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"Time and Navigation: The Untold Story of Getting from Here to There," new at the National Air and Space Museum

Type an address into your phone, and up will pop a step-by-step route from where you are to where you want to be. This is, in its way, magic -- magic that has, at this point, been rubbed and polished into a simple fact of life. The ease with which we machine-carrying humans make our way through the world, though, is quite new. And it's the product of a long, painstaking history: of people plotting a course, getting lost, and finally finding their way.

The newest exhibit at the Smithsonian's Air and Space museum, "Time and Navigation: The Untold Story of Getting from Here to There," opened this weekend, shares the story of human route-charting -- in the seas, in the sky, on the street, and in space. And it's largely a story of failure. The first spaceships we sent to the moon either missed their destination completely or crashed into it. Amelia Earhart was very likely lost due to poor navigation. Columbus and his ships were, famously, misdirected. 

But the story of navigation is also one of gradual knowledge and readjustment, of looking to the constant objects of the physical world -- the sun, the moon, the stars -- and using them to understand, ever more precisely, how to find our way in the world. "Dead reckoning" (positioning oneself using time, direction, and speed) has now given way to global positioning using satellites. And that, in turn, is giving way to atomic clocks that can keep time within three billionths of a second -- clocks that may soon make it to our phones. So it's easy to imagine that, given our tools, we have made getting lost obsolete. But that's to take the luxury of location-based living for granted. "Navigation was the great scientific challenge of our time," an animated 19th-century British "admiral" notes in a video tour of navigation's history. And it was the challenge on which many more challenges hinged. As explorers ventured off into distant, unknown lands, they needed above all to know where they were going -- to be, as they say, on the right path. Navigation was in many ways a leap of faith. It's just that the faith in question concerned calculations. 

Now, though, thanks to the man-made stars we navigate by, "the whole world is synchronized." We humans are synchronized. The problems faced by those early explorers have been solved using that time-honored combination: ingenuity, and math. 

"Time and Space" is one of the most ambitious exhibits Air and Space Museum has yet put on -- in part because it involved a collaboration among curators at different Smithsonian institutions (Air and Space as well as American History), but also because the exhibit is so theoretical in its topic and scope. It's not so much about a particular time or trend, but about, you know, space and time ... and humans' place between the two. So one particular challenge the curators faced was to make the story of navigation -- a story, ultimately, about mathematical calculations -- accessible to the range of people who come through the museum every day. They tackled it well. The tale is arranged chronologically, but also in sections: navigation in the sea, navigation in the air, navigation in space, navigation in the contemporary world. We see models of clocks designed by Galileo. We see Charles Lindbergh's sextant. We see the updated sextant used by Apollo astronauts to navigate using the stars. We see a GPS-guided glide bomb. We see a duplicate of the Mariner 10 space probe, the first craft to reach Mercury. We see Stanley, the early self-navigating car.

Below, courtesy of the Smithsonian, are some of the artifacts featured in "Time and Navigation." For more, here's the online version of the exhibit.

Bond Chronometer
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This timekeeper was the first American-made marine timekeeper taken to sea. William Cranch Bond, a 23-year-old Boston clockmaker, crafted it during the War of 1812. This artifact is part of the National Museum of American History's collection.

Bygrave Position-Line Slide Rule
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Celestial navigation requires complicated computations. Performing these calculations in cramped open cockpits with low temperatures and wind speeds of over 160 kilometers (100 miles) per hour was part of what made navigation difficult in the early years of aviation. Thankfully, Capt. L. C. Bygrave developed this handy slide rule shortly after World War I. It provided the best shortcut method of speeding up celestial computations at the time.

Ramsden Sextant
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Navigating in the sea: this sextant was one of the navigation tools invented in the 18th century by British mathematical instrument makers that permitted mariners to find their position much better than ever before. The sextant became the most essential instrument for celestial navigation, used to find the angle of a celestial body above the horizon. Jesse Ramsden, who made this sextant, also devised a machine to divide the scale on the sextant very precisely.

Apollo Sextant and Scanning Telescope
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Navigating in space: to determine position in space, an Apollo astronaut located a specific star using a single-power, wide-field telescope and then took a fix using a sextant. While this instrument does not look like a traditional sextant, the basic procedure is descended from centuries-old methods used by navigators at sea and in the air.

Dutch Pendulum Clock
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In the 17th century, several inventors were trying to make an accurate clock for finding longitude at sea. In pursuit of a sea clock, Christiaan Huygens, a Dutch mathematician, changed timekeeping forever when he patented the first working pendulum clock in 1656 and later devised a watch regulator called a balance spring. Pendulum clocks immediately became the best timekeepers for use on land, but they didn't work accurately on a heaving ship's deck. Huygens worked with several Dutch clockmakers, including Johannes van Ceulen, who made this table clock around 1680. It is one of the earliest clocks with a pendulum.

Longines Sidereal Second-Setting Watch
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Before 1927, watches used with sextants for celestial sightings could only be set to the minute. A watch error of 30 seconds caused a navigational error of up to 12 kilometers (7 miles). In 1927, P. V. H. Weems devised a watch with an adjustable second hand that could be set using radio time signals. This was one of his personal navigation watches. Sidereal refers to the watch running on a celestial day (about 23 hours, 56 minutes), rather than the 24 hour solar day.

Lockheed Vega 5C Winnie Mae
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Wiley Post's Winnie Mae circled the globe two times, shattering previous records. The first time was in 1931 with Weems associate Harold Gatty as lead navigator. The second was a solo flight in 1933 assisted by "Mechanical Mike," one of the world's first practical autopilots.

Stanley Autonomous Vehicle
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This autonomous vehicle, named Stanley, was developed by the Stanford Racing Team. Stanley is a 2005 Volkswagen Touareg modified to navigate without remote control and without a human driver in the seat. Stanley won the 2005 Grand Challenge, a robot race sponsored by the Defense Advanced Research Projects Agency (DARPA), by successfully navigating 212 kilometers (132 miles) across desert terrain.