Year Definition and 999 Threads

A year is the orbital period of a planetary body, for example, the Earth, moving in its orbit around the Sun. Due to the Earth's axial tilt, the course of a year sees the passing of the seasons, marked by change in weather, the hours of daylight, and, consequently, vegetation and soil fertility. In temperate and subpolar regions around the planet, four seasons are generally recognized: spring, summer, autumn and winter. In tropical and subtropical regions, several geographical sectors do not present defined seasons; but in the seasonal tropics, the annual wet and dry seasons are recognized and tracked.
A calendar year is an approximation of the number of days of the Earth's orbital period, as counted in a given calendar. The Gregorian calendar, or modern calendar, presents its calendar year to be either a common year of 365 days or a leap year of 366 days, as do the Julian calendars; see below. For the Gregorian calendar, the average length of the calendar year (the mean year) across the complete leap cycle of 400 years is 365.2425 days. The ISO standard ISO 80000-3, Annex C, supports the symbol a (for Latin annus) to represent a year of either 365 or 366 days. In English, the abbreviations y and yr are commonly used.
In astronomy, the Julian year is a unit of time; it is defined as 365.25 days of exactly 86,400 seconds (SI base unit), totalling exactly 31,557,600 seconds in the Julian astronomical year.The word year is also used for periods loosely associated with, but not identical to, the calendar or astronomical year, such as the seasonal year, the fiscal year, the academic year, etc. Similarly, year can mean the orbital period of any planet; for example, a Martian year and a Venusian year are examples of the time a planet takes to transit one complete orbit. The term can also be used in reference to any long period or cycle, such as the Great Year.

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  1. S

    Last year of school and im unsure of what to do.

    Hello guys. I am currently in my last year of school and I'm not sure of what I'm going to do in the future. Although i do have a slight idea but the thing is, that i have no idea on how to get there. I'm very keen on aeronautical engineering and i take the time to read articles on how engines...
  2. R

    Overcoming Academic Setbacks: Coping with Illness and Anxiety in College

    A Misfortunate Freshman Year... I normally do not like to discuss my personal problems with other people however any sort of advice or encouragement anyone can offer would be appreciated :) 0 The problem is that I am currently a Physics major (and prospective Maths major) who is close to...
  3. U

    Going to school next year: need a laptop

    I know this is such a vague question, but I really just want some ideas for a new laptop for school next year. I'm looking more at the average price range, but if there's a more advanced product that looks like it would be worth the dough, I might think about it. I'm open to any and all...
  4. W

    Comp Sci Solve C++ Leap Year Function Homework

    Homework Statement Write a function that prompts the user to enter a year and that returns a 1 if the entered year is a leap year, and a 0 otherwise. A year is a leap year if it is divisible by 4. In general, a year is not a leap year if it is divisible by 100, unless of course it is...
  5. W

    Gravity and developments in GR after WMAP 5 year data

    Since the WMAP 5 year data is now out and contains no nasty new surprises, what does everyone think about the current and future status of gravity? Please read these more detailed descriptions of the poll options before you vote! Note that these options are all basically beyond what we can know...
  6. G

    2007, year of the craddle robbing teachers?

    Emily Streb Student's age: 16 http://img529.imageshack.us/img529/9212/strebzd3.jpg http://www.foxnews.com/story/0,2933,258043,00.html Lauren Kathleen Palmer Student's age: 16 [girl] http://img529.imageshack.us/img529/1881/palmerri0.jpg...
  7. E

    MATLAB Matlab - - final year project (ion propusion)

    Homework Statement Hi, I'm trying to simulate an electrostatic craft going from low Earth orbit to a geostationary orbit, but I'm having some trouble with matlab. I'm not the most confident programmer at the best of times, but needs must and so I've given it a go. As far as I can tell my...
  8. A

    Schools OOS for every college What to do for next year?

    OK, currently I'm not a resident of any state (am a us citizen). I've been out of USA for the past few years, but am coming back for college. I've been admitted in quite a few colleges, but will have to pay OOS tuition for all of them. What do i do for next year? For some states it is a law...
  9. S

    Happy Persian New Year - Welcome Spring!

    Proper New Year, start of spring. Happy Spring everyone, lol.
  10. JasonJo

    Masters vs. Staying a 9th semester / 5th year

    All the admissions decisions are in, and I got rejected from most of my schools but I did get into one of my top choice's...Masters program. So I called this school's math department today and I got the rundown of being in the Masters program. I made it clear that it is not my intention to...
  11. H

    What is the job outlook for physicists in the next decade?

    after troll through the forums for a hour or so, i noticed an overwhelming feeling concerning the job accessibility of a physicist, mainly in the USA. so i decided to make a post and try to gather everyones opinions about the direction physics is heading in the next 10 or so years. i think...
  12. C

    WMAP 5 Year Data Release: Cosmological Interpretation

    The WMAP 5 year data was released this afternoon. In total, there are seven papers available from the following website: http://lambda.gsfc.nasa.gov/product/map/current/map_bibliography.cfm One of the papers is entitled "cosmological interpretation," and lists the new values of the cosmological...
  13. D

    Has the 140-Year-Old Schwarz-Christoffel Math Problem Finally Been Solved?

    I am not entirely sure about the details but thought I would share... Link to Press Release: http://www.eurekalert.org/pub_releases/2008-03/icl-1yo030308.php A problem, the Schwarz-Christoffel formula which has defeated mathematicians for almost 140 years has been solved by a researcher...
  14. M

    Left Handed Amino Acids Discovered in 4.5x10^9 year old metorite

    http://www.sciencedaily.com/releases/2008/02/080228174823.htm This seems exciting for origin of life research.
  15. JasonJo

    Staying a 5th Year: Pros, Cons & Plan of Action

    So it seems like I will not be getting into graduate school. I am considering staying a 5th year. As of now, I am all set to graduate in May, on time. But I really want to go to graduate school and I think staying a 5th year is ideal. Here is my plan: - Take a year long sequence in graduate...
  16. K

    The Year of Algebraic Geometry

    Which year in university do you learn algebraic geometry?
  17. W

    Sketching the Curves of a Function W/In an Interval - Simple (1st Year Calcu

    [SOLVED] Sketching the Curves of a Function W/In an Interval - Simple (1st Year Calcu Homework Statement Sketch the graph of the function on the interval [0, 2pi]. y = cosx - 1/2(cos2x) Homework Equations The Attempt at a Solution so the problems that i have been practicing...
  18. marcus

    Galaxy from 700 million year old universe

    One of the earliest, maybe the earliest galaxies seen so far. Redshift 7.6 reported at conference. If confirmed then the light from it has been traveling some 12.9 billion years and was emitted when expansion was only about 700 million years old. Put 7.6 into either of these calculators to get...
  19. L

    What does this mean? P(|Y - 1/2| > 1/4)? (2nd year stats)

    Homework Statement The question is Let Y be a continuous random variable with pdf f_Y(y) = 3(1-y)^2 and I have to find P(|Y - 1/2| > 1/4) Homework Equations Is there a formula involved here or something that can help me? The Attempt at a Solution I'm not even sure how...
  20. L

    A 2nd year stat/probability question about P(A|B) I'm sooo close

    A 2nd year stat/probability question about P(A|B) I'm sooo close! Homework Statement Consider 2 events A and B such that P(A)=x and P(B)=y, given x,y >0 and x + y > 1 Prove that P(A|B) >= 1 - [(1-x)/y] Homework Equations P(A|B) = P(A n B) / P(B) The Attempt at a Solution...
  21. L

    Can someone please check my working out - 2nd year stat/probability question

    Homework Statement Can someone please check my answers for this probability question about disease testing (negative/positives)? I will write the question on about below will write my answers, I would appreciate anyone letting me know if I'm right/wrong. Thanks Q. A test for a disease has...
  22. ZapperZ

    VOTE Photo Contest - Year of the Rat

    A strong group of pictures for this contest. Please vote for the best picture that represents either a Chinese New Year celebration, Chinese culture, rats, or mice. 1. glondor 2. 0TheSwerve0 3. ZapperZ 4. hypatia 5. mrjeffy321...
  23. K

    Last year of high school and it's time to decide a career path

    i'm in last year of high school and it's time to decide a career path. I'm mostly into biology and chemistry. can anyone of you tell about the jobs i could get in these fields. i already know some which interest me such as biotechnology, biomedical engineering, chemical engineering...
  24. S

    Participating in the Putnam competition within 2 year

    Well, i am thinking of participating in the Putnam competition within 2 years, as i am only a freshman now and this is my first semester. I am planning to first try to create a quite stiff background in math before i even try Putnam. I am planning to first take these courses before i do that...
  25. ZapperZ

    PF PHOTO CONTEST - Year of the Rat (2/2-2/8)

    Year of the Rat This week, we will be celebrating the Chinese Lunar New Year, the Year of the Rat. So pictures of rats, mice, Chinese New Year festivals, or Chinese culture will qualify for this contest. Happy Chinese New Year to all our Chinese members! Zz. Contest Rules: 1. Any...
  26. P

    Navigating a Career Change: Seeking Guidance for a 22 Year Old

    I don’t know exactly how to put across the dilemma I am in…so I would rather describe it as well as I can so that one can understand my situation and give me a very valuable guidance. I am almost 22 years of age and am currently working as a Digital Design engineer in a US based Networking...
  27. diegzumillo

    Last year - physics graduation what now?

    last year - physics graduation.. what now?? Hello everyone, :) Well, my last year (if I don't fail any class) is starting now. But what's really worrying me is that I need to do a 'course conclusion work/paper' (I'm pretty certain that there is a specific term in english for that :P ). The...
  28. lisab

    Any resolutions made for the New Year?

    How's everyone doing on any resolutions made for the New Year? Mine: Obey the posted speed limit. Progress: Good progress on side streets. Caught self doing 70-mph in a 60-mph zone on the freeway once, but generally staying within 2 or 3 mph of posted limit.
  29. ZapperZ

    Happy Most Depressing Day of the Year

    Today is http://www.time.com/time/business/article/0,8599,1704887,00.html" . So don't do anything I wouldn't do. :) Zz.
  30. V

    1st year engineering physics problem

    Im having troubles with this question for my assignment... Determine the time required for a car to travel 1km along a road if the car starts from rest, reaches a max speed at some intermediate point, and then stops at the end of the road. The car can accelerate at 1.5 m/s^2 and decelerate at...
  31. M

    Courses I really in deciding what course to take next year.

    I really need help in deciding what course to take next year. I want to have a career with something to do with computers/programming/electronics or even games. But I don't know what course to take, could anyone make some suggestions? How are the employment prospects in this field? Will I get...
  32. K

    Schools How to choose four year college?

    Ok so I'm currently attending a community college, & am working on an associates in mathematics. But its time I need to start looking into a school to transfer too, & I'd like to major in physics. But which is better, a public school or a smaller private, not well known school? Personally I'd...
  33. S

    Advice for Physics/Engineering Student After Year 12 Maths

    Hey guys, i just finished year 12 a couple of weeks ago where i took specialist maths, for those not familiar: this subject gives a pretty basic introduction to vectors, vector calculus, integration techniques, differentition techniques (like implicit), complex numbers, differential...
  34. L

    Courses Basic Physics Course Topics: 1st Year Uni

    what sort of topics should i be expecting in a basic first year uni physics course? the university websites are too general and don't usually give too much detail when desribing the topics covered
  35. ZapperZ

    Highest Scoring Entry for 2007 Physics World Quiz Contest?

    Hey, Physics World has http://images.iop.org/dl/physicsweb/PWDec07quiz.pdf" from 2007. There's a £50 prize for someone who gets most of the answer. Wouldn't it be nice if a PF member wins this? :) Zz.
  36. S

    Can you reccoment a second first year UG text book?

    Hi, at the moment I am using the set book (Physics for scientists and engineers, Tipler) for my core physics modules at uni. However I want something which has roughly the same stuff in it but which will present it in a slightly different way. A good analogy is my use of maths books, I use both...
  37. Moonbear

    What is the traditional New Year's Eve meal in Peru?

    I won't be around tomorrow night to enjoy the annual near-beer and Nyquil New Year's Eve countdown (I actually have real life friends to spend the evening with this year :biggrin:), so I thought I'd wish everyone a Happy New Year a bit early, and at least get the party started. Hopefully by...
  38. L

    Gaining a Head Start with First Year Physics: Resources and Motivation

    I'm about to begin a bachelor of science with a physics major. I've already found some books on electrodynamics and relativity and such, but I can't find the motivation nor resources to intepret some of the more abstract mathematics, especially to do with linear algebra, tensor analysis and...
  39. Ivan Seeking

    Weirdest work stories of the year

    http://edition.cnn.com/2007/LIVING/worklife/12/07/cb.freaks.at.work/index.html
  40. S

    Gregorian calendar off by 26 seconds a year

    I just read that the Gregorian calendar is off by 26 seconds a year from the solar calendar. That adds up to about 43 minutes ever 100 hundred years. Does this mean that if it starts to get dark at 5:30 pm on the East coast on December 1st, that it got darker 43 minutes earlier or later 100...
  41. wolram

    Is Losing a High-Paying Job a Sign of Failure?

    He looses his job and can not find another with equal pay, he gets one paying £28,000 a year and can not manage, is he a pathetic looser?
  42. R

    How Many Fission Reactions in a Year

    Homework Statement a - How many fission reactions would occur in 1 year of running of a nuclear reactor if the average power of the reactor is 778 MW? b - How many kilograms of U-235 would be needed to run the reactor for 1 year? c - What is the total change in mass for 1 year of running...
  43. dontdisturbmycircles

    Is Griffiths Electromagnetism understandable for first year students.

    Hi, second term is coming up, woot. I have e&m next semester and I heard that griffiths is one of the best texts around on numberable occasions, my university has it but it's not for my class but a senior class instead. I don't see why I need to use a certain textbook, I didn't for calc or...
  44. S

    What was your first to last year grade progress

    hey, I am curious to hear how everyones grades changed as they progressed through higher education? In high school I had around a 40% average, then after 5 years I re-took all my high school math and science then applied at university to get my honors in physics, my first year I had a 65%...
  45. P

    2007 the big year for string theory?

    I've always heard that 2007 was the year that may falsify string theory at a large collider in CERN or somewhere. 2007 is nearly over. I haven't heard anything about it. What has happened over there?
  46. marcus

    2007 Paper of the Year (A+ for leadership ability )

    2007 Paper of the Year (A+ for "leadership ability") in junior high school they started telling us about "leadership ability" which apparently was exemplified by some guy who was good at sports, didn't bug the teachers, and was perhaps a bit cleaner than usual. It certainly wasn't clear to me...
  47. S

    GPS Clock After One Year: Time & Relativistic Effects

    Suppose i have two clocks on Earth showing 12:00 hours. After, one of the clocks is put in a gps satellite for a year. After one year that clock returns to earth. Due to relativistic effect what time that clock shows? Less than 12:00? If so why?
  48. qspeechc

    Courses Course Selection for 2nd Year (Applied Maths, Physics, etc.)

    This is a very long story; please bare with me! I am a first year undergrad student nearing the end of the year. I am from South Africa (at the University of Cape Town). The way it is here, is that for your undergrad degree, it is standard to take two or one majors. In first year you take 4...
  49. J

    The 2 year AAS in Electronics Engineering Technology

    I am in a little dilemma. I have taken interest in a 2 year EET program at my local community college but am unsure if it is marketable. From my research, an AAS in Electronics Engineering Technology would qualify you for a technician's job. Are technician's in high demand these days? For...
  50. A

    Career Options for 3rd Year Mech Engg Student

    career option? i don't know how many times this has been asked(probably 347374 times, coz that's what this Academic & Career Guidance forum does:biggrin:), but being a stupid, i ll ask again:-p i want to do MS after my graduation. apart from clearing GRE test, what else i need to do to prepare...
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