The Writer's Almanac with Garrison Keillor

On this date in 1687, Isaac Newton (books by this author) published one of the most important books in the history of science. Its full name is Philosophiae Naturalis Principia Mathematica, or "Mathematical Principles of Natural Philosophy." It had begun as a brief tract called "On Motion," in which Newton had discussed mathematical theories of planetary motion. Almost as soon as he'd finished writing it, he began revising and expanding it. And when he'd finished, the Principia contained Newton's three laws of motion, including, "Objects in motion tend to remain in motion," and "For every action, there is an equal and opposite reaction." Newton also unified celestial and terrestrial mechanics under one umbrella: gravity, which caused planets to orbit the Sun, moons to orbit planets, and earthly objects — like apples — to fall to the ground when dropped.

On this date in 1937, SPAM was unveiled by Hormel Foods. It is precooked pork and ham in a can, with a little potato starch, salt, and sugar. Sodium nitrate is added to keep it pink; without it, pork tends to turn gray.

There's no consensus on what the name actually stands for; one theory is that it's a combination of "spiced meat" and "ham." In Britain, where it was a popular wartime food, they called it "Specially Processed American Meat" or "Supply Pressed American Meat." A host of tongue-in-cheek acronyms have also arisen, like "Something Posing As Meat," and "Special Product of Austin, Minnesota," Whatever it stands for, Hormel specifies that it should be written in all caps.

Today is the 75th birthday of American artist Chuck Close, born in Monroe, Washington (1940). He had a rough childhood: He was dyslexic and didn't do well in school; his father died when Chuck was 11, and his mother developed breast cancer soon after. Their medical bills were so high that the family lost their house, and Close was bedridden for almost a year due to a serious kidney infection. He got through by drawing and painting, and took his first trip to the Seattle Art Museum soon after his father died. As a mature artist, he's become known for his enormous portraits, painted so realistically that they look like photographs. He had been painting them for 20 years before he finally figured out why he was so obsessed with these giant portraits: It's a way to remember them. He has a condition called "face blindness," which means he's unable to recognize individual faces.

The Battle of Osan took place on this date in 1950. It was the first face-off of American and North Korean troops in the Korean War, which had begun on June 25, 1950, when the Soviet- and Chinese-backed North Korean People's Army crossed the 38th parallel into the pro-Western Republic of South Korea. Three days later, they had captured Seoul. It was the first open military action of the Cold War, and it triggered a police action by the United Nations. In turn, the United States saw it as a chance to defend democracy from the threat of Communism. President Truman, fresh from fighting the Axis Powers in World War II, was eager to prevent a similar situation in Asia.

So on this date, Task Force Smith was deployed to Osan, just south of Seoul. Their mission was to hold off the North Korean advance until further American reinforcements could arrive. They weren't adequately armed; they didn't have any anti-tank weaponry, and the North Korean tank column rolled right through them. Although they were able to buy a little time by firing at the infantry, the American forces lost the battle and the task force retreated.