Mirror-type reflections can be seen on water and almost any shiny, smooth surface.
The Salar de Uyuni in Bolivia is a flat area of over 10000 square kilometres covered by a thick salt crust, mainly lithium salt, containing 70 percent of the earth’s lithium reserves. During the rainy season, it is covered by shallow water, as the rain has nowhere to drain. This results in a huge mirror which is the largest (natural) mirror on earth. Eighty species of birds flock there, including massive flocks of Pink Flamingos. A person standing on this salt lake ‘mirror’ is in surreal surroundings – the sky and clouds above reflect on the surface below and the feeling is one of almost walking on clouds.
SPACE.COM reported on Aug. 30, 2013 that as of 2013, the largest reflecting telescope in the world was the Gran Telescopio Canarias in La Palma, Spain, with a mirror diameter of 10.4 meters. Within a decade, much larger telescopes will be coming online. The main mirror of the Giant Magellan Telescope will be 24.5 m in diameter and is composed of 7 segments. The telescope is being built at Las Campana Observatory, Chile and is planned to be operational in 2020. The primary mirror for the European Extremely Large Telescope will be 39.3 m in diameter and is composed of 798 segments. It is being built at Cerro Armazones, Chile and is planned to be operational in the early 2020s.
A fascinating new discovery was reported in Proceedings of the Royal Society 22 Dec. 2013 vol. 280, entitled “Shifting Mirrors: adaptive changes in Retinal Reflections to Winter Darkness in Arctic Reindeer”, by Karl-Arne Stokkan and five co-authors. Here is a paraphrase “Arctic reindeer experience extreme changes: Environmental light from continuous summer daylight to continuous winter darkness….We show that they may have a unique mechanism to cope…. by changing the reflection from their retina. In summer, the retina is golden, with most light reflected back directly away from the retina, whereas in winter it is deep blue with less light reflected away.
The blue reflection in winter is associated with significantly increased retinal sensitivity compared with summer animals. This is, to our knowledge, the first description of a retinal structural adaptation to seasonal changes in environmental light.” The essence is that surface layer of the retina at cell level forms a mirror-like protective lining to guard itself during the continuous summer daylight period, and the change to a more light-sensitive retina in winter allows reindeer to detect moving predators in the prolonged dark Arctic winter. This is the first description of a system in nature which provides animals with what really is like a magnificent pair of internal mirrors which protects their eyesight in bright prolonged light. The mirror effect of the tissue structure reverts in winter to allow more light in during the long winter.
The Guardian, 30 Oct. 2013 reported that giant mirrors are now reflecting winter sun into the Norwegian town of Rjukan during the winter months. The town is normally shrouded in shadow for six months a year. Faint rays from the winter sun reach the town's market square for the first time, thanks to three giant mirrors placed on a mountain. Like much of Scandinavia, Rjukan often is freezing throughout the winter, but now temperatures have improved.
The plan was thought of 100 years ago by the Norwegian industrialist Sam Eyde, who built the town to provide workers for a hydroelectric plant he located at the foot of a nearby waterfall. The renowned engineer never saw his plan become reality, but his plant and the Telemark town he founded developed a special affection in the Norwegian imagination as the site of the country's most famous wartime escapade.
Occupied by the Nazi Germans (Y’S’) during the Second World War, the factory was a staging post in Hitler's quest for the atomic bomb. The story of how twelve Norwegian saboteurs parachuted into the nearby tundra and survived freezing temperatures to destroy the factory's “heavy water” plant inspired a famous story The Heroes of Telemark. The three mirrors, measuring 17 sq. m, now capture the sunlight and send it in an ellipse that illuminates about one-third of the square below. Helicoptered in and installed 450m above the town square, the 5m kroner (£520,000) computer- controlled mirrors, or heliostats, capture the solar energy which is then used to power their tilting trajectory as they follow the sun's brief dash across the Norwegian winter sky.
Metal-coated glass mirrors were apparently first used approximately two millennia ago. Basic scientific awareness tells us that the angle of reflection of light equals the angle of incidence. If one were able to see another person’s face in a mirror it could only happen if the two were positioned such that they were both at an equal angle from the mirror’s flat surface, or if one person was looking over the other’s shoulder and both looking directly at the mirror (or some similar situation where two people are in close proximity and both looking into one mirror).
How do mirrors work and what exactly do they do? When one looks at one’s own reflection in a mirror, your right hand is facing your right hand, the left is facing the left hand, your head remains up and feet are down below – there is no left to right or upside-down inversion. Yet if you look into a mirror and point north, the image in the mirror seems to depict that you are pointing south – there seems to be some type of front-to-back inversion.
A driver of a car behind you, as seen through the rear-view mirror, has his left hand on the left, right on the right, but somehow the number-plate is reversed and cannot be easily read. Stephen Law, in his book ‘’Philosophy” says that what mirrors do is ‘a puzzle which science cannot solve’. Eminent scientists, psychologists and philosophers still are in disagreement – some scientists argue that it all can be understood from the principles of physics, but most admit that there is mystery, psychology or illusion of some sort at play as well.
Here are some excellent remarks from ‘Mathpages’ in an article entitled ‘The Mirror Question’: ‘’A ‘visual image’ may be regarded as a two-dimensional entity (which, in a purely geometric-optical sense, it is. )….The change in handedness produced by mirrors is fully represented in the 2D optical approach. Furthermore, the 2D approach is absolute and unambiguous. In contrast, any 3D “front-to-back” effects that we may attribute to a mirror are necessarily based on ambiguous psychological interpretations…..”
A ‘visual image’ can….be construed as the 3D model that we psychologically associate with a particular 2D optical image… Mirrors are somewhat unusual in that they present us with sense perceptions that we intentionally construe in a counter-factual way. A mirror… simulates the sense impressions of things that really aren't ‘there’. Notice that mirrors are among the few objects on which we almost never focus our eyes. We don't look at mirrors; we look in mirrors, with our focal lengths adjusted into the fictitious space on the ‘other side’.
The sefer ‘Shmiras Haguf Vehanefesh’, quoting also from ‘Taamei Haminhagim’ and ‘Yaaros Dvash’, talks of the custom to cover mirrors in a house during the week of shiva (202:2).
The Taamei Haminhagim points out that we have to be careful not to look into mirrors in this time because the Zohar says that in every form, a certain spirit (ruach) persists. If a person, during his lifetime, looks at the mirror without a specific need, a spirit is left to reside there and it can cause damage and evil to that person when the person passes away. The presence of any likeness of a person in an embossed or 3D type of fashion causes a potentially damaging spirit to persist there. The mirrors are covered because the spirit is still looking for a place to reside and we do not want to afford it such an inappropriate chance.
Other reasons quoted there from the sefer ‘Kol Bo Al Aveilus’ are that mirrors cause joy and also that we are not allowed to pray facing mirrors. In addition, it quotes from the Chasam Sofer (based on the Yerushalmi Moed Koton Ch.3 Halocha 5), that ….mirrors are covered because they are involved in the attraction between husband and wife and also the likeness is embedded in the mirror (in some sense) and so mirrors are turned around (or covered).
The above customs and discussion clearly seem to link the dangers of 3D forms with mirror reflections – mirror reflections are treated in this matter like 3D images or reflections. Thus we seem to be recognising that mirrors share 3D type qualities even in the realm of the spirit.
This seems to correspond in principle with the following key points reiterated from Mathpages quoted above, that mirrors involve “ambiguous psychological interpretations…..A ‘visual image’ can….be construed as the 3D model that we psychologically associate with a particular 2D optical image… Mirrors are somewhat unusual in that they present us with sense perceptions that we intentionally construe in a counter-factual way (that there is mystery and a mystical aspect in mirror images).
A mirror…. simulates the sense impressions of things that really aren't “there”. Notice that mirrors are among the few objects on which we almost never focus our eyes……” All of this sets a scene for mystery, illusion, and some sort of world of the spirit beyond our normal comprehension, even in an age where so many secrets large and small have been unraveled by scientific inquiry.