{"506741":{"#nid":"506741","#data":{"type":"news","title":"Leap Years: Why?","body":[{"value":"\u003Cp\u003EThis year brings another February 29. Why do leap years exist?\u003Cstrong\u003E Jim Sowell\u003C\/strong\u003E is a senior academic professional in the School of Physics and the director of the Georgia Tech Observatory. He says leap year was a creation of Julius Caesar.\u003C\/p\u003E\u003Cblockquote\u003E\u003Cp\u003EAs of February 29, 2016, the calendar is back on track. Every four years, the addition of one day brings us closer to a more precise calculation of the Earth\u2019s orbit.\u003C\/p\u003E\u003Cp\u003EGetting to our current calendar system has been a complicated process, mostly because of three important celestial rotations: the Earth\u2019s spin, which gives us the day; the orbit of the Earth around the sun, which gives us the year; and the orbit of the moon around the Earth, the basis for the month.\u003C\/p\u003E\u003Cp\u003EThe Romans developed one of the first calendars, which was primarily based on the moon\u2019s orbit and had 10 months. March was first. December was last. We know this because the root of \u201cDecember\u201d means \u201cten\u201d in Latin. By 70 B.C., two more months had been added, and February was last.\u003C\/p\u003E\u003Cp\u003EDuring the reign of Julius Caesar (46 \u2013 44 B.C.), the Egyptians were some of the best astronomers. They could see that the Earth\u2019s orbit was very close to 365.25 days. Caesar used their knowledge to set order to the calendar. He established that every fourth year would be a leap year, tacking one day onto the last month, February. In 45 B.C., he moved January to the beginning, thus establishing the Julian calendar. July was later named for him after his death.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EIn the late 1500s, astronomers under Pope Gregory XIII (for whom the modern Gregorian calendar is named) realized 365.25 days wasn\u2019t exactly right. The Earth\u2019s orbit is actually 365.242199 days. After hundreds of years using the Julian Calendar, spring had begun moving into winter. The astronomers worked out a new formula to skip some leap days to get closer to an exact measurement. They also took 10 days out of the calendar in 1582 to get back on track.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003EThe Gregorian calendar will work for a long time \u2014 at least for the next 3,300 years. Then a new calculation will be needed to get our calendar in sync with the Earth\u2019s orbit. Today\u2019s astronomers aren\u2019t sure what that will be, but we\u2019ve decided to let future astronomers figure it out.\u003C\/p\u003E\u003Cp\u003EAmplifier\u003Cbr \/\u003EGeorgia Tech experts on current issues\u003Cbr \/\u003EJason Maderer\u003Cbr \/\u003ENational Media Relations\u003Cbr \/\u003E404-660-2926\u003Cbr \/\u003E\u003Ca href=\u0022mailto:jason.maderer@comm.gatech.edu\u0022\u003Ejason.maderer@comm.gatech.edu\u003C\/a\u003E\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\u003C\/blockquote\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EThis year brings another February 29. Why do leap years exist?\u003Cstrong\u003E Jim Sowell\u003C\/strong\u003E is a senior academic professional in the School of Physics and the director of the Georgia Tech Observatory. He says leap year was a creation of Julius Caesar.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Jim Sowell explains how Leap Year was created"}],"uid":"28004","created_gmt":"2016-02-26 13:25:20","changed_gmt":"2016-10-08 03:20:53","author":"Dione Morton","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2016-02-26T00:00:00-05:00","iso_date":"2016-02-26T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"groups":[{"id":"126011","name":"School of Physics"}],"categories":[{"id":"150","name":"Physics and Physical Sciences"}],"keywords":[{"id":"4188","name":"astronomy"},{"id":"4111","name":"calendar"},{"id":"171772","name":"Gregorian calendar"},{"id":"171773","name":"Julian calendar"},{"id":"168419","name":"leap year"},{"id":"166937","name":"School of Physics"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003ESchool of Physics\u003C\/p\u003E\u003Cp\u003E837 State Street\u003C\/p\u003E\u003Cp\u003EAtlanta, Georgia\u0026nbsp; 30332-0430\u003C\/p\u003E","format":"limited_html"}],"email":["dione.morton@physics.gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}