Solar Analemma No. The image does not depict UFOs. Its actually Solar Analemma! “What’s

Solar AnalemmaNo. The image does not depict UFOs.Its actually Solar Analemma!“What’s a Solar Analemma?”I am so glad you asked!Photograph the position of the Sun in the sky every day, at the same time (for example 2pm) from the same place (for example a hilltop on Earth). If you do this for one complete year, you will have 365 positions recorded. If you superimpose these positions onto one image, you will notice a pattern. An obscure figure 8. This pattern is referred to as a Solar Analemma!The reason for this pattern can be attributed to the fact that the orbital path of Earth around the Sun is elliptical and that the Earth is tilted on its axis with respect to its orbit (or its plane of orbit).The size and shape of the analemma is influenced by three variables:Axial tiltOrbital EccentricityAngle between the apse line (imaginary line defined by the orbit’s eccentricity vector) and the line of solsticesDue to the aforementioned variables, different planets have different analemmas . Mars, for example, has a tear drop shaped analemma. This shape is attributed to the fact that the orbital eccentricity of Mars “outweighs” the tilt of its axis. Venus, Jupiter, Saturn, Uranus, Neptune and dwarf planet Pluto all have an analemma in the general shape of a figure 8.Mercury’s analemma (an approximate straight line) is determined by calculating the equation of time. This method is used as a single day on Mercury last two years. Therefore, plotting the position of the Sun each day at the same time will result in unusable data. Venus faces a similar problem as a single year lasts almost two days.If a planet had a circular orbit with no axial tilt the Sun would be in the same position, at the same time, everyday for the whole year. The resulting analemma would be a single point.Dennis di Cicco was the first person to create an analemma photograph. He did this in 1978-1979 in New England, USA. Using a solar filter he made 44 exposures on a single frame.You may remember that in the movie “Cast Away”, the main character (portrayed by Tom Hanks) etched an analemma in stone to keep track of the date.♞Renesh TFurther reading & image source:Image Credit:Astrosurf• http://webodysseum.com/technologyscience/analemma-location-of-the-sun-each-day-at-the-same-time/References:• www.analemma.com/• http://scienceblogs.com/startswithabang/2009/08/26/why-our-analemma-looks-like-a/• http://www.universetoday.com/50303/analemma• http://www.mtgrafix.com/programs/analemma/planets.html -- source link

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