The Panama Canal

A ship enters the Miraflores Lock while passing through the canal.

Charles the 5th, the Holy Roman Emperor and King of Spain, had a problem. A few years before in 1532 Francisco Pizarro, a Spanish conquistador, had defeated and captured the Inca Empire in Peru. The mines of that country were now producing a wealth in silver to be sent back to Spain, but the trip required ships to travel thousands of miles all the way around the tip of South America before they could make their way eastward across the Atlantic Ocean to Europe. The king pondered if perhaps there wasn’t a better way.

In 1513 Vasco Nuñez de Balboa had discovered that in Central America there was just a narrow strip of land, not much more than 50 miles (80km) wide, separating the Atlantic from the Pacific Ocean. Suppose a canal could be dug through that strip of land? It would not only shorten the trip from Peru for the Spanish vessels, it would give Spain a tactical military advantage against its rival in the new world, Portugal.

Though the distance was only fifty miles it was one of the most difficult landscapes imaginable to work in combining dense jungles with steep mountains. King Charles ordered the Panama regional governor to survey the area for a canal following the route of the Chagres River. The governor came to the conclusion, however, that building such a passageway through the rugged terrain would be impossible.

Seven Quick Facts

-Length: 48 miles (77 km)

-Maximum water height above sea level: 85 feet (26m)

-Opened: August 15, 1914

-Cost: $375 million

-Location: Panama, Central America

-Made of: The three sets of locks are composed of concrete and steel.

Other: 268 million cubic yards of earth were removed, more than 14 times what was excavated for the Suez Canal which is twice as long.

Charles’ survey was probably the first serious look at building a ship route across what we now call the Isthmus of Panama, but it would not be the last. When Ulysses S. Grant led a group of soldiers across the isthmus, part of the country of Columbia in those days, while traveling to a post in California in 1852, he became interested in the project. Later he sent several expeditions to the area to look at the possibility of a canal after he became the 18th President in the late 1860’s. The first serious attempt to build a canal, however, wasn’t made by the Americans, but by the French in 1880.

The French Attempt

Ferdinand de Lesseps led the project to build the canal. Eleven years before he had successfully completed the construction of the Suez Canal in Egypt connecting the Mediterranean Sea and the Red Sea. The Suez Canal had revolutionized shipping by letting vessels avoid the long trip all the way around Africa to get from the Far East to Europe. De Lesseps thought that a canal across the Panama Isthmus would do the same thing for the Americas. Though the Suez Canal was almost twice as long as the one planed for the isthmus, the terrain there was flatter, making construction easier.

In Panama, de Lesseps planned to build a sea-level passage just like he had done at Suez. To make this design work, however, the path of the canal must be dug out all the way down to the level of the oceans so the water can flow freely between the two bodies. This worked well at Suez where the path of the canal covers ground that is only slightly higher than sea level. In Central America, however, it created immense problems. Millions of tons of rock and soil needed to be moved out of the way. Because de Lesseps failed to have a thorough review of the geology of the region done before starting out, the cuts he made through the mountains were too steep. The frequent rains caused erosion and landslides to occur that would fill the excavations nearly as fast as they could be dug out.

A map of the canal (NASA)

Even more of a problem than the landslides was the health of the construction workers. Jungle diseases like yellow fever and malaria were rampant among the employees. By 1889 when the French finally gave up the project, almost 22,000 lives had been claimed, some by construction accidents, but most by illness.

The Americans Take Over

By that time the Americans had become interested in building a canal. They considered an alternate route across Nicaragua, but in 1902 the U.S government decided to purchase the rights to continue the canal from the French for what was then considered a reasonable price: $40,000,000.

To firm up their claim in the area, in 1903 the United States supported a revolt in the Panama region against the Columbian government. On November 3rd of that year, Panama declared its independence and the United States immediately recognized the new nation. Through Philippe Bunau-Varilla, a Frenchman serving as Panama’s new ambassador, the U.S. negotiated a treaty to control the zone around the canal.

When the Americans started construction in 1904, they had several advantages that the French hadn’t. In 1881 Dr. Carlos Finlay of Cuba identified the mosquito as the source of yellow fever infections, though his conclusions were not generally known until his theory was confirmed by Dr. Walter Reed in 1900. When the Americans started their work they invested in extensive sanitation and mosquito-abatement programs and built housing for the workers that had screens to keep insects out. With these procedures in place the disease problem was quickly brought under control.

Another advantage was that the Americans used a different design for the canal. Under the direction of Chief Engineer John Frank Stevens, the plan was changed from a sea-level design to one that would use locks. A lock is a device that allows ships to move from one water level to another. The lock is usually a chamber with an open top that is only slightly larger than the largest ship it needs to lift. At each end of the lock are large doors that can be closed to keep the water from the higher body from rushing into the lower body. To raise a ship the doors are opened from the lower body and the ship sails in. The doors are then closed and water from the upper body is allowed to flow into the lock, lifting the ship until it is at the same height as the upper body. The doors to the upper body of water are then opened so the ship can sail out. To take a ship from the higher body to the lower body the procedure is reversed.

A steam-powered shovel moves rock during construction.

The plan called for the Chagres River to be dammed to create an artificial lake called Lake Gatun. Ships from the Atlantic entering the canal would go through a three stage lock that would raise them 85 feet up to the level of the lake. They would then sail 28 miles across the lake, up the river and through a section of the mountains called the Gaillard Cut. At that point another set of locks would drop the ships down to the level of Miraflores Lake. Miraflores was another artificial lake 54 feet above sea level and running for a mile down to another set of locks. At that final 2 stage lock the ships would be lowered to the level of the Pacific Ocean and could sail out into the open sea.

Herculean Effort

The use of locks greatly reduced the amount of material that had to be removed to complete the canal. Even so, it was a tremendous construction challenge. Stevens had the Panama Railway (which paralleled the course of the canal) rebuilt so it could efficiently handle 115 new heavy-duty locomotives and 2,300 railroad cars needed to move all the dirt. In addition, 102 railroad-mounted steam shovels were brought in to actually do the excavation. The most difficult part of the construction was the Gaillard Cut (now known as the Culebra Cut) where part of a mountain had to be removed to make a path for the canal. The difficult conditions there caused the crews to nickname this section of the jobsite “Hell’s Gorge.” During construction on the cut, a 20-car train filled with dirt was loaded and removed from the area on the average of every one-and-a-half minutes all day long.

The canal cost was approximately $375 million including a payment to Panama and buying the rights from the French. It was the most expensive project the United States had ever tackled, but was still $23 million less than a cost projection made in 1907. Between the French and American efforts a total of 268 million cubic yards of earth were removed, more than 14 times what was excavated for the Suez Canal. During the American period, 56,307 people were employed in the construction and there were 5,609 casualties due to accidents and disease.

The SS Kroonland is towed through the Culebra Cut by two tugboats in 1915.

When Stevens left the project in 1907, Colonel George W. Goethals became the chief engineer until the canal was finished. With a herculean effort the project was completed two years ahead of schedule and officially opened on August 15, 1914 with the passage of the cargo ship SS Ancon. It took about 8 to 10 hours for a ship to make the passage all the way through the canal.

After Completion of the Project

The United States continued to administer the canal and the surrounding area for many years after construction was completed. As time went by, however, there was the feeling in Panama that the canal rightfully belonged to the Panamanians, leading to a series of protests in the 1960’s and 70’s. Finally, a settlement was signed by U.S. President Jimmy Carter in 1977 that arranged for the turnover of the canal to Panama by December 31, 1999. Since that date the canal has been operated by the Panama Canal Authority (PCA), part of the Panama government.

Since the canal was completed almost a century ago, the size of ocean-going ships has been getting larger and larger. Many can no longer use the canal which has locks only 110 feet (34m) wide and 1052 feet (320m) long. A ship at this upper limit in size (between 65,000-80,000 tons) is called a Panamax. However, there are a number of vessels now in operation which are much bigger that the Panamax standard, some having lengths in excess of 1200 feet. For this reason there have been several proposals to add a new set of locks to the canal which would accommodate larger ships. In 2007 the PCA selected a design and started on construction of a set of larger locks which they hope to have open by 2014. These will allow the passage of ships almost 1,400 ft (4267m) long by 180 ft (55 m) wide.

Two of the massive lock doors are installed during construction.

Even without the new locks the Panama Canal remains one of the most amazing engineering feats of the 20th century. A ship sailing from New York to San Francisco by the canal can travel less than half the distance that would be needed to go around the tip of South America (5,900 miles compared to 14,000 miles). It has also far exceeded the expectations of those that designed it. In 1934 it was estimated that the canal had a maximum capacity of 80 million tons of shipping per year. By 2009, due to improved equipment and procedures, it handled almost 300 million tons, even without the new, larger locks in place.

In 1994 the canal was named as one of the Seven Wonders of the Modern World by the American Society of Civil Engineers.

The Zuiderzee and Delta Works of the Netherlands

The Eastern Scheldt Surge Barrier, part of the Delta Works, protects the land from flooding during storms. (Credit Vladimír Šiman licenced through Creative Commons Attribution 3.0 Unported)

When people think of the Netherlands two things often come to mind: Tulips and windmills. Both of these have been symbols of this European country for centuries. The tulip was introduced from Asia in the 17th century and has been a source of income for Dutch farmers ever since. The windmills date from the 1400’s and though they are picturesque, they are actually symbols of a serious life and death struggle that has raged in the Netherlands for years: The Dutch people and their land against the sea.

The most recent of these battles took place in the 20th century when the Dutch engaged in two massive projects to enlarge and secure their land against the ocean. The Zuiderzee Works and the Delta Works took most of the century to complete and together are considered one of the Seven Wonders of the Modern World.

Polders

The Netherlands is one of the most low-lying countries in the world. Today about a quarter of the land area is actually below sea level. Because of this when a large storm raises the water level along the coast much of the country is subject to heavy flooding. In the first century A.D. people began building artificial hills, called terps, and locating their villages and towns on top of them so that when floods came their homes would be safe. After a while it occurred to the people that if they connected the terps together with long walls, called dikes, they could keep the water out of their farmlands also. Eventually the Dutch started eyeing areas that had been unusable because they were flood zones or were underwater like marshes and lakes. Dikes were built around these and they were given the name polders. For a polder to be made dry enough for framing or building they had to be drained of water. The earliest pumps were connected to windmills and driven by the wind. As more and more land was added to the Netherlands through polders more and more windmills were needed. Soon the Netherlands became known as the land of windmills.

Seven Quick Facts

Size: Created 895 square miles of land. (2318 square km)

Length: Afsluitdijk dam – 20 miles (32 km)

Cost: Afsluitdijk $710 million, Delta Works $7 billion

Started: Zuiderzee – 1918, Delta – 1950.

Completed: Zuiderzee – 1967, Delta – 1997

Location: Netherlands, Europe.

Other: Turned the Zuiderzee from a bay into a lake.

Taming the Zuiderzee

One of most notable features of the Netherlands was the Zuiderzee. The name meant “Southern Sea” in Dutch, but it was actually a shallow bay of the North Sea that ran 60 miles (100km) inland and was about 30 miles (50km) wide. Despite its great size covering almost 2000 square miles it was only about 15 feet deep.

While the Zuiderzee was a resource for fishing and allowed access for trade, it could become dangerous whenever one of the frequent North Sea storms would push water through the bay’s inlet. Dikes would fail and the resulting floods would kill hundreds or even thousands of people. In 1421 a seawall on the Zuiderzee dike broke during a storm and flooded 72 villages killing about 10,000 people.

In the 17th century the first plans to address this problem were drawn up. It wasn’t until the 19th century, however, that the technology to actually do the job was developed. Cornelis Lely, a Dutch civil engineer, came up with a plan that proposed building a long dam that would close off the Zuiderzee and turn it into a lake. The plan also included building four polders in the lake that would be drained and used mainly for agriculture.

Lely became Minister of Transport and Public Works in 1913 and tried to push his plan forward. Not everybody agreed with his ideas, however. Fishermen along the Zuiderzee were concerned that they would lose their livelihood. Others were worried that such a project might create higher water levels at other places along the coast. The government was also alarmed about the enormous price tag of the project.

In 1916 during a winter storm, however, several dikes gave way along the Zuiderzee and the result was more damaging floods. After this disaster Lely’s bold plan gained much public support. On June 14, 1918 the Zuiderzee Act was passed and the project was officially started. Its goals were to protect the region against floods from the North Sea, increase the country’s food supply by creating polders that could be turned into farmland and use what remained of the Zuiderzee to improve water management.

Construction on the Afsluitdijk in 1931

The Afsluitdijk

The first step in the plan was to enclose the Zuiderzee by building a 20 mile long dam across the bay. Something like this had never been done before, so the Dutch engineers made the wise decision to start by building a much shorter dam out to the island of Wieringen which would form the first part of the enclosure of the bay. The experience gained in the exercise was valuable when the longer dam, the Afsluitdijk, was built from the other side of Wieringen across the bay to the village of Zurich in 1927.

The engineers found that a type of material called till (or boulder clay) made an excellent base for the dam. As the name suggests it is a mixture of small boulders and clay that was deposited during the Glacial Period. Fortunately it was readily available as it could be obtained by simply dredging it up from the bottom of the Zuiderzee. The till was loaded into ships which hauled it out to the mouth of the bay and dropped it onto two parallel lines along what would be the course of the dam. The space between the two rows of till was filled with regular sand, and then a layer of till was placed on top. To complete the base of the dam a coating of basalt rock and willow branches was laid down. The dam’s design called for it to rise 25 feet above sea level, so another layer of sand was placed to top of that, which was covered with another deposit of till. The surface was then planted with grass to help guard against erosion. The project proceeded faster than planned and was two years ahead of schedule when on May 28, 1932 the last connection to the sea was closed that the Zuiderzee became a lake named Ijsselmeer. Then dam took another year to fully complete as a road was built along the top and 25 sluices were constructed to allow excess water in the lake to be discharged to the sea. Two sets of locks were also created to allow ships to move in and out of the Ijsselmeer to the ocean. It is estimated the dam cost the equivalent of $710 million in 2004 United States dollars.

Making Land

Even before the Afsluitdijk was complete, the Dutch started working on the first of the polders, the Wieringermeer. It’s dikes were completed in 1929 and by 1930 it had been pumped dry, not by windmills, but by one modern diesel powered pumping station and one electrically powered pumping station. Both used large Archimedes screw type pumps to move the water. Additional work took another four years before the land could be used for agriculture and construction. The polder added a total of 75 square miles of area to the country.

The second polder, the Noordoostpolder, was started in 1936 and draining it wasn’t finished until 1942. The area turned out to be a good resource for the Dutch Underground resistance in World War II as it provided almost 230 square miles of undeveloped land to hide from the Nazi occupation force.

World War II also brought some setbacks to the project, however. In April 1945, the retreating German forces blew up the dike of the Wieringermeer, flooding the land again. Fortunately the Dutch managed to reclaim the polder by the end of the year, though much of the infrastructure was destroyed and had to be rebuilt.

In 1950 work on the the Oostelijk Flevoland, the third polder, was started and by 1957 it had added 208 square miles of territory to the Netherlands. Two years later work on the fourth polder, Zuidelijk Flevoland, was started and finished in 1967.

The Dutch considered building a fifth polder in the Ijsselmeer, but after several false starts, it was never completed. Even so the territory created by the project totaled over 895 square miles.

The Delta Works

The Delta Works were a series of construction projects started in 1950 designed to limit flooding. Just south of the Netherlands city of Rotterdam the Rhine, Meuse and Scheldt rivers meet the North Sea. This estuary area was extremely low lying and had been subject to heavy floods for centuries. Shortly after the completion of the Afsluitdijk, the Dutch decided they could limit the damage to this area by using dams to effectively shorten the coastline. No work was started until the 1950’s however.

The Zuiderzee plan drawn up by Lely in 1891.

A major flood in the region during January 1953 killed more than 1,800 people when a storm surge caused 89 dikes to fail. Over 72,000 residents had to be evacuated and 10,000 houses and buildings were destroyed. Repair and reconstruction cost nearly a billion dollars. This prompted the government move forward with the project as quickly as it could. Originally the plan called for estuaries Oosterschelde, Haringvliet and Grevelingen to be dammed and turned into lakes, just like the Ijsselmeer. Because of environmental concerns, however, it was decided to protect the Oosterschelde from storm surges by a barrier instead. The storm surge barrier is a series of massive values that are normally open so that water can move in and out of the estuary. This helps preserve the natural environment. However the valves can be closed to create a dam during a storm so no high water enters the area. Another storm surge barrier was also built to protect the river Nieuwe Waterweg when raising the existing levees along the waterway proved too difficult.

Though officially completed in 1997 at the cost of $7 billion, the Netherlands continues to add infrastructure to the Delta works as needed. It is estimated that it will continue to need construction to protect the area against the rising water levels caused by global warming.

Victoria Falls: The Smoke That Thunders

Dr. David Livingstone had been traveling down the Zambezi River in Southern Africa for several months. Perhaps a hundred miles upriver during this expedition he had come to Ngonye Falls. Livingstone had found the cataract very impressive. The falls were only about 60 feet high but extended over the whole length of the wide river and the amount of water that rushed over them was staggering.

However, on this day, November 17th, 1855, he been told he would be seeing a spectacular cataract that would dwarf the one at Ngonye. Livingstone, like most Europeans, had some doubts about this. After all, at this point the river was flowing sluggishly across a flat plateau without a mountain or valley in sight. How could you have a big waterfall without a land feature that would cause a sudden change in the height of the river?

As the canoe they were paddling in headed downstream, however, Livingstone began to hear a distant rumble. Ahead a plume of mist arose from seemingly nowhere. By the time the canoe was pulled up on a small island and Livingstone had walked to the edge of the cataract, the sound had become a deafening roar.

Seven Quick Facts

Height: 360 feet (108m)

Width: 5,604 feet (1,708m)

Name: Local name is Mosi-oa-Tunya which means the ‘Smoke that Thunders’

Discovered: The first European to visit the falls was David Livingstone in 1855

Location: On the border of Zambia and Zimbabwe in Southern Africa

Formed By: The Zambezi River as it removes soft sandstone from cracks in a basalt rock plateau.

Other: The mist cloud formed by the falls can be seen 30 miles (50km) away

Below him, the river, which was over a half mile wide, plunged 360 feet (108m) down the side of a narrow gorge which was only 80 to 240 feet (25m – 85m) wide. “Creeping with awe to the verge,” he later related, ” I peered down into a large rent which had been made from bank to bank of the broad Zambezi…” Livingstone had never seen anything quite like this in his entire life. Afterward he wrote: “No one can imagine the beauty of the view from anything witnessed in England. It had never been seen before by European eyes; but scenes so lovely must have been gazed upon by angels in their flight.”

Livingstone, the first European to see the mighty cataract, would name it for his queen, Victoria. However, the name used by the African residents of the area, Mosi-oa-Tunya, which means the ‘Smoke that Thunders,’ seems a much more accurate description of this natural wonder.

Formation of the Cataract

Victoria Falls is the result of soft sandstone that fills huge cracks in the hard basalt rock of the plateau. As the Upper Zambezi flowed across the plateau in ancient times, it found the cracks and started wearing away the softer rock, eventually creating a series of gorges. Geologists estimate that the river has been falling into these gorges for at least the last 100,000 years. As the rock wears away, the cataract follows these gigantic cracks and moves further upriver across the plateau.

In this picture taken from the International Space Station it is easy to see the zigzag cracks that the river follows after it falls into the first gorge.

Currently the falls are almost a mile wide where they enter the first gorge. From there they take a zigzag course through a series of gorges which are designated by numbers. When the river travels through the second gorge, it passes along a pool known as “Boiling Pot.” During high water this part of the river is filled with heavy turbulence and whirlpools. It is often at this location that objects, animals, and unfortunately sometimes people, are deposited along the edge of the water after they have been unlucky enough to have been swept over the falls.

The river continues zigzagging through a total of six gorges, which range from 400 to 800 feet (120-240m) deep, before settling into a steep, walled chasm known as the Batoka Gorge which is filled with wild rapids. After traveling 120 miles (200k) the river finally empties into Lake Kariba. In ancient past, each of these gorges has been the location of an earlier version of Victoria Falls which has moved further upstream as the river has eroded away the sandstone.

In the rainy season from November to early April, the falls are (by volume of water) the largest in the world only rivaled by Iguazu Falls in South America. Victoria is higher than Iguazu by a hundred feet, but at 5,604 feet (1,708m), it isn’t nearly as wide the South America cataract (8,858 feet/ 2,700m).

Victoria Falls Bridge crosses the Second Gorge. (Photograph by JackyR licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license)

The character of Victoria Falls is greatly influenced by the time of year. During the rainy season, only two islands appear at the top of the falls. These are Livingston Island (the location where the explorer first glimpsed the cataract), and Boaruka Island, near the western bank. As the flow of the river drops during the dry season many more temporary islands appear. The change in the amount of water is so dramatic that while Victoria has had the highest recorded peak flow, it is the third behind Niagara Falls and Iguazu Falls in average yearly flow.

Tourism

Archeological sites around the Falls indicate that this area has been occupied by humans since the Middle Stone Age 50,000 years ago. To the people that lived in the area, the Matabele, the Batswana and the Makololo, the falls became a familiar sight, but for most of its history was little known outside of the region. Even after Livingstone’s visit, European visitors were infrequent due to the remote location. Then in 1905 the Victoria Falls Bridge opened as part of an ambitious effort to build a railway from Cape Town to Cairo. Cecil Rhodes, the English-born South African businessman behind the project, directed engineers to “build the bridge across the Zambezi where the trains, as they pass, will catch the spray of the Falls”. The bridge, a beautiful steel arch, crosses 420 feet (128m) above the second gorge.

About the same time the railway started operation, Victoria Falls Hotel opened. Finally visitors could use the train to travel to the site and stay in the relative comfort of the hotel. From that point on, tourism increased (though occasionally has been discouraged by unrest or war in the region) until at the end of the 20th century the location was getting over 300,000 visitors a year.

Daring tourists can swim to the edge of the cataract at the “Devil’s Pool.” (Photo by Ian Restall released into public domain.)

Today, visitors can land at the nearby airport and easily visit the falls. The cataract straddles the boundary of Zambia and Zimbabwe, and both countries have established national parks in here to preserve the natural beauty and ecology of the area. In addition to visiting the falls and the surrounding parks, the adventurous can take a rafting ride down the rapid-filled gorges or bungee jump from the Victoria Bridge.

One activity at the falls which is both terrifying and exhilarating is a swim in the “devil’s pool.” During the dry season the water level drops enough that a shallow pool forms along Livingstone Island at the edge of the falls. Normally anyone entering the water here would be swept by the strong currents over the edge to their death. When the levels are low, however, a natural lip forms at the edge of the pool that keeps swimmers from being carried over the cataract. It is possible for those bathers with nerves of steel to lean over the slippery rock lip and peer directly into the gorge.

The dry season may not be just the best time to view the gorge from devil’s pool, but also from most of the surrounding area. The heavy mist that forms while the falls are at maximum flow can totally obscure the bottom of the gorge and make viewing from much of the edge difficult.

However, the mist itself can sometimes be as fascinating as the falls. Normally it rises to over 1,300 feet (400m) and under certain conditions it can reach double that height. The cloud it forms can be seen sometimes as far away as 30 miles (50km). In the bright sunlight the mist can cause multiple rainbows to appear. Even more startling is that Victoria Falls is one of the few places in the world where under strong moonlight you can actually see a “moonbow” at night.

The mist from the falls normally rises 1,300 feet and on nights with a full moon can cause a “Moonbow.” (Photo by Graham Bould released into public domain).

Paricutin: The Volcano in a Cornfield

On February 20, 1943, Dionisio Pulido was working in his cornfield just outside the Tarascan Indian village of Paricutin, Mexico. He and his family had spent the day getting ready for the spring sowing by clearing the field of shrubbery, putting it in piles and burning it. At about four in the afternoon, Pulido left his wife and moved to a different field so that he could set fire to a new pile. When he arrived he noticed something strange: on top of a small hill in the field a huge crack, over six feet wide and 150 feet (47m) long, had appeared in the earth. At first Pulido wasn’t concerned, the crack only looked like it was about a foot deep. As he was lighting the pile of branches, however, the sound of thunder rumbled across the field and the ground began to shake. Pulido turned to look back towards the crack and saw that the ground there had swelled up over six feet in height and fine gray ashes were pouring out of the hole. “Immediately more smoke began to rise with a hiss or whistle, loud and continuous; and there was a smell of sulfur,” Pulido later told witnesses.

Seven Quick Facts

Height: 1,353 foot (424m) above the valley. 9,186 feet ( 2,800m) above sea level.

Area: Lava field covers 10 square miles (25 square km).

Eruption: 1943 to 1952.

Type of Volcano: A scoria (or cinder) cone.

Discovered: Farmer Dionisio Pulido saw it emerge out of his cornfield on February 20th , 1943, at around 4 PM.

Location: Near the destroyed town of Paricutin in the state of Michoacán, Mexico.

Other: The youngest volcano in the Western Hemisphere.

Pulido became terrified by these events and tried to find his wife and sons, but couldn’t. He tried to rescue his team of oxen, but they had disappeared also. Despairing that he would never see any of them again, he jumped on his horse and rode to town. There he was happy to find his family and friends waiting for him. “They were afraid that I was dead and that they would never see me again,” said Pulido.

What had appeared in Pulido’s cornfield was a new volcano. The incident at Paricutin would be the first time scientists would be able to observe a volcano from birth through extinction. What they would learn through these events would help them understand the powerful forces deep in the earth that shape the surface of our planet.

Trans-Mexican Volcanic Belt

The town of Paricutin was located in the heart of the Trans-Mexican Volcanic Belt, an area running 600 miles (900 km) east to west across central-southern Mexico. The belt includes the Sierra Nevada mountain range (which is an extinct set of volcanoes) along with thousands of smaller cinder cones and volcanic vents. Volcanic activity over millions of years has created a high plateau of rock deposits 6,000 feet (1.8km) deep. The soil, because of its volcanic origin, contains a wide variety of common elements which are easy for plants to absorb. This makes the land very fertile. The soil, combined with moist winds from the Pacific Ocean, makes the belt the most productive farmland in Mexico.

The volcano as it appeared in 1943 during the eruption.

Even though the belt had a long history of volcanic activity, the residents of Paricutin thought they had been hearing the sound of normal thunder in the weeks that preceded the eruption, though they were puzzled by the lack of storm clouds in the sky. What was producing the sound, however, was the movement of magma deep inside the earth. Soon, however, residents also began feeling tremors in the ground, hinting of what was to come.

After its startling appearance, the volcano grew rapidly. That first evening Celedonio Gutierrez, who witnessed the eruption from the town remembered, “…when night began to fall, we heard noises like the surge of the sea, and red flames of fire rose into the darkened sky, some rising 800 meters or more into the air, that burst like golden marigolds, and a rain like artificial fire fell to the ground.”

The volcano grew by ejecting both lapilli-sized fragments, which range from the diameter of a pea to that of a walnut, along with larger “bomb” fragments. The bombs are often still molten when they are thrown from the volcano and produce bright parabolic streaks in the sky as they fall to the ground. Because they are still soft while flying through the air, the bombs form into a streamlined, aerodynamic shape.

As the bombs and lapilli build up around the base of the eruption, they form a steep cone shape often referred to as a scoria, or cinder cone. In a little more than 24 hours the cone of the Paricutin volcano had grown to over 165 feet (50m). Within six more days it had doubled that height.

World Attention

In March, about a month after the eruption started, William F. Foshag, a curator of minerals at the U.S. National Museum, arrived. Together with his Mexican counterpart, Dr. Jenaro González-Reyna, Foshag would spend the next several years documenting the life cycle of the volcano. Froshag was responsible for gathering many of the samples and photographs from Paricutin that are still used by scientists today while doing volcanic research.

The remains of the San Juan Parangaricutiro Church which still rise above the rugged lava feild. (Photo credit: Sparksmex)

The sudden appearance of a new volcano caught the attention of the world. Newspaper and magazine reporters rushed to the area. Life Magazine featured a picture of Foshag with the volcano in the background. Pilots of airliners would point out the cone to fascinated passengers as they flew by it. Hollywood even got into the act by shooting a film, Captain from Castile, in the region and using the volcano as a dramatic backdrop.

While the residents of Paricutin might have been happy about the work they got as extras in the movie, it was hardly compensation for the damage the volcano did. In June of 1943 lava started flowing toward the village which had to be evacuated. A few months later the lava also rolled over the nearby town of San Juan. Eventually all that was left of the settlements was the church towers which rose above a sea of lava. A frozen, rugged sea that by the time it has stopped flowing covered 10 square miles.

Volcano Types

Volcanoes come in three basic types (though sometimes scientists include supervolcanoes as a fourth type). Shield volcanoes are broad, dome-like structures that can grow to over 60 miles (100km) wide. Instead of violent, explosive eruptions they are characterized by steady lava fountains and flows that broaden the size of the volcano. The volcanoes of Hawaii fall into this category.

Paricutin Today Today the volcano is silent. Visitors can experience Paricutin by traveling to the nearby town of Angahuan that survived the eruption. This location is known as the “Balcony of the Paricutin” and from its location on top of a mountain both the extinct volcano and its surrounding lava fields can be seen along with the ruins of the church of San Juan. The bell tower of the church still stands like a lonely sentinel above the frozen lava part of one of the wonders of the natural world.

Stratovolcanoes are the most violent and dangerous of volcanoes. Their slopes rise slowly at first and then become very steep with a narrow vent at the top. Stratovolcanoes often have explosive eruptions, and then go dormant for decades or even centuries. Mt. St. Helens, in the United States Pacific Northwest, is a Stratovolcano.

The final type of volcano is one like Paricutin, a scoria cone. This type of volcano can appear suddenly and build a large conic-shaped mountain with steep slopes. They often erupt for less than a decade, then go dormant and never erupt again. The type of eruptions from such cones are known as Strombolian eruptions because the lava flows out of a single vent that resembles those at the Stromboli volcano in Italy.

End of the Volcano

Paricutin was very active in its first year, growing to four-fifths of its final 1,353 foot (424m) height. During the peak of its activity that year, ashes from the volcano drifted as far as 200 miles to the east and fell on Mexico City. With each following year, however, the volcano became less active until, after a final spectacular spasm, it finally went dormant in 1952. By then the damage had been done, however. In addition to the lava fields, there were also 20 square miles of volcanic sand deposited around Paricutin and almost all vegetation had been destroyed within a few miles of the crater. Hundreds of people had been resettled to other locations and had to find new livelihoods.

Before leaving his home for the final time Pulido put a sign on his land. It read “This volcano is owned and operated by Dionisio Pulido.” Paricutin might have taken his cornfield, but the farmer still retained his sense of humor.

The quiet volcano as it appears today. (Licensed under the Creative Commons Attribution 2.0 Generic license, photo by Karla Yannín Alcázar Quintero)

Australia’s Great Barrier Reef

Branching Coral and Soldier Fish on the Great Barrier Reef (© Pniesen | Dreamstime.com)

Just before 11 pm on June 11th, 1770, the HMS Endeavour, captained by Lieutenant James Cook, ran aground. Cook had been exploring the northeast coast of Australia when the accident occurred. The ship was stuck fast on a reef and the crew made desperate attempts to refloat her by lightening the ship. This meant throwing anything not immediately useful overboard, including the ship’s ballast and most of its cannon. Long boats were then used to carry the ship’s anchors away from the reef and secure them to the bottom. By winching in chains attached to the anchors, the ship gradually pulled itself off the bank. The reef had torn a hole in the bottom of the ship, however, and the Endeavour was quickly taking on water. Working feverishly the crew managed to temporary plug the leaks. They then sailed for the safety of the shore where the ship was breached and repaired.

Though Cook hadn’t realized it at the time, the coral reef he had run onto was part of a vast system of 3,800 coral banks and islands that ran along the coast of Australia. Known as the Great Barrier Reef, it has a length of 1,600 miles (2,600 km) and covers 133,000 square miles (344,400 sq. km). It is the largest structure in the world created by living organisms and supports a wide diversity of life, including fish, whales, dolphins and sea turtles. For this reason coral reefs are often referred to as the “rainforests of the ocean.”

Seven Quick Facts

Length: 1,600 miles (2,600 km).

Area: 133,000 square miles (344,400 sq. km).

Depth: Surface to between 150 feet and 400 feet depending on how far light can reach below the surface in a particular location.

Discovered: The Australian Aboriginals have been aware of the reef for 40,000 years. The first European to notice it was French explorer Louis de Bougainville in 1768.

Location: Off the Northeastern coast of Australia.

Age: 20,000 years.

Other: Often referred to as the largest structure in the world created by living organisms.

Coral Polyps

A coral reef forms underwater when thousands of tiny animals, only a few centimeters in length, establish a colony. These coral polyps build themselves hard, carbonate, exoskeletons to protect their bodies. When the polyps die they leave these exoskeletons behind and this becomes the surface on which a new generation of coral polyps can grow. Because one generation of coral builds on the last, the coral can “grow” vertically from 1/3 of an inch to almost one inch a year under good conditions. Their habitat is limited, however, from the surface of the sea to the maximum depth that light can penetrate the water, which, depending on conditions, is between 150 feet to 400 feet in the open ocean. Most corals can only thrive in warm tropic waters near the equator. If the water temperature gets too cold, or too hot, they will die.

The coral polyps are animals that feed on a variety of small organisms, like microscopic plankton or even small fish, using tiny tentacles with poisonous stinging tips. After capturing the prey, the tentacles contract and bring it to the polyps’ stomach where it is digested.

The reef as seen from space. (NASA)

Many of the corals also have a symbiotic relationship with a type of algae. The algae live inside the polyp and use photosynthesis to give the coral energy and help it build its exoskeleton (The sunlight needed for the algae’s photosynthesis is what limits how deep the coral can live). In return the algae get a safe place to live and they consume the polyps’ waste products. The algae also give the coral its color. Under certain conditions the algae can put stress on the polyp and it will eject the algae and turn white (an effect known as “bleaching”). If stress continues on the coral it will die, so bleaching is considered a sign that the coral is sick. If conditions return to normal, however, the coral can regain algae and its color will return.

History

The most recent incarnation of the Great Barrier Reef got its start 20,000 years ago when sea levels around the coast of Australia began to rise after the peak of the last ice age. As glaciers began to melt and flow into the sea the coastal plain near the northeast Australia became flooded making hills on the plain into islands. This area was shallow and warm enough for the coral to start growing around the edge of these islands. As the water continued to get deeper the coral grew upward keeping the living part of the reef within range of the sunlight. These smaller coral reefs grew larger but never completely merged so the system is actually made up of thousands of separate reefs and coral islands. There is also evidence that there are older versions of the reef that grew in the gaps in between the earlier ice ages. These may date back as far as 600,000 years.

A Green Turtle swimming over coral outcroppings. (© Yo13dawg | Dreamstime.com)

Sea Life

There are over 400 different species of coral that inhabit the reef. Not all of them, however, create the hard exoskeletons necessary to build a reef. Those that do can take a number of different forms. Brain coral grows in a rounded lump up to six feet (1.8 m) in diameter. It gets its name from the convoluted grooves that cover their surface that resemble the folds on a brain. Table coral, elkhorn coral and staghorn coral grow in various shapes with antler-like branches. Pillar corals grow as a number of columns, or fingers, stretching up from the sea floor.

Coral reefs are a haven for sea life. They occupy less than one-tenth of one percent of the oceans, but provide a habitat for a quarter of all marine species. Over 1,500 types of fish live in the Great Barrier Reef alone. These include the colorful clownfish, angelfish and butterflyfish. Also, a large number of highly poisonous animals live on the reef including the box jellyfish, sea snakes, cone-shells and blue-ringed octopi. The top predator on the reef is the Great White Shark.

The first humans to become aware of the reef were Australian Aboriginal groups. For the past 40,000 years the reef has provided them food in the form of sea turtles and dugongs (Large marine mammals related to the manatee). About 10,000 years ago the Torres Strait Islanders also moved into the area. Like the aboriginals they used wooden outrigger canoes to hunt and move from coral island to island. The activities surrounding the hunting of these creatures was of great cultural significance to these peoples and the animals were an important resource. For example, traditionally the shell of the sea turtle would be fashioned into items such as combs and fishhooks.

Rare bush of branching black coral. – (© Caan2gobelow | Dreamstime.com )

The first European to become aware of the reef was the French explorer Louis de Bougainville who came through the area in 1768 on a trip to circumnavigate the globe. He was searching for Australia when he was forced to change course after seeing waves breaking on the reef.

Protection of the Reef

In recent years efforts have been focused on protecting the Great Barrier Reef from damage. In 1975 the government of Australia created the Great Barrier Reef Marine Park which gives protection to a large part of the reef system. Fishing and the removal of coral or artifacts is highly regulated. Commercial shipping traffic is restricted to certain lanes that avoid the most sensitive parts of the park.

The park is a popular tourist destination and much of the management effort is directed at making sure these activities are ecologically sustainable. Tourists can visit the reef on special glass bottomed boats or see it from the air by helicopter. The most popular way to visit the reef, however, is by snorkelling or scuba diving. Approximately two million people travel to the Great Barrier Reef each year which generates billions of dollars of economic activity for the region.

The Great Barrier Reef, along with many other coral reefs, is under threat from a number of environmental problems. Global warming may increase the water temperature to the point where the coral becomes stressed enough to bleach. Coral bleaching events were recorded on the reef in 1998, 2002 and 2006. Pollution can also damage the reef. Fertilizers and pesticides used in farm production can be carried out to sea and damage the fragile ecosystem.

The corals also have a natural predator in the crown-of-thorns starfish. When overfishing reduces the number of fish eating the starfish, their numbers can skyrocket, allowing them to do great damage to the reef.

Hopefully, careful management by the Great Barrier Reef Marine Park Authority will protect the reef from extensive damage. If so, it will remain a natural wonder of the world for many generations to come.

A Surgeon Fish prowls the reef. (© Ivan Sgualdini | Dreamstime.com © Ivan Sgualdini | Dreamstime.com )

The Harbor At Rio de Janeiro

It took the Portuguese explorer, Gonçalo Coelho, three months to sail from Lisbon, Portugal, to the new world. On August 17th, 1501, he arrived off the coast of what we now call Brazil. He and his small fleet of three caravels (small, maneuverable sailing ships) began working their way along the seaboard, mapping the shoreline of South America. On January 1st, 1502, the ships reached a break in the seaside that seemed to be the entrance to an enormous river. The bay they found was spectacularly surrounded by huge, oddly-shaped mountains that astounded the European explorers. Taking a cue from the date on which they’d found this amazing harbor, they named it the “January River,” or Rio de Janeiro.

Seven Quick Facts

Highest Peak Along Harbor: Corcovado 2,300 feet (700m)

Size: Harbor runs 20 miles (32km) inland.

Name: Means “January River” in Portuguese because of the date of discovery.

Discovered: By Portuguese explorers on January 1st, 1502.

Location: Brazil, along the Atlantic Coast

Formed By: The interaction of the Serra do Mar mountains with the ocean.

Other: Mt. Corcovado is capped with a 130-foot (40m) tall statue named “Christ the Redeemer.”

Geography

The inlet at Rio de Janeiro isn’t actually the beginning of a great river but a huge balloon-shaped bay that stretches 20 miles (32km) inland. The harbor is surrounded by giant mountains and at the entrance of the bay is a lopsided peak of bare granite standing 1,299 feet (396m) tall that the Portuguese named Pão de Açúcar, (“Sugarloaf”) because it reminded them of the conical sugarloaves made on the island of Madeira. The largest mountain near the harbor rises 2,300 feet (700m) above the water and is named Corcovado (“The Hunchback”) because of its mounded shape. The bay itself is studded with 130 islands, many of which are the peaks of smaller hills with their bases covered by the water.

The harbor is the result of a great mountain chain (Serra do Mar) meeting the sea. This set of gneiss and granite stone peaks runs for 1,500 miles along the coast of South America. It is the interaction of the softer gneiss rock with that of the harder granite at the harbor that gives the mountains their spectacular shapes. Wind, rain and ocean waves erode away the malleable gneiss where it has no protective layer of tough granite on top, creating the many steep cliffs and deep valleys.

A cable car takes tourists to the top of the Sugarloaf. (Photo courtesy of Wutzofant licensed under the Creative Commons Attribution-Share Alike 2.5 Generic license)

History

The Tamoio, one of the native peoples that inhabited the area, called the place Guanabara which means “arm of the sea,” a name that is still used today. When Europeans tried to settle along the edge of Guanabara Bay they found it tough going. There was practically no flat land along the water’s edge and those places that were flat were also swampy. In 1555 five hundred French colonists built a Fort on one of the Bay’s islands they named for their leader, French Admiral Nicolas Durand de Villegaignon. Five years later the citadel, Fort Coligny, fell to a siege by Portugal’s navy and the French fled. Today the location, now called The Isle of Villegaignon, is home to the Brazilian Naval School.

In March of 1565 the Portuguese got around to founding their own city at Rio de Janerio which they named Sebastião do Rio de Janeiro, in honor of St. Sebastian. Farming sugarcane was the major industry in the surrounding region. As it became an important export the harbor began to become crowded with ships bound for Europe. Unfortunately, this activity attracted the attention of buccaneers. In 1711 the French privateer René Duguay-Trouin raided the city and held the governor for ransom. In the mid-18th century gold was discovered inland and an influx of European settlers transformed Rio de Janerio into a boom town. By 1749 the city’s population had expanded to 24,000 and soon it became the capital of the Portuguese colony. Though sugar and gold declined in importance as exports in the 19th century, they were replaced by coffee. Later, cotton and rubber also began to be shipped overseas.

The gigantic face of Pedra da Gáve

The city remained the capital when Brazil became an independent kingdom in 1816 and a republic in 1889. In 1960 the capital was moved to a more central location, the city of Brasília. Rio de Janerio, however, remains the country’s second largest metropolis with a population of over 6 million, and also the third largest metropolitan area in South America.

Attractions

The city and the harbor are well known for their scenic beauty. There are a number of spectacular beaches here including the famous Copacabana and Ipanema. In the city’s South Zone, Pedra da Gávea, a rock made of granite and gneiss rises 2762 feet (842m) above the ocean. It has been eroded into the shape of a human face and can be seen for many miles out to sea. Other sites that tourists visit here include the top of Sugarloaf Mountain which is accessible by a cable car system. From the summit of Sugarloaf, visitors can get a 360-degree view of the famous harbor.

The statue of Christ the Redeemer stands on top of the peak of Corcovado. It is 130 feet high and weighs 635 tons. (Photo courtesy of Klaus licensed under the Creative Commons Attribution-Share Alike 2.5 Generic license)

In the 1850’s Catholic priest Pedro Maria Boss suggested building a large religious monument within the city. Nothing was done immediately with the idea, but it was not forgotten. In 1921 the Catholic Circle of Rio organized a crusade to attract donations and collect signatures in support of building an enormous statue. Several designs were considered including a cross and a statue of Jesus with a globe in his hands. Finally, a proposal showing Christ with his arms outstretched was selected. The statue, composed of reinforced concrete and faced with soapstone, was erected at the peak of Corcovado. It stands 130 feet (40m) tall and the outstretched arms are 98 feet (30m) across. The statue, completed in 1931 and known as “Christ the Redeemer,” weighs in at 635 tons.Overlooking the harbor, it is accessible by road and has become a major attraction in the region and a symbol of the city.

Rio de Janeiro is also known for its extensive Carnival celebration in the spring just before the sober religious period of Lent. Parades featuring music and dancers wearing colorful costumes occur in many sections of the city. One of the most popular celebrations is Cordão do Bola Preta which is held in the center of Rio de Janeiro and has been attended by as many as 500,000 people in just a single day.

There are few people that come to this place that do not appreciate its natural beauty. The harbor has been called one of the Seven Wonders of the Natural World. In 1932 when Charles Darwin, the great naturalist, visited he wrote that the location seemed almost unreal, like some kind of immense theatrical stage. “Every form, every shade, so completely surpasses in magnificence all that the European has ever beheld in his own country, that he knows not how to express his feelings. The general effect frequently recalled to my mind the gayest scenery of the Opera-house or the great theatres.”

The famous Ipanema Beach. In the distance the hills are known as The Two Brothers. (Photo courtesy of Chmouel licensed under the Creative Commons Attribution-Share Alike 3.0 Generic license)

The Northern Lights

In Norse mythology the Valkyries (immortal, war-like virgins) would come galloping across the night sky upon their horses equipped with helmets, spears and armor that would glow and shimmer in the darkness. These lights, colored red, blue, violet and green, would spread in curtains from horizon to horizon, amazing the mortals below.

This is how the Vikings explained a phenomenon we now call the aurora borealis, or the Northern Lights. The lights are usually visible in the sky from the northern latitudes though under unusual conditions they can be seen as far south as Florida and Mexico. A similar phenomenon known as the aurora australis (or the Southern Lights) can be appreciated from the southern latitudes. Historically these have been less easily observed by people, however, because of the smaller land mass and lower populations in the area of the South pole when compared to the North pole.

Seven Quick Facts

Height: Between 600 (969km) and 60 miles (96km) in altitude

Colors: Mostly green, with red, pink, blue and violet.

Name: Aurora comes from the Roman God of dawn and Boreas is the Greek word for the north wind

Discovered: Kristian Birkeland developed the first correct theory of the phenomenon in 1908.

Location: The aurora borealis is visible in the northern latitudes and its counterpart, aurora australis, is visible in Earth’s southern latitudes

Caused By: Electrons from the solar wind follow magnetic field lines to the poles where they excite gases in the atmosphere to glow

Other: Strong solar flares can cause a geomagnetic storm which causes the lights to be seen much further south than usual

The name of the effect itself comes from the Roman god of the dawn, Aurora, and the Greek name for the north wind, Boreas. The French scientist Pierre Gassendi is generally credited for coming up with the title in 1621; however, written observations of the effect stretch back as far as 2600 B.C in China.: Fu-Pao, the mother of the Yellow Empire Shuan-Yuan, saw strong lightning moving around the star Su, which belongs to the constellation of Bei-Dou, and the light illuminated the whole area.

Different societies have explained the phenomenon in diverse ways. The Alaskan Inuits thought of the lights as the souls of deer, seals, salmon and whales that they hunted. The Menominee Indians in North America thought the glow must be the torches of giants that lived in the North. In the Middle Ages the Europeans assumed that when the shimmering signs appeared in the sky they must be a message from God. Many groups thought of the lights as clashing armies in the heavens, perhaps a warning of an impending disaster. In 1862 the aurora borealis made a rare appearance in the skies of Virginia during the Battle of Fredericksburg, a sign that the Rebel forces took to mean that God was on their side.

Kristian Birkeland conducted a series of experiments in the early 20th century that helped establish the mechanism behind the aurora borealis.

Scientific Explanations

Modern times brought scientific explanations. In the late 1700’s Benjamin Franklin observed the Northern Lights during his trips across the Atlantic to Europe and theorized that they were caused by a concentration of electrical charges in the polar regions intensified by the snow and other moisture. He thought that as the area became overcharged there must be a release of power into the air causing the illumination. Franklin was right about the phenomenon involving electricity, but it wasn’t untill Kristian Birkeland, a Norwegian scientist, did a series of experiments in the early 20th century that a full theory of effect was developed. Birkeland thought that electrons coming from the sun were guided to Earth’s poles through the planet’s magnetic field. There they interacted with the Earth’s atmosphere to cause the lights.

We now know that in the corona (or upper atmosphere) of the sun, temperatures can reach over a million degrees. This is so hot that atoms break down into their component parts: electrically-charged electrons and protons. Some of them are launched out from the sun at up to 500 miles per second in a phenomenon known as the “solar wind.” After about three days these charged particles reach the earth.

From below a curtain can appear as a series of rays.

The solar wind would be dangerous to life on our planet, but fortunately our the earth possesses a magnetic field generated by the rotation of planet’s iron core. This field, called the magnetosphere, directs most of the charged particles around the globe. A small portion of the particles, however, are trapped in the field and follow it down to the earth’s magnetic North and South Poles. The electrons remain invisible to our eyes until they collide with gas molecules in the upper atmosphere. When an electron is absorbed by an atom, the atom becomes ionized, or excited. The atom then loses that excitement by emitting a photon of light or by colliding with another atom or molecule. The color of the emitted photons depends on which gas molecule is struck and at what altitude. At heights of 250 miles (402km) or above, oxygen will glow green and below that point, red or pink. A nitrogen molecule hit from 80 to 100 miles (80 to 160km) up produces blue or violet. Between 60 and 80 miles(96 to 128km) in altitude both nitrogen and oxygen glow pink.

Auroras are not limited to Earth, but have been seen on Jupiter, Saturn, Uranus and Neptune along with some of their moons. Venus also has an Aurora effect, but because the planet has no magnetic field, the lights are distributed in patches across the entire planet, not just around the poles.

An aurora in the upper atmosphere as seen from the International Space Station.

The shape of the aurora glow in Earth’s sky depends on the shape of the magnetic field lines and the location of the observer. They are most often seen as curtains that tend to run east to west. If the observer is farther south than the aurora it will appear near the horizon, if he is directly beneath it, it will be seen overhead. Lights that are located directly above often appear more as rays than curtains because of the perspective of the viewer. The shape of the aurora can be static for many hours or change rapidly. Their brightness varies from a barely visible glow to giving enough illumination so that it is possible to read a newspaper at midnight. The lights are never bright enough, however, to be seen when the sun is up.

Geomagnetic Storm

Usually the effect is limited to the auroral zone, which is typically 10° to 20° from Earth’s magnetic poles. However, powerful solar flares can cause an increase in the solar wind setting off a geomagnetic storm. The incoming wind can compress the magnetosphere of the earth, allowing charged particles to come closer to the planet than they normally would. This can cause serious damage to satellites in high orbit. The storm can also force many more charged particles to stream into the Earth’s atmosphere at lower latitudes than normal. This has been known to cause power outages on the ground. Under these extreme conditions it is possible to observe the aurora borealis much further south than usual.

In September of 1859 a gigantic solar flare caused perhaps the most spectacular Northern Lights display in recorded history. New York Times reported that even as far south as Boston that the aurora was “so brilliant that at about one o’clock AM ordinary print could be read by the light”. The connection between this solar flare and the increase in the aurora borealis was so obvious that it helped scientists firmly establish a link between the two and sent them down the right path to finally explain this wonderful, but mysterious phenomenon of nature.

The Grand Canyon

The Grand Canyon is one of the most remarkable natural wonders in the world. Located in the state of Arizona, USA, it is one of the deepest gorges on Earth with an average depth of one mile (1.6km) and an average width of ten miles (16km). The canyon was carved over the past 6 million years by the action of the Colorado River as it drops over 2,200 feet (670m) along the 277-mile (446 km) length of the gorge.

Seven Quick Facts

Average Depth: 1 mile (1.6km)

Length: 277 miles (446km)

Average Width: 10 miles (16km)

Discovered: The ancient Anasazi people moved into the area around 1200 BC. The first European visited the canyon in 1540 A.D..

Location: Arizona, USA

Formed By: The Colorado River as it cut through the Colorado Plateau.

Other: About 5 million people visit the Canyon each year.

The canyon isn’t just a single gorge, however, but also includes numerous side canyons created by erosion. Because many layers of rock were exposed during this process, the walls of the canyon are countless shades of brown, yellow, red and gray. As the sun moves across the sky the light changes making the vista transform dramatically over the course of the day. The rock levels represent a cross-section of the geological history of the earth with the stone near the river being some of the oldest on the planet with an age of nearly two billion years.

Formation

The Colorado Plateau, through which the canyon is cut, was once the bottom of a shallow sea. Along the rim visitors can still find fossilized snails, corals and shell fish. Around 20 million years ago the land was pushed upwards and the sea retreated. Around six million years ago the Colorado River changed its course and started cutting its way across the Plateau. The uplift also added new tributaries to the river, increasing the river’s flow and adding many of the side canyons. Water let loose from the glaciers of the ice ages also increased the amount of water that was moving down the river and giving it more power to erode the stone. Within two million years the river had sliced a path into the rock that was only 500 feet higher than the bottom of the canyon is today.

The Powell expedition runs a set of rapids in 1869.

History

The first European that saw the Grand Canyon was García López de Cárdenas from Spain, who visited the location in 1540 during a search for the fabled Seven “Gold” Cities of Cibola. However, Native Americans had already been familiar with the canyon for thousands of years. The ancient Anasazi people are the first thought to inhabit the area starting about 1200 B.C.. For the last 800 years or so the Havasupai people have lived in a part of the gorge known as Cataract Canyon.

In 1869 John Wesley Powell led the first known boat expedition down the Colorado River and through the canyon. Starting from Green River, Wyoming on May 24, Powell and nine men in four wooden boats with food for 10 months traveled down the Green River to where it joined the Colorado. The group then crossed through Glen Canyon and into the Grand Canyon where the boats had to navigate more than 200 rapids. The trip became so difficult that one man quit the expedition after the first month, and another three left the group at Separation Canyon two months later. The three attempted to climb out of the canyon but were never heard from again. Powell finished his journey on August 13, 1869. Two years later Powell would retrace the voyage, this time taking photographs and making detailed, accurate maps.

The Grand Canyon as seen from orbit (NASA)

Tourism

By the beginning of the 20th century the canyon, made famous by the accounts of various scientists, explorers and the paintings of artist Thomas Moran, had become a tourist attraction. In 1903 U.S. President Theodore Roosevelt visited the Grand Canyon. Roosevelt, seeing its unique value, established the Grand Canyon Game Preserve in 1906. He then designated the preserve a U.S. National Monument in 1908. Roosevelt would have liked to have made the canyon into a National Park, but opponents with interests in land and mining rights blocked the effort for 11 years.

In 1919 the canyon was finally made a national park by an act of Congress. It currently receives about five million visitors per year. While many tourists limit themselves to looking at the canyon from the rim, others chose to hike trails down into the gorge. A trip to the bottom and back generally takes two days. For those not inclined to hike, mules are available to ride to the bottom. Located near the Colorado River in the deepest part of the gorge is the Phantom Ranch which provides visitors with lodging.

Modern visitors raft down the Grand Canyon using rubber rafts. The Canyon’s rim is rarely visible from a boat on the river. (Copyright Lee Krystek, 2011).

Another way to explore the Canyon is by rafting down it following the path first used by John Wesley Powell. Modern rafts, however, are made of flexible rubber instead of wood, making the trip safer, but still exciting.

Of the two main rims of the canyon, the southern rim, is more accessible and popular with visitors. There are a number of lodges located on the South rim at Grand Canyon Village operated under contract with the park service. The average altitude of the South rim is about 7,000 feet (2133m) above sea level which can be a concern for people who are not acclimated to that height. The North rim is less accessible than the South and has fewer facilities for visitors. It is also another 1000 feet higher in altitude than the South rim.

Because of its size and splendor, the canyon is a matchless natural wonder. For this reason it is often considered as one of the Seven Wonders of the Natural World.

Kolb Studio on the south rim.(Copyright Lee Krystek, 2011)

Mount Everest

On the morning of May 29th, 1953, New Zealander Edmund Hillary found himself working his way up a snow-covered mountain. Climbing with his partner, Tenzing Norgay, Hillary was intently engaged in cutting a series of steps in the snow to allow them to climb safely up a ridge. Then, at eleven-thirty, Hillary suddenly realized there was no place left to climb. “… to my great delight I realized we were on top of Mount Everest and that the whole world spread out below us.”

On that day man had finally conquered the tallest peak on the planet. It was a challenge that had eluded realization even after other goals, like traveling to the North and South poles, had been accomplished.

Seven Quick Facts

Height: 29,029 feet (8,848 m)

First Ascent: Edmund Hillary and Tenzing Norgay on May 29th, 1953

Age: Himalaya Mountains are 25 million years old. Everest has been the highest peak for the last half million.

Discovered: A British survey of the region discovered it was the tallest mountain in the world in 1852, but didn’t release this information to the public until1856.

Location: Border of Nepal and The People’s Republic of China.

Formed By: An up-thrust at the collision of the Indian and Eurasian tectonic plates.

Other: Called Qomolangma in China and Sagarmãthã in Nepal.

Mt. Everest is part of the Himalaya Mountains in the central region of Asia, north of the Indian sub-continent. Three hundred and twenty-five million years ago the region was the bottom of an ancient sea. Then, sixty million years ago, the tectonic plate under India started moving northward and running into the Eurasian plate. This caused the land at the junction to be crushed and thrust upward. About twenty-five million years ago this up-thrusting became the Himalaya Mountains. The lifting of the mountains continues even today with the range gaining another two-inches on average, every year. Everest has been the highest peak in the Himalayas for the last half million years.

Finding the Height

Although the Himalayas have long been recognized as some of the tallest mountains in the world, it wasn’t until 1808 when the British decided to do a trigonometric survey of the region that the actual height of many of the peaks were established. The project took a number of years to accomplish and between 1830 and 1843 the effort was led by Sir George Everest, the Surveyor General of India. The British were frustrated in their attempt to get precise measurements on many of the highest peaks, however, because they lay in the country of Nepal. The government there, suspicious of British motives, turned down all requests for survey teams to enter the country. This forced the British to make their observations from as far away as 150 miles (240km) limiting their accuracy. As early as 1847 the team began to suspect that a peak beyond one called Kangchenjunga (which was at the time thought to be the highest in the world) was even higher, but they could not get precise enough measurements to be sure.

A climber makes the dangerous crossing of the Khumbu Icefall on the Southeast ridge route up the mountain. (Photo by Olaf Rieck licenced under Creative Commons Attribution 2.5 Generic)

The British persevered, however, and in 1852, Radhanath Sikdar, an Indian mathematician and surveyor with the project, used data collected the year before to conclude that this new peak, designated “XV” was the tallest in the world. The announcement was delayed until, March 1856, while the calculations were checked and rechecked. The height was determined to be 29,002 feet (8,840 m), though more recent surveys have placed the height at 29,029 feet (8,848 m), not counting the mountain’s snowcap.

The survey team had been directed to use local names for geographic features whenever possible, but Andrew Waugh, leader of the survey at the time, stated that there were so many local names that it would be hard to favor one over another and recommended it be named for his predecessor, George Everest. The Royal Geographic Society accepted the name over the objections of Sir Everest himself. The name is still not universally acknowledged and the mountain is referred to as Qomolangma in China and Sagarmãthã in Nepal. The mountain sits on the border of Nepal and the country of Tibet (which is currently under the control of the People’s Republic of China).

Ascending the Mountain

In an 1890 article entitled “Can Mount Everest be Climbed?,” mountaineer Clinton Dent pondered whether this remote peak might ever be conquered, but the immediate problem with mounting such an attempt was political, not logistical. The governments concerned, Nepal and Tibet, rejected all requests to enter the region. In 1913 Captain J.B. Noel disguised himself as a native and entered the area in an attempt to view the mountain close up, but never got closer than 40 miles (65km) before he was turned back by the Tibetan military. Finally, in 1921, Tibet allowed a British reconnaissance team to work its way up the mountain to the 23,000 foot level. The next year some of the members of the team returned to make the first attempt on the summit but when an avalanche killed seven of the porters, the expedition was cancelled.

Mount Everest and the surrounding Himalayas as seen from the International Space Station.

In 1924, George Mallory, who had been on the first two British expeditions along with newcomer Sandy Irvine, made an attempt to ascend to the summit. According to a fellow climber they appeared to be “going strong for the top” when they disappeared into a mist of swirling snow. They did not come down and Mallory’s frozen body wasn’t found until 1999. When Hillary and Tenzing reached the top 29 years later they looked for signs that the two climbers had been there, but found nothing.

Death Zone

The pair was just one of many deaths that have occurred on the mountain through the years. Temperatures on Everest can plummet without warning,leading to frostbite. Extreme high winds can knock a climber off the face of the mountain. Because of the high altitude the air is only about a third of the pressure it is at sea level making it much more difficult for the human body to get the oxygen it needs to keep running. Under these conditions a climber gets tired easily and their thinking can grow fuzzy, making mountaineering at these heights even more dangerous than it would be otherwise. For this reason climbers operating above 26,246 feet ( 8,000 m), in what is called the “Death Zone,” will often use masks that supply them with supplemental oxygen from a bottle. Hillary and Tenzing used bottled oxygen when they climbed the peak in 1953 and for many years it was thought that reaching the summit without it would be impossible. However, in May of 1978, Reinhold Messner from Italy and Peter Habeler from Austria made the first ascent without supplemental oxygen, proving that it could be done.

The sun’s rays catch the top of the mountain. (Photo by Topgold licenced under Creative Commons Attribution 2.0 Generic)

Hillary and Tenzing used a path up the mountain called the “Southeast Ridge” because it allowed access from Nepal. However, in the years since Chinese policy changed allowing access from Tibet, a second route, the “Northeast Ridge,” has become popular. There are some thirteen other routes up the mountain, but these are more difficult and rarely used.

Dangerous Over-Commercialization

Recently there have been complaints that the climbing of Everest has become over-commercialized with more and more novice climbers hiring professional guides to get them up the mountain. A guided climb may cost between $40,000 and $80,000 depending on the route traveled and the client needs little in the way of Alpine experience. On May 11, 1996, a traffic jam of climbers on one route, combined with a sudden snowstorm, killed eight people in one day. Another eight died in the course of that climbing season, making it the most deadly year on record for the mountain. Many long-time mountaineers complain that the novices being guided up Everest do not appreciate the dangerous situation into which they are placing themselves and they do not have the skills necessary to save themselves should something go wrong.

As of 2010, 3,142 different people have reached the summit 5,104 times. Another 219 have died while trying to climb the mountain. Because of the difficult conditions on Everest there is often no attempt to recover the bodies and some frozen corpes can be seen from the major routes.

Despite the dangers it seems unlikely that the adventurous will soon be dissuaded from attempting to conquer the highest mountain in the world. Why do they do it? Well as George Mallory is often quoted when he was asked why he wanted to climb Mt. Everest, “Because it is there.”