Happy New Year! A year is a unit of measure used to describe the revolution of a planet around its star-in our case this is usually given as 365 days or occasionally as 365.2429 days and some years (2012 for example) we actually say a year is 366 days. But first, the history: the word year comes from Old English gē(a)r, of Germanic origin; related to Dutch jaar and German Jahr, from an Indo-European root shared by Greek hōra meaning year, season, any part of a year, also any part of a day, hour, and the Latin word hornus meaning of this year. The root probably came from the verbal root *ei- meaning to do or make a complete cycle.
Scientists say that the year is exactly 31557600 seconds, and in the Unified Code for Units of Measure, the symbol a (without subscript) always refers to the Julian year aj. They do the math as follows: 365.25 days times 86400 seconds in a day = 1 a = 1 aj = 31.5576 Ms. Under the code of uniformity that governs all things SI, the SI multiplier prefixes may be applied to it to form ka (kiloannum), Ma (megaannum) etc.
On the planet Mars thoug,h the year is approxitmately 687 days long, and every planet has a different revolution around its star. Mecury takes 88 days, Venus 224 days, but Jupiter takes almost 12 years! Saturn takes 29 years, Uranus takes 84 years, Neptune 165 years and Pluto (still a planet in my book!) takes almost 250 years to go around the Sun a single time. And a very special Happy Birthday to the Planet Neptune! 165 years ago this past summer, unexpected changes in the orbit of Uranus led Alexis Bouvard to deduce that its orbit was subject to gravitational perturbation by an unknown planet. Neptune was subsequently observed on September 23, 1846 by Johann Galle within a degree of the position predicted by Urbain Le Verrier. Happy 1st Birthday, Neptune!
Here on Earth, we celebrate many types of years, starting with the calendar year and birth year. But we also recognize many types of years: fiscal, sidereal, academic, Julian, tropical, draconic, heliacal, Bessellian, Gaussian, Sothic, and leap. We are leaving the Year of the Rabbit according to the Chinese calendar and about to enter the Year of the Dragon on January 23.
Whatever year or years you hope to celebrate, here at kidsneedscience we wish you a very happy New Year! And a special thanks to all our followers all around the world-this is our 100th post and our 90 day anniversary (a word connected way back to the root for year, before the Romans had the word annus). In just 90 days we’ve found followers in 83 countries: from New Zealand to Chile, from China to Canada, Indonesia to Peru, Japan to Mexico, Saudi Arabia to Brazil, The United Kingdom to Egypt. Thank you to everybody for liking, posting and re-blogging! May you have a New Year filled with Science and Words! Finally, a quote from T. S. Eliot: “For last year’s words belong to last year’s language and next year’s words await another voice.” Here at kidsneedscience we’re all about digging up the meanings and origins of last year’s words. But you? Find your voice in 2012!
Image courtesy of NASA/JPL/MARS program.