A shaft of searing heat roils from the sky searing everything in its path. Buildings explode, reservoirs boil, people flee in terror. This was the vision of a group of Nazi scientists working in a small German town during World War 2.
Did Archimedes Sink Ships with Mirrors?
The sun is our greatest source of energy. Day after day it sucks billions of tons of waters from rivers, lakes and seas in the form of water vapor. Blown along by sun generated winds the clouds offload their water hundreds or thousands of miles from the vapor’s source. Without the rain cycle almost every living being on earth would perish. The sun’s light also drives photosynthesis which most plant and animal life depend upon for a bite. For thousands of years man did little to utilize our enormous power reservoir. Of all the vast wealth pouring from the sun we utilize almost nothing.
Allegedly, one of the first people to put the sun to sophisticated use was Archimedes. In 212 BCE when Rome and Carthage of present day Tunisia were vying for world supremacy, the Roman general Marcellus attacked the Greek city of Syracuse in southern Sicily. At the time, Archimedes reputedly repelled the Roman attack by concentrating sunrays with copper mirrors and setting Marcellus’s fleet ablaze. Although Rome conquered the city and put Archimedes to death, his reputed feat stirred people’s imagination ever since.
Inconveniently for those who perpetuate the story, the first clear reports of Archimedes’s feat only appeared hundreds of years later in about the 12th century when historian John Tzetzes wrote one of the first reports claiming such a feat:
“When Marcellus withdrew them [his ships] a bow-shot, the old man [Archimedes] constructed a kind of hexagonal mirror, and at an interval proportionate to the size of the mirror he set similar small mirrors with four edges, moved by links and by a form of hinge, and made it the centre of the sun’s beams… Afterwards, when the beams were reflected in the mirror, a fearful kindling of fire was raised in the ships, and at the distance of a bow-shot he turned them into ashes. In this way did the old man prevail over Marcellus with his weapons.”
Earlier historians describe the siege in detail without saying a word of fire mirrors. Some 700 years after the siege, Anthemius of Tralles suggested that Archimedes may have used a parabolic mirror to burn the Roman ships and it seems that the 12th century writers elevated his doubt into certainty.
Furthermore, modern attempts to emulate Archimedes’s feat find that although it is possible to ignite a ship with multiple mirrors, as everyone who uses small magnifying glasses to light a fire knows, the ignition is not immediate. Marcellus’s sailors could have easily escaped Archimedes’s fire weapon by keeping their ships on the move.
Hundreds of years passed before Archimedes’s reputed brainwave was utilized again. At the beginning of the 20th century scientists became interested in practical space travel and in space stations. In 1928, a young Slovene named Herman Potocnik published The Problem of Space Travel, the first book devoted to space station design, that envisions a 164 feet wide rotating “inhabitable wheel” with cabins, laboratories, workshops, kitchen, and bathroom situated in the artificial gravity of the outer ring. The station is powered by two large concave mirrors that focus the sun’s heat onto steam producing pipes. In 1933, Russian scientist Konstantin Eduardovich Tsiolkovsky (1857-1935) printed his Album of Space Travels where he describes a space station producing artificial gravity by rotating and forcing its inhabitants to its sides with centrifugal force, while a park planted with vegetables and trees supplies oxygen and food.
Another pioneer of the space station concept was Austro-Hungarian Hermann Oberth, one of the founding fathers of modern rocketry. In his 1929 Ways of Spaceflight he writes of hypothetical Raumstations (space stations) orbiting the planet at a height of 620 miles. Built of fabricated sections, they supply military intelligence and provide a platform for astronomical and weather observatories. In addition, they are a base of search and rescue centers and serve as refuel stations for interplanetary flights. And harking back to Archimedes was his plan to couple the station with a 100 yard concave mirror that would concentrate the sun’s rays onto one spot on earth. The intense heat this produced would turn out endless quantities of free electricity with steam turbines.
During World War 2 the Nazis turned Oberth’s ideas down an evil path. During their struggle for European dominion, the Germans arsenal included an incredible array of innovative weaponry such as rockets, huge Gigant planes, jets, and radio controlled missiles. In the German town of Hillersleben, 150 German engineers and physicists toiled to perfect a sinister weapon capable of making its possessor master of the planet.
After overrunning the town in 1945, United States technical experts discovered that one of the technicians’ dreams was to expand on Oberth’s idea to create the ultimate machine of destruction – a sonnengewehr (sun gun) that would burn Germany’s enemies into submission. This was a space station floating 5,100 miles above earth comprised of a monster mirror coated with reflective metallic sodium with a surface area of about 3.5 miles. This, the Germans reckoned, would focus enough heat to burn a city to ashes.
The handlers of the death-machine would live inside the mirror breathing air oxygenated by thousands of pumpkin plants. When necessary, small rockets would move the station to where it was needed and nudge it into the perfect angle necessary to blast heat rays upon enemy cities.
Obviously, all this would take quite some time. Rockets to deliver the hardware upstairs did not yet exist. Presumably, they would be more powerful versions of the V2 rockets terrorizing England and Antwerp. Questioned by Allied officers after the war, the scientists working on the sun gun insisted they never expected the weapon to win Hitler’s war. They were looking far beyond, they said, to the time when a victorious Nazi Germany might need something a little extra to keep the world at its feet.
After the war, when Lieut. Col. John A. Keck, chief of Ordnance Service’s enemy technical intelligence branch in the European theater reported these innovations, scientists protested that the project made no sense. Dr. Bergen Davis, Professor Emeritus of Physics at ColumbiaUniversity argued that it would be impossible for a body to remain in one place above earth at the height of 5,000 miles. To maintain itself in space at that height, a satellite would need to move rapidly round the earth faster than the earth’s rotation and could never hover above any particular city. Indeed, to remain locked in the same position over the planet a satellite needs an altitude of 22,500 miles. Huge boosters would be needed to reach that altitude and intense particle radiation exists there due to the van Allen belts at that height.
It has also been argued that the Nazi mirror was far too small to roast anything downstairs. To do a proper job, it would have needed to be over a thousand miles in diameter.
Since World War 2, the dream of focusing the sun’s rays has been turned to good use. In the Odeilla commune in the French Pyrenees mountains, 63 reflectors on the surrounding hillside bounce light off an eight story curved mirror concentrating the sun’s rays into an explosive 5,430 degrees Fahrenheit. The resultant furnace is used for experimental projects.
On a national scale, Israel, for its size, is a world leader in the use of solar energy. The humble dudei shemesh (solar heaters) clustered on the roofs of almost every building in the country supply 4% of Israel’s total energy and save the country 2 million barrels of oil a year. Their story began in the 1950s when Israeli engineer and entrepreneur Levi Yissar was inspired to design the first prototype solar water heater of Israeli style for his home by his wife Rina, a woman of “excellent common sense,” who painted an old water tank black to provide her baby with hot bath water.
Yissar distributed his heaters among 25 neighbors and in 1953 his NerYah Company began churning them out in commercial quantities. This was perfect timing. Power shortages during the 50s has spurred the government into outlawing the heating of water between 10 a.m. to 6 p.m. But by 1967 only a twentieth of Israeli households were heating their water with the sun and the capture of Egypt’s oil fields in Sinai during the Six Day War threatened to devastate Israel’s solar progress altogether.
Then there was a turnabout. After the energy crisis of the 70s and Israel’s return of Egypt’s oil fields in 1978, the Knesset demanded that most home’s install solar water heaters on the roof by law, and since then, the dud shemesh (solar water heater) has become an integral part of the Israeli urban landscape.
On the other hand, Israel is at the bottom of the list in producing solar electricity. Italy, Austria, and Switzerland, and even impoverished states like Senegal and Eritrea produce a higher proportion of their electricity from the sun than Israel. It is claimed that this is due to an overabundance of governmental regulations – although Israel is a leader in solar research and development, the country’s businesses find it easier to sell their technology overseas than to cut through forests of red tape. By 2020, Israel hopes to get only a measly 10 percent of its power from renewable sources.
Perhaps its time for Israel to develop a solar based energy gun operating from outer space.