When Will the Leaning Tower of Pisa Fall Over?
Experts say the famous tower at Pisa will lean for at least another 200 years. It may even stay upright — well, almost upright — forever. That’s all thanks to a restoration project, which brought the tower back from the brink of collapse a decade ago.
From the first moment of its construction on unstable subsurface soils in 1173, Pisa’s bell tower tilted farther and farther to the south. Its early-onset lean even influenced the way it was built, as its architects tried to compensate by angling the structure northward, resulting in its being banana-shaped.
A few ill-advised construction projects accelerated the Leaning Tower’s invisibly slow fall during the past couple of centuries; it tilted 5.5 degrees, its acutest angle ever, in 1990. By all calculations, the tower should have toppled at just 5.44 degrees, but fortunately it defied the predictions of computer models just long enough for engineers to come up with a fix.
Restoration work undertaken from 1999 to 2001 stabilized the tower. Engineers placed weights on the structure’s north end, while at the same time extracting soil from below, causing it to slowly sink back in that direction.
The Leaning Tower of Pisa still leans south, but now it does so at just 3.99 degrees. Barring a large earthquake or other unforeseen catastrophe, engineers believe it will stay put for at least a few hundred years.
Priceless Science: Striking Finds From a Rare-Book Fair
There are places where open flames are particularly frowned upon. A textile mill or a stationery store, for instance. And then there are places where the mere mention of a flame, fire, spark, smoke or ember elicits pandemonium. The San Francisco Antiquarian Book, Print and Paper Fair, held earlier this month, would be such a place. In a building stretching one square block sat some of the rarest texts, maps and manuscripts in the world, precariously flammable, and indubitably expensive.
Particularly fetching among these cultural treasures were the scientific tomes — works of biology, astronomy, chemistry and the like — which dealers proudly displayed with the most enticing illustration forward. It’s the intellectual equivalent of the models on the car lot with their hoods popped open, only with more flammability and much more intellect. From Audubon’s The Birds of America, a first edition of which sold last month at auction for $7.9 million, to Copernicus’ heliocentric sketch that changed the world, we’ve selected the most remarkable works the fair had to offer.
1. Anatomy of Plants(1681)
by Nehemiah Grew
If family names are derived from occupations, Nehemiah Grew’s ancestors must have been just as excited about plants as he was. His landmark work Anatomy of Plants was the first to note that a plant’s stamen is a male organ, with pollen being the seed. The text is also remarkable in its unprecedented detail, as seen above, with Grew even getting down into the first microscopic descriptions of pollen.
Owner: Liber Antiquus, Washington, D.C.
2. Theatrum Italiae(1663)
by Joan Blaeu
Moving is never easy, and moving is especially difficult when you own a 327-ton Egyptian obelisk and you want it shifted 275 yards to sit right in front of the Vatican. Such was the task assigned to Italian engineer Domenico Fontana in 1586 and detailed in this illustration from Joan Blaeu’s Theatrum Italiae(see a high-res version here). Enlisting some 900 men and 75 horses, it took Fontana a year to move the 83-foot obelisk.
Says the book’s owner, Paul Dowling: “People look at the 16th century and they look at the development of architecture and the arts and they see it as art and visually stimulating, but very rarely do they see the great technological advances that allowed the things to actually come to fruition…. It’s reminiscent of things like Apple. It’s great design, but there’s an incredible technological layer underlying it. ”
Liber Antiquus, Washington, D.C.
by Francis Willughby
Together with his mentor John Ray, the father of English natural history, Francis Willughby toured Europe for three years to gather material for this, the modestly named Ornithology. When Willughby succumbed to pleurisy during its compilation, Ray picked up the project, publishing the gorgeous work in Latin in 1676 and in English two years later. It was the first study to organize birds by their characteristics, leading distinguished zoologist Alfred Newton to call it “the foundation of scientific Ornithology.”
Owner: Liber Antiquus, Washington, D.C.
4. Cursus Mathematicus(1690)
by William Leybourn
A compendium of British mathematician William Leybourn’s writings, Cursus Mathematicus was aimed at the popular market (particularly for “a dull solitude or vacancy of Business,” as the author put it), as opposed to scholars. It was this book that James Logan, the early American scientist and mentor to Benjamin Franklin, used to teach himself math. The illustration above is a product of a century that saw the introduction of the telescope, affording the first detailed looks at our trusty satellite. We wouldn’t glimpse the far side of the moon, however, until 1959.
Owner: Antiquariat Botanicum, Lynden, Washington
Transit of Phobos from Mars, as seen by Mars Rover Opportunity
Transit of Phobos from Mars, as seen by Mars Rover Opportunity On Mars, only partial solar eclipses (transits) are possible, because neither of its moons is large enough, at their respective orbital radii, to cover the Sun’s disc as seen from the surface of the planet. Eclipses of the moons by Mars are not only possible, but commonplace, with hundreds occurring each Earth year. There are also rare occasions when Deimos is eclipsed by Phobos. Martian eclipses have been photographed from both the surface of Mars and from orbit.
The Civil War, Part 3: The Stereographs
Feb. 14, 1989: GPS Enters Orbit
1989: The first of 24 satellites that will make up the global positioning system is put into orbit.
GPS revolutionized navigation, both at sea and on land, by providing position reports with unprecedented, pinpoint accuracy. Each satellite is placed in a specific orbit at a specific altitude to ensure that four or five satellites are always within range from any point on the planet. A GPS receiver picks up signals from the satellites and trilaterates the data to fix the position.
This satellite system is so valuable — besides navigation, GPS has applications in mapmaking, land-surveying and the accurate telling of time — that even though it was developed and is maintained by the U.S. Department of Defense, it’s been available since 1993 without charge to anyone, anywhere on Earth.
Although GPS has eliminated the need for determining a ship’s position by shooting the sun or stars, no sailor worthy of the name would put to sea, even now, without the ability to use a sextant. Electronic navigation devices fail, and even GPS isn’t immune to the odd glitch, and the open ocean is a lonely place to be if you don’t know where you are.
Source: Peter H. Dana, The Geographer’s Craft Project; Wikipedia
Image: Artist’s rendering of GPS satellite courtesy NASA.
This article first appeared on Wired.com Feb. 14, 2007.
Charles Robert Darwin
“It is not the strongest of the species that survives, nor the most intelligent that survives. It is the one that is the most adaptable to change.”
On the image:
- The seven-year-old Charles Darwin in 1816, a year before the sudden, tragic loss of his mother.
- Page from Darwin’s notebooks around July 1837 showing his first sketch of an evolutionary tree.
- Darwin chose to marry his cousin, Emma Wedgwood.
Tablets and Slates Before the iPad
- Cuneiform Tablets
Cuneiform, invented by the Sumerians about 4,000 B.C.E., was one of the earliest forms of writing. Users pressed shapes into wet clay tablets with the wedge-shaped tip of a reed, so their markings became permanent once the clay dried — in some cases lasting thousands of years.
While this text-entry method was WYSIWYG, it was not easy to edit, as evidenced by the erased block shown in the lower left.
This tablet is in the collection of the British Museum in London.
Photo: Charles Tilford/Flickr
2. Hamlet’s Tables
When Hamlet finds out that his uncle has killed his father, he mutters something about “wiping records” from “the table of my memory.” This “table” was likely a Shakespearean PDA, a small notebook containing blocks of plaster. A metal pen was used to write on these “pages,” and they could be wiped clean when needed.
The “tables” may also have been ass-skin pages, coated to be erasable with moisture. Either way, reusable paper was an essential alternative to expensive real paper at the time.
It seems somehow appropriate that Hamlet, a most businesslike character, was using an early form of the personal organizer.
Photo courtesy ofSarah Werner, Wynken de Worde
Early Pressure Suits
As pilots flew to greater and greater heights during the modern era of flight, people had to don pressure suits to provide oxygen when the air became too thin. Balloonists and, later, airplane pilots were the first innovators of such clothing. One of the earliest pressure suits invented was an 1894 Australian armored outfit made of a wire frame covered with waterproof material.
Fred M. Sample patented the first pressure suit in the US on Jul. 16, 1918. It was meant “for supplying air to aviators when making flights at high altitudes or to travelers crossing high mountains.” Fabricated from an elastic material, the invention shares many characteristics with modern spacesuits, including an airtight body suit that completely encloses the wearer, a helmet that can be readily opened and closed during transition from normal atmospheric conditions to thinner atmospheres, and a flexible air-supply hose connected to a source of compressed air and a pump.
Image: US Patent Office
The Farmington coal mine disaster kills 78. West Virginia, US, 1968.
Pale Blue Dots
Iconic Images of Earth From Space
The European Space Agency launched the Rosetta spacecraft in 2004 to land a probe on comet 67P/Churyumov–Gerasimenko in November 2014.
When it swung by Earth for its third and final gravity boost on Nov. 12, 2009, Rosetta took a series of photos of the Earth. The outline of Antarctica is visible in the bottom portion of the planet.
Image: ESA/MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA [high-resolution version]
To reach asteroid 433 Eros, NASA’s Near Earth Asteroid Rendezvous Spacecraft, or NEAR, had to swing by our home planet on Jan. 23, 1998. The south poles of the Earth and moon are visible in this shot.