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. J

    Extended Essay Research question help (first year IB student)

    Hi guys, I am a first year IB student and I need to give hand in my research question for the extended essay today, the only thing is that I don't really know what I could do it on. The extended essay is basically a 4000 word research project. I was going to do it on photoelasticity, but when I...
  2. J

    Other Math Olympiad Advice Please (I will be 13 years old next year in 9th grade)

    Hi! I am 12, and will be a 13 in 9th grade ( I skipped 6th grade). I have a curiosity for mathematics and have started preparing to take the AMC 10 and 12 exams. I enjoy solving the ingeniously crafted problems, as I share the sentiment of many math competitors of not being challenged by the...
  3. Xiothus

    Solve First Year Harmonic Motion Problem: Cylinder Rolling

    Thank you guys for taking the time to read this - I'm decently struggling with first year and need some tips on how to properly conceptualize problems and learn what the right approach is on certain problems. Have a wonderful day, again thank you for checking this post out!
  4. D

    Other Extra Year of Study for Graduate Physics Research: A Possibility?

    I am interested in pursuing graduate reserch in physics. I have undergraduate and graduate degrees in engineering with a research in classical mechanics. However, PhD programs require a background in modern physics in order to be accepted and I would prefer to strengthen my preparation in...
  5. jselms99

    Time Travel: Calculating Velocity for 10 Year Trip

    So at first I thought that the time would be 10 years, and that I’d have to consider the outbound motion as v = .87c and inbound motion as v = -.87c but I’m struggling with addition of the velocities and whether or not this is even the right approach?
  6. notgoodatphysics

    Classical Recommendations for 1st year E&M practice/exercises

    Currently in 1st year (UK) going through E&M right now, the recommended textbook is University Physics by S&Z. Recently had my-mid term test and got 40%. The problem is I’m overestimating my ability as the exercises in UP are not challenging at all, the majority of them are just plugging in...
  7. K

    B Exploring the Standardization of One Light Year Distance | PF Forum

    Dear PF Forum, It's been a while since I logged in here. And I really do appreciate all the answers that I've been getting here. Now, I wonder. Is there any standardization for 1 light year distance? Is it 10 trillion kilometers, or 299,792,458 * 60 * 60 * 24 * 365.256 = ...
  8. russ_watters

    COVID Vaccines: Annual Updates and Potential Impacts on Immunity and Profit

    We've been speculating about this happening for a couple of years: https://www.cnn.com/2023/01/23/health/fda-covid-vaccines-strategy-shift/index.html I think at this point most of us saw this coming, but it will still be interesting to see how the transition happens, both for the vaccine and...
  9. olgerm

    I remember some recent year events earlier than it is now written

    Oddly I remember having read about these events before (beginning of) year 2020. murder of George Floyd: https://en.wikipedia.org/wiki/Murder_of_George_Floyd Kenosha unrest shooting: https://en.wikipedia.org/wiki/Kenosha_unrest_shooting Capitol Hill Occupied Protest...
  10. J

    A math puzzle aimed at 9 to 12 year olds

    I'm 82 and was browsing through a old comic annual that was published back in the 1950's (Eagle Annual No 3). It had a puzzles page and one of the puzzles was quote: 'I have a pair of scales and 3 weights and with these 3 weights I can weigh any number of pounds from 1 up to 13.(I may, of...
  11. E

    Final year raytracer project ideas

    Hi there. I am about to enter my final year of a computer science bachelor degree and must do a final year project that spans most of the academic year. I have some experience on the artistic side of computer graphics but none in the computer science side. I would be interested in developing...
  12. D

    Other Would it be advisable to take an extra year before graduating?

    Hello all, I am a physics major who will be starting their senior year next week. My immediate post-graduation plan is to attend graduate school in physics (my interests are in experimental condensed matter). However, I am strongly considering taking an extra year to graduate and was wondering...
  13. Manuel Cardoso

    Calculus book for 14 year old physics enthusiast

    Hello, I'm trying to learn calculus, what books would you recommend? For a beginner.
  14. A

    Time Dilation in the ISS: 2 Seconds in a Year

    Using the above formula I get that the time goes 6.5∗10−86.5∗10−8 percent faster in ISS. Thus, this is approximately 2 seconds in a year. But the answer is much lower. Where am I making a mistake?
  15. J

    B Exploring the Possibilities: A Pre-13.8 Billion Year Old Galaxy

    What would happen if they found a galaxy that dated to older than 13.8 billion years old? How would this affect cosmology?
  16. E

    Final year University Project, Music Visualisation question

    Hi there. I start my final year of my computer science degree this September and, alongside other modules, will do an independent final year project. I have not had very much CS experience outside my degree so I am a bit unsure what would be feasible for me while not being too trivial such that...
  17. bigmike94

    How much of first year Intro physics do you remember?

    Summary: I am just curious I know 🧐 Im coming up the end of intro university physics mechanics chapters. It has been quite enjoyable, especially chapters on energy, momentum and fluid mechanics. There’s so much information packed into these chapters though. I am wondering what was your...
  18. AliAllyMac

    Other Postpone Senior Year to get Better Grades to go to a Competitive Grad?

    I need advice! I know exactly what I want to do in physics: I am already doing research at my university as an undergrad and I plan to make a career out of it after I get my PhD. But I have had the absolute worst time with general motivation due to a decade of depression. I am so scared that...
  19. ZapperZ

    Could These Be the Best Photos of the Year?

    These two will be the strong contenders for my photos of the year. There's our cruise ship, the Disney Wonder. And in the background, Dawes Glacier at Endicott Arm, Alaska. We got even closer to the glacier on an excursion when we got onto a catamaran. Photos were taken on May 25, 2022. Zz.
  20. Darrencc

    B Does Gaining Weight Affect Mass?

    Hello, I am teaching eleven year olds about gravity. There is no issue about this subject, however I would like someone to help with a model answer. As mass never changes. What is the best answer when I am asked that if someone gets 'fatter', do they not put on mass? Thanks in advance.
  21. G

    Functional Analysis exchange year at Imperial

    Hey, I would like to do an exchange year at Imperial. I would like to follow as a physicist the Functional Analysis course. However, I have not heard the best things about this peculiar course. What is the audience opinion on that?
  22. X

    Admissions Failed Freshman Year: Will It Affect My Graduate Admission?

    I failed all classes in my freshman year first semester. I am going to retake them.Does that affect my graduate admission?
  23. shivajikobardan

    Python Which project should I choose for a final year major project?

    My criteria for choosing this project-: 1) Should be easy. 2) Should be doable in 1.5 months. 3) Should not to be too easy and should be just hard enough to be a major project. 4) It is a group project but since this is nepal lol mainly 1 person is going to do it. max 2 persons will do this...
  24. BillTre

    What was the top breakthrough of 2021 according to Science readers?

    The original list of 10 candidates has now been parred down to 3. The Science Top Ten list: First footprints in the Americas? 23,000-21,000 year old human footprints in New Mexico. (al local record) Dragon Man skull Great looking old skull with a great backstory of it's discovery. Maybe the...
  25. shivajikobardan

    MHB Choosing an Elective for Final Year Engineering Students

    How do I choose a good elective? I want sth that gives me good marks as i am in final year 2nd semester. I want sth that has good courses over the internet. I don’t want you to pick it up for me but in general just guide me about how to choose the elective? I will put only ones that I am...
  26. Camden

    Year 10 physics homework problem

    I got this as homework and I am not sure how to attempt it
  27. aspiringastronomer

    Struggling in my freshman year of Physics at university

    If Tl;dr I am struggling in Math 171 and Physics 191 and throwing around the idea of declaring a geology major with an astronomy minor because the Physics major "juice is not worth the squeeze" at my age(29) anyone else out there who struggled with Calculus 1 when they first took it?Hello...
  28. F

    Physics Career Advice For Final Year Physics Student (UK)

    Hi Everyone, As the title suggests, I'm looking for some career advice. I want to go into software development (but feel free to suggest any other areas where I might be a good fit, I've also been looking at risk analysis positions). I have experience in a bunch of different areas but it feels...
  29. H

    Is this 2 Nobel Prizes given in a single year?

    Sorry for the speculative title but, I kind of think so. Both subjects are great discoveries and maybe they deserve the prize on their own (maybe not that is not my point). My point is how are they connected to each other under the vague umbrella term: "Complex systems". Their subjects are WAY...
  30. Astronuc

    History 536 AD - The 'Worst' Year in History?

    536 AD - Worst Year in History (by Kings & Generals) https://en.wikipedia.org/wiki/536 Glacier cores reveal Icelandic volcano that plunged Europe into darkness https://www.science.org/news/2018/11/why-536-was-worst-year-be-alive The Worst Year Ever to Be Alive in History...
  31. Simon Peach

    Space and time -- Is the term "light year" really correct?

    When something is described as say 7 billion light years away would't it be more accurate to 7 billoin years ago?
  32. jedishrfu

    B 3700 Year Old Babylonian Tablet of Trigonometry Tables

    https://www.upworthy.com/3700-year-old-babylonian-stone-tablet-gets-translated-changes-history
  33. B

    MHB How Much Would I Earn If I Worked 4 Weeks On and 4 Weeks Off?

    If I work 4 weeks on and 4 weeks off, how much will I earn? My brother will be earning 1400 every shift, so would my brother earn $1,400 per shift x 5 days per week x 26 weeks per year = $182,000?
  34. Asker321

    Courses Should I take Calculus 2 my freshman year of college?

    I self-studied Calculus 1 (AP Calc AB) in my sophomore year of high school and I got a 4 on the AP exam. I took the class Calculus 2 (AP Calc BC) in my junior year of high school. I did not take the exam at the end of the year. I didn't take any math in my senior year of high school. Because...
  35. kyphysics

    What to do with 1 year+ expired bleach?

    Mine expired in March 2020...I had it "hidden" under a laundry area sink and was using newer ones and forgot about it... Safe to open? Safe to pour down drain?
  36. N

    What is the Linear Equation for Dollar Value of a Product Over Time?

    You are given the dollar value of a product in 2016 and the rate at which the value of the product is expected to change during the next 5 years. Use this information to write a linear equation that gives the dollar value V of the product in terms of the year t. (Let t = 16 represent 2016.)1...
  37. BalinesePhysicist

    Studying What to do in a gap year to prepare for a Physics + Math degree

    As the title says, I am now in a Coronavirus induced gap year. I have been accepted at a university, which for some reason requires us to do a double major. Hence I chose math as my second major alongside Physics since it has the most overlap, and I'm also very interested in theory. In school, I...
  38. A

    Admissions Advice for improving PhD application next year (UK)

    Hi Everyone, I applied for some PhD positions in astronomy this year and was unsuccessful. I was wondering if anyone could offer up some advice for improving my applications for next year. To give you some context: I gained my Master's in Physics with Astronomy from the University of...
  39. C

    Advice for 35+ year old wanting a Physics PhD

    Hello All! I wanted to reach out for perspectives and advice on this "old-timer" wanting to do physics. At one point I was on that track, but quickly stumbled and lost my way for personal reasons. Now, I'm 35 years old and want to finally pursue a lifelong goal of a PhD in physics. My age at...
  40. Barracuda

    Looking for advice to improve my grades in my Senior year at university

    Hello, I'm in my final year of physics major in college. I have a semester left, and have to get straight A's this semester in order to have an average grade at best to further my education. I am not an "A" student. I've always been between the 55% and 45% percentile not because I'm dull, but i...
  41. anemone

    MHB New Year Challenge: Find Real Number Triples

    Find all triples $(a,\,b,\,c)$ of real numbers such that the following system holds: $a+b+c=\dfrac{1}{a}+\dfrac{1}{b}+\dfrac{1}{c}\\a^2+b^2+c^2=\dfrac{1}{a^2}+\dfrac{1}{b^2}+\dfrac{1}{c^2}$
  42. C

    Decrease of Solar radius per year using Virial Theorem

    Hello, I am trying to solve this question: Assume that the Sun's energy production doesn't happen by fusion processes, but is caused by a slow compression and that the radiated energy can be described by the Virial Theorem: $$L_G = - \frac{1}{2} \frac{GM^2}{R^2} \frac{dR}{dt} $$ How much must...
  43. T

    How to make the most of a gap year during the Covid-19 era?

    How to make the most of a gap year during the Covid-19 era? =========================================================== Hello Everyone, Thanks for reviewing my thread. I am opening this thread to get insights into my future prospects for a career in Physics in the era of Covid-19. I...
  44. Averagesupernova

    Is My 1980s Rubik's Cube a Knockoff?

    As the title implies, I have a cube that was given to me new around 1980-1981. All the info I have found online indicates my cube is likely not an original. I would have thought at that time there wouldn't have been knock offs, but it's entirely possible I am wrong. - The colors on my cube do...
  45. StevieTNZ

    What would you like for Christmas this year?

    For me, this song sums it up quite nicely: What do you hope for Christmas this year?
  46. CherryB

    How many kWh will a 23MW generator make in 1 year

    If a power plant generates at 23MW, how many kWh will be generated in 1 year? And how many miles could you drive Tesla cars, at highway speeds (70mph), in one year? Thanks
  47. ScienceGuy42

    Studying Might need to take 5 courses one semester in second year physics/math

    Might need to take 5 courses in one semester. Are these courses too much? I would have to take: -Second year linear algebra -Real analysis -Mathematical modelling (a relatively easy course involving only high school calculus) -Second year calculus -Second year E&M. A plan I thought of...
  48. poudyalb

    Other Undergraduate 3rd Year - Need some Academic / Career Advice

    Hi, I needed some help/advice. I am a Math Major at Dickinson College. I am also taking lots of courses in Physics and Philosophy. At this point, which is the fall semester of my junior year, I have: - 3 more courses left to complete my Math major. I still need to take Abstract Algebra, a...
  49. E

    Can Virus Masks Lower Flu Cases This Year?

    Could this year's flu season be used to determine the effectiveness of virus masks? Every other person if wearing one, so if flu cases are significantly less than normal, that means that virus masks are having a noticeable effect?
  50. P

    Courses Struggling in my First Year of Graduate School

    Hey everyone! I started Astronomy Ph.D at a very good (as good as any top university) university this fall but I'm struggling a lot and it's only been 3 weeks! The problem isn't the amount of stuff that I have to do (I am taking two undergrad classes, one grad class and am being a TA), it's...
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