Taxonomy term

benchmarks

Gain some, lose some

Scientists now know that Earth’s rotation is very slowly decelerating, such that the length of the rotational day is about two milliseconds longer than the 86,400 seconds it was nearly two centuries ago. But that doesn’t mean Earth’s rotation is always slowing down. The tidal force of the moon acts to slow Earth’s rotation by taking away some of the planet’s energy. But other factors, such as the expansion and contraction of the atmosphere with the seasons, the churning of material within Earth’s core, and the rebounding of Earth’s surface as the weight of glaciers is removed, can sometimes act to speed up Earth’s rotation by redistributing its mass, thereby altering Earth’s moment of inertia and thus its speed of rotation.

30 Jun 2010

Benchmarks: May 18, 1952: Stonehenge's age solved with Carbon-14

Like sentinels standing guard over a millennia-old secret, the 8-meter-tall stones of Stonehenge rise above the rolling green hills of England’s Salisbury Plain. The origin, date and purpose of the arrangement of the giant standing stones, located about 145 kilometers west of London, have puzzled people for thousands of years. But in 1952, physical chemist Willard Libby, a professor at the University of Chicago in Illinois, finally provided a concrete answer to one of the site’s most enduring questions: when it was built. To do this, Libby used a brand-new geochemical technique that he had been developing based on the radioactive isotope carbon-14. Only a few years later, his work on this groundbreaking technique earned him a Nobel Prize for Chemistry.

18 May 2010

Nuclear Fallout

Willard Libby, who won a Nobel Prize for Chemistry in 1960, was a prominent advocate of nuclear weapons testing, and worked on the Manhattan Project to help develop an atomic bomb during World War II. During the late 1950s, chemist Linus Pauling, a peace activist who won Nobel Prizes for both Chemistry and Peace, presented the United Nations with a petition signed by more than 11,000 scientists that called for an end to nuclear weapons testing. In particular, Pauling cited a 1958 speech on carbon-14 by Libby that suggested nuclear tests would produce large amounts of the radioactive isotope. 
 
18 May 2010

Benchmarks: April 1, 1877: Prospector begins search for Tombstone's silver

On April 1, 1877, Ed Schieffelin arrived at Fort Huachuca in southeastern Arizona. Schieffelin, a prospector who had tried his luck all across the West, came to the desert looking for untapped riches. The soldiers at the fort warned him that the only thing he’d find was his own tombstone. But by Aug. 1, Schieffelin found what he was looking for: silver. He named his first mining claim Tombstone.

22 Apr 2010

March 23, 1821: Bauxite Discovered

Compared to gold, silver, lead and copper — metals that people have extracted, refined and used for millennia — aluminum is a relative newcomer. Pure aluminum was more valuable than gold when it was first discovered in the early 19th century. It graced the fine china of Napoleon III and was displayed next to the French Crown Jewels at the 1855 Paris Exhibition. Today, aluminum is cheap and plentiful, used in everyday products ranging from soda cans to jets. The transformation of the metal from unknown material to rare metal to ubiquity in fewer than two centuries is due to two pivotal discoveries: an abundant aluminum ore — bauxite — and a process of refining this ore using electricity.
 
23 Mar 2010

The Washington Monument's Apex

An aluminum pinnacle has graced the Washington Monument since 1884, but subsequent modifications have changed the look of the point. 

23 Mar 2010

Benchmarks: February 4, 1962: Five planets align - but no end of the world

In the movie "2012," released in theaters last November, an alignment of five planets in our solar system — supposedly foretold by the Mayans thousands of years ago — causes horrors that span nearly every earth science disaster movie cliché: solar flares, neutrinos, earthquakes, volcanoes, floods, poles shifting, oceans washing over the tallest mountains in the world, cities falling into the sea, mass hysteria and, basically, total destruction of life as we know it.
 
04 Feb 2010

Benchmarks: January 13, 1404: England prohibits Alchemy

Alchemy, in both ancient and medieval times, wasn’t just about turning lead into gold, although such “transmutation” was certainly one desirable goal. In a broader sense, alchemists were both philosophers and the precursors to modern chemists, in that they sought to understand thedifferent states of matter, the interactions of metals, and the way in which elements were created from the original chaos. There were thought to be four elements — earth, air, fire and water — and combining them properly could produce any substance on Earth, from medicines to gold. Among the more lofty ambitions of alchemists was the search for the fabled Philosopher’s Stone, a substance that was supposed to enable the transmutation of one substance into another (and perhaps act as an elixir of life).
 
13 Jan 2010

Benchmarks: December 1, 1959: Antarctic Treaty Signed

Science trumps all in Antarctica. For the past 50 years, Antarctica has remained a military-free, globally shared continent, dedicated to peace and scientific advancement, thanks to the Antarctica Treaty.
 
01 Dec 2009

Benchmarks: November 22, 1859: "On the Origin of Species" published

By David B. Williams

About a decade ago, I was fortunate enough to hold in my hands a first edition of Charles Darwin’s “On the Origin of Species.” The green cover was cracked and frayed. The cardboard backing protruded through the torn corners. I put the book down and stared at it in awe. The owner of this book was Asa Gray, one of America’s greatest botanists, an important early American supporter of natural selection, and a friend of Darwin’s.

23 Nov 2009

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