The Fremonts

My two “research assistants” at a Fremont
Indian State Park petroglyph site.

I’m on vacation this week and I wanted to share a postscript to an earlier column I wrote on the Fremont Indians. I had a chance to stop at another Fremont site on my way to Iowa, this one at Fremont Indian State Park near Sevier, Utah at Clear Creek Canyon.
   The site was discovered during construction of Interstate 70, and thousands of artifacts have been excavated from the ancient village and put on permanent display at the museum there.

   The Fremont Indians lived from about AD 400 to 1,300 in north and central Utah as well as in parts of Nevada, Colorado and Idaho. They were hunter-gatherers who were influenced by the Anasazi, who introduced corn and pottery which made it possible for them to settle. Clear Creek Canyon was rich in food resources which meant they spent less time hunting and gathering and had more leisure time which they used to make jewelry and other items to trade with other tribes and gave them time to create the rock art that adorns the cliff-sides today.
   The Fremont diet consisted mainly of corn, beans and squash which was harvested and stored in granaries. They supplemented this with wild grasses, nuts and berries as well as an assortment of animals such as deer and rabbits. The granaries were made of rock and adobe, and were designed to keep out vermin and protect the harvest. While some granaries were built near their homes, others were hidden away in remote locations, often high up on the cliff sides in order to protect the grain from being stolen. 

A close-up of one of the thousands of Fremont petroglyphs 
that can be seen at Fremont Indian State Park.

   The artifacts found included arrowheads, pottery, and grinding stones called manos and metates used to grind their corn into a course meal. Analysis of the teeth of the Fremont indicates that their teeth were badly worn, likely from eating corn flour with bits of rock that wore off during grinding.
   The Fremonts are often compared to the Anasazi, whom they traded with. Although they lived in the southwest at the same time, there are some significant differences. The Fremonts lived in single-room pithouses and lived in small villages. The Anasazi built larger houses, often multi-story, and they lived in large villages with many families. The Anasazi also built round, ceremonial structures while the Fremont did not.

A Tale of Two Theories

We’re well aware of Charles Darwin and his theory of natural selection which he published in his landmark 1859 book, On the Evolution of Species. But he was not the only one to develop this theory. Similar ideas were also being developed during this time by Alfred Wallace, a self-educated naturalist from Wales. 
Starting in 1848, Wallace spent four years in the Amazon on an expedition he had organized to collect specimens for rich collectors and museums. As luck would have it, his return ship caught fire and sank. He spent the next ten days at sea in an open boat before being rescued. Unfortunately, almost all his specimens were lost. And though he was disheartened and vowed to never travel again, two years later he was off to the East Indies on an incredible odyssey that would consume him for the next eight years as he amassed over 125,000 specimens. During this time he identified the dividing line between Asian and Australian fauna which is known as the “Wallace Line”, prompting some to dub him the father of biogeography. 

The Darwin-Wallace Medal was first issued by the
Linnean society to Alfred Wallace on the 50th
anniversary of the reading of Darwin and Wallace’s
papers on natural selection.

In 1855, Wallace put together some of his ideas and discoveries in a paper that outlined the principles of evolution. Darwin was initially unimpressed after reading the paper, but it did prompt him to start putting together his own book on evolution. In 1858, Wallace sent another paper to Darwin. Although he was weak with malaria, he had experienced an epiphany regarding natural selection: that because populations would always outgrow their food supply, hunger and famine was unavoidable, but those that were best-suited to deal with such a situation would survive and pass on their good traits to future generations. 
Darwin could no wait no longer. He took Wallace’s paper and an outline for his book along with some of his previously-unpublished writings and presented them jointly to the Linnean Society in London. A year later, with Wallace still in Malaysia, Origin was finally published. When Wallace eventually found out that his paper had been published without his knowledge, he was happy to have been included with the more-famous Darwin. 
Wallace would return to England in 1862 and finally go to meet Darwin. Some have tried to claim over the year that Darwin stole ideas from Wallace or that there was a conspiracy to deprive Wallace of the credit he was due for his contributions to evolution, but these are without merit. Wallace was to be one of the most loyal defenders of Darwin’s Origin. He wrote Darwinism, which explained and defended the theory of natural selection and became his best-known work. And while today we consider them cofounders of evolution, each had their own approach. For example, Darwin emphasized competition between members of the same species to survive and reproduce, while Wallace emphasized species adaptation as a result of environmental pressures. Throughout Darwin’s life they remain on friendly terms, corresponding and discussing evolution until Darwin’s death in 1882.

WR-104

False-color composite of WR104. This composite represents 

eleven shots taken over eight months.

Eight thousand light years from the Earth, in the constellation Sagittarius, lurks a massive binary-star system that is on the verge of becoming a supernova. The star is call Wolf-Rayet 104 and, like Sagittarius the archer, this star could be taking aim at us. If it finds its mark, it could hit us with enough deadly radiation to destroy our protective ozone layer. This would cause drastic climate change that could trigger a mass extinction. 

  Wolf-Rayet stars, named after the two astronomers who  discovered them first, are massive, hot, and very luminous. They are about 25 times more massive than our Sun, and 100,000 times more luminous. Super massive stars like WR-104 live fast and burn their nuclear fuel very quickly, within tens of millions of years. Compare that to the age of our Sun which is 4.6 billion years. As they exhaust their supply of nuclear fuel, they undergo gravitational collapse into a black hole, releasing a massive blast of high-energy radiation—a gamma ray burst so powerful that it would briefly outshine an entire galaxy. Gamma rays are the deadliest, most energetic type of radiation. Energy from the explosion is beamed into two narrow, oppositely directed jets.

  Because WR-104 is a binary star system it produces a spiral-patterned stream of dust and charged particles as the stars orbit each other. As the star collapses, it becomes a dense, flattened, rapidly-rotating disc and the gamma rays are ejected along the rotational axis poles, rushing out like soda from a pop can that had been shaken before opening. If the poles of the collapsing star happen to be pointed at us—look out. And because astronomers can see the spiral of this star full on it means that the star’s rotational axis is pointed in our general direction, as if Sagittarius’s arrow were pointed right at us.

  But don’t worry too much, the time line for such an event is anytime in the next 100,000 years. Also, recent evidence suggests that it is pointing slightly away from us and will miss its mark.

Mr. Bones

Tyrannosaurus rex on display at the American Museum of Natural History.

Barnum Brown was arguably the greatest fossil hunter of all time. Working for the American Museum of Natural History in New York, he had a career spanning more than 60 years. The museum boasts the largest collection of fossil dinosaurs in the world, thanks in large part to Brown’s collection efforts. Mr. Bones, as he was affectionately known by admirers, had his discoveries plastered on the front page of newspapers across the country and had been on so many radio programs and given so many lectures that he was considered one of the most famous scientists in the world during the first half of the twentieth century.

  Brown was completely dedicated to his work with the museum. One chilly December morning in 1898, Brown arrived at the museum as usual and by the time he had removed his coat he was called into Professor Osborn’s office. Osborn was the curator of vertebrate paleontology for the museum and wanted to send Brown on an expedition to Patagonia. Brown’s account from his journal follows: “Yesterday, about three hours before the Capac was to sail I was notified by Professor Osborn that arrangements had been made for me to go to South America. Four of the Dept. men packed up my kit and I took another with me home to pack up. Imagine getting an outfit together in three hours to go on a seven thousand mile journey, and be gone a year or more. Such is the life of a fossil man.”

  Brown embarked on the month-long sail to Punta Arenas, during which he was so taken with sea sickness that he was “…first hoping I would die, then afraid I wouldn’t”. He managed to survive the journey, and collected fossils for the next year and a half. Months would pass without word and at times the only evidence of Brown’s continued survival would be the shipment of tons of fossils back to the museum. Mr. Bones would face blizzards, evade quicksand, and even survive being shipwrecked near Tierra del Fuego before heading home. 

  Brown’s greatest discovery came in 1902. Brown and his team had been sent to the badlands of Montana to search through the Cretaceous rock beds of Hell Creek for Triceratops fossils, in particular an intact skull. This rugged terrain was explored by Louis and Clark and is known as the Missouri Breaks today. After supplying themselves at Miles City, Montana, they traveled by wagon for five days to Hell Creek where they made camp at the base of Mount Sheba. Before dinner on the first night, Brown found bone fragments that had fallen down the hill into the creek. After tracing them up the hillside to their point of origin, they started digging, first with plows and scrapers to remove the overlying sediment, then with dynamite when the sandstone became too hard. It would take two years to excavate, and in the end they left a hole that was nine meters long, nine meters wide and six meters deep. The surrounding rock was so hard that they removed everything in large stone blocks which were transported, first by wagon, then by train, back to the museum. The pelvis was massive—it’s block weighed over two tons and was too big to put on a wagon. Brown had to build a sled and drag it with a team of horses the 200 km back to Miles City. It turns out he had discovered the type specimen of Tyrannosaurus rex. A few years later, Brown would return to Hell Creek and discover another, even more perfectly preserved Tyrannosaurus rex which would allow the museum to fully characterize the dinosaur that has captured the imagination of so many in the hundred plus years since its discovery. This “favorite child” of Mr. Bones is still on display in the Museum’s Fossil Hall and speaks volumes about the incredible power of Tyrannosaurus rex, one of the largest carnivores to ever walk the planet.

Why Ice is Slippery

Ice has a hexagonal crystal structure, but what happens
at the surface boundary to make ice slippery?

Ice is a very common solid here on Earth yet one of the most puzzling. Take the seemingly simple question, “Why is ice slippery?”, for example. Common wisdom says that when you step on an icy surface the pressure melts the ice a little bit to create a thin layer of water that acts as a lubricant. It’s due to the unique property of water: the solid form is less dense than the liquid form. We take it for granted that an ice cube will float in a glass of water, but for most material the solid form would sink to the bottom. And because ice has a lower density it is also true that the melting point of ice is depressed as pressure increases. 
The theory goes that as you walk on ice the increase in pressure lowers the melting point of the top layer of the ice and it melts for a brief moment, then refreezes as you pass by. The problem with this explanation is that the effect is very small and would only reduce the melting point by a few hundredths of a degree at most. Yet ice is still slippery when its temperature is far below the melting point.
One possible explanation is that friction plays a part as well. The act of walking on ice creates friction which heats the ice to create a slippery surface. But the problem with this is that ice is still slippery regardless of whether or not you are moving. If you are standing still there is no friction, yet it’s still slippery.
A better theory is that ice has an intrinsic liquid layer. Water molecules at the surface remain unfrozen because there are no molecules above them to hold them in place. This was first proposed in 1859 by Michael Faraday who noticed that two ice cubes will fuse together if they are pressed against one another. Faraday’s explanation for this is that the liquid layers freeze when they are no longer at the surface. But even this theory is not quite correct. 
In 1996, a team led by Gabor Somorjai, a professor of chemistry at Lawrence Berkeley Laboratory, bombarded the surface of ice with electrons. By observing how they bounced off they were able to make an amazing discovery: What actually makes the surface of ice slippery are rapidly vibrating water molecules. These “liquid-like” water molecules do not move from side to side—only up and down. This is an important distinction. If the atoms moved from side to side, the layer would actually become liquid, which is what happens when the temperature rises above 0° C. It turns out that it is this “liquid-like” layer that makes ice slippery.

The Geology of Arches National Park

Landscape Arch, the longest arch in the park and the 

second-longest arch in the world.

Arches National Park contains more than 2,000 natural stone arches—the greatest concentration in the world. But this pales in comparison to the grandeur of the landscape—contrasting colors, textures and landforms unlike anything else on the planet. 
   Located above the Colorado River in southern Utah’s high desert, the park is part of an extended area of canyon country, sculpted by millions of years of weathering and erosion. 300 million years ago, inland seas covered the region. The seas filled and evaporated—29 times in all—leaving behind salt beds up to about 4,000 m thick in places which is known as the “Paradox Formation” today. Later, sand and material carried down by streams from the surrounding uplands buried the salt beds beneath thick layers which later became cemented into rock. Most of the formations at Arches are made of this red Entrada sandstone and tan Navajo sandstone that was deposited 150 million years ago.

Delicate Arch, the most famous of the over 

2,000 arches in the park.

   The salt beds, under tremendous pressure from the weight of the overlying sandstone, became unstable and began to flow. This movement caused the overlying rock to move and buckle. Some sections were thrusted upward into domes, while other sections dropped into the surrounding cavities. Vertical cracks developed which would later contribute to the creation of arches. 
   As the movement of salt deep underground shaped the surface, erosion carried away the younger layers of rock. Water seeped into the rock through cracks and washed away loose material and eroded weaker portions of the sandstone, leaving a series of free-standing vertical fins. Ice formed during colder periods would expand and put pressure on the rock, breaking off chunks and created openings. Many of the fins collapsed, but some that were harder and more resistant to the erosion survived to become the spectacular stone sculptures that we see today. 
   Although the park has timeless beauty, it is not indestructible. The same powerful forces that nature harnessed to carve these extraordinary arches will eventually tear it down. Wall Arch, a photographer’s favorite that was ranked 12th in size, collapsed in August 2008. Landscape Arch, which at 88 m is the longest arch in the park and the second-longest in the world, is facing a grim future at the destructive hands of gravity and erosion. Since 1991, three slabs of sandstone have fallen from the thinnest portion of the arch and the park has had to close the trail which passes beneath it to protect visitors from its eventual demise.

Alkali Metals in Water

Alkali metal are the Group 1 metals on the periodic table and include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs) and francium (Fr). All of the alkali metals are naturally occurring, but francium is exceedingly rare. These metals share similar chemical properties and are all highly reactive.