Note: This column is 2nd in a three-part series. To read the first one, click here.

 The current midlife explosion has not only increased the number of 40-year-olds. In 1996, Americans began to turn 50 at the rate of one every 8.4 seconds. By 2001, the rate will increase to one every 6.8 seconds.

And like turning 40, turning 50 will be traumatic for many of us. As comedian Bill Cosby once said, "Fifty is a nice number for the states in the Union or for a national speed limit, but it is not a number that I was prepared to have hung on me. Fifty is supposed to be my father's age." But "the Cos" did turn 50 in 1987, and he is living proof that productive life does indeed continue in one's sixth decade. Cosby is not the first to excel in his 50s. Following are other examples.

On May 24, 1844 Samuel Morse sends the first message over his new telegraph line, which stretched from Baltimore to Washington. "What hath God wrought!" writes Morse.

In 1859, Charles Darwin publishes Origin of the Species, sending shock waves throughout the scientific and religious communities.

In 1534, Martin Luther completes his translation of the Bible by writing the Old Testament in German.

In 1918, Madame C. J. Walker, pioneer inventor and marketer of hair-care products, becomes the first African-American woman millionaire with annual sales of $250,000.

Walker's legacy may soon be joined by contemporary midlifer Oprah Winfrey who, according to Forbes, is approaching billionaire status.

In 1871, Mary Ann Evans, better known by her pen name George Eliot, publishes Middlemarch, her best work.

In 1872, Susan B. Anthony becomes the first American woman to vote in a national election (she is promptly arrested).

In 1456, Johann Gutenberg produces the first major work to come from a printing press, the Gutenberg Bible.

On April 7, 1909, along with four Eskimos and 38 sled dogs, Admiral Robert Peary reaches the North Pole.

In 1959, Glenna Collett Vare captures the Rhode Island State Championship Golf Tournament, 37 years after winning it for the first time.

In 1742 at Dublin Ireland, George Frederick Handel conducts the first performance of his greatest work, "The Messiah."

In 1889, Alexander Gustav Eiffel completes the tower that bears his name in Paris.

In November 1871, missionary-explorer David Livingston is finally located by Henry Stanley beside Lake Tanganyika in Africa. "Dr. Livingston, I presume," says Stanley.

In 1920, having just seen her long battle for women's suffrage end with state ratification of the 19th amendment to the U.S. Constitution, Carrie Chapman Catt founds the National League of Women Voters.

In 1939, and with remarkable insight, Albert Einstein sends a letter to President Franklin D. Roosevelt urging research on the atomic bomb, putting in motion a plan that will end a war not yet begun.

 And yes, there is life after 60. Click here and read the accomplishments of some of history's more famous seniors.