Today in Science History – December 27 – Louis Pasteur

Louis Pasteur

Louis Pasteur (1822 – 1895)

December 27 is Louis Pasteur’s birthday. Pasteur was a French chemist best known for developing the pasteurization process to slow the development of microbes in milk and wine.

Scientists (and chefs) knew heat kills bacteria. Early food preserving methods involved putting the of food in a sealed container and placing the container in boiling water. The heat killed the bacteria but also cooked the food. This worked great for foods that required cooking. In 1864, Pasteur modified these techniques to address the acidity of local French wines. He found if he heated the young wine at a temperature just high enough to kill off any microbial life, the resulting aged wine had none of the acidity and consequently, bad taste associated with high acid wines. This process was quickly adopted by other wineries and spread to beer breweries for the same effect. He named his new process pasteurization after himself.

Milk is the food most commonly associated with pasteurization. Even so, milk was not pasteurized until the end of Pasteur’s life. American chemist Ernst Lederle experimented with milk pasteurization after showing tuberculosis could be transferred from cows to guinea pigs. When he served as New York City’s Commissioner of Health, he forced all milk to be pasteurized in 1910. The practice was quickly adopted by other dairies and governments. This practice converted milk from one of the most dangerous drinks to one of the safest.

Pasteur is also responsible for the introduction of the rabies vaccine. His vaccine was developed from the spinal tissue of infected rabbits. He dried out the infected tissue to weaken the virus and injected it into patients who were exposed to rabid animals. Pasteur risked his reputation and freedom testing his vaccine on 9-year old Joseph Meister who had been mauled by a rabid dog. The vaccine was successful, Joseph Meister lived, and Pasteur’s fame grew. He used this same technique to create a vaccine for anthrax.

Pasteur is considered one of the founders of microbiology and one of France’s greatest scientific heroes.

Notable Science History Events for December 27

2004 – Gamma burst from SGR 1806-20 reaches Earth.

SGR 1806-20

Location of SGR 1806-20 if it were visible to the naked eye.

Gamma radiation from SGR 1806-20 magnetar, a type of neutron star peaked to become the single brightest extrasolar object in terms of intensity ever observed in the night sky. SGR 1806-20 is a small neutron star with a diameter of only 20 kilometers and rotates every 7.5 seconds. This generates one of the strongest magnetic fields detected to date. The event is believed to be caused by a starquake on the surface of the star. Fortunately for us, this star is 50,000 light-years from Earth. The energy released in this event only lasted 1/10th of a second but exceeded the total output of our Sun for 150,000 years.

1822 – Louis Pasteur was born.

1571 – Johannes Kepler was born.

Johannes Kepler

Johannes Kepler (1571 – 1630)

Kepler was a German mathematician and astronomer who outlined the three Kepler laws of planetary motion. The first law says planets have elliptical orbits with the Sun at a focus. The second states a line joining the Sun and the planet sweeps out an equal area during an equal amount of time and the third law relates the orbital period of a planet and the semi-major axis of its orbit. These laws were instrumental in the development of Newton’s theory of gravitation.

1914 – Charles Martin Hall died.

Charles Martin Hall

Charles Martin Hall (1863 – 1914)

Hall was an American chemist who discovered an inexpensive method to refine aluminum from ore. He built an apparatus that passed an alternating electrical current through a solution of alumina and cryolite that would cause the aluminum metal to precipitate out. This process was also discovered by French chemist, Paul-Louis-Toussaint Héroult at nearly the same time and is generally known as the Hall-Héroult process. It was responsible for greatly reducing the cost to produce aluminum and made it one of the most widely used metals today.


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