A couple of important scientists were born on this day. The first is Adrien-Marie Legendre, who was born in 1752. He was actually a mathematician, but that’s close enough. He did a lot of great work. For example, his work on polynomials led to Galois theory. And he proved Fermat’s last theorem for *n = 5*. But most of all, he is known for the Legendre transformation. It allows you to transform a function from one set of variables to another. There are two classic examples of this. One is to transform the Lagrangian formulation of classical mechanics into the Hamiltonian formalism. The other is the transformation of thermodynamic internal energy—which we can’t measure—into enthalpy and other variables that we *can* measure. Unfortunately, the mathematics is not easy—it requires about a year of calculus and even then, it isn’t exactly trivial.

The second scientist is Leon Foucault who was born in 1819. If you’ve ever been to a big science museum, you have doubtless seen the Foucault pendulum. Basically, the idea is that the pendulum—because of its inertia and slow rate of rotation of earth—continues oscillating in the same direction. So as the earth rotates, it looks like the pendulum precesses. This was the first very simple and readily understandable experimental demonstration that we are, in fact living on a big ball that is spinning around. Of course, Foucault did much else in his short lifetime. He did a lot of work with electromagnetism and performed one of the earlier measurements of the speed of light.

Other birthdays: Dutch realist painter Anton Mauve (1838); novelist William March (1893); actor Jack Warden (1920); the best of *The Ramones*, Dee Dee Ramone (1951); actor James Gandolfini (1961); singer Frankie Avalon (74); comedian Fred Willard (74); journalist Chris Hedges (57); and cyclist Lance Armstrong (42).

The day, however, belongs to the great actor Greta Garbo, who was born on this day in 1905. At this point, she is probably better known for disappearing from public life for the last 50 years of her life. But she really was a great actor. She had an extremely naturalistic style when such things were rare. Here she is in *Grand Hotel* saying the line she is most remembered for, “I want to be alone!”

Happy birthday Greta Garbo!

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