Monday, April 26, 2010

Machu Picchu

Machu Picchu is an ancient city located in Peru. Meaning “Old Peak” in Quechua, the native language from the Inca Empire, this mountain relic is claimed as one of the new Seven Wonders of the World. The city draws its popularity not from what lies within its walls but where it was built, 2,430 meters (7,970 feet) above sea level.

The city is believed to have constructed around the 1450. Yet scientific research has shown that it was abandoned a little more than a century later, synonymous with the arrival of the Spanish Conquest. Historians speculate that the city’s population had succumbed to an outbreak of smallpox before the Spanish’s arrival.

Most archaeologists believe that Machu Picchu was built in honor of the great Inca emperor, Pachacuti (1432-1472). Others hypothesize that its purpose was to govern the economy of nearby settlements. Located on a mountain top, its inhabitants would have had a good view of their surroundings. Smaller minorities believe the city had a more simple purpose such as a prison or an agricultural testing station that would test how different types of crops survived in the variable climate.

The city sits in a valley between the two larger mountains Machu Picchu and Huayna Picchu. Early settlers would have received water from nearby springs while food would have been grown from local fields. It’s actually interesting, because there is enough land to feed four times what the city’s population at the time. Engineers also terraced the surrounding hillsides to guard against invaders and reduce soil erosion to prevent landslides.

 aerial shot of Machu Picchu

One of the area’s leading tourist attractions is the Intuhuatana Stone. A rare ritual stone found in South America, the rock is arranged to point directly at the sun during a winter solstice. This results in no shadow casted by the leading pillar during the equinoxes. It’s speculated the device was a primitive calendar.

Did you know?- There are many flights of stairs at the city consisting of one hundred steps or more carved from a single block of granite!

The important buildings inside Machu Picchu have polished-dry stone walls made with a technique called ashlar in which precision cut stones are fitted together tightly without mortar. Peru has a lot of seismic activity and the structure’s walls can shift and resettle without collapsing.

Wednesday, April 14, 2010

Human-powered Flight

While we have shared the sky with birds for the last hundred years, modern flight continues to leave many feeling disconnected from the winged creatures. My opinion for this happening is that while birds experience flight firsthand, we are simply trying to mimic their grace. Before the choice to use an external power source was even an option, man could only dream of attaining flight through our own human efforts. And with engine-powered flight now available for personal use to everyone in the planet, the idea to lift one into the heavens has lost much steam. Only a few have achieved what Icarus did in the story.

Human-powered aircraft (HPA) are propelled by only human force and gravity. In this way, they rely on many of the same principles as gliders such as air thermals and rising currents. The first recorded human-powered aircraft was the Italian designed Pedaliante (Italian for “Pedal Glider”) in 1937. Constructed with a glider-like profile, the plane had a wingspan of 58 feet (17.7 meters) and two laminated balsa wood propellers 6.2 feet (2 meters) in diameter. The plane had an aspect ratio of 13:4 meaning that for every 13 feet it traveled horizontally, it only descended 4 feet. The sole pilot sat upright and transmitted power to the props via pedaling.


While originally the plane was to have an empty weight of 160 pounds (73 Kg) the Italian Air Ministry required it to meet the same structural criteria of an engine-powered aircraft increasing its final weight to 214 pounds (97 Kg). Launched with the assistance of a catapult, the plane came to travel a length of 1 Km (0.62 miles), remarkable for its time.

It wasn’t until 1960 that a man-powered aircraft capable of taking off under its own power was created. That year’s spring, three undergraduate students at Southampton University decided to build an HPA during the middle of their last term. Duly named the Southampton University Man Powered Aircraft (SUMPAC), the plane would complete over 40 flights, the longest of which was 2,130 feet (650 meters).


Since the 60s, there have been a number of HPAs. And while each new design comes closer to the goal of easily sustained, long-distance flight, we’re still not there yet. Today, the world record for longest human-powered flight is 74 miles (119 Km), achieved on April 23, 1988 by the MIT Daedalus 88. The design only weighed 69 pounds (31 Kg).

MIT Daedalus 88

Did you know?- The first human-powered helicopter, the Da Vinci III, built by the California Polytechnic State University in 1989, flew for 7.1 seconds reaching an altitude of 20 centimeters. The video below showcases a later design, the Yuri 1, constructed in 1994 that utilizes four giant rotors.

Wednesday, March 31, 2010

The Longbow

If I was forced to fight in a war during the Middle Ages, I’d immediately choose to be an archer. You’re not fighting at close range, and you’re one of the last regiments to be attacked.

The longbow is at least four feet in length and normally extends the full height of its shooter. Its appearance in history is first seen by the Germans and Scandinavians in 500 A.D. Yet the weapon would not become famous until the technology was adopted by the English.

Traditionally the bows were made of yew, a conifer type tree that grows in central Europe. Ironically, England’s military did not find their own land’s variety of yew appropriate and had the majority of the material imported from Italy and Spain. The youngling trees were cut in winter when no sap was running where they were subsequently left to age. It would be worked upon gradually during the three to four year aging process until completed.

Mass produced versions of the bow were about 70 inches (178 cm) long with pull strength of 75-100 pounds (34-45 Kg). The arrows ranged between 27 to 36 inches long and could kill unarmored infantry up to one hundred yards away. Beyond that, the arrows could wound opponents as much as 250 yards away.

Did you know?- During the Battle of Agincourt, what became a significant English victory in the Hundred Years War, there were so many archers that it’s estimated 1,000 arrows were in the air every second! While conducting research, I found a quote from someone who saw the battle saying that there were so many arrows that afterwards the white feathers on their ends made it appear as if snow had blanketed the battlefield.

If you wanted to wield this weapon, you had to train until it became an extension of yourself. The training adopted by the English was the most rigorous. All sports were banned on Sundays and men between 12 and 65 were expected to practice their archery for several hours a day. An experienced archer could fire 12 arrows a minute.

The longbow remained the most powerful weapon in Europe from 1300 to 1588. France, having witnessed the destructive power of the longbow first hand, was quick to train their armies to wield the weapon. But surprisingly, a long line of kings declined its use on the battlefield claiming it was too much power for the meek to wield.

Did you know?- Amateur bowyers today can craft a longbow in about ten to twenty hours.

Besides the obvious difference in size, the longbow’s main distinction is its skinnier limbs and rounded cross-section. This results in an unequal distribution of stress through the bow and is believed to be the reasoning behind its recognizable length.

Modern longbows are generally wooden composites constructed from multiple types of woods glued and pressed together. Hickory is used on the front of the bow which stretches better, while the inside is lined with yew which better undergoes compression. You can find an old guide RIGHT HERE explaining how to form a longbow from a piece of lemonwood, another popular choice.

Wednesday, March 24, 2010

Meteor Crater


1. Nuclear holocaust
2. Super-virus
3. Climate change
4. Vampire-Robot-Nazis-Zombies take over the world

The list goes on and on…

One of the most frightening doomsday scenarios is something that will eventually occur; our planet’s collision with another extraterrestrial body. The idea that something could strike Earth wasn’t seriously recognized until scientists first began searching the vastness of space for the objects. And while in this case the expression “trying to find a needle in a haystack” is dead on, it’s much more difficult than that. To help understand the effects of an asteroid’s impact, scientists began to look for evidence of impacts here on Earth.

Meteor Crater

Today, what is the largest and considered to be the best conserved impact crater on Earth is Meteor Crater in Arizona. Approximately 43 miles east of Flagstaff there is a landmark so breathtaking that its image takes you back 40,000 years. At the time, this dessert was still open grassland dotted with woodlands inhabited by woolly mammoths and giant ground sloths. Perhaps on what was a crisp, summer morning, the creatures raised their heads to a bright light. The meteorite would have been the brightest thing in the sky for a few seconds during its descent into the atmosphere. Traveling at 28,600 mph (12.8 kilometers per second), the chunk of nickel and iron slammed into the ground like a golf ball in a sand trap.

satellite image of Meteor Crater

The resulting damage was immense, leaving a crater 4,000 feet (1.2 Km) in diameter and 570 feet (170 meters) deep. Believed to have been around 50 meters in diameter, scientists speculate that about half of the meteorite’s weight (300,000 metric tons) was vaporized in its descent.

While looking at the crater it’s obvious a lot of energy was transferred into the ground, although most of it was actually projected skywards. 30 tons of meteoritic iron were scattered within a 4-5 miles radius of the impact site. Closer to the crater’s lip is a 150 foot (45 meters) high rim composed of the debris.

When scientists checked if humans would have inhabited the area during this time, it was proven that most likely no one would have made their way to America yet. The crater’s existence did not become known to modern men until European settlers stumbled across it in the 19th century. Dubbed “Canyon Diablo crater”, it was believed to be the result of volcanic forces. The idea did not harbor much criticism since the San Francisco volcanic field only lies about 40 miles (64 Km) to the west.

It wasn’t until 1903, when a mining engineer and businessman by the name of Daniel Barringer suggested that the crater had been formed by a meteorite impact. Through research, Barringer found small pieces of meteoritic iron that were mixed with rocks on the crater’s border. He knew that if the meteorites had fallen at a different time from that at which the crater was formed, they would have been lodged in distinct, separate layers in the surrounding soil. In fact, upon closer examination these different classes of rock were set in the opposite order of the underlying bedrock. When Barringer found no volcanic rock near the crater, scientists began accepting his theory as the reality. To see the effect of an impact of extraterrestrial bodies, watch the simulation below.

Thinking he was sitting on a gold mine, Barringer's company, the Standard Iron Company, purchased 640 acres around the crater for private use. While it was estimated 300,000 tons of iron could be harvested from the site, later research found the material unusable for manufacturing purposes.

Did you know?- Barringer made attempts to find what remained of the meteorite for 27 years. Since impact physics was poorly understood at the time, Barringer was unaware that most of the meteorite had vaporized on impact. Over the years he would drill to a depth of 1,376 feet (419 meters) with no significant finding of iron.

mining site inside the crater

Today, the Barringer family continues to own the surrounding area around Meteor Crater and has turned the feature into a popular tourist attraction. Next to the crater is the Meteor Crater Visitor Center that contains interactive exhibits and displays about meteorites and asteroids, space, the solar system and, comets. Also, interestingly enough it contains the American Astronaut Wall of Fame. The center also contains a movie theater, gift shop, and observation areas with views inside the rim of the crater. Guided tours of the rim are offered daily through their website

Friday, March 19, 2010

Dog Dancing

Dog dancing? Dancing…with your dog? You’re kidding right?

Actually, I’m not. Known as musical canine freestyle, dog dancing is a mixture of standard obedience training and tricks that grants handlers a more intimate bond with their dog(s). There are two categories in the sport, musical freestyle and freestyle heeling. While freestyle heeling highlights the dog's ability to stay in variations of the heel position with the handler dancing, musical freestyle allows more leeway as far as tricks are concerned. The latter category is judged much more on creativity than execution. (Let’s face it…neither one of you are going to look cool out there.)

Although competition rules vary widely, there are two standards. They include:

• No use of training aids or leashes.
• Participants must compete either as a single dog and handler, a pair of dogs and handlers, or as a full team of three or more dogs and their handlers.

Since you’re more likely to win with a creative dance to Michael Jackson’s Thriller than a perfectly choreographed routine to the Macarena, the competitor’s choice of music is extremely important. Routines much match the song or judges may not even give you a score.

Did you know?- Albeit, many who participate in dog dancing choose to express themselves in competitions, it’s not the only way to get yourself seen. Exhibition freestyle is a non-competitive form of the sport that allows for the use of props, cues, and costumes. These duos are often seen on television and occasionally in movies.

If you’re brave enough to have yourself seen dancing with your canine in public, you have nothing holding you back from realizing your dog dancing rise to stardom. While there are not many instructional resources yet available to the public, the websites and can offer you some beginner’s advise and point you in the right direction.