A Panoply of Galaxies

The incredible diversity of galactic shapes and structure (NASA)

The Australian science magazine Cosmos (you’ll find it in the periodicals section) reports in its online edition (Galaxies Shaped By Dark Past) that a pair of astrophysicists have created a model called GALFORM, which simulates galaxy formation in a universe described in one of the dominant cosmological models of the cosmos (the Lambda Cold Dark Matter or LCDM model).

As Cosmos evinces, their “model was able to reproduce the evolutionary history of the universe over its 13.7 billion years. Moreover it not only got the shapes but also the numbers of various galaxies right and the rate at which galaxy mergers occur.

“‘We were completely astonished that our model predicted both the abundance and diversity of galaxy types so precisely,’ said astrophysicist Nick Devereux of Embry-Riddle University in Arizona.’”

The model, now published in the Monthly Notices of the Royal Astronomical Society, further shows that our own galaxy “the Milky Way has a complex past but so far has only undergone minor collisions and the gravitational collapse of its inner disk to form the central bar.”

Published in: on January 27, 2010 at 6:06 pm  Leave a Comment  

Callisto, Ganymede & Comets

Jupiter's second largest moon, Callisto

Four hundred years ago to the month, Galileo trained his telescope on the planet Jupiter and discovered the four largest moons of the solar system’s largest planet.

The very great differences between the two largest of those moons have puzzled scientists for decades. Ganymede, the largest moon in the solar system, and Callisto, are nearly equivalent in size, but only Ganymede has a magnetic field, a highly differentiated composition, and evidence of past tectonics. Now, a pair of scientists from the Southwest Research Institute have proposed in the journal Nature Geoscience that the contrast can be explained by the differential effects of cometary bombardment. (Here is the abstract of their article.)

Here’s how Scientific American explains their thesis in the article Early Cometary Bombardment May Explain the Divergent Path of Jupiter’s Biggest Moons:

“Each time a comet strikes an icy satellite, Barr explains, a portion of the moon’s surface melts from the heat of the impact; the heavier metallic and rocky constituents mixed in sink to the bottom of the melt pool. With enough impacts providing sufficient melting, the sinking rocks’ gravitational potential energy is released as heat, producing more melting, and the separation of rock and ice becomes self-sustaining, a process known as ‘runaway differentiation.’

“During the solar system’s period of intense impacts about 3.8 billion years ago known as the late heavy bombardment, tremendous amounts of cometary material would have been flying around Jupiter and the outer gas-giant planets. Barr and Canup estimate that Ganymede’s proximity to Jupiter, the latter of which acts as something of a gravitational sink, led to Ganymede’s experiencing double the impacts of Callisto, and at higher velocities, to boot. ‘Ganymede gets 3.5 times as much energy in the late heavy bombardment as Callisto,’ Barr says. That energy differential, Barr and Canup realized, could account for Ganymede’s much more complete state of differentiation—the so-called Ganymede–Callisto dichotomy.”

Visit the article in Scientific American, or see the original (subscription required) in Nature Geoscience for greater detail.

Jupiter's largest moon, Ganymede

Published in: on January 27, 2010 at 4:46 pm  Leave a Comment  

Hobbits and Island Dwarfism: An Update

Skull of Homo floresiensis compared with skull of Homo sapiens (Dr. Peter Brown, University of New England)

Since our review of A New Human last January, we’ve been following the remarkable unfolding story of the diminutive people who once populated the Indonesian island of Flores, known popularly as Hobbits. (For excerpts from the book, see here and here; for some of our updates, check here, here and here.)

Now, there’s a new study that buttresses the emerging consensus view that Hobbit represents a separate species in the human lineage.

Specifically, the study supports the notion that “the reduction in brain size during the evolution of Homo floresiensis is not unusual in comparison to these other primates [in the study]. Along with other recent studies on the effects of ‘island dwarfism’ in other mammals, these results support the hypothesis that the small brain of Homo floresiensis was adapted to local ecological conditions on Flores.”

BioMed Central offers a preliminary version of the study with Reconstructing the Ups and Downs of Primate Brain Evolution: Implications for Adaptive Hypotheses and Homo Floresiensis, a 64-page detailed review. For a one-page abstract of the study, look here. You’ll also find much briefer characterizations of the results at EurekAlert! and at Science Daily in Is the Hobbit’s Brain Unfeasibly Small?

Published in: on January 27, 2010 at 11:51 am  Leave a Comment  

State of the Union

The first page of George Washington's very first State of the Union address (Library of Congress)

We’ll be setting the Tivo to record tonight’s State of the Union message while we attend the special talk by Kansas author Jim Hoy tonight. But if you’re going to watch the speech live, you may be interested in some of the past State of the Union addresses delivered by previous presidents.

C-Span offers a State of the Union archive with videos of all the State of the Union speeches by the last four presidents, along with a smattering of earlier videos (President Reagan’s final State of the Union, two of Gerald Ford’s three addresses, and Richard Nixon’s final 1974 speech). You will also find transcripts of all the speeches back through the Truman administration.

Published in: on January 27, 2010 at 10:45 am  Leave a Comment  

Mars Approach

NASA explains why right now is an excellent time to observe the planet Mars.

Published in: on January 26, 2010 at 4:37 pm  Leave a Comment  

Ulysses Grant Returns

“No great American has suffered more cruelly and undeservedly at the hands of historians than Ulysses S. Grant. The dominating influence of pro-Southern historians early in the twentieth century—an influence that tainted scholarship on the Civil War for decades—helps to explain Grant’s abysmal reputation. But it does not explain Grant’s fate in full, nor why the vilification of the man has continued into our own time.”

Reviewing Joan Waugh’s new book US Grant: American Hero, American Myth in The New Republic, Sean Wilentz offers an excellent brief appraisal of the reasons behind the eclipse of Grant’s reputation in “The Return of Ulysses”:

“The imminent Civil War sesquicentennial of 2011 to 2015 augurs a full recasting of popular as well as scholarly understanding of the war and its major figures, including, inevitably, Grant. Perhaps then, Waugh concludes, visitors to the tomb ‘may be able to see all the tangled, complicated, but ultimately inspiring dimensions of a man who truly is both an American hero and an American myth.’

“If indeed justice is done and truth is served, those visitors will be inspired by far more than certain particular dimensions of Grant. A superb modern general who, with Lincoln, finally unleashed the force required to crush the slaveholders’ rebellion, Grant went on, as president, to press vigorously for the reunification of the severed nation, but on the terms of the victorious North and not of the defeated South. Given all that he was up against—not simply from Confederates and Southern white terrorists but, as president, from high-minded factional opponents and schismatics from his own Republican Party—it is quite remarkable that Grant sustained his commitment to the freedmen for as long and as hard as he did. The evidence clearly shows that he created the most auspicious record on racial equality and civil rights of any president from Lincoln to Lyndon B. Johnson. He also formulated some remarkably humane and advanced ideas on subjects ranging from federal Indian policy to public education. Given the limitations imposed on executive power by the Constitution, it is all the more remarkable that he acted as boldly as he did.

“So Grant’s full vindication—which will render him one of the greatest presidents of his era, if not of all American history—still awaits. But when it comes, we will better understand our complicated history . . . .”

(For several links to some of our earlier posts on Ulysses S. Grant, and to our review of Josiah Bunting III’s Ulysses S. Grant, see
this post.)

Published in: on January 26, 2010 at 12:53 pm  Leave a Comment  

Kansas Author Jim Hoy Speaks Tomorrow Evening

Don’t forget that tomorrow, January 27th, just two days before Kansas’ birthday, popular Kansas author Jim Hoy will be hosting a special program here in the Haysville Community Library on the Folklore of the American West. We’ll be meeting in the Community Room at 6:30 in the evening.

Pie, coffee and other refreshments will be served by the Friends of the Library.

For more details, see our earlier post here.

Published in: on January 26, 2010 at 12:06 pm  Leave a Comment  

Milky Way Transit Authority

The London Underground

London’s Daily Mail features a delightful map of the Milky Way galaxy based on the London subway system: the Milky Way Transit Authority, created by Samuel Arbesman.

Our Neighboring Andromeda Galaxy

Published in: on January 26, 2010 at 10:41 am  Leave a Comment  

Australian Extinction

Zygomaturus trilobus -- an extinct Australian Pleistocene marsupial

Much akin to the debate about large scale extinctions in North America – preceding, coincident with, or ensuing and caused by the arrival of humans – for more than a hundred fifty years much the same question has been debated concerning the great late Pleistocene extinctions of huge numbers of native marsupial species in Australia. The latest entry weighs in on the scales and tilts the evidence toward a human role in the demise of Australia’s megafauna.

Fossil Diprotodon (Queensland Museum)

Published in: on January 22, 2010 at 5:42 pm  Leave a Comment  

Cat’s Paw Nebula

Cat's Paw Nebula -- NGC 6334 (ESO)

The European Southern Observatory (ESO) has released this stunning new image of the Cat’s Paw Nebula (NGC 6334), a complex region of gas and dust near the heart of the Milky Way, 5500 light-years away. The vast cloud of gas, more than 50 light-years across, is a nursery where numerous enormous stars are being born.

As the ESO explains, “few objects in the sky have been as well named as the Cat’s Paw Nebula, a glowing gas cloud resembling the gigantic pawprint of a celestial cat out on an errand across the Universe. British astronomer John Herschel first recorded NGC 6334 in 1837 during his stay in South Africa. Despite using one of the largest telescopes in the world at the time, Herschel seems to have only noted the brightest part of the cloud, seen here towards the lower left . . . .

“NGC 6334 is one of the most active nurseries of massive stars in our galaxy and has been extensively studied by astronomers. The nebula conceals freshly minted brilliant blue stars — each nearly ten times the mass of our Sun and born in the last few million years. The region is also home to many baby stars that are buried deep in the dust, making them difficult to study. In total, the Cat’s Paw Nebula could contain several tens of thousands of stars.”

A broader view of the area surrounding the Cat's Paw Nebula (ESO)

A nebulous cat's paw.

Published in: on January 22, 2010 at 4:33 pm  Leave a Comment  

America’s Best High Schools

In December, US New & World Report published a ranking (for the third year in a row) of America’s Best 100 High Schools. To create their rankings, they analyzed 21,786 public high schools in 48 states and the District of Columbia. (You’ll find the methodology of the study here.)

There was just one gold medal winner in the state of Kansas (placing 62nd among the top 100), Sumner Academy of Arts and Science in Wyandotte County. However, more than three dozen others did well enough to earn a bronze medal. For a listing of their Best High Schools in Kansas (bronze medal winners), including two in Sedgwick County, check here.

You’ll also find a listing of the state-by-state statistics here.

Published in: on January 22, 2010 at 3:54 pm  Comments (1)  

Mount Rushmore: Library Fundraising Tour

Published in: on January 22, 2010 at 2:31 pm  Leave a Comment