According to the US Postal Service 16.6 billion cards, letters and packages will be delivered between December 1 and Christmas Day this year. They anticipated that December 14th would be the busiest mailing day, and that yesterday, December 16th, would be their busiest delivery day.
Yellowstone Supervolcano
Yellowstone Relief Map (University of Utah, Robert B Smith)
Three times during the past two million years, the Yellowstone supervolcano has erupted, leveling mountains and covering half of North America with ash.
As described in the notice for a lecture to be delivered earlier this year by the University of Utah’s Robert B. Smith — The Yellowstone Supervolcano: Past, Present and Future — “the energy responsible for creating these geologic features comes from a 50-mile-wide ‘hotspot’ or ‘mantle plume’ of molten rock that originates at least 400 miles below the Idaho-Montana border, and then angles eastward and rises until it is only 30 miles beneath Yellowstone. There, the plume hits cooler rock and spreads out to a width of 300 miles.
“The buoyancy of the hot plume lifts Yellowstone and the surrounding region into a 500-mile-wide ‘topographic swell’ that pushes the ground well above 7,000 feet elevation, or about 1,600 feet higher than it would be without the underground plume.
“The volcanic plume also fuels a shallow ‘magma chamber’ of hot and partly molten rock that extends from about five miles beneath Yellowstone to a depth of at least 10 miles.”
This immense powerhouse is the source for all the amazing wonders which attract hundreds of thousands of visitors to the nation’s first National Park. “The crustal magma body continues to fuel Yellowstone’s geysers and power a restless caldera, which, like others on Earth, huffs upward and puffs downward for millennia without erupting — often by many feet over the decades. The caldera floor rose 40 inches during 1923-1984, fell 8 inches during 1985-1995, rose a few inches maximum during 1995-2000, mostly sank about an inch during 2000-2003, then mostly rose more than 3 inches since mid-2004 — three times faster than its historic rate of uplift.
“Movement of magma and hydrothermal fluids cause these ups and downs. Studies have revealed Yellowstone’s hydrothermal systems release 100 watts per 36 square feet — in other words, a square of ground measuring 6 feet on a side emits enough heat to power a 100 watt light bulb. That’s more than 20,000 times the heat emitted by the average rock in North America.
“During late December 2008 and early January 2009, Yellowstone experienced its second-largest earthquake swarm in recorded history, and it was well-documented by the University of Utah real-time seismic network. The sequence consisted of about 1,000 earthquakes, including a dozen quakes of magnitude 3.0 or higher, and one as large as 3.9 on the Richter scale.”
Now, a new study of the Yellowstone supervolcano has determined that the magma chamber is 20 percent larger than previously believed, and verified that it reaches deep beneath the earth’s crust into the mantle.
The three historical eruptions, which took place 2.05 million years ago, 1.3 million years ago, and 642,000 years ago, were respectively 2,500, 280, and 1,000 times larger than the eruption of Mount Saint Helens in 1980.
Yellowstone Plume (University of Utah)
Kansas Population: Anticipating the Census
As we approach a new national census in the coming year, what is the best current estimate of where Kansas and the Wichita Metropolitan Statistical Area stand?
According to the most recent population estimates released by the Census Bureau, Kansas has experienced a 4.2 percent increase in population from the year 2000 through July 1, 2008, to an estimated population of 2,802,134. This represents an increase of 113,318 Kansans.
Kansas would thus rank 33rd among the states in population at present (versus 32nd in 2000), and 34th in percent change.
The Midwest as whole averaged a 3.4 percent increase, slightly below that of Kansas, during the same time period.
The Wichita Metropolitan Statistical Area, meanwhile, grew by an estimated 32,545 to 603,716 as of July 1, 2008, ranking 84th among all metro areas (versus 80th in 2000).
Six Armies in Tennessee
Steven E Woodworth’s Six Armies in Tennessee, in print now for just over a decade, is a well-written, highly readable and deftly paced short history of the Civil War campaign for Central and Eastern Tennessee in 1863.
Beginning with the aftermath of the battle of Stone’s River, continuing through the battle of Chickamauga and the battles for Chattanooga, and concluding just after the failed siege of Knoxville, Six Armies in Tennessee explores a campaign, overshadowed in the popular imagination by the Union victories at Gettysburg and Vicksburg that same year, but no less decisive in its results. Chickamauga, which took place precisely one year after Antietam, was the bloodiest two-day engagement of the entire war. (Antietam witnerssed the single bloodiest day for American troops in all our history.)
Woodworth’s treatment of the oft-disparaged Confederate commander General Braxton Bragg is an eminently fair and balanced one, far more sympathetic than most. Bragg’s greatest failing was not so much strategic acumen or its lack as it was a plague of truly dismal subordinates who failed him repeatedly, and whom he could not or would not motivate or break.
Similarly, Woodworth’s analysis of the merits of the successive Union commanders, Major Generals William S. Rosecrans and Ulysses S. Grant, is equally perceptive and balanced.
At just under 220 pages, Six Armies in Tennessee is brief, but not too brief, graced with good footnotes, an adequate index and a short but useful Bibliographical Essay.
I heartily recommend this history to anyone curious about this vitally important but too often ignored campaign.
Confederate Commander throughout the campaign, Braxton Bragg
Phobos and Deimos
Phobos & Deimos Aligned (Mars Express Orbiter - ESA)
In early November the European Space Agency’s Mars Express Orbiter captured this amazing image of Mars’ two moons, Phobos and Deimos in alignment. On the ESA website there is a great video of successive images captured as the Mars Express approached the position depicted above. See “Pioneering Images of Both Martian Moons” for the video and more.
Here’s a closeup of the smaller moon, Deimos:
And here’s an image of the larger moon, Phobos:
Top 100 Books of 2009 (Amazon)
Amazon.com’s Top 100 Editor’s Books of 2009 is heavily skewed toward popular fiction titles and very light on the nonfiction, but worth a quick perusal.
Their Top 100 Customer Favories for 2009 is a very different take on the publishing year, equally worth a look.
On this page, you’ll find a number of category listings for both editors’ and customers’ picks from Art & Photography to Teens, as well as preceding years’ listings back to 2000.
