1618 – Johannes Kepler confirms his discovery of the third law of planetary motion. Kepler had initially discovered it on March 8 but rejected the idea after some initial calculations were made.
In astronomy, Kepler’s laws of planetary motion are three scientific laws describing the motion of planets around the Sun.
- 1. The orbit of a planet is an ellipse with the Sun at one of the two foci.
- 2. A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.
- The square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit.
1793 – Spanish inventor Diego Marín Aguilera flies a glider for “about 360 meters”, at a height of 5–6 meters, during one of the first human attempts at flight.
Marín was inspired by the eagles he spotted while tending his animals and fields: he wanted to build a flying machine. For six years, he worked on one he invented. The machine was built out of wood, iron, cloth, and feathers. He gathered eagle and vulture feathers by setting up special traps on which he placed rotting meat to attract these birds.
Marín made calculations regarding the weight, volume, size, dimensions of the feathers, as well as the weight of the bodies of these birds. He also carefully studied the movement of their wings and tail and, with the assistance of the local blacksmith, Joaquín Barbero, constructed a pair of wrought iron “joints” that moved about like a fan. He also built stirrups for his feet and hand-cranks that controlled the direction of the flying machine
1836 – Francis Baily observes “Baily’s beads” during an annular eclipse.
The Baily’s beads effect, or diamond ring effect, is a feature of total and annular solar eclipses. As the Moon covers the Sun during a solar eclipse, the rugged topography of the lunar limb allows beads of sunlight to shine through in some places while not in others. The effect is named after Francis Baily, who explained the phenomenon in 1836.[ The diamond ring effect is seen when only one bead is left, appearing as a shining “diamond” set in a bright ring around the lunar silhouette.
1869 – The National Woman Suffrage Association is formed in NYC.
The National Association was created in response to a split in the American Equal Rights Association over whether the woman’s movement should support the Fifteenth Amendment to the United States Constitution. Its founders, Susan B. Anthony and Elizabeth Cady Stanton, opposed the Fifteenth Amendment unless it included the vote for women. Men were able to join the organization as members; however, women solely controlled the leadership of the group. The NWSA worked to secure women’s enfranchisement through a federal constitutional amendment. Contrarily, its rival, the American Woman Suffrage Association (AWSA), believed success could be more easily achieved through state-by-state campaigns. In 1890 the NWSA and the AWSA merged to form the National American Woman Suffrage Association (NAWSA)
1928 – Walt Disney’s Mickey Mousee premieres in his first cartoon, “Plane Crazy”.
Mickey Mouse was created as a replacement for Oswald the Lucky Rabbit, an earlier cartoon character created by the Disney studio for Charles Mintz, a film producer who distributed product through Universal Studios. In the spring of 1928, with the series going strong, Disney asked Mintz for an increase in the budget. But Mintz instead demanded that Walt take a 20 percent budget cut, and as leverage, he reminded Disney that Universal owned the character, and revealed that he had already signed most of Disney’s current employees to his new contract. Angrily, Disney refused the deal and returned to produce the final Oswald cartoons he contractually owed Mintz. Disney was dismayed at the betrayal by his staff but determined to restart from scratch. The new Disney Studio initially consisted of animator Ub Iwerks and a loyal apprentice artist, Les Clark, who together with Wilfred Jackson were among the few who remained loyal to Walt. One lesson Disney learned from the experience was to thereafter always make sure that he owned all rights to the characters produced by his company.