Galvani (1737 – 1798)

Galvani was an Italian physician and physicist who first identified electricity in living tissue. He demonstrated how frog legs would twitch when touched by static electricity or by different metals. He believed the current was caused by the fluids in the frog’s body, but it was later shown the electricity was caused by a reaction between the fluids and the different metals. This discovery would lead to the invention of the galvanic battery.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.