What Is Dark Matter and More Questions From Our Readers

You asked, we answered

Scotty Reifsnyder

Who contributed more to the origin of baseball—Abner Doubleday or Alexander Cartwright?

Patrick Ian, Catonsville, Maryland

Baseball evolved from a host of precursors, but here the power hitter was Cartwright (above), says David Ward, senior historian at the National Portrait Gallery. In the early 20th century, baseball organizers accepted a claim that Doubleday (1819-93) invented it in 1839 during an Army posting in Coopers-town, New York, because it helped promote the game as bucolic and all-American. But that claim has been debunked. Cartwright (1820-92), a ex-bank clerk, helped codify the game’s rules while playing for New York’s Knickerbocker Base Ball Club in the mid-1840s. (Ninety feet between bases? His idea.) He may have been forgotten because he headed west for the California gold rush and then to Hawaii, but he was inducted into the National Baseball Hall of Fame in Cooperstown in 1938 in recognition of his contributions to the game. 

Can IBM’s Watson solve a crossword puzzle? 

John Kudlaty, St. Paul, Minnesota

IBM programmed Watson to play Jeopardy!, but not other games, says Peggy Kidwell, curator of mathematics at the National Museum of American History. Of course, Watson is no dummy—IBM is now training the supercomputer to work with doctors in determining cancer treatments. But another computer program, developed by a computer specialist and frustrated crossword solver named Matt Ginsberg, solves crosswords. He calls it Dr. Fill. Unlike Watson, it has not bested human competition. Yet.

In terms a layperson can understand, what is dark matter?

Art Rubin, Randolph, New Jersey

We should have named it “invisible matter,” says Doug Finkbeiner, professor of astronomy and physics at the Harvard–Smithsonian Center for Astrophysics. It’s hidden from view because it does not emit, absorb or reflect light. It makes up about five-sixths of the matter in the universe, and we know it’s there only because it exerts a gravitational pull on the visible objects. Dark matter may even be holding entire galaxies together.

During a presidential inauguration, five U.S. flags hang vertically from the Capitol. At the center is the 50-star flag, and two 13-star Betsy Ross flags are at either end. But what are the other two? 

Richard Stalter, Concord, California

The flags flanking the 50-star flag represent the new president’s home state, says Jennifer L. Jones, chair of the division of armed forces history at the National Museum of American History. The number of stars on these flags corresponds to when the president’s home state joined the nation. The flags at President Trump’s inauguration bore 13 stars because New York was one of the original states, while the flags at President Obama’s inaugurations bore 21 stars because he came to the presidency from Illinois, the 21st state.

Get the latest on what's happening At the Smithsonian in your inbox.